Aire Acondicionado SEBD036406

© 2005 All Rights Reserved 00-1Printed in Japan 01-05(03) (6)

SEBM036406

00-2 Air conditioner (6)

LIST OF REVISED PAGES

CONTENTS01 GENERAL ................................................................................................................................. 01-1

10 DENSO (Freon Gas Type)11 STRUCTURE AND FUNCTION........................................................................................... 11-1

12 TESTING AND ADJUSTING................................................................................................ 12-1

13 DISASSEMBLY AND ASSEMBLY ....................................................................................... 13-1

20 ZEXEL (DIESEL KIKl)21 STRUCTURE AND FUNCTION........................................................................................... 21-1



30 DAIKIN31 STRUCTURE AND FUNCTION........................................................................................... 31-1



40 DENSO (New Refrigerant Type)41 STRUCTURE AND FUNCTION........................................................................................... 41-1


50 TAKAHASHI WORKS51 STRUCTURE AND FUNCTION........................................................................................... 51-1


60 SANDEN61 STRUCTURE AND FUNCTION........................................................................................... 61-1



70 ZEXEL VALEO (NEW REFRIGERANT (R134a) TYPE)71 STRUCTURE AND FUNCTION........................................................................................... 71-1


73 TROUBLESHOOTING ......................................................................................................... 73-1

No. of page

(6)

Air conditioner 00-3 (5)


<Reference>DENSO : Denso Corporation

Corporate name has ChangedFrom Nippon Denso to Denso Corporation in 1996.

ZEXEL : Zexel Valeo Climate Control CorporationCorporate name has Changed

From Diesel Kiki to Zexel in 1990, andFrom Zexel to Zexel Valeo Climate Control Corporation in 2001.

DAIKIN : Daikin Industries, Ltd.Corporate name has changed

From Daikin Kogyo to Daikin Industries, Ltd. in1982.

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The affected pages are indicated by the use of the fol-lowing marks. It is requested that necessary actionsmust be taken to these pages according to the list be-low.

Pages having no marks are not revised at this time.


Mark Indication Action required

Q Page to be newly added Add

q Page to be replaced Replace

( ) Page to be deleted Discard

Mark Pages Revisionnumber Mark Pages Revision

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SAFETY SAFETY NOTICE

00-3

SAFETYSAFETY NOTICE

IMPORTANT SAFETY NOTICE

Proper service and repair is extremely important for safe machine operation. The service andrepair techniques recommended by Komatsu and described in this manual are both effectiveand safe. Some of these techniques require the use of tools specially designed by Komatsu forthe specific purpose.

To prevent injury to workers, the symbol k is used to mark safety precautions in this manual.The cautions accompanying these symbols should always be followed carefully. If any danger-ous situation arises or may possibly arise, first consider safety, and take the necessary actionsto deal with the situation.

GENERAL PRECAUTIONS

Mistakes in operation are extremely dangerous.Read the Operation and Maintenance Manual care-fully BEFORE operating the machine.

1. Before carrying out any greasing or repairs, readall the precautions given on the decals which arefixed to the machine.

2. When carrying out any operation, alwayswear safety shoes and helmet. Do not wearloose work clothes, or clothes with buttonsmissing.• Always wear safety glasses when hitting

parts with a hammer.• Always wear safety glasses when grinding

parts with a grinder, etc.

3. If welding repairs are needed, always have atrained, experienced welder carry out the work.When carrying out welding work, always wearwelding gloves, apron, hand shield, cap andother clothes suited for welding work.

4. When carrying out any operation with two ormore workers, always agree on the operatingprocedure before starting. Always inform yourfellow workers before starting any step of theoperation. Before starting work, hang UNDERREPAIR signs on the controls in the operator'scompartment.

5. Keep all tools in good condition and learn thecorrect way to use them.

6. Decide a place in the repair workshop to keeptools and removed parts. Always keep the toolsand parts in their correct places. Always keepthe work area clean and make sure that there isno dirt or oil on the floor. Smoke only in the areasprovided for smoking. Never smoke while work-ing.

PREPARATIONS FOR WORK

7. Before adding oil or making any repairs, park themachine on hard, level ground, and block thewheels or tracks to prevent the machine frommoving.

8. Before starting work, lower blade, ripper, bucketor any other work equipment to the ground. Ifthis is not possible, insert the safety pin or useblocks to prevent the work equipment from fall-ing. In addition, be sure to lock all the controllevers and hang warning signs on them.

9. When disassembling or assembling, support themachine with blocks, jacks or stands beforestarting work.

10.Remove all mud and oil from the steps or otherplaces used to get on and off the machine.Always use the handrails, ladders or steps whengetting on or off the machine. Never jump on oroff the machine. If it is impossible to use thehandrails, ladders or steps, use a stand to pro-vide safe footing.

SAFETY SAFETY NOTICE

00-4

PRECAUTIONS DURING WORK

11.When removing the oil filler cap, drain plug orhydraulic pressure measuring plugs, loosenthem slowly to prevent the oil from spurting out.Before disconnecting or removing componentsof the oil, water or air circuits, first remove thepressure completely from the circuit.

12.The water and oil in the circuits are hot when theengine is stopped, so be careful not to getburned.Wait for the oil and water to cool before carry-ing out any work on the oil or water circuits.

13.Before starting work, remove the leads from thebattery. Always remove the lead from the nega-tive (–) terminal first.

14.When raising heavy components, use a hoist orcrane.Check that the wire rope, chains and hooks arefree from damage.Always use lifting equipment which has amplecapacity.Install the lifting equipment at the correct places.Use a hoist or crane and operate slowly to pre-vent the component from hitting any other part.Do not work with any part still raised by the hoistor crane.

15.When removing covers which are under internalpressure or under pressure from a spring,always leave two bolts in position on oppositesides. Slowly release the pressure, then slowlyloosen the bolts to remove.

16.When removing components, be careful not tobreak or damage the wiring. Damaged wiringmay cause electrical fires.

17.When removing piping, stop the fuel or oil fromspilling out. If any fuel or oil drips onto the floor,wipe it up immediately. Fuel or oil on the floorcan cause you to slip, or can even start fires.

18.As a general rule, do not use gasoline to washparts. In particular, use only the minimum ofgasoline when washing electrical parts.

19.Be sure to assemble all parts again in their origi-nal places.Replace any damaged parts with new parts.• When installing hoses and wires, be sure

that they will not be damaged by contactwith other parts when the machine is beingoperated.

20.When installing high pressure hoses, make surethat they are not twisted. Damaged tubes aredangerous, so be extremely careful when install-ing tubes for high pressure circuits. Also, checkthat connecting parts are correctly installed.

21.When assembling or installing parts, always usethe specified tightening torques. When installingprotective parts such as guards, or parts whichvibrate violently or rotate at high speed, be par-ticularly careful to check that they are installedcorrectly.

22.When aligning two holes, never insert your fin-gers or hand. Be careful not to get your fingerscaught in a hole.

23.When measuring hydraulic pressure, check thatthe measuring tool is correctly assembled beforetaking any measurements.

24.Take care when removing or installing the tracksof track-type machines.When removing the track, the track separatessuddenly, so never let anyone stand at eitherend of the track.

FOREWORD GENERAL

00-5

FOREWORDGENERALThis shop manual has been prepared as an aid to improve the quality of repairs by giving the serviceman anaccurate understanding of the product and by showing him the correct way to perform repairs and make judge-ments. Make sure you understand the contents of this manual and use it to full effect at every opportunity.

This shop manual mainly contains the necessary technical information for operations performed in a serviceworkshop. For ease of understanding, the manual is divided into the following chapters; these chapters are fur-ther divided into the each main group of components.

STRUCTURE AND FUNCTIONThis section explains the structure and function of each component. It serves not only to give an under-standing of the structure, but also serves as reference material for troubleshooting.In addition, this section may contain hydraulic circuit diagrams, electric circuit diagrams, and mainte-nance standards.

TESTING AND ADJUSTINGThis section explains checks to be made before and after performing repairs, as well as adjustments tobe made at completion of the checks and repairs.Troubleshooting charts correlating "Problems" with "Causes" are also included in this section.

DISASSEMBLY AND ASSEMBLYThis section explains the procedures for removing, installing, disassembling and assembling each com-ponent, as well as precautions for them.

MAINTENANCE STANDARDThis section gives the judgment standards for inspection of disassembled parts.The contents of this section may be described in STRUCTURE AND FUNCTION.

OTHERSThis section mainly gives hydraulic circuit diagrams and electric circuit diagrams.In addition, this section may give the specifications of attachments and options together.

NOTICE

The specifications contained in this shop manual are subject to change at any time and without anyadvance notice. Use the specifications given in the book with the latest date.

FOREWORD HOW TO READ THE SHOP MANUAL

00-6

HOW TO READ THE SHOP MANUAL

VOLUMESShop manuals are issued as a guide to carrying outrepairs. They are divided as follows:

Chassis volume: Issued for every machine modelEngine volume: Issued for each engine series

Electrical volume: Attachments volume:

These various volumes are designed to avoid dupli-cating the same information. Therefore, to deal withall repairs for any model , it is necessary that chas-sis, engine, electrical and attachment volumes beavailable.

DISTRIBUTION AND UPDATINGAny additions, amendments or other changes will besent to KOMATSU distributors. Get the most up-to-date information before you start any work.

FILING METHOD1. See the page number on the bottom of the page.

File the pages in correct order.2. Following examples show how to read the page

number.Example 1 (Chassis volume):

10 - 3

Item number (10. Structure andFunction)Consecutive page number for eachitem.

Example 2 (Engine volume):

12 - 5

Unit number (1. Engine)Item number (2. Testing and Adjust-ing)Consecutive page number for eachitem.

3. Additional pages: Additional pages are indicated by a hyphen (-) and number after the page number. File as in the example.Example:10-410-4-110-4-210-5

REVISED EDITION MARK

When a manual is revised, an edit ion mark((1)(2)(3)....) is recorded on the bottom of the pages.

REVISIONS

Revised pages are shown in the LIST OF REVISEDPAGES next to the CONTENTS page.

SYMBOLS

So that the shop manual can be of ample practicaluse, important safety and quality portions aremarked with the following symbols.

Symbol Item Remarks

k SafetySpecial safety precautionsare necessary when per-forming the work.

a Caution

Special technical precau-tions or other precautionsfor preserving standardsare necessary when per-forming the work.

4 Weight

Weight of parts of sys-tems. Caution necessarywhen selecting hoistingwire, or when working pos-ture is important, etc.

3 Tighteningtorque

Places that require specialattention for the tighteningtorque during assembly.

2 CoatPlaces to be coated withadhesives and lubricants,etc.

5 Oil, waterPlaces where oil, water orfuel must be added, andthe capacity.

6 DrainPlaces where oil or watermust be dra ined, andquantity to be drained.

·

Each issued as onevolume to cover allmodels

12-20312-203-112-203-212-204

Added pages

FOREWORD HOISTING INSTRUCTIONS

00-7

HOISTING INSTRUCTIONS

HOISTING

k Heavy parts (25 kg or more) must be liftedwith a hoist, etc. In the DISASSEMBLYAND ASSEMBLY section, every partweighing 25 kg or more is indicated clearlywith the symbol

• If a part cannot be smoothly removed from themachine by hoisting, the following checksshould be made:1) Check for removal of all bolts fastening the

part to the relative parts.2) Check for existence of another part causing

interference with the part to be removed.

WIRE ROPES1) Use adequate ropes depending on the

weight of parts to be hoisted, referring tothe table below:

Wire ropes(Standard "Z" or "S" twist ropes

without galvanizing)

The allowable load value is estimated to be one-sixth or one-seventh of the breaking strength ofthe rope used.

2) Sling wire ropes from the middle portion of thehook.

Slinging near the edge of the hook may causethe rope to slip off the hook during hoisting, anda serious accident can result. Hooks have max-imum strength at the middle portion.

3) Do not sling a heavy load with one rope alone,but sling with two or more ropes symmetricallywound onto the load.k Slinging with one rope may cause turning

of the load during hoisting, untwisting ofthe rope, or slipping of the rope from itsoriginal winding position on the load, whichcan result in a dangerous accident.

4) Do not sling a heavy load with ropes forming awide hanging angle from the hook.When hoisting a load with two or more ropes,the force subjected to each rope will increasewith the hanging angles. The table belowshows the variation of allowable load kN kgwhen hoisting is made with two ropes, each ofwhich is allowed to sling up to 9.8 kN 1000 kgvertically, at various hanging angles.When two ropes sling a load vertically, up to19.6 kN 2000 kg of total weight can be sus-pended. This weight becomes 9.8 kN 1000 kgwhen two ropes make a 120° hanging angle.On the other hand, two ropes are subjected toan excessive force as large as 39.2 kN 4000kg if they sling a 19.6 kN 2000 kg load at alifting angle of 150°.

Rope diameter Allowable load

mm kN tons

1011.512.514161820

22.430405060

9.813.715.721.627.535.343.154.998.1176.5274.6392.2

1.01.41.62.22.83.64.45.6

10.018.028.040.0

4

SAD00479

41%71%79%88%100%

FOREWORD METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER

00-8

METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER

k Before carrying out the following work, releasethe residual pressure from the hydraulic tank.For details, see TESTING AND ADJUSTING,Releasing residual pressure from hydraulictank.

k Even if the residual pressure is released fromthe hydraulic tank, some hydraulic oil flows outwhen the hose is disconnected. Accordingly,prepare an oil receiving container.

Disconnection1) Release the residual pressure from the hydrau-

l ic tank. For details, see TESTING ANDADJUSTING, Releasing residual pressure fromhydraulic tank.

2) Hold adapter (1) and push hose joint (2) intomating adapter (3). (See Fig. 1) The adapter can be pushed in about 3.5

mm. Do not hold rubber cap portion (4).

3) After hose joint (2) is pushed into adapter (3),press rubber cap portion (4) against (3) until itclicks. (See Fig. 2)

4) Hold hose adapter (1) or hose (5) and pull it out.(See Fig. 3) Since some hydraulic oil flows out, prepare

an oil receiving container.

Connection1) Hold hose adapter (1) or hose (5) and insert it in

mating adapter (3), aligning them with eachother. (See Fig. 4) Do not hold rubber cap portion (4).

2) After inserting the hose in the mating adapterperfectly, pull it back to check its connectingcondition. (See Fig. 5) When the hose is pulled back, the rubber

cap portion moves toward the hose about3.5 mm. This does not indicate abnormality,however.

Type 1

FOREWORD METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER

00-9

Type 2 Type 3D

isas

sem

bly

1) Hold the mouthpiece of the tightening portionand push body (2) in straight until sliding pre-vention ring (1) contacts contact surface a ofthe hexagonal portion at the male end.

2) Hold in the condition in Step 1), and turnlever (4) to the right (clockwise).

3) Hold in the condition in Steps 1) and 2), andpull out whole body (2) to disconnect it.

1) Hold the mouthpiece of the tightening portionand push body (2) in straight until sliding pre-vention ring (1) contacts contact surface a ofthe hexagonal portion at the male end.

2) Hold in the condition in Step 1), and pushuntil cover (3) contacts contact surface a ofthe hexagonal portion at the male end.

3) Hold in the condition in Steps 1) and 2), andpull out whole body (2) to disconnect it.

Con

nect

ion

• Hold the mouthpiece of the tightening portionand push body (2) in straight until sliding pre-vention ring (1) contacts contact surface a ofthe hexagonal portion at the male end to con-nect it.

• Hold the mouthpiece of the tightening portionand push body (2) in straight until sliding pre-vention ring (1) contacts contact surface a ofthe hexagonal portion at the male end to con-nect it.

FOREWORD COATING MATERIALS

00-10

COATING MATERIALS

The recommended coating materials such as adhesives, gasket sealants and greases used for disassemblyand assembly are listed below.

For coating materials not listed below, use the equivalent of products shown in this list.

Category Komatsu code Part No. Q'ty Container Main applications, features

Adhesives

LT-1A 790-129-9030 150 g Tube• Used to prevent rubber gaskets, rub-

ber cushions, and cock plug fromcoming out.

LT-1B 790-129-9050 20 g(2 pcs.)

Polyethylenecontainer

• Used in places requiring an immedi-ately effective, strong adhesive.Used for plastics (except polyethyl-ene, polyprophylene, tetrafluoroeth-lene and vinyl chloride), rubber,metal and non-metal.

LT-2 09940-00030 50 g Polyethylenecontainer

• Features: Resistance to heat andchemicals

• Used for anti-loosening and sealantpurpose for bolts and plugs.

LT-3790-129-9060

(Set of adhesive and hardening

agent)

Adhesive:1 kg

Hardeningagent:500 g

Can

• Used as adhesive or sealant for met-al, glass and plastic.

LT-4 790-129-9040 250 g Polyethylenecontainer

• Used as sealant for machined holes.

HoltzMH 705 790-126-9120 75 g Tube

• Used as heat-resisting sealant for re-pairing engine.

Three bond1735 790-129-9140 50 g Polyethylene

container

• Quick hardening type adhesive• Cure time: within 5 sec. to 3 min.• Used mainly for adhesion of metals,

rubbers, plastics and woods.

Aron-alpha201 790-129-9130 2 g Polyethylene

container

• Quick hardening type adhesive• Quick cure type (max. strength after

30 minutes)• Used mainly for adhesion of rubbers,

plastics and metals.

Loctite648-50 79A-129-9110 50 cc Polyethylene

container• Resistance to heat, chemicals• Used at joint portions subject to high

temperatures.

Gasketsealant

LG-1 790-129-9010 200 g Tube• Used as adhesive or sealant for gas-

kets and packing of power train case,etc.

LG-5 790-129-9080 1 kg Can• Used as sealant for various threads,

pipe joints, flanges.• Used as sealant for tapered plugs,

elbows, nipples of hydraulic piping.

LG-6 790-129-9020 200 g Tube

• Features: Silicon based, resistanceto heat, cold

• Used as sealant for flange surface,tread.

• Used as sealant for oil pan, finaldrive case, etc.

LG-7 790-129-9070 1 kg Tube

• Features: Silicon based, quick hard-ening type

• Used as sealant for flywheel hous-ing, intake manifold, oil pan, thermo-stat housing, etc.

Three bond1211 790-129-9090 100 g Tube

• Used as heat-resisting sealant for re-pairing engine.

Three bond1207B 419-15-18131 100 g Tube

• Features: Silicone type, heat resist-ant, vibration resistant, and impactresistant sealing material

• Used as sealing material for transfercase

FOREWORD COATING MATERIALS

00-11

Category Komatsu code Part No. Q'ty Container Main applications, features

Molybdenum disulphide lubricant

LM-G 09940-00051 60 g Can • Used as lubricant for sliding portion(to prevent from squeaking).

LM-P 09940-00040 200 g Tube

• Used to prevent seizure or scufflingof the thread when press fitting orshrink fitting.

• Used as lubricant for linkage, bear-ings, etc.

Grease

G2-LI

SYG2-400LISYG2-350LISYG2-400LI-ASYG2-160LISYGA-160CNLI

Various Various

• General purpose type

G2-CA

SYG2-400CASYG2-350CASYG2-400CA-ASYG2-160CASYGA-160CNCA

Various Various

• Used for normal temperature, lightload bearing at places in contactwith water or steam.

MolybdenumdisulphidegreaseLM-G (G2-M)

SYG2-400MSYG2-400M-ASYGA-16CNM

400 g × 10400 g × 20

16 kg

Bellows typeBellows type

Can

• Used for heavy load portion

Hyper White Grease G2-TG0-T (*)*: For use in cold

district

SYG2-400T-ASYG2-16CNTSYG0-400T-A (*)SYG0-16CNT (*)

400 g16 kg

Bellows typeCan

• Seizure resistance and heat resist-ance higher than molybdenum di-sulfide grease

• Since this grease is white, it doesnot stand out against machinebody.

Biogrease G2BG2-BT (*)*: For high

temperature and large load

SYG2-400BSYGA-16CNBSYG2-400BT (*)SYGA-16CNBT (*)

400 g16 kg

Bellows typeCan

• Since this grease is decomposedby bacteria in short period, it hasless effects on microorganisms,animals, and plants.

Primer

SUNSTAR PAINT PRIMER 580 SUPER

417-926-3910

20 ml Glass container

Adhe

sive

for c

ab g

lass

• Used as primer for cab side(Using limit: 4 months)

SUNSTAR GLASS PRIMER 580 SUPER

20 ml Glass container

• Used as primer for glass side(Using limit: 4 months)

Adhesive

SUNSTAR PENGUINE SEAL 580 SUPER "S" or "W"

320 ml Polyethylene container

• "S" is used for high-tempera-ture season (April - October)and "W" for low-temperatureseason (November - April) asadhesive for glass. (Using limit: 4 months)

Sika Japan, Sikaflex 256HV 20Y-54-39850 310 ml Polyethylene

container• Used as adhesive for glass.

(Using limit: 6 months)

Caulking material

SUNSTAR PENGUINE SEAL No. 2505

417-926-3920 320 ml Polyethylene container

• Used to seal joints of glassparts.(Using limit: 4 months)

SEKISUI SILICONE SEALANT

20Y-54-55130 333 ml Polyethylene container

• Used to seal front window.(Using limit: 6 months)

FOREWORD STANDARD TIGHTENING TORQUE

00-12

STANDARD TIGHTENING TORQUE

STANDARD TIGHTENING TORQUE TABLE (WHEN USING TORQUE WRENCH) In the case of metric nuts and bolts for which there is no special instruction, tighten to the torque given in

the table below.

TABLE OF TIGHTENING TORQUES FOR FLARED NUTS In the case of flared nuts for which there is no

special instruction, tighten to the torque given inthe table below.

Thread diameter of bolt

Width across flats

Tightening torque

mm mm Nm kgm

68

101214

1013171922

11.8 – 14.727 – 3459 – 7498 – 123

153 – 190

1.2 – 1.52.8 – 3.5

6 – 7.510 – 12.5

15.5 – 19.5

1618202224

2427303236

235 – 285320 – 400455 – 565610 – 765785 – 980

23.5 – 29.533 – 41

46.5 – 5862.5 – 7880 – 100

2730333639

4146505560

1150 – 14401520 – 19101960 – 24502450 – 30402890 – 3630

118 – 147155 – 195200 – 250250 – 310295 – 370

Thread diameter of bolt

Width across flats

Tightening torque

mm mm Nm kgm

68

1012

10131427

5.9 – 9.813.7 – 23.534.3 – 46.174.5 – 90.2

0.6 – 1.01.4 – 2.43.5 – 4.77.6 – 9.2

SAD00483

Sealing surface

Thread diameter Width across flat Tightening torque

mm mm Nm kgm

1418222430333642

1924273236414655

24.5 ± 4.949 ± 19.6

78.5 ± 19.6137.3 ± 29.4176.5 ± 29.4196.1 ± 49245.2 ± 49294.2 ± 49

2.5 ± 0.55 ± 28 ± 2

14 ± 318 ± 320 ± 525 ± 530 ± 5


00-13

TABLE OF TIGHTENING TORQUES FOR SPLIT FLANGE BOLTS In the case of split flange bolts for which there is no special instruction, tighten to the torque given in the

table below.

TABLE OF TIGHTENING TORQUES FOR O-RING BOSS PIPING JOINTS Unless there are special instructions, tighten the O-ring boss piping joints to the torque below.

TABLE OF TIGHTENING TORQUES FOR O-RING BOSS PLUGS Unless there are special instructions, tighten the O-ring boss plugs to the torque below.

Thread diameter Width across flat Tightening torque

mm mm Nm kgm

101216

141722

59 – 7498 – 123

235 – 285

6 – 7.5 10 – 12.5

23.5 – 29.5

Norminal No.Thread diameter Width across flat Tightening torque (Nm kgm)

mm mm Range Target

0203, 0405, 0610, 12

14

1420243342

Varies depending on type of connector.

35 – 63 3.5 – 6.584 – 132 8.5 – 13.5

128 – 186 13.0 – 19.0363 – 480 37.0 – 49.0

746 – 1010 76.0 – 103

44 4.5103 10.5157 16.0422 43.0883 90.0

Norminal No.Thread diameter Width across flat Tightening torque (Nm kgm)

mm mm Range Target

08101214161820243033364252

08101214161820243033364252

141719222427303232—36——

5.88 – 8.82 0.6 – 0.99.8 – 12.74 1.0 – 1.314.7 – 19.6 1.5 – 2.019.6 – 24.5 2.0 – 2.524.5 – 34.3 2.5 – 3.534.3 – 44.1 3.5 – 4.544.1 – 53.9 4.5 – 5.558.8 – 78.4 6.0 – 8.0

93.1 – 122.5 9.5 – 12.5107.8 – 147.0 11.0 – 15.0127.4 – 176.4 13.0 – 18.0181.3 – 240.1 18.5 – 24.5274.4 – 367.5 28.0 – 37.5

7.35 0.7511.27 1.1517.64 1.822.54 2.329.4 3.039.2 4.049.0 5.068.6 7.0

107.8 11.0124.4 13.0151.9 15.5210.7 21.5323.4 33.0


00-14

TIGHTENING TORQUE FOR 102 ENGINE SERIES 1) BOLT AND NUTS

Use these torques for bolts and nuts (unit: mm) of Cummins Engine.

2) EYE JOINTSUse these torques for eye joints (unit: mm) of Cummins Engine.

3) TAPERED SCREWSUse these torques for tapered screws (unit: inch) of Cummins Engine.

TIGHTENING TORQUE TABLE FOR HOSES (TAPER SEAL TYPE AND FACE SEAL TYPE) Tighten the hoses (taper seal type and face seal type) to the following torque, unless otherwise specified. Apply the following torque when the threads are coated (wet) with engine oil.

Thread diameter Tightening torque

mm Nm kgm

68

1012

10 0 224 0 443 0 6

77 0 12

1.02 0 0.202.45 0 0.414.38 0 0.617.85 0 1.22


mm Nm kgm

68

101214

8 0 210 0 212 0 224 0 436 0 5

0.81 0 0.201.02 0 0.201.22 0 0.202.45 0 0.413.67 0 0.51


inch Nm kgm

1 / 161 / 81 / 43 / 81 / 23 / 4

1

3 0 18 0 2

12 0 215 0 224 0 436 0 560 0 9

0.31 0 0.100.81 0 0.201.22 0 0.201.53 0 0.412.45 0 0.413.67 0 0.516.12 0 0.92

Nominal size of hose

Width across flats

Tightening torque (Nm kgm) Taper seal type Face seal type

Range Target Thread size (mm)

Nominal thread size - Threads per inch, Thread series

Root diameter (mm) (Reference)

02 1934 – 54 3.5 – 5.5 44 4.5 – – 18UN 14.3

34 – 63 3.5 – 6.5 44 4.5 14 – –

0322 54 – 93 5.5 – 9.5 74 7.5 – – 16UN 17.5

24 59 – 98 6.0 – 10.0 78 8.0 18 – –

04 27 84 – 132 8.5 – 13.5 103 10.5 22 – 16UN 20.6

05 32 128 – 186 13.0 – 19.0 157 16.0 24 1 – 14UNS 25.4

06 36 177 – 245 18.0 – 25.0 216 22.0 30 1 – 12UN 30.2

(10) 41 177 – 245 18.0 – 25.0 216 22.0 33 – –

(12) 46 197 – 294 20.0 – 30.0 245 25.0 36 – –

(14) 55 246 – 343 25.0 – 35.0 294 30.0 42 – –

9—16

11—16

13—16

3—16

FOREWORD ELECTRIC WIRE CODE

00-15

ELECTRIC WIRE CODEIn the wiring diagrams, various colors and symbols are employed to indicate the thickness of wires.This wire code table will help you understand WIRING DIAGRAMS.Example: 5WB indicates a cable having a nominal number 5 and white coating with black stripe.

CLASSIFICATION BY THICKNESS

CLASSIFICATION BY COLOR AND CODE

Norminalnumber

Copper wire

Cable O.D.(mm)

Current rating

(A)Applicable circuit

Number of strands

Dia. of strands(mm2)

Cross section(mm2)

0.85 11 0.32 0.88 2.4 12 Starting, lighting, signal etc.

2 26 0.32 2.09 3.1 20 Lighting, signal etc.

5 65 0.32 5.23 4.6 37 Charging and signal

15 84 0.45 13.36 7.0 59 Starting (Glow plug)

40 85 0.80 42.73 11.4 135 Starting

60 127 0.80 63.84 13.6 178 Starting

100 217 0.80 109.1 17.6 230 Starting

Priori-ty

Circuits

Classi-fication

Charging Ground Starting Lighting Instrument Signal Other

1 Pri-mary

Code W B B R Y G L

Color White Black Black Red Yellow Green Blue

2

Auxi-liary

Code WR — BW RW YR GW LW

Color White & Red — White & Black Red & White Rellow & Red Green & White Blue & White

3Code WB — BY RB YB GR LR

Color White & Black — Black & Yellow Red & Black Yellow & Black Green & Red Blue & Yellow

4

Code WL — BR RY YG GY LY

Color White & Blue — Black & Red Red & Yellow Yellow & Green

Green & Yellow Blue & Yellow

5Code WG — — RG YL GB LB

Color White & Green — — Red & Green Yellow & Blue Green & Black Blue & Black

6Code — — — RL YW GL nColor — — — Red & Blue Yellow & White Green & Blue n

FOREWORD CONVERSION TABLE

00-16

CONVERSION TABLE

METHOD OF USING THE CONVERSION TABLEThe Conversion Table in this section is provided to enable simple conversion of figures. For details of themethod of using the Conversion Table, see the example given below.

EXAMPLE• Method of using the Conversion Table to convert from millimeters to inches1. Convert 55 mm into inches.

(1) Locate the number 50 in the vertical column at the left side, take this as A, then draw a horizontal linefrom A.

(2) Locate the number 5 in the row across the top, take this as B, then draw a perpendicular line downfrom B.

(3) Take the point where the two lines cross as C. This point C gives the value when converting from mil-limeters to inches. Therefore, 55 mm = 2.165 inches.

2. Convert 550 mm into inches.(1) The number 550 does not appear in the table, so divide by 10 (move the decimal point one place to the

left) to convert it to 55 mm.(2) Carry out the same procedure as above to convert 55 mm to 2.165 inches.(3) The original value (550 mm) was divided by 10, so multiply 2.165 inches by 10 (move the decimal point

one place to the right) to return to the original value. This gives 550 mm = 21.65 inches.

Millimeters to inches

1 mm = 0.03937 in

0 1 2 3 4 5 6 7 8 9

010203040

5060708090

00.3940.7871.1811.575

1.9692.3622.7563.1503.543

0.0390.4330.8271.2201.614

2.0082.4022.7953.1893.583

0.0790.4720.8661.2601.654

2.0472.4412.8353.2283.622

0.1180.5120.9061.2991.693

2.0872.4802.8743.2683.661

0.1570.5510.9451.3391.732

2.1262.5202.9133.3073.701

0.1970.5910.9841.3781.772

2.1652.5592.9533.3463.740

0.2360.6301.0241.4171.811

2.2052.5982.9923.3863.780

0.2760.6691.0631.4571.850

2.2442.6383.0323.4253.819

0.3150.7091.1021.4961.890

2.2832.6773.0713.4653.858

0.3540.7481.1421.5361.929

2.3232.7173.1103.5043.898

B

AC


00-17

Millimeters to Inches1 mm = 0.03937 in

Kilogram to Pound1 kg = 2.2046 lb

0 1 2 3 4 5 6 7 8 9

0

10

20

30

40

50

60

70

80

90

0

0.394

0.787

1.181

1.575

1.969

2.362

2.756

3.150

3.543

0.039

0.433

0.827

1.220

1.614

2.008

2.402

2.795

3.189

3.583

0.079

0.472

0.866

1.260

1.654

2.047

2.441

2.835

3.228

3.622

0.118

0.512

0.906

1.299

1.693

2.087

2.480

2.874

3.268

3.661

0.157

0.551

0.945

1.339

1.732

2.126

2.520

2.913

3.307

3.701

0.197

0.591

0.984

1.378

1.772

2.165

2.559

2.953

3.346

3.740

0.236

0.630

1.024

1.417

1.811

2.205

2.598

2.992

3.386

3.780

0.276

0.669

1.063

1.457

1.850

2.244

2.638

3.032

3.425

3.819

0.315

0.709

1.102

1.496

1.890

2.283

2.677

3.071

3.465

3.858

0.354

0.748

1.142

1.536

1.929

2.323

2.717

3.110

3.504

3.898

0 1 2 3 4 5 6 7 8 9

0

10

20

30

40

50

60

70

80

90

0

22.05

44.09

66.14

88.18

110.23

132.28

154.32

176.37

198.42

2.20

24.25

46.30

68.34

90.39

112.44

134.48

156.53

178.57

200.62

4.41

26.46

48.50

70.55

92.59

114.64

136.69

158.73

180.78

202.83

6.61

28.66

50.71

72.75

94.80

116.85

138.89

160.94

182.98

205.03

8.82

30.86

51.91

74.96

97.00

119.05

141.10

163.14

185.19

207.24

11.02

33.07

55.12

77.16

99.21

121.25

143.30

165.35

187.39

209.44

13.23

35.27

57.32

79.37

101.41

123.46

145.51

167.55

189.60

211.64

15.43

37.48

59.53

81.57

103.62

125.66

147.71

169.76

191.80

213.85

17.64

39.68

61.73

83.78

105.82

127.87

149.91

171.96

194.01

216.05

19.84

41.89

63.93

85.98

108.03

130.07

152.12

174.17

196.21

218.26


00-18

Liter to U.S. Gallon1l = 0.2642 U.S. Gal

Liter to U.K. Gallon1l = 0.21997 U.K. Gal

0 1 2 3 4 5 6 7 8 9

0

10

20

30

40

50

60

70

80

90

0

2.642

5.283

7.925

10.567

13.209

15.850

18.492

21.134

23.775

0.264

2.906

5.548

8.189

10.831

13.473

16.115

18.756

21.398

24.040

0.528

3.170

5.812

8.454

11.095

13.737

16.379

19.020

21.662

24.304

0.793

3.434

6.076

8.718

11.359

14.001

16.643

19.285

21.926

24.568

1.057

3.698

6.340

8.982

11.624

14.265

16.907

19.549

22.190

24.832

1.321

3.963

6.604

9.246

11.888

14.529

17.171

19.813

22.455

25.096

1.585

4.227

6.869

9.510

12.152

14.795

17.435

20.077

22.719

25.361

1.849

4.491

7.133

9.774

12.416

15.058

17.700

20.341

22.983

25.625

2.113

4.755

7.397

10.039

12.680

15.322

17.964

20.605

23.247

25.889

2.378

5.019

7.661

10.303

12.944

15.586

18.228

20.870

23.511

26.153

0 1 2 3 4 5 6 7 8 9

0

10

20

30

40

50

60

70

80

90

0

2.200

4.399

6.599

8.799

10.998

13.198

15.398

17.598

19.797

0.220

2.420

4.619

6.819

9.019

11.281

13.418

15.618

17.818

20.017

0.440

2.640

4.839

7.039

9.239

11.438

13.638

15.838

18.037

20.237

0.660

2.860

5.059

7.259

9.459

11.658

13.858

16.058

18.257

20.457

0.880

3.080

5.279

7.479

9.679

11.878

14.078

16.278

18.477

20.677

1.100

3.300

5.499

7.969

9.899

12.098

14.298

16.498

18.697

20.897

1.320

3.520

5.719

7.919

10.119

12.318

14.518

16.718

18.917

21.117

1.540

3.740

5.939

8.139

10.339

12.528

14.738

16.938

19.137

21.337

1.760

3.950

6.159

8.359

10.559

12.758

14.958

17.158

19.357

21.557

1.980

4.179

6.379

8.579

10.778

12.978

15.178

17.378

19.577

21.777


00-19

kgm to ft. lb1 kgm = 7.233 ft. lb

0 1 2 3 4 5 6 7 8 9

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

0

72.3

144.7

217.0

289.3

361.7

434.0

506.3

578.6

651.0

723.3

795.6

868.0

940.3

1012.6

1084.9

1157.3

1129.6

1301.9

1374.3

7.2

79.6

151.9

224.2

296.6

368.9

441.2

513.5

585.9

658.2

730.5

802.9

875.2

947.5

1019.9

1092.2

1164.5

1236.8

1309.2

1381.5

14.5

86.8

159.1

231.5

303.8

376.1

448.5

520.8

593.1

665.4

737.8

810.1

882.4

954.8

1027.1

1099.4

1171.7

1244.1

1316.4

1388.7

21.7

94.0

166.4

238.7

311.0

383.4

455.7

528.0

600.3

672.7

745.0

817.3

889.7

962.0

1034.3

1106.6

1179.0

1251.3

1323.6

1396.0

28.9

101.3

173.6

245.9

318.3

390.6

462.9

535.2

607.6

679.9

752.2

824.6

896.9

969.2

1041.5

1113.9

1186.2

1258.5

1330.9

1403.2

36.2

108.5

180.8

253.2

325.5

397.8

470.2

542.5

614.8

687.1

759.5

831.8

904.1

976.5

1048.8

1121.1

1193.4

1265.8

1338.1

1410.4

43.4

115.7

188.1

260.4

332.7

405.1

477.4

549.7

622.0

694.4

766.7

839.0

911.4

983.7

1056.0

1128.3

1200.7

1273.0

1345.3

1417.7

50.6

123.0

195.3

267.6

340.0

412.3

484.6

556.9

629.3

701.6

773.9

846.3

918.6

990.9

1063.2

1135.6

1207.9

1280.1

1352.6

1424.9

57.9

130.2

202.5

274.9

347.2

419.5

491.8

564.2

636.5

708.8

781.2

853.5

925.8

998.2

1070.5

1142.8

1215.1

1287.5

1359.8

1432.1

65.1

137.4

209.8

282.1

354.4

426.8

499.1

571.4

643.7

716.1

788.4

860.7

933.1

1005.4

1077.7

1150.0

1222.4

1294.7

1367.0

1439.4


00-20

kg/cm2 to lb/in2

1kg/cm2 = 14.2233 lb/in2

0 1 2 3 4 5 6 7 8 9

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

210

220

230

240

0

142.2

284.5

426.7

568.9

711.2

853.4

995.6

1138

1280

1422

1565

1707

1849

1991

2134

2276

2418

2560

2702

2845

2987

3129

3271

3414

14.2

156.5

298.7

440.9

583.2

725.4

867.6

1010

1152

1294

1437

1579

1721

1863

2005

2148

2290

2432

2574

2717

2859

3001

3143

3286

3428

28.4

170.7

312.9

455.1

597.4

739.6

881.8

1024

1166

1309

1451

1593

1735

1877

2020

2162

2304

2446

2589

2731

2873

3015

3158

3300

3442

42.7

184.9

327.1

469.4

611.6

753.8

896.1

1038

1181

1323

1465

1607

1749

1892

2034

2176

2318

2460

2603

2745

2887

3030

3172

3314

3456

56.9

199.1

341.4

483.6

625.8

768.1

910.3

1053

1195

1337

1479

1621

1764

1906

2048

2190

2333

2475

2617

2759

2901

3044

3186

3328

3470

71.1

213.4

355.6

497.8

640.1

782.3

924.5

1067

1209

1351

1493

1636

1778

1920

2062

2205

2347

2489

2631

2773

2916

3058

3200

3343

3485

85.3

227.6

369.8

512.0

654.3

796.5

938.7

1081

1223

1365

1508

1650

1792

1934

2077

2219

2361

2503

2646

2788

2930

3072

3214

3357

3499

99.6

241.8

384.0

526.3

668.5

810.7

953.0

1095

1237

1380

1522

1664

1806

1949

2091

2233

2375

2518

2660

2802

2944

3086

3229

3371

3513

113.8

256.0

398.3

540.5

682.7

825.0

967.2

1109

1252

1394

1536

1678

1821

1963

2105

2247

2389

2532

2674

2816

2958

3101

3243

3385

3527

128.0

270.2

412.5

554.7

696.9

839.2

981.4

1124

1266

1408

1550

1693

1835

1977

2119

2262

2404

2546

2688

2830

2973

3115

3257

3399

3542


00-21

TemperatureFahrenheit-Centigrade Conversion ; a simple way to convert a Fahrenheit temperature reading into a Cen-tigrade temperature reading or vice versa is to enter the accompanying table in the center or boldface col-umn of figures.These figures refer to the temperature in either Fahrenheit or Centigrade degrees.If it is desired to convert from Fahrenheit to Centigrade degrees, consider the center column as a table ofFahrenheit temperatures and read the corresponding Centigrade temperature in the column at the left.If it is desired to convert from Centigrade to Fahrenheit degrees, consider the center column as a table ofCentigrade values, and read the corresponding Fahrenheit temperature on the right.

1°C = 33.8°F

°C °F °C °F °C °F °C °F

–40.4–37.2–34.4–31.7–28.9

–28.3–27.8–27.2–26.7–26.1

–25.6–25.0–24.4–23.9–23.3

–22.8–22.2–21.7–21.1–20.6

–20.0–19.4–18.9–18.3–17.8

–17.2–16.7–16.1–15.6–15.0

–14.4–13.9–13.3–12.8–12.2

–40–35–30–25–20

–19–18–17–16–15

–14–13–12–11–10

–9 –8 –7 –6 –5

–4 –3 –2 –1 0

1 2 3 4 5

6 7 8 9 10

–40.0–31.0–22.0–13.0 –4.0

–2.2 –0.4 1.4 3.2 5.0

6.8 8.6 10.4 12.2 14.0

15.8 17.6 19.4 21.2 23.0

24.8 26.6 28.4 30.2 32.0

33.8 35.6 37.4 39.2 41.0

42.8 44.6 46.4 48.2 50.0

–11.7–11.1–10.6–10.0 –9.4

–8.9 –8.3 –7.8 –7.2 –6.7

–6.1 –5.6 –5.0 –4.4 –3.9

–3.3 –2.8 –2.2 –1.7 –1.1

–0.6 0

0.6 1.1 1.7

2.2 2.8 3.3 3.9 4.4

5.0 5.6 6.1 6.7 7.2

1112131415

1617181920

2122232425

2627282930

3132333435

3637383940

4142434445

51.8 53.6 55.4 57.2 59.0

60.8 62.6 64.4 66.2 68.0

69.8 71.6 73.4 75.2 77.0

78.8 80.6 82.4 84.2 86.0

87.8 89.6 91.4 93.2 95.0

96.8 98.6100.4102.2104.0

105.8107.6109.4111.2113.0

7.8 8.3 8.9 9.410.0

10.611.111.712.212.8

13.313.914.415.015.6

16.116.717.217.818.3

18.919.420.020.621.1

21.722.222.823.323.9

24.425.025.626.126.7

4647484950

5152535455

56575859 0

6162636465

6667686970

7172737475

7677787980

114.8116.6118.4120.2122.0

123.8125.6127.4129.2131.0

132.8134.6136.4138.2140.0

141.8143.6145.4147.2149.0

150.8152.6154.4156.2158.0

159.8161.6163.4165.2167.0

168.8170.6172.4174.2176.0

27.227.828.328.929.4

30.030.631.131.732.2

32.833.333.934.435.0

35.636.136.737.237.8

40.643.346.148.951.7

54.457.260.062.765.6

68.371.173.976.779.4

81 82 83 84 85

86 87 88 89 90

91 92 93 94 95

96 97 98 99100

105110115120125

130135140145150

155160165170175

117.8179.6181.4183.2185.0

186.8188.6190.4192.2194.0

195.8197.6199.4201.2203.0

204.8206.6208.4210.2212.0

221.0230.0239.0248.0257.0

266.0275.0284.0293.0302.0

311.0320.0329.0338.0347.0

FOREWORD UNITS

00-22 10-04

UNITS

In this manual, the measuring units are indicated with Internatinal System of units (SI).As for reference, conventionally used Gravitational System of units are indicated in parentheses .

Example:N kgNm kgmMPa kg/cm2kPa mmH2OkPa mmHgkW/rpm HP/rpmg/kWh g/HPh

Air conditioner 01-11

01 GENERAL

Basic information on air conditioners ....... 01- 2• Units related to refrigeration ............... 01- 2

Heat ......................................................... 01- 2Temperature ........................................... 01- 2Pressure .................................................. 01- 3Humidity ................................................. 01- 4

• Principle of cooling ............................... 01- 5• Refrigerants ............................................ 01- 9• Refrigerator oil ....................................... 01-10Applicable machine ..................................... 01-14Specifications ............................................... 01-161. Freon gas (R-12) type............................ 01-162. New refrigerant (R134a) type ............... 01-34

fl Refer to the section 40 for the explanationof New Refrigerant (R134a).

01-14

Air conditioner01-141

APPLICABLE MACHINE

1. Freon gas type

D40, 41A-3 PC150-3 GD405A-2 HD325-6D40, 41-5 PC200-3 GD505A-2 HD465-5D50, 53A-17 PC220-2 GD505A-3 HD785-3 WA200-1D50, 53-18 PC300-2 GD525A-1 HD1200M-1 WA250-3D57S-1 PC300-3 GD605A-2 WA300-1D60, 65A-8 PC400-1 GD605A-3 WA320-3D60, 65-12 PC400-3 GD605A-5 WA350-1

DENSO 10 D66S-1 PC650-1, 3, 5 GD625A-1 WA380-3D75S-5 PC1500-1 GD655A-2 WA400-1D80, 85A-18 PC100, 120-5, 6 GD705A-2 WA420-3D150, 155A-1 PC200, 210, GD705A-3 WA450-1D355A-3 PC220-6 GD705A-4 WA470-3D375A-1 PC1000-1 GD805A-1 WA500-1D475A-1 PC1600-1 GD825A-1 WA600-1

PW150-1 GD825A-2 WA700-1PW200-1 WA800-2

HD180-4HD200-2HD205-3HD320, 325-3HD325-5

ZEXEL 20 — — — HD465-2 —HD465-3HD785-1HD785-2HD1200-1HD1200M-1HD1600M-1

WA200-1WA300-1WA350-1

DAIKIN 30 — — — — WA400-1WA450-1WA500-1WA600-1WA800-1

Manufacturer Chapter

Applicable machine model

Bulldozer Hydraulicexcavator Motor grader Dump truck Wheel loader

GENERAL APPLICABLE MACHINE

01-144

GENERAL SPECIFlCATIONS

Air conditioner 01-15(5)

2. New refrigerant type

Manufacturer Chapter

Applicable machine model

BulldozerHydraulicexcavator

Motor grader Dump truck Wheel loader

DENSO 40

D40, 41-5D50, 53-18D60, 65-12D275AX-5D375A-3D375A-5D475A-3D575A-2D575A-3

PC200-6PC210-6PC220-6PC650-5PC1000-1PC1600-1

GD305A-1GD355A-1GD405A-2GD505A-3GD605A-5GD705A-4GD825A-2

HD255-5HD325-6HD465-5HD605-5HD785-3HD785-5HD985-5HD1200-1HM400-1

WA80-3WA120-3WA180-3WA250-3WA320-3WA380-3WA420-3WA470-3WA500-1WA500-3WA600-1WA600-3WA700-1WA700-3WA800-2WA800-3WA900-3WA1200-3

ZEXEL -HD205-3

TAKAHASHIWORKS

50

PC100-6PC120-6PC300-5PC400-5A57

GD305A-2GD355A-3GD405A-3

SANDEN 60

PC27MR-2PC30MR-2PC35MR-2PC40MR-2PC50MR-2

APPLICABLE MACHINE



SPECIFlCATIONS1. FREON GAS (R-12) TYPEDENSO

Manufacturer DENSO

Applicable machine

D40, 41A-3D50, 53A-17D57S-1D60, 65A-8D75S-5

D66S-1D80, 85A-18D150, 155A-1D355A-3

D375A-1 D475A-1

Power source DC, 24V

Cooling capacity kcal/h 3,200 3,400 3,200 3,500

Heating capacity kcal/h 4,800 4,500 4,800 4,500

Type Crank type(2M110B) Crank type(2M126B)

No. of cylinders-bore x stroke mm 2-50 x 28 2-50 x 32

Max. speed rpm 2,200 2,180

Delivery cc/rev 110 126

Magnet clutch type Electromagnetic, dry disc

Power consumption of clutch W 40

Condenser type Corrugated fin Plate fin

Motor type 70F Cooling by engine fan

Power consumption W 125 -

Max. air flow m3/min 23.3 20.5 -

Air flow control ON io OFF -

Auxiliary equipment Fusible plug (melting point : 100-105fC/30 kg/cm2),desiccant

Capacity cc 424 475 580

Evaporator type Plate fin Corrugated fin

Type Sirocco fan

Power consumption of motor W 150 160

Max. air flow m3/min 7 6.3 7

Air flow control 3-stage selection (H,M, L)

Temperature control Air mix type

Refrigerating method Vapour (gas) compression refrigerating system

Name of refrigerant R-12

Amount kg 1.6-2.0 1.5-1.7

Name of refrigerator oil DENSO OIL 6 or SUNISO 4 GS

Amount cc 210 300

Protective equipment Fusible plug (receiver)

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DENSO

D40, 41-5 D50, 53-18

D60, 65-12

DC, 24V

2,650 v 265 3,500 v 350

- 5,300 v 530

Crank type(2M110B) Crank type(2M126B)

2-50 x 28

3,000

110 126

Electromagnetic, dry disc

40

Corrugated fin Plate fin

70F Cooling by engine fan

Max. 80 v 20% -

1,100 m3/n v 200 -

Hi io Lo -

Fusible plug (103fC-110fC)

600

Plate fin Corrugated fin

Sirocco fan

70 180W v 10%

330 v 10% m3/n 460 v 10%

Hi io Med io Lo

Thermistor type(ON io OFF) Reheat type

Vapour (gas) compression refrigerating system

R-12

1.0

ND-Oil 6

210 380

Fusible plug (receiver)

4



Manufacturer DENSO

Applicable machine

PC100, 120-5, 6PC200, 210, 220-6PC150-3, PC300-3PC200-3, PC400-1PC220-3, PC400-3PC300-2PW150-1, PW200-1

PC650-1, 3, 5 PC1500-1 PC1000-1 PC1600-1


Cooling capacity kcal/h 2,800 3,200

Heating capacity kcal/h 3,100 4,800

Type Crank type(2M110B)

No. of cylinders-bore x stroke mm 2-50 x 28

Max. speed rpm 2,500-3,100 2,200

Delivery cc/rev 110



Condenser type Aluminium tube, corrugated fin

Motor type 70F

Power consumption W 80 125

Max. air flow m3/min 15 20.5

Air flow control ON io OFF

Auxiliary equipment Fusible plug (melting point : 100-105fC/30 kg/cm2), desiccant

Capacity cc 525 475

Evaporator type Corrugated fin Plate fin

Type Sirocco fan


Max. air flow m3/min 5.5 6.3





Amount kg 1.2 1.6-2.0


Amount cc 280 210


Com

pre

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DENSO

WA200-1WA250-3WA300-1WA320-3

WA350-1WA380-3WA400-1WA420-3

WA450-1WA470-3WA500-1WA600-1WA700-1WA800-2

DC, 24V

3,500

4,000

Crank type(2M126B)

2-50 x 32

-

126


40

Copper tube 4 lines plate fin

86F

160

23.3

ON io OFF

Fusible plug (melting point : 100-105fC/30 kg/cm2), desiccant

580

Aluminium tube, corrugated fin

Sirocco fan

150

Cooling: 7 (Heating: 5.3)

3-stage selection (H,M, L)

Air mix type


R-12

1.5-1.6 1.6-1.7 1.5-1.6

DENSO OIL 6 or SUNISO 4 GS

380

Fusible plug (receiver), pressure switch (air conditioner unit)

4



Manufacturer DENSO

Applicable machine GD405A-2

GD505A-2GD605A-3GD655A-3GD705A-3GD705A-4

GD505A-3GD525A-1

GD605A-2GD655A-2GD705A-2




Type Crank type(2M110B)


Max. speed rpm 2,196 2,470 2,057 2,455

Delivery cc/rev 110




Motor type 70F

Power consumption W 80 125 80 125

Max. air flow m3/min 15 23.3 15 23.3

Air flow control ON io OFF


Capacity cc 580

Evaporator type Corrugated fin

Type Sirocco fan

Power consumption of motor W 110 80 110

Max. air flow m3/min 5.5 4.3 5.5

Air flow control 3-stage selection (H,M, L) 2-stage selection 3-stage selection 2-stage selection




Amount kg 1.6 1.2 1.6 1.2


Amount cc 210


Com

pre

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Cond

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DENSO

GD605A-5GD805A-1GD825A-1

GD825A-2

DC, 24V

2,800 3,800

3,200 4,000

Crank type(2M110B) -

2-50 x 28 2-50 x 32

1,589 1,706 6,000

110 126


40

Aluminium tube, corrugated fin

70F Cooling by engine fan

80 -

15 -

ON io OFF -

100-105fC/30 kg/cm2

580 600

Corrugated fin -

Sirocco fan

110 -

5.5 7

3-stage selection

Air mix type


R-12

1.6 1.6-2.0 1.6

DENSO OIL 6 or SUNISO 4 GS DENSO OIL 6

210 300

Fusible plug (receiver)

4



BOSCH (ZEXEL)

*1. Pressure switch: OFF at max. 0.2 MPa 2 kg/cm2, OFF at min. 2.7 27 kg/cm2

Manufacturer BOSCH (ZEXEL)

Applicable machineHD180-4, HD200-2, HD205-3 (• - #2084), HD320, 325-3, HD325-5,HD465-2, HD465-3, HD785-1, HD785-2, HD1200-1, HD1200M-1,HD1600M-1


Cooling capacity kcal/h 3,100

Heating capacity kcal/h 3,200

Type Crank type


Max. speed rpm -

Delivery cc/rev 123


Power consumption of clutch W Max. 30

Condenser type Corrugated fin

Motor type Forced cooling by engine fan

Power consumption W -

Max. air flow m3/min -

Air flow control -

Auxiliary equipment Fusible plug (melting point : 105fC/30 kg/cm2)

Capacity cc 500

Evaporator type Aluminium tube, aluminium fin

Type Sirocco fan

Power consumption of motor W 180

Max. air flow m3/min 450


Temperature control Reheat air mix type



Amount kg 1.2

Name of refrigerator oil SUNISO 351 or SUNISO 5 GS

Amount cc 300

Protective equipment Fusible plug (receiver), pressure switch (*1)

Co

mpre

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Cond

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rece

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Blo

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01-24



DAIKIN

Manufacturer DAIKIN

Applicable machine(TXF40A1)WA350-1WA400-1

(TXF40A2)WA200-1WA300-1

(TXF40A3)WA600-1WA800-1

(TXF40A4)WA450-1WA500-1

Power source DC, 24V (22V - 30V)



Type Vane rotary type (TXC40A, SS170P)

No. of cylinders-bore x stroke mm -

Max. speed rpm 2,000

Delivery cc/rev 121




Motor type -

Power consumption W 190


Air flow control -


Capacity cc -


Type Sirocco fan


Max. air flow m3/min 6.7


Temperature control Air mix type (frost thermo)


Name of refrigerant R-12 (DF-12)

Amount kg 1.3

Name of refrigerator oil Daphene 7963

Amount cc 220

Protective equipment Fusible plug, pressure switch (receiver), temperature fuse (resistor), thermo protector (compressor)

Co

mpre

ssor

Cond

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01-28



2. NEW REFRIGERANT (R134a) TYPEDENSO

Manufacturer DENSO

Applicable machine D40, 41-5 D50, 53-18

D60, 65-12 D375A-3 D475A-3


Cooling capacity kcal/h 2,650 v 265 3,400 v 340 4,300 v 430

Heating capacity kcal/h - 4,400 v 440 5,400 v 540

Type Swash plate type(10PA15C)

No. of cylinders-bore x stroke mm 10 x 29.5 x 22.7


Delivery cc/rev 155



Condenser type Corrugated fin Plate fin

Motor type 70F Cooling by engine fan

Power consumption W Max. 80 v 20% - 250 v 25

Max. air flow m3/min 1,100m3/n v 200 - 500 v 50

Air flow control Hi io Lo -

Auxiliary equipment -

Capacity cc 370

Evaporator type Plate fin Corrugated fin

Type Sirocco fan

Power consumption of motor W 70 180W v 10%

Max. air flow m3/min 350 v 10% m3/n 460 v 10% 500 v 10%

Air flow control Hi io Med io Lo

Temperature control Thermistor type(ON io OFF) Reheat type


Name of refrigerant R134a

Amount kg 1.0

Name of refrigerator oil ND-Oil 8

Amount cc 180

Protective equipment Pressure relief valve (compressor)

Com

pre

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Cond

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DENSO

D575A-3 D275AX-5 D375A-5

DC, 24V

3,500 v 350 4,300 v 430

4,500 v 450 5,400 v 540

Swash plate type(10PA15C)

10 x 29.5 x 22.7

3,000

155


40

Corrugated fin Plate fin

Cooling by engine fan

Cool: 160 v 16Hot: 150 v 15 250 v 25

500 v 50

-

-

550 370

Corrugated fin

Sirocco fan

180W v 10%

500 v 10

Hi io Med io Lo

Reheat type


R134a

1.0

ND-Oil 8

180

Pressure relief valve Pressure relief valve (compressor)

4



Manufacturer DENSO

Applicable machine PC200-6PC210-6

PC220-6 PC650-5 PC1000-1


Cooling capacity kcal/h 3,300 3,200 2,800

Heating capacity kcal/h 3,700 3,500 3,100

Type Swash plate type(10PA15C)


Max. speed rpm 2,000 2,400 2,100

Delivery cc/rev 155.3



Condenser type Corrugated fin

Motor type Cooling by engine fan - Cooling by engine fan -

Power consumption W - 120 - 80

Max. air flow m3/min - 30 - 15

Air flow control - ON io OFF - ON io OFF

Auxiliary equipment Desiccant

Capacity cc 550


Type -


Max. air flow m3/min 420 360 330

Air flow control 3-stage selection

Temperature control Air mix type Thermostat type


Name of refrigerant R134

Amount kg 1.00-1.14 0.98-1.12

Name of refrigerator oil DENSO OIL 8

Amount cc 180 220

Protective equipment Receiver

Co

mp

ress

or

Con

den

ser

fan

Dry

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rece

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Blo

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Re

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DENSO

PC1600-1

DC, 24V

3,500

4,500

Swash plate type(10PA15C)

10 x 29.5 x 22.7

2,400

155.3


40

Corrugated fin

Cooling by engine fan

-

-

-

-

550

Corrugated fin

-

130

420

3-stage selection

Thermostat type

Vapour (gas) compres-sion refrigerating system

R134a

1.38-1.52

DENSO OIL 8

180

Receiver

4



Manufacturer DENSO

Applicable machine

WA120-3WA180-3WA250-3WA320-3WA380-3WA420-3WA470-3

WA500-1WA600-1WA700-1WA800-2




Type Swash plate type

No. of cylinders-bore x stroke mm 30 x 22


Delivery cc/rev 155

Magnet clutch type Rubber hub


Condenser type Serpentine type

Motor type Ferrite (o 70)

Power consumption W 110


Air flow control 2-stage (Hi/Lo)

Auxiliary equipment With sight glass

Capacity cc 370

Evaporator type Single tank Serpentine

Type Ferrite (o 86)

Power consumption of motor W (Cooler) 225,(Heater) 215 Max. 480

Max. air flow m3/min 9 7

Air flow control 4-stage selection (Hi/Mez//Mel/Lo)

3-stage selection (Hi/Me/Lo)


Refrigerating method Expansion


Amount kg 1.3-1.5

Name of refrigerator oil ND-OIL 8

Amount cc 180

Protective equipment Pressure switch relief valve

Co

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Ref

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DENSO

WA80-3

WA100-3WA150-3WA200-3WA250-3

WA300-3, WA380-3,WA420-3, WA470-3,WA500-3, WA600-3,WA700-3, WA800-3,WA900-3

WA1200-3

DC, 24V

3,000 4,000 4,300 4,600

5,000

Swash plate type (10P08E) Swash plate type (10PA15C)

10-25 x 16.9 10-29.5 x 22.7

6,000

82.9 155.3

Electromagnetic, dry disc (S25) Electromagnetic, dry disc (L50)

Max. 35 Max. 40

Corrugated fin

Ferrite motor

80 120 x 2 80 x 2

19 26.7 18 x 2 19 x 2

2-stage (Hi/Lo)

-

550

Aluminium tube, aluminium fin

Sirocco fan

225

9

4-stage selection (Hi/Mz//Ml/Lo)

Reheat type


R134a

1.05 1.25 1.40

DENSO OIL 8

120-135 220-235

Pressure switch (*1)



Manufacturer DENSO

Applicable machine GD825A-2 GD505A-3A

GD705A-4GD605A-5GD505A-3GD405A-2GD355A-1GD305A-1




Type Swash plate type (10PA15C)



Delivery cc/rev 126

Magnet clutch type Electromagnetic, dry disc (L50)


Condenser type Aluminium tube, aluminium fin

Motor type Cooling by engine fan -

Power consumption W - 132

Max. air flow m3/min - 18

Air flow control - ON io OFF

Auxiliary equipment -

Capacity cc 550

Evaporator type -

Type Sirocco fan



Air flow control 4-stage selection


Refrigerating method Gas compression refrigerating system


Amount kg 1.6 -

Name of refrigerator oil DENSO OIL 8

Amount cc 180

Protective equipment -

Com

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Co

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oil




DENSO

HD325-6 #5267-HD405-6 • - #1054HD465-5 #4192 -HD605-5 • - #1012 -HD785-3 #2269 -HD985-5 • - #1020HD1200-1 #1848 -

HD255-5 HM400-1

HD325-6 #5680 -HD405-6 #1055 -HD465-5 #4626 -HD605-5 #1013 -HD785-5 #4001 -HD985-5 #1021 -

DC, 24V

3,200 4,000

3,500 5,100

Swash plate type (10PA15C) Swash plate type (10S15C)

Swash plate type (10PA15C)

10-29.5 x 22.7 10-32 x 20.8 10-29.5 x 22.7

6,000

155.3 157.3 155.3

Electromagnetic, dry disc Electromagnetic, dry disc (L50T)

Electromagnetic, dry disc (L50)

Max. 40

Corrugated fin

Forced cooling by engine fan -

- -

- -

- -

Fusible plug (melting point : 105fC/30 kg/cm2) -

550

Aluminium tube, aluminium fin

Sirocco fan

150 225

360 550

3-stage selection(H, M, L) 4-stage selection (H, Mz, Ml, L)

Reheat type


R134a

1.1

DENSO OIL 8

180 220-235

Pressure switch (*1)



ZEXEL


Manufacturer ZEXEL

Applicable machine HD205-3 (#2085 -)





No. of cylinders-bore x stroke mm 6-37 x 25.8


Delivery cc/rev 167



Condenser Corrugated fin type

-

Motor type Forced cooling by engine fan



Air flow control -

Auxiliary equipment Fusible plug (melting point : 105fC/30 kg/cm2)

Capacity cc 500

Evaporator type Aluminium tube, aluminium fin

Type Sirocco fan




Temperature control Reheat air mix type



Amount kg 1.1

Name of refrigerator oil ZXL100PG

Amount cc 300

Protective equipment Fusible plug (receiver), pressure switch(*1)

Com

pres

sor

Con

dens

er fa

nD

ryer

,re

ceiv

erB

low

erR

efrig

-er

ant

Ref

rig-

erat

or o

il

01-44 (6)

Type

Heat dissipation kW



Manufacturer ZEXEL

Applicable machine PC78US-6PC78UU-6

PC128US-2PC138US-2


Cooling capacity kW 5 (Air flow: 450m3/h)

Heating capacity kW 4.65 (Air flow: 400m3/h)

Type Swash plate (DKS15CH), piston type



Delivery cc/rev 147



CondenserParallel flow type Sub cool type

8.13 (at 5 m/s) 7.93 (at 5 m/s)

Motor type Cooling by engine fan



Air flow control -

Auxiliary equipment Desiccant 150g Desiccant 100g

Capacity cc 400 190

Evaporator type Plate fin

Type Sirocco fan


Max. air flow m3/h 400

Air flow control 4-stage selection, automatic

Temperature control 8-stage selection, automatic



Amount kg 0.9 ± 0.05 0.7 ± 0.05

Name of refrigerator oil ZXL100PG

Amount cc Compressor: 210, Receiver dryer (tank): 50

Protective equipment Pressure switch

Com

pres

sor

Con

dens

er fa

nD

ryer

,re

ceiv

erB

low

erR

efrig

-er

ant

Ref

rig-

erat

or o

il

TypeHeat dissipation kW



TAKAHASHI WORKS

Manufacturer TAKAHASHI WORKS

Applicable machine PC100-6PC120-6

PC300-5PC400-5

A57GD305A-3GD355A-3GD405A-3




Type Vane rotary type Rotary type(SS-990)

Elliptical type,Vane rotary

No. of cylinders-bore x stroke mm - (No. of vanes : 5)

Max. speed rpm 6,500 2,000 6,500

Delivery cc/rev 99

Magnet clutch type Dry single plate type Electromagnetic Electromagnetic, dry disc

Power consumption of clutch W 42.3 40 40 (DC, 24V, 20fC)

Condenser type Aluminium tube,corrugated fin Corrugated fin Aluminium tube,

corrugated fin

Motor type Cooling by engine fan - Cooling by engine fan

Power consumption W - 160 -

Max. air flow m3/min - 24 -

Air flow control - ON io OFF -

Auxiliary equipment 100-105fC/30 kgm Desiccant Desiccant 300 g

Capacity cc 600 780 780

Evaporator type Serpentine Corrugated fin

Type Sirocco fan - Sirocco fan

Power consumption of motor W - 190 -


Air flow control 3-stage selection 3-stage selection 3-stage selection (H, M, L)

Temperature control Air mix type Electronic thermo Electronic thermo



Amount kg 0.8 0.95-1.09 (Estimated calcula-tion value : 1.1)

Name of refrigerator oil PAG SK20 SK08 Idemitsu [DH-PR] (compres-sor maker nominal SK20)

Amount cc 220

Protective equipment ReceiverPressure switch (air conditioner unit), thermal switch (compres-sor) relief valve (compressor)

01-50

Com

pre

ssor

Con

den

ser

fan

Dry

er,

rece

ive

rB

low

er

Re

frig

-e

ran

tR

efri

g-e

rato

r oi

l



SANDEN

Manufacturer SANDEN

Applicable machine

PC27MR-2PC30MR-2PC35MR-2PC40MR-2PC50MR-2







Delivery cc/rev 99.8



Condenser type Plate fin

Motor type Cooling by engine fan



Air flow control -

Auxiliary equipment Desiccant 100g

Capacity cc 240

Evaporator type Plate fin

Type Sirocco fan




Temperature control Electronic thermostat type



Amount kg 0.6-0.7

Name of refrigerator oil SP10A

Amount cc 100

Protective equipment Pressure switch

01-60

Co

mp

ress

or

Cond

ense

r fa

nD

ryer,

rece

ive

rB

low

er

Re

frig

-e

ran

tR

efr

ig-

era

tor

oil

STRUCTURE AND FUNCTION



DENSO (FREON GAS TYPE)

Piping diagram............................................................................................................................................11- 2

Electric wiring diagram ...............................................................................................................................11- 3

Compressor ................................................................................................................................................11- 4

Magnetic clutch...........................................................................................................................................11- 7

Condenser ..................................................................................................................................................11- 8

Receiver .....................................................................................................................................................11- 10

Air conditioner unit......................................................................................................................................11- 12

1. Expansion valve .....................................................................................................................................11- 13

2. Evaporator ..............................................................................................................................................11- 15

3. Thermostat .............................................................................................................................................11- 15

4. Pressure switch ......................................................................................................................................11- 16

5. Heater.....................................................................................................................................................11- 18

6. Blower unit..............................................................................................................................................11- 18

7. Piping......................................................................................................................................................11- 19

8. Air control system ...................................................................................................................................11- 20

Names and functions..................................................................................................................................11- 21

Operation....................................................................................................................................................11- 22

(5)

TROUBLESHOOTING


TESTING AND ADJUSTING


Service tool................................................................................................................................................ 12- 2

1. Gauge manifold ..................................................................................................................................... 12- 2

2. Gas leak detector .................................................................................................................................. 12- 5

3. Valve for service cans............................................................................................................................ 12- 8

Maintenance procedure............................................................................................................................. 12- 9

Troubleshooting ......................................................................................................................................... 12- 23

1. Defective heating .................................................................................................................................. 12- 24

2. Troubleshooting table ............................................................................................................................ 12- 25

3. Defective heating................................................................................................................................... 12- 27

4. Troubleshooting using gauge manifold.................................................................................................. 12- 28

DISASSEMBLY AND ASSEMBLY




Special tools .............................................................................................................................................. 13- 2

Disassembly of magnetic clutch ................................................................................................................ 13- 3

Assembly of magnetic clutch ..................................................................................................................... 13- 7

Disassembly of air conditioner unit............................................................................................................ 13- 9

Disassembly of blower unit........................................................................................................................ 13- 20

Disassembly of condenser ........................................................................................................................ 13- 22




ZEXEL (DIESEL KIKI)

Location of unit .......................................................................................................................................... 21- 2

Electrical circuit diagram............................................................................................................................ 21- 3

Piping diagram........................................................................................................................................... 21- 4

Compressor ............................................................................................................................................... 21- 5

Magnetic clutch.......................................................................................................................................... 21- 7

Condenser ................................................................................................................................................. 21- 8

Receiver (liquid tank)................................................................................................................................. 21- 9

Expansion valve ........................................................................................................................................ 21- 10

Evaporator ................................................................................................................................................. 21- 12

(5)

TROUBLESHOOTING



ZEXEL (DIESEL KIKI)

Tightening torque tables ............................................................................................................................ 22- 2

Special tools .............................................................................................................................................. 22- 4

Service procedure ..................................................................................................................................... 22- 12

Inspection and maintenance...................................................................................................................... 22- 23





ZEXEL (DIESEL KIKI)

Special tools .............................................................................................................................................. 23- 2

Disassembly of compressor assembly ...................................................................................................... 23- 3

Judging defective locations when disassembling ...................................................................................... 23- 6

Disassembly .............................................................................................................................................. 23- 8

Assembly ................................................................................................................................................... 23- 12




DAIKIN

Piping diagram........................................................................................................................................... 31- 2

Electrical circuit diagram............................................................................................................................ 31- 3

Compressor (Rotary type) ......................................................................................................................... 31- 4

Condenser ................................................................................................................................................. 31- 6

Receiver dryer ........................................................................................................................................... 31- 8

Air conditioner unit..................................................................................................................................... 31- 9

Operating procedure.................................................................................................................................. 31- 13

(5)

TROUBLESHOOTING



DAIKIN

Service tools .............................................................................................................................................. 32- 2

Service procedure ..................................................................................................................................... 32- 6

In-season checks....................................................................................................................................... 32- 13

Off-season checks..................................................................................................................................... 32- 13

Using air compressor dipstick.................................................................................................................... 32- 15


Electric system functional sequence..................................................................................................... 32- 16

Defective cooling................................................................................................................................... 32- 17




DAIKIN

Tools .......................................................................................................................................................... 33- 2

Disassembly of compressor ...................................................................................................................... 33- 5

Assembly of compressor ........................................................................................................................... 33- 8

Disassembly and testing of air conditioner unit ..........................................................................................33- 11

Condenser unit .......................................................................................................................................... 33- 20

Receiver dryer ........................................................................................................................................... 33- 20




DENSO (NEW REFRIGERANT TYPE)

Fundamentals of air conditioning

1. Principle of air conditioning.................................................................................................................... 41- 2

2. Basic refrigerating cycle ........................................................................................................................ 41- 3

3. Refrigerant............................................................................................................................................. 41- 6

4. Refrigerating cycle of air conditioner ..................................................................................................... 41- 8

Configuration of refrigerating cycle

1. Structure of each refrigerating cycle part............................................................................................... 41- 10

2. Compressor ........................................................................................................................................... 41- 12

3. Magnetic clutch...................................................................................................................................... 41- 16

4. Condenser ............................................................................................................................................. 41- 17

5. Receiver tank......................................................................................................................................... 41- 17

6. Expansion valve .................................................................................................................................... 41- 18

7. Evaporator ............................................................................................................................................. 41- 21

8. Sight glass ............................................................................................................................................. 41- 22

Control system

1. Outline of control ................................................................................................................................... 41- 23

2. Temperature control............................................................................................................................... 41- 24

3. Air flow control ....................................................................................................................................... 41- 25

4. Circulated air and fresh air selection ..................................................................................................... 41- 26

5. Defrosting control .................................................................................................................................. 41- 26

6. Compressor control ............................................................................................................................... 41- 27

(5)

41-24

Air conditioner

STRUCTURE AND FUNCTION FUNDAMENTALS OF AIR CONDITIONING

FUNDAMENTALS OF AIRCONDITIONING

1. Principle of air conditioning

If alcohol is applied to your skin, you feel cold. Ifyou sprinkle water over your garden in summer,you feel cool. The cause of these phenomena is thatalcohol and water absorb heat (which is called la-tent heat) from material around them when theyevaporate. That is, a liquid (such as alcohol, water,etc.) needs heat (heat of vaporization) to change toa gas (alcohol vapor, steam, etc.) and the materialfrom which heat is absorbed (the material in con-tact with the liquid) is cooled.These natural phenomena directly show the prin-ciple of air conditioning. Coolness and coldness areobtained by utilizing these phenomena. If the vaporof the liquid used for air conditioning is dischargedinto the atmosphere, however, the liquid must besupplied constantly, and that is not practical. Ac-cordingly, the vapor is cooled to be liquefied againand circulated.To liquefy a gas, it must be cooled first. If it iscompressed at this time, it is liquefied more easily.Then, a compressor and a condenser are used tocompress and cool the gas.

Alcoholevaporates.

Heat

Sanitary cottonsoaked in alcohol

(Liquid absorbs heat from material around it)Evaporation

Gas

Condensation(Heat of gas is radiated)

Liquid

41-34

Air conditioner


2. Basic refrigerating cycle

2.1 Configuration

Generally, an air conditioner means equipment which circulates a volatile liquid (called a refrigerant)in a sealed pipe circuit and evaporates and liquefies it repeatedly during circulation.The basic components of this equipment are as follows.

• EvaporatorThe refrigerant evaporates in the evaporator to absorb heats from around the pipe and cool the room.• CompressorThe compressor compresses the refrigerant gas evaporated in the evaporator so that the gas will beliquefied easily in the condenser.• CondenserThe condenser cools and liquefies the high-temperature and high-pressure refrigerant gas compressedwith the compressor.• Expansion valveThe expansion valve is a kind of a choke valve, which keeps the pressure in the evaporator low. Thatis, the high-pressure refrigerant liquid is spouted through a narrow gap into the evaporator, where itbecomes low-pressure and low-temperature mist and evaporates rapidly.

Heat is absorbed frommaterial around evaporator.

Expansion valve

Evaporator

Compressor

Condenser

Heat is radiated.

41-44

Air conditioner


2.2 Good condition for air conditioner

The first good condition for an air conditioner is that the refrigerant evaporates at low temperatureand liquefies easily and it evaporates much in the evaporator.

The condition of the refrigerant in the refrigerating cycle is as follows.1 The refrigerant compressed in the compressor is high-temperature and high-pressure gas.2 As the refrigerant passes through the condenser, it is cooled and liquefied. It must be liquefied

completely at the outlet of the condenser. If the refrigerant is not cooled sufficiently in thecondenser, some of it is still gas at the outlet of the condenser and the refrigerating capacity islowered.

3 After the liquefied refrigerant passes the expansion valve, it becomes mist. The expansion valve iscalled the choke valve, too. The high-pressure refrigerant liquid is spouted through a small hole sothat it will evaporate easily.

4 In the evaporator, the refrigerant mist evaporates rapidly and absorbs the heat inside the cab. Therefrigerant gasifies completely near the outlet of the evaporator.

Liquid

Mist

Gas

Heat is absorbed. Expansion valve

Lowpressure High

pressure

Evaporator

Compressor

Condenser

Heat is radiated.

41-54

Air conditioner


If the refrigerant is insufficient, all of it vaporizes before it reaches the evaporator outlet and theevaporator capacity lowers. If the refrigerant is too much, on the other hand, all of it does not vaporizein the evaporator and flows in the compressor in the form of liquid and the compressor may be brokensince it compresses the liquid. Accordingly, the quantity of the refrigerant must be controlled accord-ing to various conditions.The air conditioner does not only lower the indoor temperature but lowers the indoor humidity to keepthe environment fresh. That is, if the warm indoor air passes through the evaporator, it is cooled andits moisture is condensed into water drops on the evaporator fins. As a result, the moisture in the airis removed and the humidity is lowered. The water drops on the fins are discharged out of themachine through a hose.

[Reference]• CondensationIf a glass containing iced water is left in the atmo-sphere, water drops are formed on the glass sur-face. This phenomenon shows that the steam in theair (the vaporized water which the air always con-tains) is cooled and condensed by the iced water inthe glass. (The iced water is warmed by the heat ofcondensation.)

41-64

Air conditioner


3. Refrigerant

A material which circulates in a refrigerating cycle to transfer heat is called the refrigerant.In air conditioners, HFC134a (R134a) which is a kind of Freon and which contains no chlorine is used.

3.1 Characteristics of refrigerant

The characteristics of HFC134a (R134a) are shown in the following figure.

As indicated by the above curve, the refrigerant under high pressure is liquid up to a relatively hightemperature. Under low pressure, however, the refrigerant vaporizes at 0°C or even at –10°C.If the refrigerant vaporizes at 0°C, the evaporator is also at 0°C. The air passes through the evaporatoris cooled consequently. If the pressure is lowered to a state where the refrigerant vaporizes at –5°C,the evaporator is kept at –5°C. As a result, the surface of the evaporator is frosted and air does not flowwell and the refrigerating performance is lowered.

The gasified refrigerant must be liquefied. Considering the environment of the condenser on a con-struction machinery in summer, it is impossible to keep the condenser temperature as low as 40°C. Ifthe condenser temperature can be kept as low as about 60°C, HFC134a is liquefied under pressure ofabout 1.7 MPa about 17 kg/cm2. In addition, if the refrigerant gas is compressed to 1.7 MPa (with thecompressor), its temperature rises to about 80°C. That is, the above curve shows the following; Therefrigerant gas is heated to about 80°C at the condenser inlet. If it is cooled by about 20°C at thecondenser outlet, however, it becomes liquid of about 60°C.

Refri

gera

nt te

mpe

ratu

re (°

C)

GasLiquefied ifcooled bythistempera-ture

Liquid

Gauge pressure

41-74

Air conditioner


[Reference]• Refrigerant HFC134a (R134a)HFC134a is used as the refrigerant of air conditioners for the following reasons.1. HFC134a does not break the ozone layer which preserves the global environment.2. HFC134a has much heat of vaporization and liquefies easily.3. HFC134a does not burn or explode.4. HFC134a is not toxic or corrosive and does not injure foods and clothes.5. It is easy to obtain HFC134a.

• Substitutive FreonCFC12 (R12) which was a conventional Freon (halogenated carbide containing fluorine) had been usedfor air conditioners of construction machines. In 1996, however, it was resolved in Montreal WorldConference that CFC12 should not be used any more to preserve the global environment.As a result, HFC134a (R134a) which does not break the ozone layer is used as a substitute for theconventional Freon.

41-84

Air conditioner


4. Refrigerating cycle of air conditioner

The refrigerating cycle of an air conditioner consists of a compressor, condenser, receiver tank,expansion valve, evaporator, etc. The refrigerant is circulated in this cycle to absorb the indoor heatwith the evaporator and radiate it outside through the condenser.

The structure of the expansion valve is different and the receiver tank is added in the above cyclecompared to the basic refrigerating cycle described before.To cool the air efficiently, much refrigerant must vaporize in the evaporator. In addition, all therefrigerant must vaporize at the evaporator outlet.

Evaporator Cool airExpansion valve

Heat sensor tube Low-pressure andlow-temperaturerefrigerant mist

Servicevalve onlow-pressureside

Indoor air Indoor air

Refri

gera

ntliq

uid

Sight glass

Service valveon high-pressure side

Hot air

High

-pre

ssur

e an

d hi

gh-

tem

pera

ture

gas

Desiccant

Compressor

Cooling air from front sideCondenser

Receiver tank

41-94

Air conditioner


The environment and structure of a constructionmachine air conditioner are different from a homeair conditioner in the following points.1 Indoor temperature varies largely.The temperature in the operator’s cab is affected bythe outside temperature largely. It becomes veryhigh particularly when the machine is parked undera burning sun in summer.That is, The necessary quantity of the refrigerant inthe refrigerating cycle varies largely.

2 Compressor speed varies largely.The compressor speed of the home air conditioneris kept constant by the motor.On the other hand, the compressor of the construc-tion machine air conditioner is driven with the en-gine and its speed varies largely.That is, The circulation rate of the refrigerant in therefrigerating cycle varies largely.

To solve these problems, the expansion valve doesnot only work as a simple choke valve but regulatesthe circulation rate of the refrigerant automaticallyaccording to the compressor speed and air condi-tioning load. For this purpose, the receiver is in-stalled to store excessive refrigerant temporarily.An actual construction machine air conditioner hasvarious devices to control temperature, air flow, etc.and keep the operator’s cab comfortable.

41-104

Air conditioner

STRUCTURE AND FUNCTION CONFIGURATION OF REFRIGERATING CYCLE

CONFIGURATION OF REFRIGERATING CYCLE

1. Structure of each refrigerating cycle part

An air conditioner consists of many functional parts. The refrigerating cycle parts among them aremainly explained below.

fl The diagram shows a general example of system. The shape of each unit may differ according tothe machine model.

Evaporator

Expansion valve

Pressure switch

Compressor

Condenser

Receiver tank

41-114

Air conditioner


1. Air conditioner compressor2. Condenser3. Refrigerant piping4. Window defroster5. Side defroster6. Air conditioner unit7. Air outlet8. Blower motor

• Layout of refrigerating cyclefl The diagram shows the equipment for the D475A-3.

9. Valve (Hot water outlet)10. Hot water output piping11. Receiver tank12. Hot water return piping13. Valve (Hot water inlet)

A. Outside airB. Inside airC. Hot air/Cool air

41-124

Air conditioner


2. Compressor

The compressor compresses the refrigerant gas which absorbed the indoor heat through the evapora-tor so that it will be liquefied easily and sends it to the high-pressure side again.The types of the compressor are classified by the structure as shown below.1 Swash plate type2 Through vane type3 Sliding vane type4 Scroll typeIn addition to the above, the variable-capacity compressor is also used. Its capacity changes accordingto the necessary air conditioning capacity. The swash plate-type compressor is explained below.

2.1 Swash plate-type compressor

Pressure relief valve

Shaft seal

Magnetic clutchRear housing

Front housing

Swash plate

Cylinder

Piston

41-134

Air conditioner


(1) StructureIn the swash plate-type compressor, 3 pairs (6 cylinders) or 5 pairs (10 cylinders) of pistons are set tothe swash plate fixed to the shaft diagonally. If the shaft rotates, the swash plate reciprocates thepistons in the axial direction of the shaft.Both ends of each pair of the pistons are in cylinders. When the cylinder of one end of the pistons isin the compression process, the cylinder of the other end is in the suction process.

On the valve plate at the cylinder end, there are asuction hole and a discharge hole to which a suc-tion valve and a discharge valve are installed re-spectively.

The inside of the compressor is lubricated with thecompressor oil containing in the refrigerant gas andthe oil splashed by the centrifugal force of the swashplate. Some models are lubricated forcibly with com-pressor oil by an oil pump.

Piston

Arrangement of pistons (10 cylinders)

Swash plateCylinder

Shaft

Principle of swash plate type compressor

Piston

Discharge valve

Discharge

Suction

Valve plate Suction valve

Note: Both valves are keptclosed in stationarystate.

Cylinder

Piston

Piston

41-144

Air conditioner


(2) Operation

1 SuctionAs the swash plate rotates, the pistons move. If a piston moves and the cylinder capacity is increasedand the pressure in the cylinder lowers below the pressure on the low-pressure side of the refrigerat-ing cycle, the suction valve is pushed open and the refrigerant gas flows in the cylinder. At this time,the discharge valve is fitted to the valve plate by the pressure on the high-pressure side to block thedischarge hole of the valve plate. Accordingly, the refrigerant gas does not flow back from the high-pressure side into the cylinder.

2 CompressionIf the cylinder capacity is reduced and the pressure in the cylinder rises above the pressure on thedischarge side (high-pressure side), the discharge valve opens and the high-temperature and high-pressure refrigerant gas is sent to the condenser. At this time, the suction valve is fitted to the valveplate by the pressure in the cylinder to block the suction hole of the valve plate. Accordingly, therefrigerant gas does not flow back into the suction side (low-pressure side).

Suction valve

Discharge valve

Suction valve

Discharge valve

41-154

Air conditioner


[Reference]• Pressure relief valveIf the pressure on the high pressure side of therefrigerating cycle rises abnormally for some rea-son, the pressure relief valve of the compressordischarges a part of the refrigerant.Usually, however, the high-pressure pressure switchinstalled to the control system operates first to stopthe compressor. Accordingly, the pressure reliefvalve does not operate immediately.

fl Once the pressure relief valve operates, removethe cause. If the cause is not removed, the pres-sure relief valve will operate again.

Gas discharge path whenrelief valve operates

Pressure relief valve

41-164

Air conditioner


3. Magnetic clutch

The air conditioner compressor is driven with theengine. Accordingly, it must be stopped or startedagain when the temperature reaches the set tem-perature or rises high. The magnetic clutch installedto the compressor is used for this purpose.

The clutch hub of the magnetic clutch is fitted to thecrankshaft of the compressor. While the compres-sor is turned off, only the pulley rotates. If the airconditioner switch is turned on, a current flows inthe coil embedded in the stator. As a result, thestator becomes a strong electromagnet and attractsthe clutch hub and the compressor rotates togetherwith the pulley.

Magnetic clutch

Damper

Center piece Pulley

Compressorshaft

Stator coil

Principle

Rotor

Stator coil

Snap ring

Bearing

Stator

Center piece

Structure



4. Condenser

The condenser cools the high-temperature and high-pressure refrigerant gas sent from the compressor to liq-uefied it.The condenser consists of tubes, fins, and a fan motor and is installed to the machine body.The refrigerant gas discharged from the compressor is about 1.7 MPa about 17 kg/cm2 in pressure andabout 80°C in temperature, for example. When this refrigerant passes through the tubes, it is cooled and liq-uefied.Note: The pressure and temperature of the refrigerant vary with the atmospheric temperature, operating con-

dition, etc.

5. Receiver tank

The refrigerant liquefied in the condenser is stored inthe receiver temporarily so that it can be supplied tothe evaporator according to the air conditioning load.The receiver tank has strainers and desiccant in it toremove "dirt" and "moisture" contained in the refriger-ating cycle.If there is moisture in the refrigerating cycle, it can cor-rode the functional parts and can be frozen in thesmall hole of the expansion valve to block the refriger-ant flow.

a In this case, replace the receiver tank since the absorbing performance of the desiccant is lost.If the strainer is clogged badly (If the high pres-sure rises and the low pressure lowers), replace the receiver tank since the strainer cannot be cleaned.

[Reference]• Separation of refrigerant gas and liquidThe receiver tank does not only store the refrieger-ant temporarily but separates the refrigerant gas andliquid.All the refrigerant cooled in the condenser may not beliquefied, depending on the atmosphere condition. Ifthe refrigerant gas is sent to the expansion valve, theair conditioning capacity is lowered. The refrigerantliquid is accumulated on the lower side of the receivertank and the refrigerant gas is accumulated on theupper side. Since the refrigerant is taken out throughthe outlet pipe installed to the bottom of the receivertank, the gas is separated from the liquid.

Strainer

Desiccant

Refrigerant gas

Refrigerant liquid



6. Expansion valve

The expansion valve has the following 2 functions.(1) Expand the high-temperature and high-pressure

refrigerant liquid sent from the receiver rapidlyand change it to low-temperature and low-pres-sure mist by spouting it through a small hole.

(2) Regulate the refrigerant flow rate according tothe vaporizing condition of the refrigerant in theevaporator.

To utilize the evaporator capacity fully, the refrigerant liquid must so absorb the heat from the air around theevaporator that it will vaporize completely at the evaporator outlet.For this porpose, the refrigerant flow rate is regulated automatically according to the fluctuation of the indoortemperature (air conditioning load) and the fluctuation of the compressor speed.a If the refrigerant flow rate is insufficient, the refrigerant in the evaporator vaporizes early and the cooling effect

lowers. If the former is too high, on the other hand, the excessive refrigerant liquid does not vaporize but re-turns to the compressor, and the cooling effect lowers and the compressor valve is damaged.

6.1 Regulation of refrigerant flow rate

The refrigerant flow rate is regulated basically with the diaphragm chamber and the needle valve coupled with it.In the following figure, chamber A of the diaphragm chamber is filled with the refrigerant gas and sealed. Thepressure in chamber A is high (low) when the refrigerant temperature near the evaporator outlet is high (low).(Since how the pressure in chamber A changes depends on the structure of the expansion valve, the con-crete operation is explained later.)On the other hand, the evaporation pressure in the evaporator is applied from near the evaporator outlet tochamber B. While the refrigerant flow rate is constant, the diaphragm keeps the opening rate of the needlevalve constant with the pressure in chambers A and B and the force of the spring. If the air conditioning load(indoor temperature, etc.) changes, the pressure in chamber A changes and moves the needle valve to theright or left to regulate the refrigerant flow rate.

Expansion valve Evaporator

Diaphragm

Filled with refrigerant gasand sealed

Refrigerant temperature nearevaporator outlet is transmitted.

To compressor(Low pressure)

Evaporator

Spring

(High pressure)

From receiver tankNeedle valve

41-194

Air conditioner


6.2 Expansion valve (Box type)

(1) StructureThe box-type expansion valve consists a diaphragm,heat sensor rod, needle valve (ball), etc. The upperpart of the diaphragm is filled with the refrigerantand sealed.The pressure at the evaporator outlet is applied tothe lower part of the diaphragm.

(2) OperationThe heat sensor rod senses the refrigerant temperature after it passes through the evaporator. Thetemperature at this time is transmitted through the heat sensor rod to the refrigerant gas in the upperpart of the diaphragm chamber. As a result, the gas pressure changes according to the temperatureand moves the heat sensor rod coupled with the diaphragm to regulate the opening rate of the needlevalve.• When evaporator outlet temperature is low (When air conditioning load is low)

The gas pressure in the diaphragm chamber lowers and the gas volume decreases. As a result, theheat sensor rod moves to the right to close the needle valve.

• When evaporator outlet temperature is high (When air conditioning load is high)The gas pressure in the diaphragm chamber rises and the gas volume increases. As a result, theheat sensor rod moves to the left to open the needle valve, and more refrigerant is supplied to theevaporator.

To compressor(Low pressure)

Spring

(Evaporator) Diaphragm

(From receivertank)

Needlevalve

(To compressor)

Heat sensorrod

From receiver tank(High pressure)

(Evaporator)

Diaphragm

Needlevalve

Heat sensor rod

41-204

Air conditioner


[Reference]• Expansion valve of even internal pressure typeIf the evaporator capacity is relatively little, this ex-pansion valve of even internal pressure type is used.In this type, the evaporation pressure of the evapo-rator under the diaphragm is applied through thesmall hole (inlet of the evaporator) in the expansionvalve. The other structure and operation are thesame with the conventional type described above.

• Expansion valve of even external pressure typeIf the evaporation pressure is sensed at the inlet ofa large-sized evaporator, it is affected by the inter-nal path resistance. To avoid this, an even-pressuretube is passed from near the evaporator outlet tosense the pressure. The above described conven-tional valve is this type.

• Flow regulation standard of expansion valveTo efficiently cool the indoor air which passesthrough the evaporator, the refrigerant in the evapo-rator must vaporize well to cool the air and mustvaporize completely near the evaporator outlet.The figure at right shows this state of the refriger-ant. The refrigerant liquid and gas are mixed to-gether, that is, the refrigerant vapor is saturated inthe part from the evaporator inlet to point A. Ac-cordingly, the temperature is kept constant in thispart. All the refrigerant is evaporated completely inthe part from point A to point B, however, and itstemperature rises (Superheated vapor).The flow regulation standard of the expansion valveis so set that the superheating temperature of therefrigerant vapor will be constant (e.g. 10°C).

Pe: Evaporator inlet pressurePs: Spring forcePf: Pressure in heat sensor tube

Refrigerant inlet

Pressure spring

Capillary tubeDiaphragm

Needle valve

Adjusting screw

Heatsensortube

[Evaporator inlet] [Evaporator outlet]

Liquid100%

Stat

e of

refri

gera

nt

Liquid

Gas

Gas100%

Superheated vapor(Gas 100%)

Superheat-ingtemperature(10°C)Saturated vapor

(Mixture of liquidand gas)

Temperatureis constant.

Refrigerantinlet

Pressurespring

Capillary tubeDiaphragm

Needle valveExternal even-pressure tube

Part ofsaturated

vapor

Part ofsuperheated

vapor L

41-214

Air conditioner


7. Evaporator

The refrigerant mist cooled and decompressedthrough the expansion valve vaporizes in large quan-tities. As a result, the evaporator is cooled.The warm air in the cab is moved and cooledthrough the evaporator by the fan. If the warm air iscooled below the dew point by the evaporator fins,the moisture in it condenses into water drops onthe evaporator fins. These water drops are dis-charged through the drain hose out of the cab.

Serpentine type

(1) Cooler unitAn actual evaporator has an expansion valve, thermistor, etc., and they are handled as a unit. It isequipped with a blower motor and even a heater core on some models.

(2) ThermistorThe thermistor is installed to the rear of the evapo-rator to sense the temperature of the air just aftercooled by the evaporator.

Evaporator

Expansion valve

Thermistor

Outside view Inside of unit



8. Sight glass

The sight glass is "an window" to observe the condi-tion of the refrigerant flowing through the refriger-anting cycle. Generally, if bubbles are seen in thiswindow, the refrigerant is insufficient. If the quantityof the refrigerant is proper, no bubbles are seen.The sight glass is usually installed to the top of thereceiver. If it cannot be used at that position, it maybe installed to the piping.

a No bubbles are seen, too, when there is not re-frigerant (or there is too much refrigerant).

a When HFC134a is used, if the testing conditionssuch as the compressor speed, pressure, etc.are wrong, bubbles are seen.

a If the operation of the air conditioner is continuedwhile the refrigerant is insufficient, the compres-sor may be broken.

Sight glass

41-234

Air conditioner

STRUCTURE AND FUNCTION CONTROL SYSTEM

CONTROL SYSTEMTo use the functions of the air conditioner fully and keep the inside of the cab comfortable, the airoutlet mode and various items, as well as the temperature and air flow, must be controlled.

1. Outline of control

1.1 Control panel

fl The figure below shows the control panel of D375A.

1 Temperature control switchUsed to control the temperature steplessly from low level to high level.

2 Circulated air and fresh air selector switchUsed to select “Fresh air” or “Circulated air”.

3 Blower switchUsed to set the air flow to 3 levels.

4 Air conditioner switchUsed to turn on and off the air conditioner.

Temperature control switch

Circulated air and fresh air selector switch

Blower switch

Air conditioner switch

41-244

Air conditioner


1.2 Contents of control

The main controls of the air conditioner are as follows.

1. Temperature control

2. Air flow control

3. Circulated air and freshair selection

4. Defrosting control

5. Compressor control

Item

• The temperature of the air cooled by the evaporator is mea-sured with a thermistor and the compressor is turned on andoff automatically at the set temperatures.

• The blower motor speed is set to 3 levels.

• The damper to select fresh air or circulated air is controlled.• The damper to select air outlet in the cooling mode and

heating mode is controlled.

• Frosting of the evaporator is prevented.• Thermistor is used for this control.

• Abnormal refrigerant pressure is detected.

Outline of control

2. Temperature control

2.1 Thermistor method

When the cooler unit and heater unit are indepen-dent from each other and the airs from them cannotbe mixed, the thermistor method is applied. Thethermistor is a semiconductor, the resistance ofwhich varies remarkably with the temperature. Asshown in the figure, the resistance of the thermistordecreases as the temperature rises, and increasesas the temperature lowers.The thermistor is installed to the rear of the evapo-rator to sense the temperature of the air flowingthrough the evaporator.

The temperature control switch is on the controlpanel. The temperature is controlled by comparingthe signal of the temperature control switch (de-sired temperature) with the signal of the thermistorin the air conditioner amplifier and turning on andoff the compressor through the magnetic clutch.The signal of the thermistor is used to prevent frost-ing of the evaporator, too (This is described later).

Thermistor

Structure

Resistance

Temperature (°C)

Characteristics of thermistor



3. Air flow control

The quantity of the air blown into the cab is con-trolled by adjusting the blower motor speed.The blower motor is a ferrite motor. Its speed (air flow)is controlled to 3 levels by changing the resistorconected to the motor in series with the blower switchas shown in the circuit diagram.

[Reference]• Motor speedThe speed (N) of a DC motor is in proportion to themotor terminal voltage (V) and in inverse proportionto the magnetic flux (ø).

Speed N = KqV/ø

If ferrite magnets are used, the magnetic flux (ø) isconstant. Accordingly, the speed is controlled bychanging the voltage applied to the motor with theresistor connected to the motor in series.

4. Circulated air and fresh air selection

If the circulated air and fresh air selector switch on the control panel is operated, the damper moves to selectthe fresh air or the circulated air. Fresh air: The outside air is taken into the cab. This mode is selected normally. Circulated air: This mode is used when the outside air is dirty or you need to cool or heat the cab quickly.

Circulated air

Fresh air

Ferrite magnet



5. Defrosting control

If warm air blows against the evaporator fins and cooled there, the moisture in the air condenses into waterdrops on the evaporator fins. If the fin temperature is below 0°C at this time, the water drops are frozen orfrosted. This phenomenon is called frosting. If frosting occurs, the heat exchange efficiency of the evaporatorlowers and the full cooling capacity is not obtained.Frosting can be prevented by the following method.

Thermostat method (ON/OFF switch)The evaporator temperature is sensed from the sig-nal of the evaporator sensor installed to the rear ofthe evaporator. The compressor is turned OFF be-fore the evaporator is frosted.

Evaporatorsensor

41-274

Air conditioner


6. Compressor control

Judgment of abnormal refrigerant pressureThe pressure on the high-pressure side of the re-frigerating cycle is sensed with a pressure switch. Ifit rises high abnormally, the compressor is stoppedto prevent a trouble in the refrigerating cycle de-vices.Generally, the refrigerant pressure is sensed with apressure switch installed between the receiver tankon the high-pressure side and expansion valve.

(1) Pressure switchThe pressure switch is a dual type, that is, it candetects both abnormally high pressure and abnor-mally low pressure.

1 Detection of abnormally high pressureIf the high pressure in the refrigerating cycle risesabnormally, it can cause a trouble or breakage ofthe devices.Generally, the pressure switch to detect high pres-sure is turned off when the pressure rises aboveabout 3.1 MPa 32 kg/cm2.

2 Detection of abnormally low pressureWhen the refrigerant in the refrigerating cycle isextremely insufficient or lost completely because ofleakage, etc., if the compressor is started, it is notlubricated well and may be seized. To prevent this,the pressure switch turns off the compressor whenthe pressure on the high-pressure side lowers be-low about 0.2 MPa 2.0 kg/cm2 because of insuffi-ciency of the refrigerant.

Location of pressure switch

Expansion valve

Evap

orat

or

Receivertank

Cond

ense

r

Compressor

Contactmechanism

Structure

Characteristics

TROUBLESHOOTING



DENSO (NEW REFRIGERANT TYPE)

Service tools

1. Service tool kit ....................................................................................................................................... 42- 2

2. Gauge manifold ..................................................................................................................................... 42- 3

3. Gas leak detector .................................................................................................................................. 42- 7

4. Vacuum pump........................................................................................................................................ 42- 8

5. Service can valve .................................................................................................................................. 42- 9

6. Belt tension gauge................................................................................................................................. 42- 10

7. Connection of service tools ....................................................................................................................42- 11

Troubleshooting

1. Troubleshooting procedure.................................................................................................................... 42- 12

2. Inspection of refrigerating cycle............................................................................................................. 42- 19

3. Check for abnormal noise...................................................................................................................... 42- 27

4. Electric system ...................................................................................................................................... 42- 29

5. Replacement of parts ............................................................................................................................ 42- 30

Charging with refrigerant

1. Precautions for charging with refrigerant............................................................................................... 42- 32

2. Evacuation............................................................................................................................................. 42- 34

3. Charging with refrigerant ....................................................................................................................... 42- 37

4. Check of quantity of refrigerant ............................................................................................................. 42- 41

Periodic inspection and maintenance

1. Inspection and maintenance items ........................................................................................................ 42- 44

2. Check of quantity of refrigerant ............................................................................................................. 42- 45

3. Inspection of functional parts................................................................................................................. 42- 46

42-24

Air conditioner

TESTING AND ADJUSTING SERVICE TOOLS

SERVICE TOOLS

The following tools and devices are necessary for servicing the air conditioners.(1) Service tool kit (2) Vacuum pump(3) Torque wrench (4) Belt tension gauge(5) Gas leak detector (6) General tools

1. Service tool kit

The service tool kit is a kit of the gauge manifold and the small tools shown below.

fl For air conditioners which use HFC134a (R134a), use the service tool kit for HFC134a, the joints ofwhich are so changed that the air conditioners will not be charged with wrong refrigerant.

Gauge manifold

Low-pressure charginghose (Blue) High-pressure charging

hose (Red)

Quick joint(LO)

Center charging hose(Green)

Service can T-jointQuick joint

(HI)

Service can valve

Service tools for HFC134a

42-34

Air conditioner


2. Gauge manifold

The gauge manifold is used to check the operating pressure of the refrigerating cycle, evacuate therefrigerating cycle, and charge the refrigerating cycle with refrigerant.

2.1 Structure of gauge manifold

The knobs on the front side of the gauge manifold are used to open and close the valves securely. Themarks of “LO” and “HI” on those knobs denote the “low-pressure valve” and “high-pressure valve”respectively.

Low-pressure gauge High-pressure gauge

Air purgevalve is built in.

Low-pressure valve(LO)

High-pressure valve(HI)

Outside view

Low-pressure gauge High-pressure gauge

Low-pressure valve(LO)

High-pressure valve(HI)

Internal circuit

Air purge valveis built in.

42-44

Air conditioner


2.2 Handling of gauge manifold

You can form the following 4 circuits by opening orclosing the high-pressure and low-pressure valves.

(1) When both low-pressure valve (LO) and high-pressure valve (HI) are closed

(2) When low-pressure valve (LO) is opened andhigh-pressure valve (HI) is closed

(3) When low-pressure valve (LO) is closed andhigh-pressure valve (HI) is opened

(4) When both low-pressure valve (LO) and high-pressure valve (HI) are opened

Closed Closed

Open Closed

Closed Open

Open Open

42-54

Air conditioner


2.3 Charging hoses

The 3 charging hoses are colored in blue, green,and red. Connect the blue hose to the low-pressureside, the green one to the central adapter, and thered one to the high-pressure side.When storing the gauge manifold, be sure to con-nect each charging hose to an adapter to prevent“dirt” and “water” from entering the gauge mani-fold.

The nut at the end of each hose has packing in it. Ifyou screw it lightly over the mating adapter, it isconnected securely. You do not need to tighten itwith priers, etc.

Blue

Green

Red

42-64

Air conditioner


2.4 Quick joint

With the quick joint (having a check valve), you canconnect each hose of the gauge manifold to thecharging valve in an instant.

(1) Connection of quick jointPress the quick joint against the charging valve andpush part A until a click is heard.

fl When pressing the quick joint to connect it, takecare not to bend the pipe.

fl If the sleeve has moved without connecting thejoint to the charging valve, set it to the originalposition again, then try again.

fl If any refrigerant is left in the charging hose, thequick joint may not be connected easily. In thiscase, release the residual pressure from the hose.

(2) Disconnection of quick jointSecuring part A of the quick joint, slide up part B(sleeve).

fl After disconnecting the quick joint, cap the charg-ing valve.

Charging valve

Press the pusher to releasethe residual pressure.

Quick joint Charging hose

Sleeve “Click”

Sleeve“Click”

42-74

Air conditioner


3. Gas leak detector

The gas leak detector is an electric tester used to check each joint of the refrigerating cycle forrefrigerant leakage.Apply the probe to a part to be checked and move it slowly to check for leakage. If any refrigerantleaks from that part, the sounding intervals and flashing intervals become short.This leak detector can be used for both HFC134a (R134a) and R12 which is used for the conventionalair conditioners.

Gas leak detector

fl The conventional leak tester of halide torch type cannot detect HFC134a (R134a) which does notcontain chlorine.

Battery charger

Internal battery

Sensor (Under cover)

Speaker

Sensitivity selector switch

Suction probe

Power switchCheck leak bottle

42-84

Air conditioner


4. Vacuum pump

When charging a refrigerating cycle with refriger-ant, you must remove the all water from it. For thispurpose, the refrigerating cycle is evacuated with avacuum pump (Evacuation will be described later).

fl When a vacuum pump for conventional refrig-erant R12 is used for HFC134a (R134a), a vacuumpump adapter is necessary. With this adapter,the above vacuum pump can be used for bothHFC134a (R134a) and R12.[The current vacuum pump (manufactured byour company) can be used for both new andconventional refrigerants.]

[Reference]• Vacuum pump adapterAfter the refrigerating cycle of an air conditioner isevacuated, if the vacuum pump is stopped, the oilin the vacuum pump flows back into the charginghose since the inside of the gauge manifold hose isa vacuum. If the refrigerating cycle is charged withthe refrigerant under this condition, the vacuumpump oil left in the charging hose flows togetherwith the refrigerant into the refrigerating cycle.The adapter equipped with a solenoid valve is usedto prevent the backflow of the oil from the vacuumpump.If the solenoid valve is turned on, it closes to stopthe inflow of the atmosphere and the refrigeratingcycle can be evacuated. If it is turned off, it allowsinflow of the atmosphere and the refrigerating cyclecannot be evacuated.

Vacuumpump

Vacuum pump adapter

Solenoid valve

Atmosphere

Blind cap

Atmosphere

42-94

Air conditioner


5. Service can valve

The service can valve is used to supply the refriger-ant from a service can to the refrigerating cycle.

Handling method1 Turn the handle to the left end to raise the

needle. Be sure to raise the disc at this time,too.

2 Screw the service can valve into the service can,then tighten the disc. At this time, take caresufficiently not to damage the service can bytightening the disc too strongly.

3 Install the charging hose (green) of the gaugemanifold to the valve.

4 Turn the handle of the service can valve to theright to lower the needle and make a hole in theservice can.

5 Turn the handle to the left to raise the needle,and the refrigerant flows through the valve intothe refrigerating cycle.

6 To stop supplying the refrigerant, turn the handleto the right end to lower the needle.

fl Check that the packing is usable. If the packingis coated with compressor oil, it lasts long.

Service can

Needle

Handle

Hose adapter

Disc Packing

42-104

Air conditioner


6. Belt tension gauge

If the belt tension is not proper, the lives of thebearings and belt are shortened. The belt ten-sion gauge is used to measure the belt tensioncorrectly and easily. Be sure to use this gaugeparticularly to adjust the tension of the V-belt.

Remote cable

If the remote cable is connected to the belt tension gauge, you can measure the belt tension efficientlyeven if the engine compartment is narrow.

42-114

Air conditioner


7. Connection of service tools

Connect the gauge manifold, vacuum pump, and other service tools as shown below.(1) Close the high-pressure valve (HI) and low-pressure valve (LO) of the gauge manifold.(2) Connect the red (HI) and blue (LO) charging hoses to the service valves of the high-pressure and

low-pressure pipes. The service valves may be installed to the compressor. Use the quick joints toconnect the hoses.

(3) Connect the green hose at the center of the gauge manifold to the following parts.1 For evacuation: Connect to the vacuum pump.

fl Be sure to use the vacuum pump adapter.2 For charging with refrigerant: Connect to the service can valve of the service can.

Refrigerant can

When connecting the charging hoses, take care not to mistake the high-pressure side and low-pressure side of the gauge manifold.

fl Connect the quick joints at the ends of both high-pressure hose and low-pressure hose. If eitherone is not connected, the atmosphere enters it and a vacuum is not obtained. (The check valve ofthe quick joint cannot maintain a vacuum.)

Low-pressure valve

High-pressure valve

Blue Red

Greenquick joint

Service valve on low-pressure side Service valveon high-pressure side

Compressor

Vacuum pump

Service can valve

42-124

Air conditioner

TESTING AND ADJUSTING TROUBLESHOOTING

TROUBLESHOOTING

1. Troubleshooting procedure

The following figure shows the basic troubleshooting procedure.The troubles of an air conditioner are roughly classified into the troubles of the refrigerating cycle andthose of the electric system. In this chapter, the troubleshooting method is explained according to thebasic procedure.

Examination by interview

• Control mechanism• V-belt• Sight glass• Pipe joints

Confirmation of trouble

Basic inspection

Troubleshooting

Inspection ofrefrigerating cycle Check for abnormal noise Inspection of

electric system

Replacement of parts(Repair and check)

Completion



1.1 Examination by interview and confir-mation of trouble

Before carrying out troubleshooting, you must checkthe contents and condition of the trouble thoroughly.If the trouble occurs sometime or cannot be repro-duced, “examination by interview” to obtain theoccurrence condition of the trouble is important.

<Points of examination by interview>• What Model and serial No.• When Date, time, and frequency of occur-

rence• Where Condition of working place• Condition Working condition, and weather• How How operator felt about trouble

1.2 Basic inspection(1) Inspection of Control mechanismOperate the levers and switches on the control panelto see if they work smoothly and securely.s Check the fuses, if necessary.

(2) Inspection of V-beltCheck that the belt tension is proper and belt is notdamaged.

(3) Inspection of quantity of refrigerant through sight glass

If many bubbles are seen in through the sight glass,the refrigerant may be insufficient. In this case, in-spect with the gauge manifold.(For the criterion, see 4.2 CHARGlNG WITH REFRIG-ERANT, inspection through sight glass.)

(4) Inspection of pipe jointsIf a pipe joint is coated with oil, the refrigerant maybe leaking through it. In this case, wipe off the oiland check for refrigerant leakage.

4


42-14 Air conditioner(5)

1.3 Troubleshooting1.3.1 Troubles in cooling modeDEFROSTER-FACE mixed blow type

a. Air flow is insufficient

b. Air flow is normal

c. Refrigerant pressure is abnormally high or low

Cause Remedy

• Clogging of indoor air filter • Clean filter• Clogging of outdoor air filter • Clean filter• Obstacle near air suction opening • Remove obstacle• Deformed or broken blower • Replace blower• Frosting of evaporator • Stop air

conditioner andmelt iceGo to Causes andremedies oftroubles, A

• Dirt sticking to evaporator surface • Clean evaporator surface

• Low source voltage • Check battery charge system

• Bad contact of battery terminal • Repair• Defective blower motor • Replace• Defective blower Hl relay • Replace

• Breakage of resistor (Blower rotates at only Hl)

• Replace

• Breakage of fuse • Replace fuseGo to Causes andremedies oftroubles, B

• Defective power-up relay on machine side

• Replace

• Defective blower motor • Replace• Interference of blower with case • Repair• Defective blower switch • Replace panel• Defective grounding to chassis • Ground securely• Defective wiring or disconnection of connector

• Check wiring

• Entry of outside air • Close windows and door Adjust Circulated air and fresh air selector damper

• Removal of air mixing link • Set link again

• Pressure on low-pressure side is too high (Above about 0.29 MPa)

• Go to Causes and remedies of troubles, C-2

• Pressure on high-pressure side is too low (Below about 0.98 MPa)


• Pressure on low-pressure side is too low (Below about 0.05 MPa)


• Pressures on both high- pressure side and low-pressure side are high


• Pressures on both high- pressure side and low-pressure side are low

• Insufficient refrigerant

• Breakage or slip of V-belt • Replace V-belt• Defective compressor (Locked) • Replace• Defective magnetic clutch • Repair or replace

Go to Causes and remedies of troubles, D-1

• Clutch is not engaged because of trouble in electric system

• Check wiring Go to Causes and remedies of troubles, D-2


-


-

Does blower motor rotate?

Is rotationnormal?

Does compres-sor rotate nor-mally?

Is compressor pressure normal?

High-pressure cutting system operates

Low-pressure cutting system operates

YES

NO

YES

NO

YES

NO

YES

NO

1

2

1

2



DEFROSTER-FACE separate blow type

a. Air flow is insufficient


c. Refrigerant pressure is abnormally high or low

42-14-1

Cause Remedy

• Clogging of indoor air filter • Clean filter• Clogging of outdoor air filter • Clean filter• Obstacle near air suction opening • Remove obstacle• Deformed or broken blower • Replace blower• Frosting of evaporator • Stop air

conditioner andmelt iceGo to Causes andremedies oftroubles, A

• Dirt sticking to evaporator surface • Clean evaporator surface

• Low source voltage • Check battery charge system

• Bad contact of battery terminal • Repair• Defective blower motor • Replace• Defective blower Hl relay • Replace

• Defective power transistor • Replace

• Breakage of fuse • Replace fuseGo to Causes andremedies oftroubles, B

• Defective power-up relay on machine side

• Replace

• Defective blower motor • Replace• Interference of blower with case • Repair• Defective blower switch • Replace panel• Defective grounding to chassis • Ground securely• Defective wiring or disconnection of connector

• Check wiring

• Entry of outside air • Close windows and door Adjust Circulated air and fresh air selector damper

• Removal of air mixing link • Set link again

• Pressure on low-pressure side is too high (Above about 0.29 MPa)


• Pressure on high-pressure side is too low (Below about 0.98 MPa)


• Pressure on low-pressure side is too low (Below about 0.05 MPa)


• Pressures on both high- pressure side and low-pressure side are high


• Pressures on both high- pressure side and low-pressure side are low

• Insufficient refrigerant

• Breakage or slip of V-belt • Replace V-belt• Defective compressor (Locked) • Replace• Defective magnetic clutch • Repair or replace

Go to Causes and remedies of troubles, D-1

• Clutch is not engaged because of trouble in electric system

• Check wiring Go to Causes and remedies of troubles, D-2


-


-

Does blower motor rotate?

Is rotationnormal?

Does compres-sor rotate nor-mally?

Is compressor pressure normal?

High-pressure cutting system operates

Low-pressure cutting system operates

YES

NO

YES

NO

YES

NO

YES

NO

1

2

1

2

(5)



• Causes and remedies of troubles

No. Cause Remedy

A

Voltage is applied to magnetic clutch

<DEFROSTER-FACE mixed blow type>• Defective magnetic clutch circuit• Defective frost sensor wiring• Defective frost sensor characteristics• Defective adjustment of gap between frost

sensor and evaporator (Defective sensitiv-ity)

• Check clutch circuit and replace relay• Check for short circuit, then repair or replace• Check characteristics and replace sensor• Adjust gap to 12 v 5mm

<DEFROSTER-FACE separate blow type>• Defective magnetic clutch circuit• Defective thermostat wiring

• Malfunction of thermostat

• Check clutch circuit and replace relay• Check for short circuit, then repair or

replace• Check operation and replace thermo-

stat

Voltage is not applied to mag-netic clutch

• Defective magnetic clutch • Replace

B -• Blower motor is locked• Wrong wiring• Short circuit of wiring

• Replace blower motor• Repair• Repair or replace

C

1

• Ambient temperature is abnormally high• Insufficient cooling by condenser- Fins are clogged with dirt and soil

• Too much refrigerant• Air in refrigerating cycle

-• Clean fins(with water)

• Discharge refrigerant properly• Discharge all refrigerant, then evacuate

refrigerating cycle and charge it with refrigerant again by proper quantity

2

• Too much refrigerant•Breakage of head gasket

• Defective •Breakage of suction valve compressor •Foreign matter caught

in suction valve• Expansion valve •Defective valve

is opened too •Bad contact of heat sensor much tube

• Discharge refrigerant properly

• Replace compressor

• Replace• Repair

42-15



No. Cause Remedy

C

3

• Ambient temperature is abnormally low• Refrigerant is insufficient

•Swash plate shoe is locked• Defective •Piston is locked compressor •Defective suction/

discharge valve• Defective •Clogging of valve

expansion valve •Leakage of refrigerant from heat sensor tube•Tentative clogging by freezing of valve

-• Charge with proper quantity of refrigerant• Perform leak test and repair leak-

ing part, then charge with refriger-ant

• Replace compressor

• Replace valve• Replace valve

• Replace valve and receiver, thenevacuate sufficiently

4

• Ambient temperature is abnormally low• Refrigerant is insufficient

• Clogging of refrigerating cycle

• Defective •Clogging of valveexpansion valve Leakage of refrigerant

from heat sensor tube•Tentative clogging by freezing of valve

• Frosting of evaporator

-• Charge with proper quantity of

refrigerant• Perform leak test and repair leak-

ing part, then charge with refriger-ant

• Replace receiver and dryer• Replace piping• Replace valve• Replace valve

• Replace valve and receiver, then evac-uate sufficiently

• (Go to A)

5• Insufficient cooling by condenser• Too much refrigerant

• Clean fins• Discharge refrigerant properly

42-16

42-174

Air conditioner


• Breakage of stator coil• Too much air gap between rotor and sta-

torKey is broken or notinserted

• Slip of clutch Oil on clutch surfaceLayer short circuit orlow battery voltage

• Foreign matter caught between rotor andstator

• Defective air conditioner switch• Defective blower switch• Defective compressor clutch relay• Defective thermo-sensor• Defective refrigerant high-pressure/low-

pressure switch• Abnormally high Too high

pressure on (above 2.5 MPahigh-pressure 25 kg/cm2)side Too low

(below 0.9 MPa10 kg/cm2)

Cause Remedy

1

2

• Replace• Repair or replace

• Replace key

• Remove oil• Replace• Charge• Overhaul

• Replace control panel• Replace control panel• Replace• Replace• Replace

• (Go to C-1)

• (Go to C-4)

No.

D

42-184

Air conditioner


1.3.2 Troubles in heating modefl Be sure to check that the pump pressure is normal and the heater hoses IN and OUT are connected

correctly.

a. Air flow is insufficientfl See 1.3.1 Troubles in cooling mode.


1.3.3 Water leakage into cab

1.3.4 Defective selection of circulated air and fresh air

YES

NO

1

YES

NO

1

YES

NO

1

Cause Remedy

Is hot water temperature normal?

Does temperature regulator LED operate normally?

Is circulated air/fresh air servomotor normal?

• Air in hot water circuit• Clogging or bend of piping• Ambient temperature is very

low• Engine water level is low

• Breakage of heater core

• Bleed air• Repair or replace

—

• Supply water to proper level

• Replace heater core

• Disconnection of temperature regulator link

• Entry of foreign matter

• Set link again

• Remove foreign matter

• Defective or broken wiring or disconnection of connector

• Defective servomotor

• Check wiring

• Replace

• Disconnection of link • Set link again

• Defective or broken wiring or disconnection of connector

• Defective servomotor• Entry of foreign matter

• Check wiring

• Replace• Remove

foreign matter

• Clogging of drain hole • Clean

• Entry of outside air • Close windows and door

42-194

Air conditioner


2. Inspection of refrigerating cycle

2.1 Inspection with gauge manifold

Measure the low pressure and high pressure of the refrigerating cycle with the gauge manifold underthe following condition, then carry out troubleshooting.fl For connection of the gauge manifold, see 7. Connection of service tools.<Condition>Warm up the engine, then measure under the following condition.• Door: Open fully• Air conditioner suction opening temperature: 30°C – 35°C• Circulated air/Fresh air selector switch: Circulated air• Blower speed: HI• Engine speed: 1,500 rpm• Temperature control: Lowest temperature

fl The values indicated by the gauge manifold may vary more or less with the condition.

(1) When normalThe pressures must be as follows under the abovecondition.Pressure on low-pressure side:

0.15 – 0.25 MPa 1.5 – 2.5 kg/cm2Pressure on high-pressure side:

1.37 – 1.57 MPa 14 – 16 kg/cm2The illustrated gauges have only the divisions of SIunits. The actual gauges have the divisions of theconventional units, too, however.

(2) When refrigerant is insufficient• Trouble1 Both pressures on the low-pressure side and

high-pressure side are low.2 Bubbles pass the sight glass continuously.3 Air is not cooled well.• Cause1 Refrigerant is insufficient or it is leaking.• Points of remedy1 Check and repair refrigerant leaking point.2 Charge with refrigerant again.

Low-pres-sure side

High-pres-sure side

Low-pres-sure side

High-pres-sure side

42-204

Air conditioner


(3) Too much refrigerant in refrigerating cycleor insufficient cooling by condenser

• Trouble1 Both pressures on the low-pressure side and

high-pressure side are high.2 No bubbles are seen in the sight glass even in

the low speed range.3 Air is not cooled well.• Cause1 Too much refrigerant is in the refrigerating cycle.2 Insufficient cooling by the condenser.• Points of remedy1 Adjust the quantity of refrigerant properly.2 Clean the condenser.3 Inspect the cooling system of the machine (elec-

tric fan, etc.)

(4) Water in refrigerating cycle• Trouble1 After a certain using time, the pressure on the

low-pressure side becomes negative gradually.• Cause1 Water is in the refrigerating cycle.• Points of remedy1 Replace the receiver tank.2 Before charging the refrigerating cycle with re-

frigerant, evacuate it thoroughly to remove allwater.

(5) Insufficient compression by compressor• Trouble1 The pressure on the low-pressure side is high

and that on the high-pressure side is low.2 Just after the air conditioner is turned off, the

pressures on the high-pressure side and low-pressure side become the same.

• Cause1 The compressor is defective.• Points of remedy1 Inspect and repair the compressor.

Low-pres-sure side

High-pres-sure side

Low-pres-sure side

High-pres-sure side

Low-pres-sure side

High-pres-sure side

42-214

Air conditioner


Low-pres-sure side

High-pres-sure side

Low-pres-sure side

High-pres-sure side

Low-pres-sure side

High-pres-sure side

(6) Refrigerant does not circulate (Refrigerat-ing cycle is clogged)

• Trouble1 If the refrigerating cycle is clogged completely,

the pressure on the low-pressure side becomesnegative soon. If the former is clogged a little,the latter becomes negative gradually.

2 The temperatures before and after the cloggedpart are different.

• Cause1 Dirt, water, etc. block the small hole of the ex-

pansion valve or they are frozen, and the refrig-erant does not flow.

• Points of remedy1 Replace the receiver tank.2 Evacuate the refrigerating cycle thoroughly.

(7) Air in refrigerating cycle• Trouble1 Both pressures on the low-pressure side and

high-pressure side are high.2 The low-pressure piping is not cold.3 Bubbles are seen in the sight glass.• Cause1 Air in the refrigerating cycle.• Points of remedy1 Replace refrigerant.2 Evacuate the refrigerating cycle thoroughly.

(8) Too wide opening of expansion valve• Trouble1 Both pressures on the low-pressure side and

high-pressure side are high.2 Low-pressure piping is coated with frost (dews).• Cause1 The expansion valve does not work normally.• Points of remedy1 Check the installation condition of the heat sen-

sor tube.

42-224

Air conditioner


2.2 Troubleshooting tableRemedy

Replace compressor

Replace expansion valve

Stick heat sensor tube firmly

Adjust quantity of refriger-ant properly

Clean condenser fins (withwater) or check and repair itCheck and repair coolingsystem on machine side(electric fan, radiator, etc.)

Tense or replace belt.

Replace motor or fix fan

Install in normal direction

Install genuine shroud

Clean condenser fins (withwater) or check and repair it

Charge with refrigerant toproper level.

Adjust

Repair or replace

Clean fins (with water)

Adjust quantity of refriger-ant properly

Replace refrigerant (Evacu-ate refrigerating cycle thor-oughly)

Cool condenser efficiently



Replace expansion valve, re-ceiver tank, and drier, thenevacuate refrigerating cyclethoroughly


No. Possible causeConditionRelated sectionTrouble

Defective compression bycompressor

Expansion valve is openedtoo wide (Defective adjust-ment)

Bad contact (Removal) ofheat sensor tube

Too much refrigerant in re-frigerating cycle

Insufficient cooling by con-denser

Looseness or breakage offan belt

If electric fan is used, motoris defective or fan slips

Installation of fan in reverse

Fan shroud is not installed

Condenser fins are cloggedwith dirt

Insufficient cooling water oroil

Wrong ignition timing

Trouble or insufficient capac-ity of water pump

Radiator fins are cloggedwith dirt

Too much refrigerant in re-frigerating cycle

Air in refrigerating cycle

Ambient temperature is ab-normally high

Clogging of expansion valve(Defective adjustment, entryof foreign matter, etc.)

Leakage of refrigerant fromheat sensor tube

Temporary clogging of ex-pansion valve caused byfreezing (Trouble by water inrefrigerating cycle)

Expansion valve is cloggeda little (Defective adjustmentor entry of foreign matter)

Just after compressor isstopped, pressures on high-pressure side and low-pres-sure side become the same.

Both pressures on high-pres-sure side and low-pressureside are high. Low-pressurehose and parts near servicevalve on low-pressure side areabnormally cold and piping iscoated with frost (dews).

Both pressures on high-pres-sure side and low-pressureside are high. If condenser iscooled forcibly, pressure onlow-pressure side lowers.

Condenser cooling fan doesnot suck in air sufficiently(Cooling air is insufficient)

Engine is overheated

Bubbles do not disappearfrom sight glass even if con-denser is cooled with water

Just after compressor stops,pressure lowers by about 0.2MPa 2 kg/cm2

Thermal load is too high

Expansion valve is not frostedand low-pressure piping is notcold

Expansion valve is frosted

Compressor

Expansionvalve

Refrigeratingcycle

Condenser

Engine

Refrigeratingcycle

Othersections

Expansionvalve

Pressure onlow-pressureside isabnormallyhigh(above about0.3 MPa 3.1kg/cm2)

Pressure onhigh-pressureside isabnormallyhigh(above about2 MPa 20kg/cm2)

Pressure onlow-pressureside isabnormallylow(below about0.05 MPa0.5 kg/cm2)

1

2

3

42-234

Air conditioner


Remedy


Check and repair leaking part

Replace receiver tank anddrier (Evacuate refrigeratingcycle thoroughly)

Check and adjust amplifierand thermistor

—

Replace compressor



Replace expansion valve, re-ceiver, and drier, then evacu-ate refrigerating cycle thor-oughly


Replace compressor

Retighten joints or replacepiping

Replace

Connect, repair, or replacedisconnected parts

Repair or replace

Repair or replace

Charge battery

Remove oil

Replace

No. Possible causeConditionRelated sectionTrouble

Insufficient refrigerant

Leakage of refrigerant

Clogging of receiver tankand drier(Entry of foreign matter, etc.)

Evaporator is frosted

Ambient temperature is ab-normally low

Defective compression bycompressor

Clogging of expansion valve(Defective adjustment, entryof foreign matter, etc.)

Leakage of refrigerant fromheat sensor tube

Temporary clogging of ex-pansion valve caused byfreezing (Trouble by water inrefrigerating cycle)


Refrigerant leakage throughshaft seals

Leakage of gas from pipejoints

Broken coil

Disconnection, defective wir-ing, or bad contact in wiringparts (ground wire, fuse,etc.)

Bad contact or defective op-eration of switches

Too wide clearance betweenrotor and stator

Low battery voltage

Clutch surface is stained withoil

Layer short circuit in coil

Air is not cooled well andbubbles pass through sightglass continuously

Receiver tank and drier are ab-normally cold (frosted)

Blown air temperature is lowand air flow is little

Thermal load is too low

Just after compressor isstopped, pressures on high-pressure side and low-pres-sure side become the same.

Expansion valve is not frostedand low-pressure piping is notcold

Air is not cooled well andbubbles pass through sightglass continuously

Shaft seals are stained withoil clearly and refrigerant islost

Pipe joints are stained with oilclearly and refrigerant is lost

When air conditioner switch isturned ON, clutch is not en-gaged

When air conditioner switch isturned ON, rotor moves. If ro-tor is pushed with fingers, itis attracted.

Clutch slips during rotation

Refrigeratingcycle

Othersections

Compressor

Expansionvalve

Refrigeratingcycle

Compressor

Refrigeratingcycle

Clutch

Clutch

Pressure onlow-pressureside isabnormallylow(below about0.05 MPa0.5kg/cm2)

Pressure onhigh-pressureside isabnormallylow(below about1 MPa10 kg/cm2)

Leakage ofrefrigerantand oil

Magneticclutch is notengaged

Magneticclutch slips

3

4

5

6

7

42-244

Air conditioner


2.3 Check for refrigerant leakage

If refrigerant seems to be leaking as a result of thebasic inspection, check for leakage with the gas leaktester according to the following procedure.

(1) Preliminary checkConnect the gauge manifold and check the condi-tion of the refrigerant remaining in the refrigeratingcycle. Then, add new refrigerant, if necessary, toheighten the pressure in the refrigerating cycle andincrease the accuracy of the gas leak check.1 Read the gauge pressure while the compressor

is stopped. The ambient temperature must be15°C or higher at this time.

2 If the gauge pressure is 0.4 MPa 4 kg/cm2 orhigher, start the inspection.

3 If the gauge pressure is below 0.4 MPa 4 kg/cm2, add new refrigerant to heighten the gaugepressure above 0.4 MPa 4 kg/cm2, then startthe inspection.

fl Perform the gas leak test in a place ventilatedwell. An electric gas leak tester may react togasoline, diesel fuel, exhaust gas of a car, etc. Ifit does so, it will misjudge.

fl Gas leaking from a pipe joint, etc. is blown awayby even a light wind. Accordingly, apply theprobe tip all around the joint.

Do not check for refrigerant leakage with a leakdetector of halide torch type. Since this detec-tor detects gas leakage by utilizing reaction tochlorine, it cannot detect refrigerant HFC-134awhich does not contain chlorine. In addition, itdecomposes HFC-134a into harmful matters. Ac-cordingly, do not use it.

Probe

Gas leaktester

Probe

42-254

Air conditioner


(2) Refrigerant leakage check procedure

Refrigerant leakage check in machine cab

YES

NO

YES

YES

NO

Is oozing oil from each pipe joint detected visually or by feeling with fingers?

Does leak tester react on refrigerant?

Repair joint.

Refrigerant leakage check in operator's cab (from cooler unit) (with engine stopped)

Charge with specified quantity of refrigerant and turn on air conditioner. After vibrating devices and applying pressure to them, check for leakage again.

Set blower to HI and ventilate unit with fresh air for about 15 seconds.

Turn blower on for a moment (0.5 seconds) and off, then check each air outlet for leakage again.

Select circulated air and leave for about 10 minutes (with blower turned off).

Does leak tester react on refrigerant in each air outlet?

Check each part to specify leaking part.

Check connecting surfaces for flaw and corrosion. If they are normal, replace O-ring and check again.

42-264

Air conditioner


[Reference]• Check for refrigerant leakage by applying air pressure)When it seems that little refrigerant is left in the refrigerating cycle, the leak check accuracy can beincreased by heightening the internal pressure of the refrigerating cycle with compressed nitrogen gasor air.1. Necessary tools1 Air attachment: Special attachment to connect gauge manifold2 Plug: Plug to connect to utility piping of factory

(Select a proper plug on the market)2. Check method(1) Read the gauge pressure while the compressor is stopped. (The ambient temperature must be

15°C or above at this time.)1 If the gauge pressure is about 0.2 – 0.4 MPa 2 – 4 kg/cm2, apply air pressure and start the

inspection.2 If the gauge pressure is below 0.2 MPa 2 kg/cm2, add new refrigerant until the gauge pressure

rises above 0.4 MPa 4 kg/cm2, then apply air pressure and start the inspection.(2) Check for refrigerant leakage with a gas leak tester.(3) After checking for refrigerant leakage, be sure to replace the mixture of the air and refrigerant with

new refrigerant.

<Method of applying air pressure>1 Using the gauge, air attachment, and plug, con-

nect an air compressor to the air conditionerpiping.

2 Start the air compressor to supply air.fl Air pressure: Approx. 1.0 MPa 10 kg/cm2

3 After applying air pressure, close the valves ofthe gauge to keep the pressure in the air condi-tioner piping.

fl Be sure to drain water from the air compressorused for applying air pressure. If it is drained,little water is supplied to the refrigerating cycle.

fl The applied air pressure must be 1.0 MPa 10kg/cm2 or less.

To air condi-tioner piping

PlugAir attachment

To air compressor

42-274

Air conditioner


3. Check for abnormal noise

(1) Since an abnormal noise is produced under various operating conditions, check the following.• Is the abnormal noise produced even after the air conditioner is turned off?• Is the abnormal noise produced only while the air conditioner is turned on?• Is the abnormal noise produced at intervals, continuously, or just after the air conditioner is

turned on?To specify the noise generating part, check the result of the examination by interview carefully.

(2) The general parts which can produce abnormal noises and the causes of those noises are asfollows.

V-belt

Magnetic clutch

Blower motor

Compressor

Piping

Looseness

Wear or damage of bearing

Contact of stator and rotor

Foreign matter in motor

Insufficient tightening of blower

Looseness of bracket bolts

Defective valves

Wear or damage or bearing

Misalignment

Defective tightening and installation of clamps

Improper safety gap

Production of noise

42-284

Air conditioner


[Reference]• Identification of noise producing partA noise producing part can be identified with astethoscope. How to check the abnormal noise fromthe compressor with the stethoscope is explainedbelow, as an example.If an abnormal noise is heard from around the com-pressor, you must see if it is produced by loosenedbracket bolts, auxiliary parts used to secure the com-pressor and belt, or internal parts of the compres-sor.1 Apply the stethoscope to the auxiliary parts to

find out the noise source.2 Apply the stethoscope to the compressor to see

if a noise similar to the above is heard. If thesimilar noise is heard, the compressor may havea trouble.

3 Generally, if the compressor has a trouble, itproduces an abnormal noise, regardless of theengine speed.



4. Electric system

4.1 Inspection of electric system

See the circuit diagram (refer to the Shop Manual for each machine) and understand the electric circuit. Then,check the connections of the electric parts systematically with a circuit tester, etc. The parts to be inspectedgenerally are as follows.

(1) Breakage of fuse 1) Referring to the wiring diagram, check the circuits where a fuse may be broken. 2) To check each functional part for internal short circuit, disconnect its connector.(2) Bad contact of connector 1) Note that a functional part may not work because of bad contact of its connector. 2) Unstable operation and malfunction under vibration are caused by bad contact of a connector in many

cases.(3) Defective grounding to chassisEven if a ground wire seems firm, it may be insulated by paint film, rust, etc.

a PC400-7 is used as an example in the following explanation.

4.2 General block diagram (PC400-7) and circuit diagram

a Blower relay R30 and compressor relay R31 are installed to the side of the air conditioner unit (on the leftside of the unit).


42-29-1 Air conditioner(6)

Circuit diagram related to air conditioner (PC400, 400LC-7, PC450, 450LC-7)


Air conditioner 42-29-2(6)

4.3 General drawing of air conditioner unit (PC400-7)

4.4 Self-diagnosis (PC400-7)

1. Turn the starting switch ON and turn switch (1) of control panel P OFF.

2. Hold " " and "v" of temperature setting switch (2) simultaneously for 3 seconds.

3. The error codes are displayed in (3).

4. Press " " or "v" of temperature setting switch (2) to check all the error codes.

Display of error codes and failure modes

a The sunlight sensor is "S" at the top of the moni-tor panel.

Display Failure mode

E-- No failures

E11 Disconnection in internal air sensor

E12 Short circuit in internal air sensor

E15 Disconnection in water temperature sensor

E16 Short circuit in water temperature sensor

E17 Disconnection in sunlight sensor

E18 Short circuit in sunlight sensor

E43 Abnormality in air outlet damper

E44 Abnormality in air mix damper

E45 Abnormality in internal/external air damper

v

v

42-304

Air conditioner


5. Replacement of parts

5.1 Interchangeability of air conditioner parts

The refrigerating cycle parts, functional parts closely related to them, and compressor oil for an airconditioner which uses HFC134a (R134a) are not interchangeable with those for an air conditionerwhich uses R12. Accordingly, different joints are used for each part of these air conditioners so that awrong part will not be used. Since the compressor oil, O-ring, etc. cannot be distinguished at a glance,classify them into the HFC134a (R134a) group and the R12 group securely.

5.2 Connection of piping

(1) O-ring• If any piping or refrigerating cycle part is removed, be sure to use a new O-ring for HFC134a

(R134a).• When removing an O-ring, use a soft rod such as a toothpick so that the piping will not be

damaged.• When connecting the piping, apply compressor oil to the O-ring and tighten the adapter to the

specified torque.

(2) Tightening torque

Block joint

Tightening torqueNm kgcm

12 – 15120 – 150

20 – 25200 – 250

30 – 35300 – 350

4.0 – 7.040 – 70

8.0 – 1280 – 120

Connector

Nut type

Block joint

Tube size orbolt size

φ 8 pipe

D1/2 pipe

D5/8 pipe

M6 bolt (4T) ofreceiver

M6 bolt (6T) otherthan above

Nut type

42-314

Air conditioner


5.3 Adding compressor oil

(1) When replacing function partWhen replacing a functional part (condenser, evapo-rator, etc.), add the following quantity of new com-pressor oil.fl Add compressor oil for HFC134a (R134a). Supple-

mentary oil is supplied in 40-cc cans.

(2) When replacing compressorA new compressor is filled with oil necessary forthe refrigerating cycle. Accordingly, when replacingan existing compressor, drain the excessive oil fromthe new compressor.

fl Since the compressor oil for HFC134a (R134a)absorbs moisture easily, seal the oil can imme-diately after supplying the oil.

5.4 Charging with refrigerant

After replacing a refrigerating cycle part, be sure toperform the following work.

• Evacuation• Charging with refrigerant

For the procedure for the above work, see Chargingwith refrigerant.

<Quantity of supplementary compressor oil>

Replacement parts

Compressor Condenser Evaporator Receiver tank Piping

10 cc80 cc 40 cc 40 cc 10 cc (per piece)

Quantity of supplementarycompressor oil(Reference value)

Compressor oil• Piston-type compressor (10P, 10PA series): ND-OIL8

• Vane-type compressor (TV, SV series): ND-OIL9

New compressor Compressor tobe replaced

Drainexcessive oil(A – B).

42-324

Air conditioner

TESTING AND ADJUSTING CHARGING WITH REFRIGERANT

CHARGING WITHREFRIGERANT1. Precautions for charging with re-

frigerant ( Safety items)

(1) Only the appointed person must work.Since high-pressure refrigerant is dangerous, onlythe appointed person must handle it.

(2) Put on protective goggles during work.If refrigerant liquid enters your eyes, the water inthe eyeballs is frozen and you may lose your eye-sight. Accordingly, be sure to put on protectivegoggles for safety while you are charging the airconditioner with refrigerant. If the refrigerant liquidis splashed over your hands, you may be frostbit-ten. Take care extremely. When installing and re-moving the service can and connecting and discon-necting the charging hoses, take care particularly.

(3) Never work near your face.Never install and remove the service can or connectand disconnect the gauge manifold and compres-sor charging hoses near your face. If the refrigerantliquid spouts out, you may be injured seriously.

Actions to take when refrigerant enters youreyes

1) Do not rub your eyes with the hands or a hand-kerchief.

2) Immediately wash your eyes with clean waterfor more than 15 minutes, then see a eye doc-tor.

Put o

n pr

otec

tive

gogg

les.

Eye doctor

Appointedperson

42-334

Air conditioner


(4) Take care in handling the high-pressurevalve.

When charging the air conditioner with the refriger-ant while the engine is running, never open thehigh-pressure valve (HI) of the gauge manifold. If the high-pressure valve is opened by mistake,

the high-pressure gas may flow back into theservice can to burst.

(5) Never heat the service can.If the service can is heated directly or put in a hotwater, the pressure in it rises to burst the can, andthat can injure you seriously.1) If it is obliged to warm the service can in winter,

be sure to use water under 40°C.2) Never put the service can in boiling water.3) Do not put the service can on a hot engine, etc.

(6) Do not leak the refrigerant gas near a fireor a hot part of a stove, etc.

If the refrigerant gas comes in contact with the fireor hot part, it is decomposed into harmful matters.

(7) Charge the refrigerating cycle with the re-frigerant in a place ventilated well.

(8) Never return the refrigerant to the servicecan.

If the refrigerant in the refrigerating cycle is returnedto the service can, the can may burst, and that isvery dangerous.

(9) Do not apply pressure higher than 1 MPa10 kg/cm2 to the service can.

(10)Do not shake the service can strongly.If the service can is not installed securely, it maycome off.

(11)When storing and handling the service can,observe the following.

1) Store the service can away from children.2) Do not put the service can in direct sunshine,

near a fire, or hot place.3) Do not store the service can in a place where it

may be corroded. (Take care of humidity.)4) Do not give a shock to the service can by drop-

ping it, etc.

Do not leak!

Neveropen thisvalve.

Hotwater

Below40°C

42-344

Air conditioner


2. Evacuation

If a refrigerating cycle part is replaced, the refrigerating cycle is opened to the atmosphere. Since airalways contains moisture, it must be dried. If there is any moisture in the refrigerating cycle, it may befrozen in the small of the expansion valve and may rust the compressor valves, and that can cause atrouble, even if it is little in quantity. Accordingly, the moisture in the refrigerating cycle must beremoved before the refrigerant is supplied.To remove the moisture, the refrigerating cycle is evacuated with a vacuum pump to vaporize themoisture. This work is called evacuation.

2.1 Connection of gauge manifold

(1) Connect the charging hoses to the high-pres-sure and low-pressure service valves.fl Red hose — High-pressure side (Mark of H)fl Blue hose — Low-pressure side (Mark of L)

(2) Connect the central charging hose (green) ofthe gauge manifold to the vacuum pump.

Take care not to mistake the high-pressure sideand low-pressure side.

The service valves may be installed to the com-pressor.

Star

t of e

vacu

atio

n

10minutes

Max. –0.1MPa(–750mmHg)

Stop

of e

vacu

atio

n Leavingfor awhile

(5minutes)

Check ofairtightness

Chec

k of

indi

catio

nof

gau

ge

Chec

k of

airt

ight

-ne

ss w

ith re

frige

rant

Gauge pointerreturns

Check and repair ofconnections

Char

ging

with

refri

gera

nt

Supply refrigerant in gasstate until gauge pressurerises to 0.1 MPa (1 kg/cm2).

ValvesLO – ClosedHI – Closed

Low-pressurevalve (LO)

High-pressurevalve (HI)

Blue

Green

Red

Service valve onlow-pressure side

Service valve onhigh-pressure side

Vacuum pump

42-354

Air conditioner


ValvesLO – OpenHI – Open

2.2 Evacuation

(1) Open the high-pressure valve (HI) and low-pres-sure valve (LO) of the gauge manifold.

(2) Turn on the vacuum pump to start evacuation(for 10 minutes).

(3) After the low-pressure gauge reaches –0.1 MPa–750 mmHg, close the high-pressure valve andlow-pressure valve of the gauge manifold andturn off the vacuum pump.

fl If the vacuum pump is stopped before the valvesof the gauge manifold are closed, the atmo-sphere enters the refrigerating cycle.

2.3 Check of airtightness 1 (Check ofgauge pointer)

Leave the high-pressure valve and low-pressurevalve of the gauge manifold closed for a while (for5 minutes) and check that the gauge pointer doesnot return.

fl If the gauge pointer returns, the refrigerant isleaking through some part. In this case, checkthe pipe connections for looseness and repairthem, then evacuate and inspect again.

Check and repairpipe connections


Low-pressureside

High-pressureside

Pump isturned on

Leave for5 minutes

Low-pressure gauge

Returns

42-364

Air conditioner


ValvesLO – ClosedHI – Open

2.4 Check of airtightness 2(Check with refrigerant)

Supply the refrigerant a little to the refrigeratingcycle, then check the airtightness with a gas leakdetector.(1) Disconnect the charging hose (green) from the

vacuum pump and connect it to the service can.For the method of installing the service can, see“Service can valve (on page 42-9)”.

(2) Discharge the air from the charging hose (green).1 Tighten the handle of the service can valve

to make a hole in the service can and openthe valve.

2 Push the valve of the gauge manifold to dis-charge the air from the hose with the refrig-erant pressure until the refrigerant flows witha hiss.

At this time, keep both high-pressure valve andlow-pressure valve of the gauge manifold closed.

Take care that the refrigerant will not stick toyour hands. (You may be frostbitten.)

(3) Open the high-pressure valve of the gauge mani-fold and supply the refrigerant until the low-pressure gauge indicates 0.1 MPa 1 kg/cm2.

(4) After supplying the refrigerant, close the high-pressure valve.

(5) Check for refrigerant leakage carefully with thegas leak detector.If any part is leaking, repair it.

fl Be sure to use a detector for HFC134a (R134a)to check for refrigerant leakage.

Service can

Service can


Push valve

BlueRed

Green

Open valve

To service valve

After supplyingrefrigerant, closehigh-pressure valve.

Low-pressureside

High-pressureside

Valve: Open

42-374

Air conditioner


ValvesLO – ClosedHI – Open

3. Charging with refrigerant

After evacuating the refrigerating cycle, charge it with the refrigerant according to the followingprocedure.(1) Stop the engine and supply the refrigerant from the high-pressure side.(2) Run the engine and supply the refrigerant from low-pressure side additionally.

Evac

uatio

n

Chec

k of

airt

ight

ness

Supply ofrefrigerant

Supp

ly fr

om h

igh-

pres

sure

sid

e

Supp

ly fr

om lo

w-

pres

sure

sid

e

Chec

k of

qua

ntity

of

refri

gera

nt

Chec

k fo

r re

frige

rant

leak

age

3.1 Supply from high-pressure side

(1) Stop the engine and open the high-pressurevalve of the gauge manifold and the service canvalve and supply about a can of the refrigerant.

Never turn on the compressor at this time. If itis turned on, the refrigerant flows back to burstthe hoses or service can, and that is very dan-gerous.

Do not turn on the compressor before chargingthe refrigerating cycle with refrigerant. If it isturned on, it may be seized.

Do not open the low-pressure valve of the gaugemanifold. If it is opened, the compressor maycompress the refrigerant liquid and may be bro-ken.

(2) Close the high-pressure valve of the gauge mani-fold and the service can valve.

After supplyingrefrigerant, closehigh-pressure valve.

BlueRed

Green

Valve: Open

Service can



42-384

Air conditioner


3.2 Supply from low-pressure side (Addi-tional supply)

(1) Check that the high-pressure valve of the gaugemanifold is closed.

(2) Set the machine under the following condition.• Run the engine and open the cab door fully.• Air conditioner switch ....... ON• Temperature control lever ... Lowest temperature• Blower switch ..................... HI• Engine speed ...................... Approx. 1,500 rpm

(3) Open the low-pressure valve of the gauge mani-fold and the service can valve to supply therefrigerant to the specified level.

(4) After supplying the refrigerant, close the low-pressure valve of the gauge manifold and theservice can valve and stop the engine.

Never open the high-pressure valve (HI) of thegauge manifold. If it is opened, the refrigerantflows back to burst the service can or charginghoses, and that is very dangerous.

Never hold the service upside down. If it is heldupside down, the refrigerant in liquid state issucked in and compressed by the compressor.As a result, the compressor valves may be bro-ken.Erect the service can to supply refrigerant ingas state.

ValvesLO – OpenHI – Closed

High-pressurevalve: Closed

Note: If this valve is opened,service can will burstand injure you seri-ously.

(Lowest temperature)

Open cabdoor fully.

Temperaturecontrol lever

Never open high-pressure valve.

Low-pressure sideHigh-pressure side

Blue Red

Green

Valve: Open

Low-pressureside

High-pressureside

Service can

Run engine at1,500 rpm

42-394

Air conditioner


ValvesLO – OpenHI – Closed

[Reference]• Supplying refrigerant when ambient tempera-

ture is lowWhen the ambient temperature is low, the refriger-ant may not be supplied quickly. In this case, warmthe service can in warm water below 40°C toheighten the internal pressure of the can.

Do not heat the service can in hot water or overa fire. If it is heated so, it will burst and injureyou seriously. Be sure to use warm water be-low 40°C. (Check the temperature with a ther-mometer.)

fl When warming the service can in warm water,do not submerge the service can valve in thewater. If it is submerged, moisture may enterthe refrigerating cycle.

fl Supplying refrigerant when ambient tempera-ture is highWhen the ambient temperature is high, cool thecondenser with an electric fan so that the refrig-erant will be supplied quickly.

After supplyingrefrigerant, closethis valve.

Low-pressurevalve High-pressure

valve

Low-pressureside

High-pressureside

Valve: Open

Warm waterbelow 40°C

42-404

Air conditioner



3.3 Replacement of service can

If the service can becomes empty while the refriger-ant is supplied from it, replace with new can ac-cording to the following procedure.(1) Close the high-pressure valve and low-pressure

valve of the gauge manifold.(2) Raise the service can valve needle and disc.(3) Install a new service can to the service can valve.(4) Discharge the air from the charging hose ac-

cording to the following procedure.1 Tighten the handle of the service can valve

to make a hole in the service can and openthe valve.

2 Push the valve of the gauge manifold to dis-charge the air from the hose with the refrig-erant pressure until the refrigerant flows witha hiss.

At this time, keep both high-pressure valve andlow-pressure valve of the gauge manifold closed.

Take care that the refrigerant will not stick toyour hands. (You may be frostbitten.)

(5) Continue supplying the refrigerant.

Service can

Handle

Hose adapter

Disc NeedlePacking

Service can

Push valve Open valve

BlueRed

Green

To service valve

42-414

Air conditioner


4. Check of quantity of refrigerant

After supplying the refrigerant, check the quantityof supplied refrigerant according to the followingprocedure.

4.1 Check with gauge manifold

(1) Set the machine under the following condition.• Door ................................. Full open• Temperature control ...... Lowest temperature• Blower speed .................. HI• Circulated air/Fresh air

selector switch ................ Circulated air• Engine speed .................. 1,500 rpm

fl Measure the quantity of the refrigerant whilethe pressure on the high-pressure side is below1.86 MPa 19 kg/cm2.If the ambient temperature is high (above 40°C)and the pressure on the high-pressure side ishigher than 1.86 MPa 19 kg/cm2 under the speci-fied judgment condition, perform the followingto lower the pressure below 1.86 MPa 19 kg/cm2.1 Close the door fully and set the blower speed

to LO.2 Move the machine indoors or into the shade.

(2) Read the gauge manifold.When normal

Pressure on low-pressure side:0.15 – 0.25 MPa 1.5 – 2.0 kg/cm2

Pressure on high-pressure side:1.37 – 1.57 MPa 14 – 16 kg/cm2

fl The values indicated by the gauge manifold mayvary more or less with the condition.

fl Too much refrigerant in the refrigerating cyclecan cause insufficient cooling capacity, overheat-ing, etc.

Low-pres-sure side

High-pres-sure side

42-424

Air conditioner


4.2 Check with sight glass (Simple inspection)


selector switch ................ Circulated air• Engine speed .................. 1,500 rpm

(2) Under the above condition, check the refriger-ant flow in the sight glass.

<Judgment>fl Proper: Little bubbles are seen.

If the engine speed isincreased from idling to1,500 rpm, the bubblesdisappear and the refrig-erant becomes transpar-ent.

fl Too much refrigerant: No bubbles are seen. Inthis case, both pressureson the high-pressureside and low-pressureside are high and the airin the cab is not cooledwell.

fl Insufficient refrigerant: Bubbles pass the sightglass continuously.

Too muchrefrigerant

Proper Insufficientrefrigerant

Sight glass

42-434

Air conditioner



4.3 Disconnection of gauge manifold

After finishing supplying the refrigerant, stop theengine and disconnect the charging hoses accord-ing to the following procedure.(1) Disconnect the charging hose (quick joint) on

the low-pressure side from the service valvequickly.

(2) Before disconnecting the charging hose on thehigh-pressure side, wait until the value indicatedby the high-pressure gauge lowers sufficiently(to 1 MPa 10 kg/cm2 or below).

(3) Disconnect the charging hose on the high-pres-sure (red) side similarly to the one on the low-pressure side.

Perform the above work as quickly as you canto minimize the leakage of the refrigerant. Whendisconnecting the high-pressure charging hose,wait until the gauge indicates 1 MPa 10 kg/cm2 or less, since compressor oil may spoutout together with refrigerant, then disconnectit quickly, covering it with a cloth so that the oilwill not be splashed.

Take care extremely that the refrigerant willnot stick to your hands or enter your eyes. (Puton safety goggles.)

Leave charging hoseon high-pressureside until valueindicated by high-pressure gaugelowers sufficiently,then disconnect it.

Blue Red

Green

Valve: Closed



Service can

TESTING AND ADJUSTING PERIODIC INSPECTION AND MAINTENANCE


PERIODIC INSPECTION AND MAINTENANCE

1. Inspection and maintenance items

You are required to inspect and maintain each air conditioner properly to use it always under the best condition.Generally, perform the following inspections and maintenance for the air conditioner.

a The manufacturer (DENSO CO., LTD.) recommends replacing the receiver drier and blower motor every 4years.

1.1 Inspection and cleaning of condenser finsa For PC400-7

Open the engine right side cover and cleancondenser fins (1) with compressed air orwater.See Operation manual, Inspection andmaintenance, 500-hour maintenance

1.2 Cleaning of air filter (Internal/Exter-nal air filters)a For PC400-7• Internal air filter: E (Left rear of seat)• External air filter: F (Open cover at left rear

of operator's cab and take out filter)Clean the filter with compressed air or neu-tral detergentSee Operation manual, Inspection andmaintenance, 500-hour maintenance

Inspection/Maintenance items Inspection/Maintenance period

6 months 12 months

Refrigerant (Gas) (Sight glass) Quantity q q

Condenser Clogging of fins q q

Compressor Operating condition q

Air filters (for internal/external air) Clogging q (3 months)

Belt Damage and tension q q

Blower motor Operating condition and abnormal sound q

Control mechanism Operating condition q

Mounting parts and piping Mounting condition, looseness of tightening parts and connections, gas leakage, and damage

q q

42-454

Air conditioner


2. Check of quantity of refrigerant(Check with sight glass)


selector switch ................ Circulated air• Engine speed .................. 1,500 rpm• Air conditioner ................ ON

(2) Check the condition of the refrigerant in the sightglass.

<Judgment>fl Proper: Little bubbles are seen.

If the engine speed isincreased from idling to1,500 rpm, the bubblesdisappear and the refrig-erant becomes transpar-ent.

fl Too much refrigerant: No bubbles are seen. Inthis case, both pressureson the high-pressureside and low-pressureside are high and the airin the cab is not cooledwell.

fl Insufficient refrigerant: Bubbles pass the sightglass continuously.

Too muchrefrigerant

Proper Insufficientrefrigerant

Sight glass

42-464

Air conditioner


3. Inspection of functional parts

(1) Inspection of control mechanismOperate the levers and switches on the control panelto see if they work smoothly and securely. If anypart is troubled, adjust or repair it.

(2) Inspection of beltCheck the belt for damage. If it is damaged, replaceit.In addition, check the belt tension (See the ShopManual for each machine). If it is out of the stan-dard range, adjust it.

Inspection of idling-up speedCheck the idling-up speed. (See the Shop Manualfor each machine.) If it is out of the standard range,adjust it.

(3) Inspection of compressor and magneticclutch

Turn the air conditioner switch on to see if the mag-netic clutch is turned on. Check that magnetic clutchand compressor for abnormal noise. If any abnor-mal noise is produced, adjust or repair.

Smooth

42-474

Air conditioner


(4) Inspection of idler pulleyCheck the idler pulley for abnormal noise. If anyabnormal noise is produced, adjust or repair.

(5) Cleaning of condenserIf much soil and dirt stick to the condenser fins, thecooling capacity is lowered. Accordingly, wash awaythe soil and dirt with water. If the fins are dirtyextremely, clean them with a soft brush.

(6) Inspection of each fitting partCheck each fitting part (mounting bolt, screw, nut,etc.) for looseness. If any part is loosened, retightenit.

(7) Inspection of pipe jointsCheck the pipe joints for oil sticking to them. If anyjoint is coated with oil, the refrigerant may be leak-ing through it. In this case, check the joint with agas leak detector. If the refrigerant is leaking, repairor replace the joint.

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TAKAHASHI WORKS

Outline ....................................................................................................................................................... 51- 2

Refrigerating cycle system diagram .......................................................................................................... 51- 4

Compressor ............................................................................................................................................... 51- 6

Condenser ................................................................................................................................................. 51- 9

Receiver drier ............................................................................................................................................ 51- 9

Air conditioner unit..................................................................................................................................... 51- 10

• Air circuit...................................................................................................................................................51- 11

• Evaporator............................................................................................................................................... 51- 12

• Expansion valve ...................................................................................................................................... 51- 13

• High and low pressure switch.................................................................................................................. 51- 14

• Heater core.............................................................................................................................................. 51- 15

• Water valve ............................................................................................................................................. 51- 15

• Temperature regulation amplifier............................................................................................................. 51- 16

• Blower motor ........................................................................................................................................... 51- 16

• Resistor ................................................................................................................................................... 51- 16

• Damper actuator...................................................................................................................................... 51- 17

• Relay ....................................................................................................................................................... 51- 17

• Internal air filter and external air filter ...................................................................................................... 51- 17

(5)

STRUCTURE AND FUNCTION OUTLINE


OUTLINEReference: The following figure shows PC100-6 as an example.

• PC100-6 is equipped with an air conditioner offull heat type, in which the cooler and heater arearranged in series against air flow and made in 1unit.

• The compressor is of vane rotary type. It isdriven by the engine through V-belt to compressrefrigerant gas of low pressure and lower tem-perature. As a result, the pressure and tempera-ture of the refrigerant gas are heightened, andthen the refrigerant gas is sent to the condenser.

• The air conditioner unit is installed to the rear ofthe operator's seat in the cabin. The air cooledor heated in this unit is sent through the ducts tothe air blow grilles at the rear and right of theoperator's seat.

• The air temperature, air outlet, selection of exter-nal or internal air, and strength of air flow areselected with the air conditioner switches on thecontrol panel.

1. Control switch2. Compressor3. Condenser

4. Receiver drier5. Air conditioner unit6. Duct

(5)

STRUCTURE AND FUNCTION OUTLINE


Layout of air conditioner parts in cab

1. Grille for rear FACE(Air flow direction: Changeable vertically and horizontally)

2. Heater core3. Evaporator4. EXTERNAL/INTERNAL air changeover damper5. External air filter6. Internal air filter7. Blower motor8. Refrigerant inlet (M16 x 1.5)9. Refrigerant outlet (M22 x 1.5)10. Hot water inlet11. Hot water outlet12. Selector damper13. FOOT grill

(Air flow direction: Fixed)

14. DEFROSTER grill(Air flow direction: Changeable vertically and horizontally)

15. FOOT-DEFROSTER selector lever(Operated manually)

16. Right side FACE grill(Air flow direction: Changeable vertically and horizontally)

17. FACE control wire18. Control panel19. Chassis-side wiring harness

a. FACEb. FACEc. External air inletd. Internal air inlete. FOOTf. DEFROSTERg. FACE

(5)

STRUCTURE AND FUNCTION REFRIGERATING CYCLE CIRCUIT DIAGRAM


REFRIGERATING CYCLE CIRCUIT DIAGRAM

(5)

STRUCTURE AND FUNCTION REFRIGERATING CYCLE CIRCUIT DIAGRAM


1. Air outlet2. Heater core3. Evaporator4. Blower motor5. Expansion valve6. High and low pressure switch7. Relief valve8. Liquid eye9. Magnetic clutch10. Thermal switch11. Filter12. Desiccating agent13. Receiver drier14. Condenser15. Electric cooling fan16. Compressor17. Filter18. Filter19. Heat sensor tube20. Thermistor21. Water valve22. Control switch23. Air outlet

A. EvaporationB. ExpansionC. CompressionD. Condensation

a. Charged with gasb. Liquid of low temperature and low pressurec. Temperature: 50 - 60fCd. Temperature: 8 - 15fC

Pressure: 0.1 - 0.2 MPa 1 - 2 kg/cm2e. Liquid of high temperature and high pressuref. Suctiong. Dischargeh. Gas of high temperature and high pressurei. Temperature: 50 - 60fCj. Liquid of high temperature and high pressurek. Temperature: 80 - 120fC

(Reference value for normal operation)Pressure: 1.37 - 1.57 MPa 14 - 16 kg/cm2(Reference value for normal operation)

l. Gas of low temperature and low pressurem. External airn. Internal airo. Hot water OUTp. Hot water IN

(5)

STRUCTURE AND FUNCTION COMPRESSOR


COMPRESSORThe rotation of the engine is transmitted through thebelt to the clutch, which is turned ON and OFF bythe temperature regulator thermostat. Then, therotor of the compressor coupled directly with theclutch is rotated. The rotor has 5 vanes. As therotor rotates, the vanes slide on the inside wall of thecylinder to compress and suck the refrigerant gasrepeatedly.

Function

• The compressor sucks the refrigerant gas of lowpressure and low temperature evaporated in theevaporator and compresses it. The pressureand temperature of the compressed refrigerantgas become high, and then the refrigerant gas isdischarged into the condenser. The refrigerantgas is circulated in the refrigerating cycle. Thetemperature and pressure of the refrigerant gasare heightened by the compressor, and then therefrigerant gas is cooled and liquefied in the con-denser

1. Oil separator2. Front head3. Mechanical seal4. Clutch5. Front side block6. Case7. Rear side block8. Rotor9. Cylinder10. Vanea. Discharge openingb. Suction opening

(5)



Operation processes of compressor

(1) Starting suction

Suction of the refrigerant gas starts when vaneA passes by suction opening (1) (White arrow).As the rotor rotates, the space (hatched part)formed by vanes A and E, rotor, and cylinder isincreased to continue sucking the refrigerantgas.

(2) Finishing suction (Closing) - Starting compression

Suction finishes when vane E passes by suctionopening (1).The hatched part in the figure at this time is themaximum space and compression starts at thispoint.

(3) Compression - Discharge

The compressed refrigerant gas pushes up thelead valve installed at discharge opening (2) andgoes out (Black arrows).Just after this time, vane A starts suction throughsuction opening (1) on the opposite side.

s As explained above, each compression spaceperforms the cycle of suction, compression, anddischarge 2 times in 1 turn. Accordingly, thecompressor performs 10 cycles in 1 turn.

(5)



Relief valve (Installed to compressor)

When the high pressure in a car air conditioner forR12 becomes abnormally, a melt bolt is melted todischarge the refrigerant into the atmosphere toprotect the air conditioner cycle. In this case, allthe refrigerant in the cycle is discharged.On the other hand, a car air conditioner for R134aemploys a pressure relief valve instead of the meltbolt to minimize discharge of the refrigerant whenabnormally high pressure is generated.The refrigerant discharge route made when therelief valve operates is shown in the figure.

s Operating pressureStart of blowing: 3.4 MPa 35 kg/cm2Stop of blowing: 2.9 MPa 30 kg/cm2

Thermal switch (Installed to compressor)

This switch is installed near the discharge port ofthe compressor. It turns the power for the clutchOFF when the temperature of the compressorbecomes abnormally high. When the temperatureof the compressor lowers to the normal level, thethermal switch turns the power for the clutch ONagain.

s Operating temperatureON : 95fCOFF: 140fC

1. Wiring harness2. Diaphragm bimetal3. Compressor4. Contact

(5)

STRUCTURE AND FUNCTION CONDENSER


CONDENSER

The refrigerant of high pressure and high tempera-ture sent from the compressor to the condenser iscooled and liquefied with a cooling fan.The condenser consists of aluminum tubes and cor-rugated fins.

1. Louver fin2. Tube made by extrusiona. Passage of refrigerant gasb. Passage of airc. Inlet (M20 x 1.5 with O-ring)d. Outlet (M16 x 1.5 with O-ring)

RECEIVER DRIER

The liquefied refrigerant of high pressure and hightemperature sent from the condenser is stored in thereceiver drier. Even if bubbles are mixed in the liq-uefied refrigerant, depending on the radiating condi-tion of the condenser, only liquefied refrigerant issent to the expansion valve. The filter and desiccat-ing agent remove the dirt and water in the cycle.The operator can see the flow of the refrigerantthrough the liquid eye at the top of the receiver drier

to judge the quantity of the refrigerant.1. Desiccating agent2. Filter3. Liquid eye4. Thread size: M16 x 1.5a. Flow of liquefied refrigerant from condenserb. Stored liquefied refrigerantc. Connection to air conditioner unit

CONDENSER ANR RECEIVER DRIER

(5)

STRUCTURE AND FUNCTION AIR CONDITIONER UNIT


AIR CONDITIONER UNIT

The temperature in the cab is controlled through therespective heat exchangers of the refrigerant gas forcooling and the hot water for heating. The externalor internal air is sent by the blower in the unitthrough the filters to the air outlets after divided bythe selector damper.

1. Upper air outlet2. External air suction opening3. Internal air suction opening4. Refrigerant gas inlet (M16 x 1.5 with O-ring)5. Refrigerant gas outlet (M22 x 1.5 with O-ring)6. Hot water inlet7. Hot water outlet8. Side air outlet9. Selector duct actuator

1. Drain pan2. Damper case3. Heater core4. Evaporator5. Blower motor

6. EXTERNAL/INTERNAL air changeover damper7. External air filter8. Internal air filter9. Cover



Air circuit

1. External/Internal air changeover damper (Oper-ated with actuator)

2. Fan3. Evaporator

4. Heater core5. Damper (Operated with actuator)6. Blower motor

a. External airb. Internal airc. Side air outletd. Upper air outlet



Evaporator

The fins of the evaporator are cooled by the low-temperature refrigerant mist sent through the expan-sion valve. Then, the fins cool and dry the warm airsent by the blower motor.

1. Refrigerant inlet2. Refrigerant outlet3. Slit fins4. Refrigerant passage holes

a. Air (Room temperature)b. Air (Cooled)c. Plate thickness: 5 mm



Expansion valve

The refrigerant liquid of high pressure and high tem-perature sent from the receiver drier is sprayedthrough the expansion valve. As a result, the refrig-erant becomes mist of low pressure and low temper-ature. The closing ratio of the expansion valve ischanged according to the thermal load of the cab tocontrol the refrigerant flow rate in the refrigeratingcycle automatically.

1. Diaphragm2. Valve stem3. Adjustment screw4. Adjustment spring5. Ball6. P27. Evaporator8. Heat sensor tube (to sense gas temperature on

cooler outlet side)9. Capillary tube

a. Refrigerant liquid inletb. To compressorc. Volume changes according to temperature

(Filled with gas).



High and low pressure switch

This switch is installed to the liquid tube. Whenabnormally low or high pressure is generated in theair conditioner cycle, this switch turns the compressorOFF to protect the parts in the air conditioner cycle.

1. Spring 5. Belleville spring2. Stopper 6. Diaphragm3. Contact 7. Pin4. Plate 8. Terminal

a. Refrigerant pressure

Operation• When pressure is normal

When the refrigerant pressure is higher than0.21 MPa 2.1 kg/cm2, its force is larger thanthe force of spring (2). As a result, diaphragm(6) is deformed and plate (4) is pushed up toclose contact (3).

• When pressure is abnormally lowWhen the refrigerant pressure is lower than 0.20MPa 2.0 kg/cm2, plate (4) is pushed down bythe force of spring (2) and contact (3) is opened.

• When pressure is abnormally highWhen the refrigerant pressure is lower than 3.1MPa 32 kg/cm2, diaphragm (6) is deflected andbelleville spring (5) buckles back. As a result,the contact is pushed up and opened throughpin (7).



Heater core

The hot water from the engine flows into the heatercore to warm the air flowing through the heater core.The temperature of the air flowing through theheater core can be controlled by adjusting the hotwater flow rate with the water valve.

Water valve

The water valve controls the flow rate of the hotwater flowing from the engine to the heater coreaccording to the command from the control switch.It is driven by the motor actuator.

1. Hot water inlet pipe (φ14 mm)2. Hot water outlet pipe (φ14 mm)3. Hot water passage4. Air passage

a. Hot water inletb. Hot water outlet

1. Rod2. Valve3. Hot water inlet pipe (φ16 mm)4. Hot water outlet pipe (φ16 mm)

a. Driven by motorb. Hot water inletc. Hot water outlet



Temperature regulation amplifier

There are relays and a temperature regulation boardin this amplifier unit. The thermistor senses hot airfrom the evaporator and the thermal amplifier com-pares the hot air temperature with the value set withthe control knob and turns the compressor ON andOFF.The thermistor is also used to prevent freezing of theevaporator.

1. Thermistora. Connected to variable resistor or fixed resistor

Blower motor

The blower sucks external or internal air and sendsit to the evaporator and heater core to exchangeheat. The heat-exchanged air is directed by thedamper and sent through the duct to the air outletgrille. The blower motor speed is set to 3 levels bymeans of resistor according to the fan switch whichis set manually.

1. Scroll2. Motor3. Sirocco fan

Resistor

This resistor is used to lower the blower motor cur-rent, or the blower motor speed, to 3 levels.

1. Resistor (Low)2. Resistor (Mid)3. Temperature fuse (Turned OFF at 76fC, not reset

automatically)



Damper actuator

This motor damper actuator sets the selectordamper to the displayed position of the control panelswitch. The damper is rotated and sets to 3 posi-tions through reduction gears.

Relay

This relay turns a large current ON and OFF accord-ing to the signals from the switch and temperatureregulation amplifier.

1. Output side2. Signal input3. Ground4. Input side

Internal air filter and external air filter

If dust and dirt sticks to the heat exchanger, the cool-ing and heating capacity is reduced. To prevent thistrouble, filters are installed to the internal and exter-nal air suction openings of the air conditioner unit toremove the dust and dirt from the air.

1. External air filter2. Internal air filter




TAKAHASHI WORKS

List of tools for testing, adjusting, and troubleshooting............................................................................ 52- 2

Precautions for measuring refrigerant pressure, charging with refrigerant, and discharging refrigerant. 52- 3

Testing quantity of refrigerant .................................................................................................................. 52- 6

Procedure for charging with refrigerant ................................................................................................... 52- 10

Procedure for replacing service can ........................................................................................................ 52- 13

Procedure for discharging refrigerant ...................................................................................................... 52- 14

Cleaning internal and external air filters .................................................................................................. 52- 16

Troubleshooting ....................................................................................................................................... 52- 101

(5)

TESTING AND ADJUSTING LIST OF TOOLS FOR TESTING, ADJUSTING, AND TROUBLESHOOTING


LIST OF TOOLS FOR TESTING, ADJUSTING, AND TROUBLE-SHOOTING

Testing and adjusting item

Sym-bol Part No. Part name Remarks

Measuring refrigerant pressure in air condi-tioner, charging with refrigerant, and discharg-ing refrigerant

N

1 799-703-1200 Service tool kit For new refrigerant R134a

2

799-703-1100 Vacuum pump For new refrigerant R134a in Japan (100 V)

799-703-1111 Vacuum pump For new refrigerant R134a in over-seas countries (220 V)


799-702-1320 Vacuum pump For Freon R12 in USA (115 V)

799-702-1330 Vacuum pump For Freon R12 in overseas coun-tries (220 V)

3 799-703-1300 Adapter For use of vacuum pump for R12

Leakage of refrigerant O 799-703-1400 Gas leak tester For countries other than USA

(6)


TESTING AND ADJUSTING PRECAUTIONS FOR MEASURING REFRIGERANT PRESSURE, CHARGING


PRECAUTIONS FOR MEASURING REFRIGERANT PRESSURE, CHARGING WITH REFRIGERANT, AND DISCHARGING REFRIG-ERANT1. Precautions for using service tool kit N1 for

car air conditioner• The joints of service tool kit N1 for R134a car

air conditioner are different from those forthe other refrigerants.

1. Gauge manifold2. High-pressure charging hose (Red)3. Quick joint (Hi) [Large diameter]4. Center charging hose (Green)5. Quick joint (Lo) [Small diameter]

6. Low-pressure charging hose (Blue)7. Service can valve8. Service can valve joint

a. Since the threads are course and loosened eas-ily, take care.

s Use R134a service tool kit N1 for R134a carair conditioner.

s Do not use R134a service tool kit N1 for R12car air conditioner.

s Do not use R12 service tool kit.

PRECAUTIONS FOR MEASURING REFRIGERANT PRESSURE, CHARG-ING WITH REFRIGERANT, AND DISCHARGING REFRIGERANT

(5)



2. Precautions for connecting quick joint• Press the quick joint against the charging

valve and push in part A securely until itclicks.

Completion of connection

3. Precautions for disconnecting quick joint• Securing part A of the quick joint, slide part

B (sleeve) up.

Completion of disconnection

Precautions for handling R134a charging valve• When operating valve (4) of R134a charging

valve (6), observe the following.

s When pressing the joint to connect it, takecare not to bend the piping.

s If sleeve (1) has moved without connecting tothe charging valve, return it to the set positionand connect again.

s If any refrigerant is left in the charging hose,the joint may not be connected easily. In thiscase, release the residual pressure in thehose.

s After disconnecting the quick joint, install thecap to the charging valve.

s When discharging the refrigerant, be sure touse special quick joint (2).

s Never push in valve (4) with screwdriver (3),etc. to discharge the refrigerant. If it is pushedin strongly (with force of 2.4N 3 kg or larger),spring (5) may come off and refrigerant mayleak.


(5)



5. Precautions for using vacuum pump• If R12 vacuum pump N2 is equipped with

vacuum pump adapter N3 additionally, it canbe used for both R134a car air conditionerand R12 car air conditioner.

6. Precautions for charging with refrigerant andchecking for refrigerant leakage• Charge with the refrigerant by the conven-

tional method.

a. When using the R12 vacuum pump, use adapter N3.b. Close the gauge manifold before turning the switch

OFF.

s When evacuating, connect the vacuum pump

to the quick joints on both high-pressure and

low-pressure sides. If the pump is not con-

nected to both sides, the atmosphere enters

through the unconnected joint. (The check

valve of the quick joint cannot keep vacuum.)

s Before stopping the vacuum pump (turning the

switch OFF) after evacuating, close the gauge

manifold.

If the vacuum pump is stopped before the

gauge manifold is closed, the evacuated air

conditioner circuit is opened to the atmosphere.

s Precautions for checking refrigerant leakage (*1)

When checking refrigerant leakage from the

R134a car air conditioner, be sure to use R134a

gas leak tester O. Do not use the R12 gas leak

tester, since its sensitivity is too low.

( )


(5)

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Negative pressure : Min100kPa750mmHg

Leaving

Abnormal indication by gauge

Checking andrepairing joints

Charge with refrigerant gas up to gauge pressure of0.1 MPa 1 kg/cm2.

(*1)

TESTING AND ADJUSTING TESTING QUANTITY OF REFRIGERANT


TESTING QUANTITY OF REFRIGERANT

1. Visual inspection (Inspection through liquid eye)

k If the refrigerant liquid enters your eyes orsticks to your hand, you may lose your eyes oryour hand skin may be frozen. Accordingly, donot loosen a refrigerant circuit part.

• Test the quantity of the refrigerant while thecompressor is turned ON under the conditionin Table 1.s When the compressor is turned OFF, bub-

bles are made even if the quantity of therefrigerant is proper. Accordingly, checkthat the compressor is turned ON whentesting the quantity of the refrigerant.

Table 1

Item Condition

Door Open full

Temperature control Max.

Blower speed Hi

External/Internal air Internal

Engine speed 1,500rpm

Air conditioner switch ON

s Judge the quantity of the refrigerant while thepressure on the high pressure side is below1.9MPa 19kg/cm2.

s When the ambient temperature is high (above40fC), if the pressure on the high pressureside is higher above 1.9MPa 19kg/cm2under the judging condition, lower it below1.9MPa 19kg/cm2 by the following method.1. Close the door fully and set the blower speed

to Lo.2. Test indoors or under a shade.

(5)



[Judgment]Check table for quantity of refrigerant

Note that the contents of the above table change a little during the very cold season and very hot season.Generally, bubbles are made easily in the very hot season and are not made easily (the refrigerant becomes transparent) inthe very cold season.

1. Liquid eye2. Receiver drier

Condition ofair conditioner

Normal Abnormal

Temperature of high and low pressure tubes

High-pressure tube is hot and low-pres-sure tube is cold. Temperature differ-ence between them is clear.

High-pressure tube is warm and low-pressure tube is cool. Temperature difference between them is not so clear.

There is little temper-ature difference between high-pres-sure tube and low-pressure tube.

High-pressure tube is hot and low-pres-sure tube is cool. There is some tem-perature difference between them.

Condition of liquid eye

Almost transparent. Even if some bub-bles are flowing, they disappear when engine speed is increased or decreased.See Fig. a.

Bubbles flow con-stantly. Transparent. White bubbles may flow.

See Fig. b.

Fog-like thing flows slightly.

See Fig. c.

Even if fan is set to Hi (with doors closed) while engine is running idle, no bubbles flow.

See Fig. d.

Condition of pipe joints

NormalSome parts are stained with oil.

Some parts are stained with oil badly.

Normal

Condition of this air conditioner

Quantity of refriger-ant is proper.

Refrigerant may be leaking a little.

Almost all refriger-ant has leaked.

Quantity of refriger-ant is too much.

(5)



2. Measuring refrigerant pressure

kTake care that the refrigerant will not stick toyour hand.k Put on protective goggles to prevent the refrig-erant from entering your eyes.

1) Stop the engine and install service tool kit N1.s Close the high-pressure valve and low-

pressure valve of the gauge manifold.s Connect blue hose (1) to the low-pressure

piping and red hose (2) to the high-pres-sure piping.

2) Release air from service tool kit N1.i) Open the high-pressure valve gradually.

When the refrigerant comes out of thegreen charge hose with a hiss, close thehigh-pressure valve.

ii) Open the low-pressure valve gradually.When the refrigerant comes out of thegreen charge hose with a hiss, close thelow-pressure valve.

3) While the compressor is turned ON, measurethe refrigerant pressure and air conditioner suc-tion temperature under the condition in Table 2.s If the compressor is turned OFF, the

refrigerant pressure lowers extremely.Accordingly, turn the compressor ONwhen measuring the refrigerant pressure.

Table 2

s Note that the proper refrigerant pressure dependson the air conditioner suction temperature.

Air conditioner refrigerant pressure standard

a. Quantity of refrigerant is too muchb. Quantity of refrigerant is properc. Quantity of refrigerant is insufficientd. Air conditioner suction temperaturee. High-pressure gauge pressure

Item Condition

Door Open full


Blower speed Hi




Air conditioner suc-tion temperature(fC)

High-pressure gauge pres-sure(MPakg/cm2)

15 1.03-1.32 10.5-13.5

20 1.17-1.47 12.0-15.0

25 1.32-1.62 13.5-16.5

30 1.47-1.77 15.0-18.0

35 1.62-1.91 16.5-19.5

(5)



[Reference]When the air conditioner suction temperature is inthe normal range of 30-35fC, the gauge pressurebecomes as shown in Table 3.

Table 3<Gauge pressure indicated under normal condition>

s The figure shows the median of the gaugepressure under the normal condition as anexample.

1. Gauge on high pressure side2. Gauge on low pressure side

Pressure on low pressure side

0.15-0.25MPa1.5-2.5 kg/cm2

Pressure on high pressure side

1.37-1.57MPa14-16 kg/cm2

(5)

TESTING AND ADJUSTING PROCEDURE FOR CHARGING WITH REFRIGERANT


PROCEDURE FOR CHARGING WITH REFRIGERANT

k Take care that the refrigerant will not stick toyour hand.k Put on protective goggles to prevent the refrig-erant from entering your eyes.

s If the quantity of the refrigerant is insufficient,add new refrigerant according to the followingprocedure.

1. Evacuation1) Stop the engine and install service tool kit N1.

s Close high-pressure valve (1) and low-pressure valve (2) of the gauge manifold(in direction a).

s Connect red hose (3) to the high-pressurepiping and blue hose (4) to the low-pres-sure piping.

2) Connect green hose (5) to vacuum pump N2.3) Open high-pressure valve (1) and low-pres-

sure valve (2) gradually (in direction b).s Do not operate the valves quickly.

4) Turn switch (6) of vacuum pump N2 ON andevacuate the air conditioner circuit for 30minutes.

5) Close high-pressure valve (1) and low-pres-sure valve (2) gradually (in direction a) andturn switch (6) of the vacuum pump OFF.

2. Charging with refrigerant1) Charging from high-pressure side

i) Disconnect charging hose (Green) (5) ofthe gauge manifold from vacuum pumpN2 and connect it to service can (7).s When using 2 service cans, use ser-

vice can valve T-joint (8).ii) Tighten the handle of service can valve

(9) to pierce a hole in service can (7),and then open service can valve (9) (indirection b).

iii) Hold the valve of air purge valve (10) withflat-head screwdriver (11) so that the air ingreen hose (5) and gauge manifold will bedischarged by the refrigerant pressure.s Continue the above work until the

refrigerant gas comes out with "a hiss".iv) Stop the engine and open high-pressure

valve (1) and service can valve (9) to sup-ply the refrigerant from service can (7) (indirection b).

k Never drive the compressor.

k Do not drive the compressor while the air condi-tioner circuit is not charged with the refrigerant.

k Never open low-pressure valve (2).(Set it in direction a.)



v) Close high-pressure valve (1) and ser-vice can valve (9).

2) Charging from low-pressure side (Additionalcharge)i) Check that high-pressure valve (1) is

closed (in direction a).ii) Open low-pressure valve (2) and service

can valve (9) under the condition in Table1 and supply the refrigerant to a properlevel. (Each valve opens when it is set indirection b.)

k Never open high-pressure valve (1).

k Never put service can (7) upside down.

s When measuring the refrigerant pres-sure, close low-pressure valve (2)and high-pressure valve (1) (in direc-tion a).

s Note extremely that the proper refrig-erant pressure depends on the airconditioner suction temperature.

Table 1


iii) After finishing charging with the refriger-ant, close low-pressure valve (2) and ser-vice can valve (9) and stop the engine.

iv) Check that the refrigerant is not leakingwith gas leak tester O.


Item Condition

Door Open full


Blower speed Hi




Air conditioner suc-tion temperature (fC)

High-pressure gauge pres-sure (MPakg/cm2)

15 1.03-1.32 10.5-13.5

20 1.17-1.47 12.0-15.0

25 1.32-1.62 13.5-16.5

30 1.47-1.77 15.0-18.0

35 1.62-1.91 16.5-19.5



[Reference]1. If the refrigerant circuit is empty, supply about

800 g of the refrigerant.2. When the air conditioner suction temperature is in

the normal range of 30-35fC, the gauge pressurebecomes as shown in Table 2.



1. Pressure on low pressure side2. Pressure on high pressure side


0.15-0.25MPa1.5-2.5 kg/cm2


1.37-1.57MPa14-16 kg/cm2

TESTING AND ADJUSTING PROCEDURE FOR REPLACING SERVICE CAN


PROCEDURE FOR REPLACING SERVICE CAN

kTake care that the refrigerant will not stick toyour hand.

k Put on protective goggles to prevent the refrig-erant from entering your eyes.

1. Close high-pressure valve (1) and low-pressurevalve (2) (in direction a).

2. Raise needle (4) and disc (5) of service canvalve (3).

3. Install service can valve (3) to new service can(6).

4. Tighten handle (7) of service can valve (3) topierce a hole in service can (6), and then openhandle (7) of service can valve (3) (in directionb).

5. Hold the valve of air purge valve (8) with a flat-head screwdriver so that the air in green hose(10) and gauge manifold (11) will be dischargedby the refrigerant pressure.s Continue the above work until the refrigerant

gas comes out with "a hiss".

TESTING AND ADJUSTING PROCEDURE FOR DISCHARGING REFRIGERANT


PROCEDURE FOR DISCHARGING REFRIGERANT

kTake care that the refrigerant will not stick toyour hand.

k Put on protective goggles to prevent the refrig-erant from entering your eyes.

1) Stop the engine and install service tool kit N1.s Close the high-pressure valve and low-

pressure valve of the gauge manifold.s Connect blue hose (1) to the low-pressure

piping and red hose (2) to the high-pres-sure piping.

s If service tool kit N1 has not beenremoved from the compressor after therefrigerant pressure was measured, startthe work with 3) below.

2) Bleed air from service tool kit N1.i) Open the high-pressure valve gradually.

When the refrigerant comes out of thegreen charge hose with "a hiss", close thehigh-pressure valve.

ii) Open the low-pressure valve gradually.When the refrigerant comes out of thegreen charge hose with "a hiss", closethe low-pressure valve.

3) Open the high-pressure valve (Hi) graduallyto release the refrigerant until the refrigerantpressure lowers to the proper level when thecompressor is turned ON under the conditionin Table 1.s Keep the low-pressure valve closed.

k Do not operate the high-pressure valvequickly.

s When measuring the refrigerant pressure,close the low-pressure valve and high-pressure valve.

Table 1

Item Condition

Door Open full


Blower speed Hi




TESTING AND ADJUSTING PROCEDURE FOR DISCHARGING REFRIGERANT


s Note that the proper refrigerant pressuredepends on the air conditioner suctiontemperature.


[Reference]When the air conditioner suction temperature is inthe normal range of 30-35fC, the gauge pressurebecomes as shown in Table 3.




1. Pressure on low pressure side2. Pressure on high pressure side

Air conditioner suc-tion temperature (fC)

High-pressure gauge pres-sure (MPakg/cm2)

15 1.03-1.32 10.5-13.5

20 1.17-1.47 12.0-15.0

25 1.32-1.62 13.5-16.5

30 1.47-1.77 15.0-18.0

35 1.62-1.91 16.5-19.5


0.15-0.25MPa1.5-2.5 kg/cm2


1.37-1.57MPa14-16 kg/cm2

TESTING AND ADJUSTING CLEANING INTERNAL AND EXTERNAL AIR FILTERS


CLEANING INTERNAL AND EXTERNAL AIR FILTERS

1. Remove the upper 4 bolts of the luggage boxand bracket (1).

2. Remove the lower 2 bolts of the luggage boxand raise box (2) to remove.

3. Loosen wing bolt (3), move stopper (4), and pullup internal air filter (5) to remove. Pull externalair filter (6) aside (to the left of the chassis) toremove.

4. Clean filters (5) and (6) with compressed air. Ifthey are coated with oil or stained badly, washthem in neutral detergent. After washing them inwater, dry them up.

s If the filters are clogged so badly that they can-not be cleaned with air or water, replace them.

TROUBLESHOOTING


TROUBLESHOOTING

TAKAHASHI WORKS

Electric circuit diagram of air conditioner................................................................................................. 52- 102

Wiring diagram related to air conditioner................................................................................................. 52- 104

Flowchart of troubleshooting ................................................................................................................... 52- 108

TROUBLESHOOTING ELECTRIC CIRCUIT DIAGRAM OF AIR CONDITIONER


ELECTRIC CIRCUIT DIAGRAM OF AIR CONDITIONER

TROUBLESHOOTING ELECTRIC CIRCUIT DIAGRAM OF AIR CONDITIONER


TROUBLESHOOTING WIRING DIAGRAM RELATED TO AIR CONDITIONER


WIRING DIAGRAM RELATED TO AIR CONDITIONER* The actual locations of the Hi, Mid, and Lo blower relays may be different from this drawing. Accordingly,

when carrying out troubleshooting, see the color symbols of the wiring harnesses in the electric circuitdiagram of the air conditioner and take care not to mistake the relays.

1. Servomotor for internal air and external air2. Hi blower relay3. Mid blower relay4. Lo blower relayReference: The above figure is seen from front upper part of the chassis.



1. Thermistor amplifier2. Power supply relay3. Hot water selector motor valve4. Blower motor5. Servomotor for blow modeReference: The above figure is seen from front upper part of the chassis.



1. Wiring harness on chassis side2. Thermistor amplifier3. Servomotor for internal air and external air4. Hi blower relay5. Mid blower relay6. Lo blower relay7. Blower resistor

8. Blower motor9. Air conditioner panel10. Pressure cutout switch11. Servomotor for blow mode12. Servomotor for automatic damper13. Power supply relay



M-26. Air conditioner does not operate

* Carry out the following troubleshooting when the battery and battery relay are normal.* Before carrying out the following troubleshooting, check that fuses 3 and 5 are normal.* Before carrying out the following troubleshooting, check that all the related connectors are properly inserted.* Always connect any disconnected connectors before going on to the next step.

a) Air does not come out

Is resistance betweenfuse 3-M26 (female) (2),fuse 5-M26 (female) (5),and M26 (female) (6)-chassis ground normal?

Are internal andexternal air filters clogged?

When air conditionerpanel is replaced,does air come out?

Is resistance of eachair conditioner wiringharness as shown inTable 1?

Is voltage between power supply relay (4)and chassis groundnormal?

• Max. 1Ω• Turn starting switch OFF.• Disconnect M26 and fuses 3 and 5.

• Turn starting switch ON.• Turn Hi, Mid, and Lo switches ON in order.• Turn air conditioner switch ON.

• Turn starting switch OFF.

• 24 V• Turn starting switch ON.• Turn air conditioner switch ON.

Is there continuitybetween blower resis-tor (2)-(5), (6)-(1),and (6)-(4)?

• Turn starting switch OFF.• Disconnect blower resistor.

YES

YES

YES

YES

YES

NO

NONO

NO

NO

1

2

3

4

5

6

M-26(a)



Cause Remedy

Clogging of filters See TESTING AND ADJUSTING, Cleaning internal and external air filters of air conditioner

Clean or replace

Defective air conditioner panel

Replace

Defective air conditioner unit

Replace

Defective blower motor Replace

Defective Lo blower relay Replace

Defective Mid blower relay

Replace

Defective Hi blower relay Replace

Defective blower resistor Replace

Defective power supply relay

Replace

Defect of defective con-tact in related wiring har-ness

Replace

Disconnection or defec-tive contact in wiring har-ness between fuse 3-M26 (female) (2), fuse 5-M26 (female) (5), or M26 (female) (6)-chassis ground

Repair or replace

Is there continuitybetween blower resis-tor (1) and (2)?

• Turn starting switch OFF.• Disconnect blower motor.

( )

Is voltage betweenMid blower relay (4)and chassis groundnormal?

• 24 V• Turn starting switch ON.• Turn air conditioner switch ON.• Turn Mid switch ON.

Is voltage between Hiblower relay (4) andchassis ground nor-mal?

• 24 V• Turn starting switch ON.• Turn air conditioner switch ON.• Turn Hi switch ON.

Is voltage betweenLo blower relay (4)and chassis groundnormal?

• 24 V• Turn starting switch ON.• Turn air conditioner switch ON.• Turn Lo switch ON.

YES

NO

7

8

9

10

YES

NO

YES

NO

YES

NO

YES

NO

M-26(a)



Table 1

Terminals of both ends of wiring harness to bemeasured

Connector to be disconnectedResis-tance

M26 (male) (5) - power supply relay (female) (1) M26, power supply relay

Max. 1Ω

M26 (male) (5) - Hi blower relay (female) (3) M26, Hi blower relay

M26 (male) (5) - Mid blower relay (female) (3) M26, Mid blower relay

M26 (male) (5) - Lo blower relay (female) (3) M26, Lo blower relay

M26 (male) (5) - air conditioner panel (female) (11)M26, air conditioner panel

M26 (male) (6) - air conditioner panel (female) (1)

M26 (male) (2) - blower resistor (female) (5) M26, blower resistor

M26 (male) (6) - blower motor (female) (2) M26, blower motor

Blower motor (female) (1) - blower resistor (female) (6) Blower motor, blower resistor

Blower motor (female) (1) - Hi blower relay (female) (4) Blower motor, Hi blower relay

Blower resistor (female) (2) - power supply relay (female) (2) Blower resistor, power supply relay

Blower resistor (female) (2) - Hi blower relay (female) (2) Blower resistor, Hi blower relay

Blower resistor (female) (1) - Mid blower relay (female) (4)Blower resistor, Mid blower relay

Blower resistor (female) (2) - Mid blower relay (female) (2)

Blower resistor (female) (2) - Lo blower relay (female) (2)Blower resistor, Lo blower relay

Blower resistor (female) (4) - Lo blower relay (female) (4)

Power supply relay (female) (3) - air conditioner panel (female) (6) Power supply relay, air conditioner panel

Hi blower relay (female) (1) - air conditioner panel (female) (15) Hi blower relay, air conditioner panel

Mid blower relay (female) (1) - air conditioner panel (female) (5) Mid blower relay, air conditioner panel

Lo blower relay (female) (1) - air conditioner panel (female) (16) Lo blower relay, air conditioner panel

M-26(a)



b) Air comes out but it is not cold

Notes) 1. If troubleshooting item 5 cannot be judged, carry out troubleshooting item 6 or call the electric devicemanufacturer.

2. If the result of troubleshooting item 6 is abnormal, carry out troubleshooting further, referring to Trou-bleshooting with gauge manifold.

M-26(b)

Is condenser cloggedor are fins bent down?

Is voltage betweenM34 and chassis ground normal?

Does compressorclutch click?


• Turn starting switch ON.• Turn air conditioner switch ON.

Is compressor belttension normal?

• Referring to opera-tion manual, test com-pressor belt tension.

YES

YES

YES

NO

NO

1

2

3

4

Go to A in page 52-114.

NO



Cause Remedy

Clogging of condenser or bending of fins

Clean or replace

Go to item 1 or call elec-tric device manufacturer

-

Entry of air, too much refrigerant, or clogging of condenser

Evacuate, dis-charge refrig-erant, and clean

Insufficient refrigerant, defec-tive compressor, or defective piping on low pressure side (flattening or clogging)

Charge with refrig-erant or replace

Defective air conditioner unit or too much refrigerant

Replace or discharge refrigerant

Insufficient refrigerant, defective air conditioner unit, or defective piping on low pressure side

Charge with refrig-erant or replace

Too much refrigerantSee TESTING AND ADJUSTING, Procedure for discharging refrigerant

Discharge refrigerant

Insufficient refrigerant See TESTING AND ADJUSTING, Procedure for charging with refriger-ant Insufficient refrigerant (See TESTING AND ADJUSTING, Pro-cedure for charging with refrigerant)

Charge with refrig-erant

Too much refrigerantSee TESTING AND ADJUSTING, Procedure for discharging refrigerant

Discharge refrigerant

Insufficient refrigerantSee TESTING AND ADJUSTING, Procedure for charging with refriger-ant Insufficient refrigerant (See Pro-cedure for charging with refrigerant)

Charge with refrig-erant

Defective adjustment of compressor belt(See operation manual)

Adjust

Defective compressor Replace

M-26(b)

Is quantity of refriger-ant in receiver tanknormal?

• Referring to section of checking refrigerant, check refrigerant level visually.

YES

Is refrigerant pres-sure normal?

• Referring to section of checking refrigerant, measure refrigerant pressure.

NO

NO

NO

YES

YES

6

5

( )

( )

Only pressure on high pres-sure side is low

Only pressure on low pressure side is high

Only pressure on low pressure side is low

Both pressures on high and low sides are high

Both pressures on high and low sides are low

Only pressure on high pres-sure side is high

Too much refrigerant


( )



Is resistance betweenM26 (female) (3) andM34 (female) normal?

• Max. 1Ω• Turn starting switch OFF.• Disconnect M26 and M34.

7

A

When air conditionerpanel is replaced, isair cooled?


YES

NO

Is resistance of each airconditioner wiring har-ness as shown in Table 1?


NO

YES

YESIs voltage between powersupply relay (4) andchassis ground normal?


NO

YESIs resistance betweenpressure cutout switch(1) and (2) normal?

• Max. 1Ω• Turn starting switch ON.• Turn air conditioner switch ON.• Disconnect pressure cutout switch.

NO

8

9

10

11

M-26(b)



Cause Remedy


Replace

Defective thermistor ampli-fier

Replace

Defective hot water selec-tor motor valve

Replace

Defective air conditioner unit

Replace

Defective pressure cutout switch

Replace

Defective power supply relay

Replace

Defect or defective contact in related wiring harness

Repair or replace

Disconnection or defective contact in wiring harness between M26 (female) (3) - M34 (female)

Repair or replace

When thermistor ampli-fier is replaced, is aircooled?


When hot water selec-tor motor valve isreplaced, is air cooled?


YES

NO

12

13

YES

NO

YES

NO

M-26(b)



Table 1



M26 (male) (3) - Pressure cutout switch (female) (2) M26, pressure cutout switch

Max. 1Ω

M26 (male) (6) - Thermistor amplifier (female) (3) M26, thermistor amplifier

Blower resistor (female) (2) - Power supply relay (female) (2) Blower resistor, power supply relay

Power supply relay (female) (4) - Thermistor amplifier (female) (4) Power supply relay, thermistor amplifier

Thermistor amplifier (female) (2) - Pressure cutout switch (female) (1) Thermistor amplifier, pressure cutout switch

Hot water selector motor valve (female) (1) - Air conditioner panel (female) (18)

Hot water selector motor valve, air conditioner panel





M-26(b)



Troubleshooting from gauge pressure

• You can detect a defect in the refrigerating cycle bychecking the high and low pressure pointers of thegauge manifold.[Condition] * Warm up the engine, and then check

under the following condition.

1. Air conditioner is normal<Gauge pressure indicated under normal condition>

2. Refrigerant is insufficient<Indicated gauge pressure>

Item Condition

Door Open full


Blower speed Hi

EXTERNAL/INTERNAL air INTERNAL


Air conditioner suction temperature and condenser suction temperature

30fC-35fCAir conditioner switch ON

Pressure on low pressure side 0.15-0.25MPa1.5-2.5kg/cm2

Pressure on high pressure side 1.37-1.57MPa14-16kg/cm2



Phenomenon Cause Check and remedy point

1.Both pressures on high and low sides are low

2.Bubbles pass through liquid eye constantly

3.Blown air temperature is not low

• Insufficiency of refrigerant

• Leakage of refrigerant

• Check and repair leaking part.

• Add refrigerant.

• If pressure indicated when gauge is connected is near 0, check and repair leaking part, and then evacuate circuit.

M-26(b)



3. Circuit is charged with too much refrigerant orcondenser is not cooled sufficiently

<Indicated gauge pressure>

4. Compressor does not compress normally<Indicated gauge pressure>

5. Expansion valve is opened too wide<Indicated gauge pressure>



Phenomenon Cause Check and rem-edy point

1. Both pressures on high and low sides are high

2.Even when engine speed is low, no bubbles are seen.

3.Air is not cooled sufficiently

• Too much refrigerant• Insufficient cooling of condenser

• Check quantity of refrigerant.• Adjust quantity of refrigerant properly.• Check and repair condenser fins.• Check CHASSIS COOILNG SYSTEM, Fan and radiator, etc.




1.Pressure on low pressure side is high and that on high pressure side is low

2.Just after air conditioner is turned OFF, pressures on high and low pressure sides become the same

• Defective compressor

• Replace compres-sor.

Reference: If com-pressor does not compress normally <Its body is not hot>




1. Both pressures on high and low sides are high

2. Piping on low pressure side is frosted (or coated with dew)

• Defective expansion valve

• Check expansion valve.

• Check installation condition of heat sensor tube.

Reference: This trou-ble occurs after expan-sion valve is replaced in many cases.

M-26(b)



6. Air is in cycle<Indicated gauge pressure>

7. Refrigerant does not circulate (Cycle is clogged)<Indicated gauge pressure>

8. Water is in cycle<Indicated gauge pressure>

• When normal

• When abnormal




1.Both pressures on high and low sides are high2.Low-pressure piping is not cold3.Bubbles pass through liquid eye

• Entry of air

• Replace refrigerant.

• After finishing work, evacuate cycle securely.

Pressure on low pressure side Negative pressure



1. If cycle is clogged fully, negative pressure is indicated soon on low pressure side2. If cycle is clogged a little, negative pressure is indicated gradually on low pressure side

• Clogging of air conditioner cycle

• Check receiver, expansion valve, and compressor.Reference: Temper-atures at IN and OUT sides of defec-tive part are different.• After finishing work, evacuate cycle securely.



Pressure on low pressure side Negative pressure



1. Air conditioner operates normally when it is started. After a while, however, negative pressure is indicated on low pressure side.

• Freezing of water around expansion valve

• Check expansion valve, etc.• Replace receiver drier• After finishing work, evacuate cycle securely.

M-26



c) Internal air and external air cannot be selected

Table 1

Cause Remedy


Replace

Defective servomotor for internal air and external air

Replace

Defective linkage or defec-tive air conditioner unit

Adjust or replace


Repair or replace



Servomotor for internal air and external air (female) (1) - Air conditioner panel (female) (17)Servomotor for internal air and external air, air conditioner panel

Max. 1ΩServomotor for internal air and external air (female) (2) - Air conditioner panel (female) (13)

Servomotor for internal air and external air (female) (3) - Air conditioner panel (female) (3)

When air conditionerpanel is replaced, caninternal air and exter-nal air be selected?• Turn starting switch ON.• Turn air conditioner switch ON.• Change EXTERNAL/ INTERNAL air changeover switch between EXTERNAL and INTERNAL positions.



1

2

YES

NO

YES

NO

When servomotor for inter-nal air and external air isreplaced, can internal air andexternal air be selected?

YES

NO

3

M-26(c)



d) Air outlet cannot be selected

Table 1

e) Air flow rate does not change

Cause Remedy


Replace

Defective servomotor for blow mode

Replace

Defective linkage or defec-tive air conditioner unit

Adjust or replace


Repair or replace



Servomotor for blow mode (female) (1) - Air conditioner panel (female) (7)Servomotor for internal air and external air, air conditioner panel

Max. 1ΩServomotor for blow mode (female) (2) - Air conditioner panel (female) (4)

Servomotor for blow mode (female) (3) - Air conditioner panel (female) (14)

Cause Remedy


Replace

Melting of contacts between related blower relay (2) - (4)

Replace

M-26(d,e)

When air conditionerpanel is replaced, canair outlet be selected?

• Turn starting switch ON.• Turn air conditioner switch ON.• Set air outlet selector switch to FACE and FOOT.



1

2

YES

NO

YES

NO

When servomotorfor blow mode isreplaced, can airoutlet be selected?

YES

NO

3

• Turn starting switch ON.• Turn air conditioner switch ON.• Set air outlet selector switch to FACE and FOOT.

Is resistance betweenHi and Mid blowerrelay (2) and (4) nor-mal?

YES

NO

1

• Min. 1ΜΩ• Turn starting switch OFF.• Disconnect related blower relay.




SANDEN

Basic system of air, heater, and cooler...................................................................................................... 61- 3

Control panel ............................................................................................................................................. 61- 7

Compressor, condenser, and receiver drier............................................................................................... 61- 9

STRUCTURE AND FUNCTION SANDEN


STRUCTURE AND FUNCTION BASIC SYSTEM OF AIR, HEATER, AND COOLER


1. BASIC SYSTEM OF AIR, HEATER, AND COOLER

1. Air conditioner unit2. Control panel3. Condenser4. Air conditioner piping5. Compressor6. Receiver drier7. Engine coolant piping

a. To engineb. From engine

OutlineThis system is an air conditioner unit which consistsof a evaporator, heater core, blower, etc. and blowsout cold air and hot air.

• In heating modeAir in the cab is sucked in through the suction open-ing and heat-exchanged (heated) in the heater coreof the air conditioner unit, and then blown outthrough the duct and grille. The heat source of theheater core is the engine coolant.The blow temperature is adjusted with the tempera-ture adjustment switch on the control panel. If thetemperature adjustment switch is operated, thewater valve of the air conditioner unit opens orcloses to adjust the engine coolant flow rate, oradjust the temperature.

• In cooling modeAir in the cab is sucked in through the suction open-ing and heat-exchanged (dehumidified and cooled)in the evaporator of the air conditioner unit, and thenblown out through the duct and grille.



1-1. Detail of air conditioner unit



1. Unit fixing frame2. Packing3. Packing4. Bell mouth5. Blower case6. Blower and blower motor assembly7. Motor fixing plate8. Packing9. Unit panel10. Bracket11. Packing12. Packing13. Wiring harness assembly14. Band15. Packing16. Spacer17. Intake damper18. Spring19. Lever knob20. Sensor holder21. Thermistor22. Evaporator23. Expansion valve24. Outlet and inlet pipe assembly

(Equipped with dual pressure switch)25. Packing26. Resistor27. Packing28. Packing29. Packing30. External air intake duct31. EXTERNAL/INTERNAL air changeover lever32. Heater core and evaporator mounting bracket33. Heater core34. Hose clamp35. Heater hose36. Hose packing37. Bracket38. Bracket39. Water valve assembly40. Heat insulation material

41. Packing42. Unit bottom plate43. Drain fitting44. Packing45. Packing46. Grommet47. Unit fixing frame48. Packing49. Grommet50. Unit case51. Packing52. Packing



1-2. Component parts in air conditioner unit (Parts related to control)

ResistorThe resistor outputs signals according to the posi-tion of the blower switch to change the fan motorspeed of the blower.

ThermistorThe thermistor senses the blow-out temperature ofthe evaporator, outputs signals, and turns the com-pressor ON and OFF to prevent the evaporator fromfreezing. It is installed to the outlet side of the evap-orator.

Dual pressure switchWhen the refrigerant pressure on the high pressureside becomes abnormal, the dual pressure switchoutputs a signal to turn the compressor OFF to pro-tect the refrigerating cycle. This switch is installed tothe high-pressure piping side of the outlet and inletpipe assembly.This switch is turned OFF when the refrigerant pres-sure is below 0.1MPa 2.0 kg/cm2 or above 3.1MPa32 kg/cm2.

STRUCTURE AND FUNCTION CONTROL PANEL


2. CONTROL PANEL

1. Band2. Air conditioner relay3. Knob4. Air conditioner switch5. Nameplate6. Case7. Air flow selector switch (Blower switch)8. Temperature adjustment switch (Thermal control

knob)9. Bracket10. Control amplifier

2-1. Operation unit of panel

1. Temperature adjustment switch2. Air flow selector switch3. Air conditioner switch

OutlineThe control panel compares and calculates the inputsignals of various switches and sensors with themicrocomputer of the control amplifier in it and con-trols the water valve actuator, blower motor, andcompressor.

STRUCTURE AND FUNCTION CONTROL PANEL


2-2. Component parts in control box

Temperature adjustment switch (Thermal control knob)If the knob of the temperature adjustment switch isturned, the ON-OFF operation point of the air condi-tioner compressor and the opening ratio of the watervalve change. As a result, the temperature of the airfrom the evaporator and heater core changes. Con-sequently, the temperature of the air blown out fromthe air conditioner unit changes.

Air conditioner switchIf this switch is pressed while the air flow selectorswitch is turned ON, the compressor operatesaccording to the position of the temperature adjust-ment switch and blow-out temperature of the evapo-rator.

Air flow selector switch (Blower switch)If the knob of the air flow selector switch is turned, theair flow from the air conditioner unit is stopped or set to3 levels.

Compressor relayThe compressor relay turns the compressor ON andOFF according to the setting of the control amplifierand electronic thermal control system.

STRUCTURE AND FUNCTION COMPRESSOR, CONDENSER, AND RECEIVER DRIER


3. COMPRESSOR, CONDENSER, AND RECEIVER DRIER

1. Air conditioner piping (Low pressure)2. Air conditioner piping (High pressure)3. Condenser4. Air conditioner piping (High pressure)5. Bracket6. Receiver drier7. Air conditioner piping (High pressure)8. Compressor

a. From air conditioner unit (evaporator)b. To air conditioner unit (evaporator)

OutlineThe refrigerant gas returned from the evaporator iscompressed by the compressor and its temperatureand pressure rise. Then, it is sent to the condenserand cooled and liquefied there. Dirt and water in therefrigerant liquid are removed by the receiver drier.Then, the refrigerant liquid is sent through theexpansion valve to the evaporator and evaporatedthere.

STRUCTURE AND FUNCTION COMPRESSOR, CONDENSER, AND RECEIVER DRIER


TROUBLESHOOTING



SANDEN

Troubleshooting ........................................................................................................................................ 62-101

TROUBLESHOOTING


TROUBLESHOOTING


TROUBLESHOOTING

SANDEN

Information in troubleshooting table ......................................................................................................... 62-102

Air conditioner is defective........................................................................................................................ 62-103

Related electric circuit diagram ................................................................................................................ 62-107

TROUBLESHOOTING INFORMATION IN TROUBLESHOOTING TABLE


INFORMATION IN TROUBLESHOOTING TABLE

s The following information is summarized in the troubleshooting table and the related electrical circuit dia-gram. Before carrying out troubleshooting, understand that information fully.

User code Error code Failure codeTrouble

Trouble name displayed in trouble record

Panel display Panel display Panel display

Contents of trouble Condition at the time when the monitor panel or controller detects the trouble

Action of monitor panel or controller

The action taken by the monitor panel or controller to protect the system or devices when the monitor panel or controller detects the trouble

Problem that appears on

machine

The problem that appears on the machine as a result of the action taken by the monitor panel or controller (shown above)

Related information Information related to the detected trouble or troubleshooting

Possible causes and

standard value in normal state

Cause Standard value in normal state/Remarks on troubleshooting

1

Possible causes of troubleGiven numbers are refer-ence numbers, which do not indicate priority

<Contents of description>• Standard value in normal state to judge possible causes• Remarks on judgment

<Troubles in harness>• Disconnection Connector is connected imperfectly or harness is broken.• Grounding fault Harness which is not connected to chassis ground circuit

is in contact with chassis ground circuit.• Short circuit with power source Harness which is not connected to power source (24-V)

circuit is in contact with power source (24-V) circuit.

2

3

4

5

( )

TROUBLESHOOTING AIR CONDITIONER IS DEFECTIVE


AIR CONDITIONER IS DEFECTIVE

a) Air conditioner does not operate


Air conditioner is defectivea) Air conditioner does not operate- - -

Contents of trouble • The air conditioner does not operate.


-


machine

-

Related information

• Check that the fuse is not broken and the wiring harness between connectors is free of dis-connection in advance.

• If the air conditioner switch is turned ON but no air comes out when the air flow selector switch (blower switch) is turned ON (set in position 1, 2, or 3), carry out troubleshooting for "b) Air does not come out or air flow does not change" in advance.

Possible causes and



1Defective air condi-tioner switch

s Prepare with starting switch OFF, then carry out trouble-shooting without turning starting switch ON.

Air conditioner switch con-nector

Switch position Resistance

C-DON Max. 1ΩOFF Min. 1MΩ

2

Disconnection in wir-ing harness(Disconnection in wir-ing harness or defec-tive contact in connector)


Referring to the circuit diagram, check continuity between connectors. Resis-

tanceMax. 1Ω

3

Short circuit with chassis ground in wiring harness(Contact with ground circuit)


Referring to the circuit diagram, check insulation between each connector and ground (excluding ground circuit).

Resis-tance

Min. 1MΩ

4Defective control amplifier

s Prepare with starting switch OFF, then turn starting switch ON and carry out troubleshooting.

Replace with normal control amplifier.

Condition becomes normal

Control ampli-fier is defective

Condition does not become normal

Control ampli-fier is normal



b) Air does not come out or air flow does not change


Air conditioner is defectiveb) Air does not come out- - -

Contents of trouble • Air does not come out or air flow does not change


-


machine

-

Related information • Check that the fuse is not broken and the wiring harness between connectors is free of dis-connection in advance.

Possible causes and



1Defective air flow selector switch (blower switch)


Knob position Air flow selector switch terminal Resistance

0 Between all terminals Min. 1MΩ

1Between B - L/R, B - L/W, and L/R - L/W Max. 1ΩBetween terminals other than above Min. 1MΩ

2Between B - L/R, B - L/Y, and L/R - L/Y Max. 1Ω

Between terminals other than above Min. 1MΩ

3Between B - L/R, B - L/B, and L/R - L/B Max. 1ΩBetween terminals other than above Min. 1MΩ

2 Defective resistor


Resistor terminals Resistance

Between L and M1 Approx. 1.8ΩBetween M1 and M2 Approx. 0.7ΩBetween M2 and M0 Approx. 0.3Ω

3 Defective blower motor


Replace with normal blower motor


Blower motor is defective


Blower motor isnormal

4

Disconnection in wir-ing harness(Disconnection in wiring harness or defective contact in connector)


Referring to the circuit diagram, check continuity between connectors.

Resis-tance Max. 1Ω

5Short circuit with chassis ground in wiring harness(Contact with ground circuit)



Resis-tance Min. 1MΩ

6 Defective control amplifier


Replace with normal control amplifier


Control ampli-fier is defective


Control ampli-fier is normal



c) Blow-out temperature cannot be adjusted


Air conditioner is defectivec) Blow-out temperature cannot be adjusted

- - -

Contents of trouble • The blow-out temperature cannot be adjusted.


-


machine

-

Related information • Check that hot water is supplied to the inlet side of the water valve in advance.• Check that the fuse is not broken and the wiring harness between connectors is free of disconnection in advance.

Possible causes and



1Defective tempera-ture adjustment switch

s Prepare with starting switch OFF, then turn starting switch ON and turn blower switch ON (Set it in 1, 2, or 3) and carry out troubleshooting.

Temperature adjustment switch connector (2) Voltage

G/B-G/W Changes between 0 and approx. 5 V

G/B-Y/B Changes between 0 and approx. 5 V

G/B-Y/W Approx. 5V


Temperature adjustment switch connector (2) (Switch side) Knob position Resistance

Y/W-Y/BCOOL-MAX m Middle position Approx. 2.3kΩm Max. 1ΩMiddle position m HOT-MAX Max. 1Ω

Y/W-G/WCOOL-MAX m Middle position Approx. 2.3kΩMiddle position m HOT-MAX Approx. 2.3kΩm Max. 1Ω

2 Defective water valve assembly

s Prepare with starting switch OFF, then turn starting switch ON and turn blower switch ON (Set it in 1, 2, or 3) and carry out troubleshooting.


Replace with normal water valve assembly

Condition becomes normal Water valve assembly is defective

Condition does not become normal Water valve assembly is normal

3

Disconnection in wir-ing harness(Disconnection in wiring harness or defective contact in connector)


Referring to the circuit diagram, check continu-ity between connectors.


4

Short circuit with chas-sis ground in wiring harness(Contact with ground circuit)







Condition becomes normal Control amplifier is defective

Condition does not become normal Control amplifier is normal

Operation Rod operates according to operation of temperature adjustment switch



d) Air is not cooled or temperature cannot be adjusted (Electrical system)


Air conditioner is defectived) Air is not cooled or temperature cannot be adjusted (Electrical system)- - -

Contents of trouble • Air is not cooled or temperature cannot be adjusted (Electrical system).


-


machine

-

Related information • When the ambient temperature is below 2fC, this phenomenon does not indicate a trouble.• Check that the fuse is not broken and the wiring harness between connectors is free of disconnection in advance.

Possible causes and



1 Defective compres-sor clutch

s Prepare with starting switch OFF, then turn starting switch ON and carry out troubleshooting.Between (12) and chassis ground Voltage 10-15V

2 Defective dual pres-sure switch


Dual pressure switch connector Resis-tance Max. 1Ω

3 Defective air condi-tioner switch


Air conditioner switch connector Switch position Resistance

C-DON Max. 1ΩOFF Min. 1MΩ

4 Defective compres-sor relay


Compressor relay connector Source voltage between (1) and (2) Resistance

(3)-(4)Applied Max. 1Ω

Not applied Min. 1MΩ

5 Defective thermistor


Thermistor connector Test temperature Resistance

B/W-B/R0fC Approx. 7.2kΩ25fC Approx. 2.2kΩ

6

Disconnection in wiring har-ness(Disconnection in wiring harness or defective contact in connector)


Referring to the circuit diagram, check continuity between connectors.


7

Short circuit with chas-sis ground in wiring harness(Contact with ground circuit)







Condition becomes normal Control amplifier is defective

Condition does not become normal Control amplifier is normal

Compressor relay connector Resistance(1)-(2) Approx. 320Ω



Related electric circuit diagram



e) Air is not cooled sufficiently (Mechanical system)


Air conditioner is defectivee) Air is not cooled sufficiently (Mechanical system)- - -

Contents of trouble • Air is not cooled sufficiently because of a trouble in the mechanical system.


-


machine

-

Related information -

Possible causes and



1Refrigerant leakage through piping joint or part

• Check, then repair or replace if necessary.

2

Natural leakage through hoses (Refrig-erant has not been added for long period)

• Check quantity of refrigerant, then add new refrigerant if necessary.

3 Insufficient refrigerant • Add refrigerant to proper level.

4Defective expansion valve

• Check, then repair or replace if necessary.sCheck expansion valve for opening too wide and check

heat sensor tube for defective contact.

5Clogging of low-pres-sure circuit or evaporator

• Check for clogging, then clean or replace.

6Clogging of evapora-tor fins

• Check for clogging, then clean evaporator if necessary.

7 Clogging of filter • Check, then clean or replace.

8Defective installation of thermistor


9Air leakage through joint of air conditioner unit and duct

• Check, then repair or replace leaking part.

10Insufficient set air flow rate

• Increase set air flow rate.

11 Too much refrigerant• Check quantity of refrigerant, then discharge refrigerant to

proper level if necessary.

12 Entry of air• Evacuate cycle, then charge it with refrigerant to proper

level and replace receiver drier.

13 Clogging of condenser fins • Check for clogging, then clean fins if necessary.

14Defective compres-sion by compressor

• Check, then repair or replace.

15 Water in refrigerant circuit• Evacuate cycle, then charge it with refrigerant to proper

level and replace receiver drier.



f) Air is not heated sufficiently (Hot water circuit is defective)

g) Abnormal sound comes out


Air conditioner is defectivef) Air is not heated sufficiently (Hot water circuit is defective)- - -

Contents of trouble Air is not heated sufficiently (Hot water circuit is defective).Action of monitor panel or controller

-


machine

-

Related information • Check that water is not leaking through the hot water circuit.• Check that air if blown from air outlet.

Possible causes and



1 Clogging of heater core fins

• Check heater core fins for clogging. If clogged, clean them.s If this is the cause, the temperature of the heater core hot water inlet is high and that of the heater core hot water outlet is also high.

2 Air leakage through air conditioner unit

• Check the air conditioner unit for air leakage, then repair or replace if necessary.s If this is the cause, the temperature of the heater core hot water inlet

is high and that of the heater core hot water outlet is also high.

3Defective water valve (clogging, defective valve)

• Check the water valve for clogging of defect in the valve, then clean or replace it.s If this is the cause, the temperature of the heater core hot water

inlet is high but that of the heater core hot water outlet is low.

4 Clogging of heater core

• Check inside of the heater core for clogging, then repair or replace it if necessary.s If this is the cause, the temperature of the heater core hot water

inlet is high but that of the heater core hot water outlet is low.

5Clogging before hot water inlet of heater core

• Check the piping before the heater core for clogging, then repair or replace if necessary.s If this is the cause, the temperature of the heater core hot water inlet is low.


Air conditioner is defectiveg) Abnormal sound comes out- - -

Contents of trouble • Abnormal sound comes out.Action of monitor panel or controller

-


machine

-


Possible causes and



1 Defective installation of case mounting bolts (screws) • Check, then repair if necessary.

2 Interference of fan case, etc. or breakage of fan • Check, then repair or replace if necessary.

3 Foreign matter in blower motor or defective blower motor

• Check, then remove foreign matter and repair or replace if necessary.

4 Defective expansion valve

• Check, then replace if abnormal sound (blowing sound or hiss of refrigerant) is detected.

5 Loosened or worn compressor belt

• Check, then repair or replace if looseness or wear is detected.

6 Too much or insuffi-cient refrigerant

• Check the quantity of the refrigerant. If it is too much or insufficient, adjust it properly.

7 Defective compressor • Check, then repair or replace if necessary.



h) Water leaks


Air conditioner is defectiveh) Water leaks- - -

Contents of trouble • Water leaks.


-


machine

-


Possible causes and



1Clogging of water drain hole in air con-ditioner unit

• Check, then repair if necessary.

2

Clogging, bending, defective installation, or hole of drain hose of air conditioner unit


3Cracking of air condi-tioner unit case

• Check, then repair or replace if any crack is detected.

4Defective mounting bolts (screws) of air conditioner unit case


5Development pipe joints of hot water circuit


6 Defective heater core • Check, then repair or replace if necessary.

7 Defective water valve • Check, then repair or replace if necessary.

(5)



i) Internal air and external air cannot be selected


Air conditioner is defectivei) Internal air and external air cannot be selected- - -

Contents of trouble • Internal air and external air cannot be selected.


-


machine

-


Possible causes and



1Malfunction of exter-nal/internal air changeover lever

• Check, then clean and repair or replace if necessary.

2Malfunction of intake damper

• Check, then clean and repair or replace if necessary.

3Clogging of external air intake duct of unit

• Check, then clean if necessary.

(5)




SANDEN

Disassembly, assembly of air conditioner unit .......................................................................................... 63- 2

Disassembly, assembly of control panel....................................................................................................63- 11

DISASSEMBLY AND ASSEMBLY DISASSEMBLY, ASSEMBLY OF AIR CONDITIONER UNIT


DISASSEMBLY, ASSEMBLY OF AIR CONDITIONER UNIT



1. Unit fixing frame2. Packing3. Packing4. Bell mouth5. Blower case6. Blower and blower motor assembly7. Motor fixing plate8. Packing9. Unit panel10. Bracket11. Packing12. Packing13. Wiring harness assembly14. Band15. Packing16. Spacer17. Intake damper18. Spring19. Lever knob20. Sensor holder21. Thermistor22. Evaporator23. Expansion valve24. Outlet and inlet pipe assembly

(Equipped with dual pressure switch)25. Packing26. Resistor27. Packing28. Packing29. Packing30. External air intake duct31. EXTERNAL/INTERNAL air changeover lever32. Heater core and evaporator mounting bracket33. Heater core34. Hose clamp35. Heater hose36. Hose packing37. Bracket38. Bracket39. Water valve assembly40. Heat insulation material

41. Packing42. Unit bottom plate43. Drain fitting44. Packing45. Packing46. Grommet47. Unit fixing frame48. Packing49. Grommet50. Unit case51. Packing52. Packing



DISASSEMBLY

1. Remove external/internal air changeover lever(31).

2. Remove unit fixing frame (1).3. Remove bracket (10) and unit panel (9) from unit

case (50).

4. Remove wiring harness assembly (13).5. Remove blower case (5) from unit case (50).

6. Remove bell mouth (4) from blower case (5).

7. Remove motor fixing plate (7) from blower case(5).

8. Remove clip (53) and fan (54).s Remove fan (54) stamped with R.

9. Pull blower and blower motor assembly (6) outof blower case (5).



10. Remove unit bottom plate (42) and packing (41)from unit case (50).

11. Remove evaporator, expansion valve, and out-let/inlet pipe assembly (55).

s Take care not to damage wiring harness (57).

12. Disassemble the evaporator, expansion valve,and outlet/inlet pipe assembly into evaporator(22), expansion valve (23), and outlet/inlet pipeassembly (24).

13. Remove 2 sensor holders (20) from evaporator(22).

14. Remove thermistor (21) from sensor holder (20).



15. Remove grommets (49).16. Remove heater hose (35).17. Remove brackets (37) and (38) and heater core

(33).

18. Remove water valve assembly (39) from unitcase (50).



ASSEMBLY

1. Install water valve assembly (39) to unit case(50).

2. Install heater core (33) and secure it with brack-ets (37) and (38).

3. Install heater hose (35).s Install hose clamp (34) securely.s Install heater hose (35) so that part "a" will be

in parallel.

4. Install grommets (49) to outlet and inlet of theheater pipe.

5. Install thermistor (21) to sensor holder (20).s Install the thermistor so that only sensor unit (56)

will be projected to the side of sensor holder (20).6. Install sensor holder (20) to evaporator (22).s Install the sensor holder so that sensor unit (56) of the

thermistor will be set as shown in the following figure.Distance a: 130 mm from end of fineDistance b: 210 mm from end of evaporator (19th fin)



7. Install expansion valve (23) and outlet/inlet pipeassembly (24) to evaporator (22).

8. Install evaporator, expansion valve, and outlet/inlet pipe assembly (55).

s Put wiring harness (57) on water valve assem-bly (39) side.

9. Install packing (41) and unit bottom plate (42) tounit case (50).

10. Install blower and blower motor assembly (6) toblower case (5).

11. Install fan (54) to the motor shaft and secure itwith clip (53).

s Check that there is the a stamp of R on fan(54).

12. Install motor fixing plate (7) to blower case (5) andsecure blower and blower motor assembly (6).

s Tighten 2 bolts a first.



s Install blower and blower motor assembly (6)so that wiring harness (58) and motor coolinghole (59) will be set as shown in the followingfigure.

s Install the blower and blower motor assemblyso that clearance a between fan (55) andblower case (5) will be as follows.Clearance a: 4 v0.5 mm

13. Install bell mouth (4) to blower case (5).

14. Install blower case (5).s Set the blower case diagonally as shown in the

following figure, and then push in the partmarked with the arrow to install.

s Pass wiring harness (58) through part a inadvance.



15. Connect wiring harness assembly (13) to eachpart in the unit.

16. Install unit panel (9) to unit case (50).s Fix the grommet of wiring harness assembly

(13) to the cut of part a.17. Install bracket (10).

18. Install unit fixing frame (1).19. Install external/internal air changeover lever

(31).

(5)

DISASSEMBLY AND ASSEMBLY DISASSEMBLY, ASSEMBLY OF CONTROL PANEL


DISASSEMBLY, ASSEMBLY OF CONTROL PANEL

1. Band2. Air conditioner relay3. Knob4. Air conditioner switch5. Nameplate

6. Case7. Air flow selector switch (Blower switch)8. Temperature adjustment switch (Thermal control knob)9. Bracket10. Control amplifier

DISASSEMBLY

1. Remove knob (3).2. Remove air flow selector switch (blower switch)

(7) and temperature adjustment switch (thermalcontrol knob) (8).

3. Hold the stopper claws and remove air condi-tioner switch (4).

4. Remove bracket (9) and control amplifier (10)together.

s Do not give an impact to these parts.5. Remove air conditioner relay.

ASSEMBLY

1. Install air conditioner relay (2).2. Install bracket (9) and control amplifier (10)

together.3. Push air conditioner switch (4) straight into case

(6) to install.4. Install air flow selector switch (blower switch) (7)

and temperature adjustment switch (thermalcontrol knob) (8).

5. Install knob (3).s Check that you can operate the control panel

smoothly.

(5)




ZEXEL VALEO (NEW REFRIGERANT (R134a) TYPE)

Comparison of applicable models and air conditioner units .................................................................... 71- 2

Configuration and functions of refrigerating cycle ................................................................................... 71- 3

Outline of refrigerating cycle.................................................................................................................... 71- 4

Outline of main parts................................................................................................................................ 71- 6

Outline of control system ......................................................................................................................... 71- 10


STRUCTURE AND FUNCTIONCOMPARISON OF APPLICABLE MODELS AND AIR CONDITIONER UNITS

COMPARISON OF APPLICABLE MODELS AND AIR CONDITIONER UNITSNote 1) Many machine models are equipped with air conditioners as shown below. For troubleshooting for dif-

ferent models, different wiring harness connectors are checked. The air conditioner units and controlunits are basically the same, however.

Note 2) Some air conditioner units have different configurations, depending on the serial No. and type (auto-matic or manual) as shown below. They are basically the same, however.The automatic air conditioners for PC78US-6 and PC128US-2 are used as examples for the followingexplanation.

• Applicable models

• Comparison of air conditioner units

1

Standard machine models described in this manual

PC78US-6S/No. 4001 - 6500

PC78US-6S/No. 6501 and up


PC128US-2S/No. 7301 - 9500



Other hydraulic excavator models (Having the same connectors)

PC78UU-6PC138US-2

PC78UU-6PC138US-2

PC78UU-6PC138US-2

Other hydraulic excavator models for which this manual can be used for referencea Wiring harnesses are unknown

PC308US-3 PC228US-3 PC308US-3

Other models for which this manual can be used for referencea Wiring harnesses are unknown

CD110R-2 - GD655-3

Part No. of air conditioner unit 22B-979-1660 22U-979-1730 22U-979-1720

2 SpecificationCommon to auto-matic and manual

types

Special to automatic type

Special to manual type

SpecificationCommon to

automatic and manual types

Special to automatic type

Special to manual type

3

Different part Part name Part No. Part No. Part No. Contents1 Case assembly 534136-9921 534138-6620 534138-6620 Eliminate lining

from case and wind onto evapora-tor

2 534136-9321 534138-6720 534138-6720

3 Evaporator assembly 503700-4760 503700-4770 503700-4770

4 Pipe assembly 534057-3720 535237-9220 535237-9220 Add sight glass

5 Wiring harness 536021-6501 536021-6501 536022-3500Common to

automatic and manual types

6 Sensor (Internal air) 582623-8500 582623-8500 Eliminated7 Bracket 534102-6000 534102-6000 Eliminated8 Tapping screw 012514-1640 012514-1640 Eliminated9 Sensor (Water temperature) 582623-1800 582623-1800 Eliminated

10 Clip 580529-7000 580529-7000 Eliminated11 Screw 012155-1440 012155-1440 Eliminated12 Insulator 583032-2300 583032-2300 Eliminated

COMPARISON OF APPLICABLE MODELS AND AIR CONDITIONER UNITS


STRUCTURE AND FUNCTION CONFIGURATION AND FUNCTIONS OF REFRIGERATING CYCLE

CONFIGURATION AND FUNCTIONS OF REFRIGERATING CYCLE

Component

ItemCompressor Condenser Expansion valve Evaporator

Location Engine compartment Front of radiator in many cases

Under operator's seat (In air conditioner unit)

Under operator's seat (In air conditioner unit)

Function

Circulates refrigerant gas and increases its temperature and pressure so that it can be liquefied easily in condenser.

(Compression of refrigerant)

Condenses refrigerant to discharge heat absorbed in evaporator.

(Condensation of refrig-erant)

Makes refrigerant liquid and gas of low temperature which can evaporate easily and controls flow rate.

(Restriction of refriger-ant)

Evaporates refrigerant to absorb heat from (or cool) air around evaporator.

(Evaporation of refrig-erant)

State of refrigerant

Adiabatic compres-sion

Constant pressure change

Adiabatic expansion Constant pressure change

6249

LiquidGasGasGas Liquid LiquidGas GasLiquid

Gas


STRUCTURE AND FUNCTION OUTLINE OF REFRIGERATING CYCLE

OUTLINE OF REFRIGERATING CYCLE

The refrigerating cycle performs the following 4 actions and the refrigerant is liquefied and gasified repeatedly while it is circuited in the cycle.

1. Compression (Compressor)

The refrigerant gas is compressed by the com-pressor to the state where it can be liquefied easily at the normal temperature (ambient tem-perature).The refrigerant evaporated in the evaporator issucked in the compressor.This action is performed to keep the refrigerantpressure in the evaporator low so that the refrig-erant liquid can continue evaporation activelyeven if the ambient temperature is close to 0°C.The refrigerant gas sucked in the compressor iscompressed in the cylinder and its pressure andtemperature are so changed that it can be lique-fied easily when it is cooled with the external airat the normal temperature.

2. Condensation (Condenser)

The refrigerant gas in the condenser is cooled tobe liquefied with the external air.The refrigerant gas of high temperature and highpressure discharged from the compressor iscooled to be liquefied with the external air andthen stored in the receiver drier.The heat discharged from the refrigerant of hightemperature and high pressure discharged fromthe compressor is called the condensation heat,which is the total of the heat that the refrigerantabsorbed from the operator's cab through theevaporator (vaporization heat) and the work per-formed to compress the refrigerant (the valueconverted into heat).During condensation, the refrigerant gas andrefrigerant liquid are mixed together in the con-denser. While the refrigerant gas changes to therefrigerant liquid, the relationship between thepressure (condensation pressure) and tempera-ture (condensation temperature) is kept con-stant.

Reference: The pressure varies with the type ofthe refrigerant and condensationtemperature.

3. Expansion (Expansion valve)

The pressure of the refrigerant liquid is lowered bythe restricting action of the expansion valve to alevel at which the refrigerant is evaporated easily.The action to lower the pressure of the refriger-ant to a level at which the refrigerant is evapo-rated easily before the refrigerant is sent to theevaporator is called expansion.The expansion valve which performs this actionalso controls the flow rate of the refrigerant.In other words, the quantity of the refrigerant liq-uid evaporated in the evaporator is decided bythe quantity of heat to be removed (refrigerationload) at the specified evaporation temperature(evaporation pressure), and the expansion valvesenses it and controls the refrigerant flow rateproperly.

[* 1] RestrictionIf there is a sharply narrowed part in a pipe inwhich a liquid is flowing, it is resistance to theflow. Since the sectional area is increasedsharply after this part, the liquid expands quicklyand its pressure and temperature lower. No heatis exchanged between the inside and outside ofthe pipe during this action.

4. Evaporation (Evaporator)

The refrigerant changes from liquid to gas(superheated vapor) in the evaporator.The refrigerant mist in the evaporator evapo-rates actively.At this time, the refrigerant evaporates quickly,absorbing heat necessary for evaporation (latentheat of vaporization) from the air around thecooling fins (air in the operator's cab). Thecooled air is spread in the operator's cab by thefan to lower the temperature in the operator'scab.


STRUCTURE AND FUNCTION The refrigerating cycle performs the following 4 actions and the

The refrigerant mist sent through the expansionvalve and the evaporated refrigerant are mixedtogether in the evaporator. While the refrigerantliquid changes to the refrigerant gas, the rela-tionship between the pressure (evaporationpressure) and temperature (evaporation temper-ature) is kept constant. If the pressure is set, thetemperature is decided automatically.That is, the relationship between the above pres-sure and temperature is equal to the relationshipbetween saturation pressure and saturation tem-perature.To evaporate the refrigerant at lower tempera-ture, the pressure in the evaporator must be keptlower.Accordingly, the evaporated refrigerant issucked in the compressor.The refrigerant circulates in the refrigeratingcycle, repeating the above 4 actions, to movethe heat from the operator's cab where the tem-perature is low to the outside where the temper-ature is high.

OUTLINE OF REFRIGERATING CYCLE


STRUCTURE AND FUNCTION OUTLINE OF MAIN PARTS

OUTLINE OF MAIN PARTS

1. Compressor assembly

1) CompressorThe compressor is of swash plate type.The swash plate is installed to the shaft. Therotary motion of the shaft is converted intothe reciprocating motion to suck, compress,and discharge the refrigerant.

2) Magnet clutchThe magnet clutch is used to drive or stopthe compressor while the engine is running.While the compressor is not driven, only thepulley is revolving.When the compressor is driven, a currentflows in the field coil to make a strong elec-tromagnet, which attracts the drive plate torotate the compressor shaft and the pulleytogether.

3) Relief valve (Installed to only PC1238US-2)When the pressure in the compressorexceeds the set pressure of the relief pres-sure, the relief valve opens to discharge therefrigerant. If the pressure lowers, the reliefvalve closes.

2. Condenser

The condenser is of parallel flow type.The refrigerant gas of high temperature and highpressure sent from the compressor is cooled tobe liquefied with the cooling fan of the engine.a PC128US-2 has a sub-cool condenser made

one with the receiver drier.

3. Receiver drier

The receiver drier is of aluminum flat head type.The receiver drier has the following functions.q The receiver drier stores the refrigerant to

operate the cooling cycle smoothly.q The receiver drier removes dirt and water

from the refrigerant.q Flowing condition of the refrigerant is seen

through the sight glass.q If the temperature of the cycle rises for some

reason, the lead at the center of the fusibleplug melts and the refrigerant is dischargedout to secure the safety.

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• The main parts under the operator's seat are roughly classified into air conditioner unit (1), intake duct (2),and mode duct (3).

4. Intake duct (2)

The intake duct selects the external air or inter-nal air to be sucked in the fan motor of the airconditioner unit.Filter (4) is installed to the air outlet side of theintake box to remove dust from the external airand internal air and supply clean air to the airconditioner unit. The intake duct includes theintake actuator and intake door.

5. Mode duct (3)

The mode duct changes the flow of the aircooled with the evaporator of the air conditionerunit, air heated with the heater core, or mixtureof the cooled air and heated air to each air out-let.There are 3 selectable positions and the opera-tor can select a favorite flow with the controlpanel.The mode duct includes the mode actuator andmode door.

6. Air conditioner unit (1)

The air conditioner unit includes the blowermotor, evaporator, heater core, mix door, andinternal air filter (5). Its piping has the pressureswitch for protection and the sight glass to checkthe refrigerant. It is thin and compact and has aconnecting hole to take in external air.

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1) Expansion valveThe expansion valve is of internal equal pres-sure type.The expansion valve converts the high pressurerefrigerant liquid sent from the receiver drier intolow pressure refrigerant mist by restricting actionand sends it to the evaporator.The expansion valve also adjusts the refrigerantflow rate automatically according to the variablethermal load.

2) EvaporatorThe evaporator is of serpentine type.The refrigerant mist made by the expansionvalve evaporates actively in the evaporator andits temperature lowers.The air in the operator's cab is sucked in the fanand passed and cooled through the evaporator.

3) ThermostatThe thermostat senses the temperature of thecooled air just after it is blown out of the evapo-rator and turns the compressor OFF before theevaporator is frozen.a If the thermostat does not touch the evapo-

rator, it cannot sense the temperature andcooling does not stop. As a result, evapora-tor is frosted and air flow rate is lowered.

4) Pressure switchThe pressure switch senses abnormally low orhigh pressure and turns the compressor OFF.

k When replacing the pressure switch, collect therefrigerant in advance.

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5) Fan motorA sirocco fan is used to lower the noise.

6) Heater coreThe hot water from the engine cooling water(hot) outlet flows in the heater core, where itheats the air sent by the fan motor.

Pressure Between terminals

Max. approx. 0.177 MPa 1.8 kg/cm2, Min. approx.

2.65 MPa 27 kg/cm2There is not continuity

Between approx. 0.177 and 2.65 MPa

1.8 - 27 kg/cm2There is continuity

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STRUCTURE AND FUNCTION OUTLINE OF CONTROL SYSTEM

OUTLINE OF CONTROL SYSTEMThe control panel is installed to the top of the control unit. It receives various signals and indicates them withthe LED and controls the air conditioner unit, actuators of 3 types, and compressor.

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STRUCTURE AND FUNCTION OUTLINE OF CONTROL SYSTEM

• Configuration of control panel and air conditioner unitThe relationship between the switches on the control panel (top of the control unit) and the actuators of theair conditioner unit is shown by [1] - [5] in the following figures.

• Control panela The control panel shown below is for the automatic air conditioner.

• Configuration of air conditioner unit

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List of tools for testing, adjusting, and trouble shooting ......................................................................... 72- 2Inspection and maintenance table for air conditioner ............................................................................ 72- 3Inspection and maintenance table for heater ........................................................................................ 72- 4Inspection with self-diagnosis function .................................................................................................. 72- 5

Outline ....................................................................................................................................... 72- 5Self-diagnosis procedure ........................................................................................................... 72- 6Step 1 inspection of display unit and display led ...................................................................... 72- 7Step 2 inspection of each sensor and actuator ........................................................................ 72- 8Step 3 display of past troubles ................................................................................................. 72- 9Step 4 inspection of each output device ................................................................................... 72- 10Step 5 set temperature correcting function .............................................................................. 72- 11

Inspecting temperature adjustment (air mix door and mix actuator) ..................................................... 72- 12Inspecting selection of air outlet (mode door and mode actuator) ......................................................... 72- 13Inspecting selection of intake (intake door and intake actuator) ............................................................ 72- 13Inspecting relays .................................................................................................................................... 72- 14Checking for refrigerant leakage ........................................................................................................... 72- 15Charging with refrigerant ....................................................................................................................... 72- 18Handling refrigerant can and compressor oil ......................................................................................... 72- 19Precautions for connecting air conditioner piping .................................................................................. 72- 22

TESTING AND ADJUSTING LIST OF TOOLS FOR TESTING, ADJUSTING, AND TROUBLESHOOTING



Testing and adjusting item

Sym-bol Part No. Part name Remarks

Measuring refrigerant pressure in air condi-tioner, charging with refrigerant, and dis-charging refrigerant

N

1 799-703-1200 Service tool kit For new refrigerant R134a

2

799-703-1100 Vacuum pump For new refrigerant R134a in Japan (100 V)



Leakage of refrigerant O 799-703-1400 Gas leak tester For countries other than USA


TESTING AND ADJUSTING INSPECTION AND MAINTENANCE TABLE FOR AIR CONDITIONER


The air conditioner (cooler/heater) needs "periodic inspection and maintenance" (there is a charge for it) for constant use under the best condition.

If the air conditioner has a trouble, much repair cost is required. Accordingly, recommend that the cus-tomer should take periodic inspection and mainte-nance.

INSPECTION AND MAINTENANCE TABLE FOR AIR CONDITIONER

a Daily inspection. Q Inspection. w Disassembly. q Replacement

AdviceqInspect the belt at intervals of 6 months or about 50 operating hours.qDirect the customer to inspect the items marked with a every day.

No. Inspection item Contents of inspection MaintenanceInspection/Maintenance

period (interval)6

months12

months24

months36

months

1 Start and stop Flow of cold air Q

2 Refrigerant and pressure Quantity of refrigerant and gauge pressure Q

3 Condenser Stain and clogging Clean aQ

4 Condenser fan motor Operating condition Q

5 Belt Tension, flaw, and deterioration Adjust or replace Q

6 Air filter Stain, clogging, and removal Adjust or replace aQ

7 Clean or replace Stain, clogging, and removal Adjust or replace aQ

8 Piping and its connections Refrigerant leakage Q

9 Cycle parts and their mounting parts Refrigerant leakage, loose-ness, and breakage Q

10 Clearance between cycle parts and machine parts Clearance Secure clearance Q

11 Pressure switchOFF when high pressure is above 2,648 kPa 27 kg/cm2GOFF when high pressure is below 176 kPa 1.8 kg/cm2G

If defective, replace Q

12 Compressor Operating condition Q w

13 Valve of compressor Breakage Q w

14 Bearing of compressor Operating condition (Abnor-mal sound) Q w

15 Magnet clutch Operating condition and wear of attracting surface Q

16 Bearing of magnet clutch Operating condition (Abnor-mal sound) Q

17 Tension pulley Operating condition (Abnor-mal sound) Q

18 High pressure and low pressure hoses Flaw, deterioration, and breakage Q

19 Air conditioner unit (Evaporator) Stain, clogging, and breakage If clogged, disassemble Q

20 Electric parts and their wiring Operating condition and breakage Q

21 Receiver drier Clogging and breakage Q q

22 Expansion valve Operating condition Q

23 Compressor assembly w

INSPECTION AND MAINTENANCE TABLE FOR AIR CONDITIONER

TESTING AND ADJUSTING INSPECTION AND MAINTENANCE TABLE FOR HEATER


INSPECTION AND MAINTENANCE TABLE FOR HEATER

Q Inspection

No. Inspection item Contents of inspection Maintenance

Inspection/Maintenance period (interval)

6 months 12 months

1 Start and stop Flow of hot air Q

2 Engine coolant Coolant level Q

3 Piping and its connections Water leakage and clamping condition

Q

4 Cycle parts and their mounting parts

Water leakage, loose-ness, and breakage

Q

5 Clearance between cycle parts and machine parts

Clearance Q

6 Heater hose Flaw, deterioration, and breakage

Q

7 Fan motor Operating condition Q

8 Air conditioner unit (Heater core) Stain and clogging If clogged, disassemble Q

9 Electric parts and their wiring Operating condition and breakage

Q

TESTING AND ADJUSTING INSPECTION WITH SELF-DIAGNOSIS FUNCTION


INSPECTION WITH SELF-DIAGNOSIS FUNCTION1. Outline• There are steps 1 - 5 in the self-diagnosis. You can check each sensor (which is not installed to the air con-

ditioner having only the manual mode) for trouble according to those steps. You can also output control sig-nals specified for each output device and inspect the operation of the device (excluding the intakeactuator). If a troubled section is detected, every part of that section must be inspected.

Step 1 Inspection of display unit and display LEDStep 2 Inspection of each sensor and actuator (excluding intake actuator)

Each sensor, mix actuator, and mode actuator are inspected in real time.Step 3 Display of past troubles

The recorded past troubles of each sensor, mix actuator, and mode actuator are displayed.Step 4 Inspection of each output device

The pattern operation of each output device is performed.Step 5 Set temperature correcting function

• Starting self-diagnosis mode1) Turn the air conditioner OFF.2) While pressing the air conditioner switch and foot switch, turn the key switch from the OFF position to

the START position to start the engine, and the self-diagnosis (step 1) starts.

Note: If the battery voltage lowers below 24V during step 4, the operating speed of the actuator lowers.As a result, the actuator may be judged NG, even if it is operating normally. Accordingly, start theengine when performing the self-diagnosis.

• Finishing self-diagnosis1) Turn the key switch OFF.2) Hold the OFF switch for 3 seconds.

a Selecting a step• Select step 1 - 5 with the fan switch.

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2. Self-diagnosis procedure

Outline

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3. Step 1 Inspection of display unit and display LEDThe display LED of each switch on the panel is inspected.All of the LEDs flash in the following order. (Up to 6 LEDs flash simultaneously.)If normal, each LED is turned ON and OFF twice at intervals of 0.5 seconds in the flashing period.

Display order of LED

Note) -- means that LED is turned OFF.

When normal: All the display LEDs light up.When abnormal: The LED of a troubled section does not light up.

Is the display LED normal?YES > Go to step 2NO > Replace the control unit.

STEP 1 STEP 2 STEP 3 STEP 4 STEP 1 • • •

A/C Flashing Flashing Flashing Flashing Flashing Flashing

Front/Rear vent Flashing -- -- -- Flashing --

Rear vent -- Flashing -- -- -- Flashing

Foot -- -- Flashing -- -- --

AUTO Flashing Flashing Flashing Flashing Flashing Flashing

LO Flashing -- -- -- -- Flashing

ML -- Flashing -- -- -- --

MH -- -- Flashing -- -- --

HI -- -- -- Flashing -- --

TEMP 1 Flashing -- -- -- Flashing --

TEMP 2 -- Flashing -- -- -- Flashing

TEMP 3 -- -- Flashing -- -- --

TEMP 4 -- -- -- Flashing -- --

TEMP 5 Flashing -- -- -- Flashing --

TEMP 6 -- Flashing -- -- -- Flashing

TEMP 7 -- -- Flashing -- -- --

TEMP 8 -- -- -- Flashing -- --

Same operation is repeated

DisplayLED



4. Step 2 Inspection of each sensor and actuator1. Press the fan UP switch to select step 2.2. During step 2, the front/rear vent LED flashes. After the inspection is finished, the front/rear vent LED

lights up.When normal: Only front/rear vent LEDs lights up.When abnormal: Front/rear vent LEDs lights up and TEMP LED flashes.

After operation is confirmed, each output returns to the initial position.

How is the inspection result?OK > Go to step 3NG > See the following

Inspection of troubled sensor and actuatorIf a sensor or an actuator is troubled, the TEMP LED corresponding to it flashes.If multiple sensors or actuators are troubled, the LED flashes twice at intervals of 0.5 seconds, and then the next trouble is displayed.

Contents of display by LED

Caution: While the sunlight sensor is not exposed to the sunlight, a trouble is displayed.• Not installed to the air conditioner having only manual mode. (* 1)• The external air sensor is not installed to the automatic air conditioner of PC78US-6, either.

Object of diagnosis Location of display LED Reference section

Mix actuator TEMP 1 Inspecting temperature adjustment (Air mix door and mix actuator) (Page 72-12)

Mode actuator TEMP 2 Inspecting selection of air outlet (Mode door and mode actuator) (Page 72-13)

Internal air sensor (* 1) TEMP 3 Troubleshooting, How to inspect electric parts, internal air sensor (Page 73-8)

External air sensor (* 1) TEMP 4 Troubleshooting, How to inspect electric parts, external air sensor (Page 73-8)

Water temperature sensor (* 1) TEMP 5 Troubleshooting, How to inspect electric parts, water temperature sensor (Page 73-8)

Sunlight sensor (* 1) TEMP 6 Troubleshooting, How to inspect electric parts, sunlight sensor (Page 73-8)



5. Step 3 Display of past troubles1) Press the fan UP switch to select step 3.2) During step 3, the front/rear vent LED flashes. After the inspection is finished, the front/rear vent LED

lights up.If there is not a past trouble: Only front/rear vent LEDs lights up.If there is any past trouble: Front/rear vent LEDs lights up and TEMP LED flashes.

How is the inspection result?OK > Go to step 4NG > See the following

Inspection of past trouble of sensor and actuatorIf a sensor or an actuator has been troubled, the TEMP LED corresponding to it flashes.If multiple sensors or actuators have been troubled, the LED flashes twice at intervals of 0.5 seconds, and then the next trouble is displayed.

Contents of display by LED

Caution: As trouble of the sunlight sensor, only short circuit is recorded.• Not installed to the air conditioner having only manual mode. ( * 1 )• The external air sensor is not installed to the automatic air conditioner of PC78US-6, either.

How to delete past trouble recordHold the air conditioner switch for 3 seconds in step 3, and the past trouble record is deleted. At this time, the air conditioner LED flashes 5 times, and then it returns to the normal control mode.Each switch is initialized.

Object of diagnosis Location of display LED

Mix actuator TEMP 1

Mode actuator TEMP 2

Internal air sensor ( * 1 ) TEMP 3

External air sensor ( * 1 ) TEMP 4

Water temperature sensor ( * 1 ) TEMP 5

Sunlight sensor ( * 1 ) TEMP 6



6. Step 4 Inspection of each output device1) Press the fan UP switch to select step 4.2) Each time the foot switch is pressed, TEMP LEDs light up one by one from the left to the right.3) Inspect the air outlet, spurting air temperature, voltage applied to the blower fan motor, and operation

of the compressor (magnet clutch).

How is the inspection result?OK > Finish self-diagnosisNG > • The air outlet does not change: See Inspecting selection of air outlet. (Mode door and mode actuator)

• The spurting air temperature does not change: See Inspecting temperature adjustment. (Air mix door and mix actuator)

• Defective operation of blower fan motor: See Troubleshooting table • Defective operation of compressor: See Troubleshooting table

Objective deviceSTEP Same opera-

tion is repeated

1 2 3 4 1 • • • •

Lighting of LED TEMP 1 TEMP 2 TEMP 3 TEMP 4

Mode door Front/Rear vent Rear vent Rear vent Foot

Opening ratio of air mix door Full cool 50% 50% Full heat

Voltage applied to blower fan motor 10V 14.5 19.5 Source

voltage

Compressor (Magnet clutch) ON ON ON OFF



7. Step 5 Set temperature correcting function (Function of setting difference between set tempera-ture and control temperature)OutlineWhen the set spurting air temperature is different from the sensory temperature, you can change the con-trol temperature of the control unit from the set (displayed) temperature.Method1) Select the self-diagnosis mode.2) In self-diagnosis step 4, press the fan UP switch and AUTO switch simultaneously.3) The temperature setting LEDs (2 pieces at the center) light up.4) Each time the temperature setting switch (UP or DOWN) is pressed, a different temperature setting

LED lights up and you can set the correction temperature freely between +2 °C and -2 °C.

Reference: If the correction temperature is set while the leftmost temperature setting LED (-2 °C) is lighting, the control unit controls the temperature to 25 °C - 2 °C = 23 °C. Accordingly, the actual tempera-ture is controlled below the displayed temperature.

Caution: If the negative terminal of the battery is disconnected or the battery voltage lowers below 20V, the difference between the set (displayed) temperature and control temperature is cancelled.

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TESTING AND ADJUSTING INSPECTING TEMPERATURE ADJUSTMENT (AIR MIX DOOR AND MIX AC-


INSPECTING TEMPERATURE ADJUSTMENT (AIR MIX DOOR AND MIX ACTUATOR)

• If a mix actuator error is detected by the self-diagnosis, inspect the mix actuator visually.

1. Remove operator's seat undercover (1).

2. Turn the starting switch ON (and start theengine) and operate the temperature settingswitch of the control panel from the left end (FC)to the right end (FH) to see if levers 1 and 2operate in 8 steps.

a If the result is NG, see Troubleshooting, E-4 Temperature cannot be adjusted

• Front side of air conditioner unit under operator's seat

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INSPECTING TEMPERATURE ADJUSTMENT (AIR MIX DOOR AND MIX ACTUATOR)

TESTING AND ADJUSTINGINSPECTING SELECTION OF AIR OUTLET (MODE DOOR AND MODE ACTU-


INSPECTING SELECTION OF AIR OUTLET (MODE DOOR AND MODE ACTUATOR)

• If a mode actuator error is detected by the self-diagnosis, inspect the mode actuator visually.

1. Remove monitor panel under cover (1).2. Loosen right console (2) and move it inward, and

then remove cover (3).3. Disconnect connector M88, move duct joint A in

the direction of the arrow, and then removemode duct (5) toward you (so that you can seeinside)

4. Connect connector M88 and turn the startingswitch ON (and start the engine).

5. Operate the mode switch of the control panel tosee if mode door (4) operates normally.

a If the result is NG, see Troubleshooting, Trouble-shooting for selection of air outlet (Mode door and mode actuator)

INSPECTING SELECTION OF INTAKE (INTAKE DOOR AND INTAKE ACTUATOR)

• Since selection of the intake cannot be inspectedby the self-diagnosis, inspect it according to thefollowing procedure.

1. Disconnect M83 from under the rear left of theoperator's seat and remove intake duct (1).

2. Make the internal intake door visible, connectconnector M83, and turn the starting switch ON(and start the engine).

3. Operate the intake switch of the control panel tosee if the intake door operates normally.a If the result is NG, see Troubleshooting,

Troubleshooting for selection of intake (intake door and intake actuator)

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INSPECTING SELECTION OF AIR OUTLET (MODE DOOR AND MODE ACTUATOR)INSPECTING SELECTION OF INTAKE (INTAKE DOOR AND INTAKE ACTUATOR)

TESTING AND ADJUSTING INSPECTING RELAYS


INSPECTING RELAYS

a If the compressor revolves and air spurts to the maximum level, the relays are normal. Omit the following inspection, in this case.Inspect the relays of 3 types by sound. (If each relay is normal, it clicks when it is turned ON and OFF.)

a Bring your ear close to each relay and hear it clicks.

• Air conditioner relay: Turning ON/OFF of com-pressor

• OFF relay: Turning ON/OFF of fan motor• MAX HI relay: Turning ON when air flow is at

maximum

1. Remove operator's seat undercover (1).

2. While the starting switch is turned OFF, discon-nect pressure switch connector (I) and fan motorconnector (O) (to prevent the compressor andfan motor from starting)

3. Turn the starting switch ON (Do not start theengine, however) and turned the air conditionerswitch of the control panel ON/OFF to check thatthe relays make sound.a The air conditioner relay and OFF relay

sounds independently, thus the sound is made twice. If the sound is made only once, turn the starting switch OFF and remove either relay to see with relay is broken.

4. Set the fan motor speed between the maximumand medium to check that the MAX HI relaymakes sound.

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TESTING AND ADJUSTING CHECKING FOR REFRIGERANT LEAKAGE


CHECKING FOR REFRIGERANT LEAKAGE

Since refrigerant leakage has bad effects on the per-formance and durability of the air conditioner and global environment, it must be stopped immediately, if detected.

Flow of checking for refrigerant leakage

1. Checking for refrigerant leakageUsing a special gas leak detector for HFC-134a,check for refrigerant leakage. If any troubled partis found, repair it.In this case, repeat the procedure from the firststep.

k CautionNever use a CFC-12R (R-12) leak detector of halide torch type to check for refrigerant leak-age.The leak detector of halide torch type detects CFC-12 leakage by reacting on chlorine con-tained in CFC-12.Since HFC-134a does not contain chlorine, the leak detector of halide type cannot detect it. In addition, if HFC-134a come in contact with flame, it is decomposed and poisonous gas is produced.

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• Check for refrigerant leakage according to thefollowing procedure.

a Before starting the check, confirm that there is no refrigerant or smoke around the machine to prevent misjudgment of refrigerant leakage. Perform the check in a place where leaking refrigerant will not be blown off by wind.

a Perform the check mainly on pipe joints and parts which are stained oil remarkably.If refrigerant leaks, internal oil always leaks, too.

• When leakage is not detected by the ordinarycheck, operate the compressor for at least 5minutes and then check the high pressure sidesimilarly.

a After the compressor is stopped, the high pres-sure lowers gradually. Refrigerant leakage from the high pressure side can be detected easily while the pressure is higher.Accordingly, operate the compressor. Immedi-ately after stopping the engine, check the high-pressure parts immediately for refrigerant leak-age with the gas leak detector.

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• Important parts to be checked for refrigerant leakage

2. Adding refrigerant• Referring to 42-11, Connecting service tool prepared by DENSO CO., LTD. (New refrigerant specifica

tion), connect the gauge manifold.• To make sure, perform 42-19, Checking with gauge manifold.• Add refrigerant. See 42-38, Charging with (Adding) refrigerant from low pressure side.

kSince refrigerant is high-pressure gas, it must be handled by only designated persons.

kIf refrigerant gets in your eyes, you may lose your sight. (Put on protective goggles.)

3. After adding refrigerant, perform the final refrigerant leakage test.

Part name Check point Remarks

CompressorPipe jointsShaft sealsCylinder fitting parts

Check through clearance of magnet clutch

Condenser Pipe jointsWelded parts of body

Receiver drier

Pipe jointsDual pressure switchFusible plugAround sight glass

Air conditioner unitPipe jointsExpansion valve jointsBrazed parts of evaporator

Check through hole for drain hose

Piping (Hoses and pipes)Pipe jointsCaulked parts of hosesHoses and pipes

Service valve Around service valve Install a cap when checking



CHARGING WITH REFRIGERANT

See 42-32, Charging with refrigerant (New refrigerant specification) prepared by DENSO CO., LTD

k Since refrigerant is high-pressure gas, it must be handled by only designated persons.

k If refrigerant gets in your eyes, you may lose your sight. (Put on protective goggles.)

TESTING AND ADJUSTING HANDLING REFRIGERANT CAN AND COMPRESSOR OIL


HANDLING REFRIGERANT CAN AND COMPRESSOR OIL

1. Refrigerant can (HFC-134a) (For repair)a HFC-134a and R134a are the same material.

a The label and the adapter thread size of the refrigerant can valve are different from those of the CFC-12 can for distinction.

2. Precautions for storing and handling refrig-erant canWhen handling the refrigerant can, observe the precautions printed on it.q Do not store the refrigerant can in place

where the temperature is heightened above 40°C by the direct sunlight, fire, etc.

q Be sure to store the refrigerant can in a dark and cool place. Do not corrode it.

q Carry the minimum necessary quantity of refrigerant cans and keep them in a place where the temperature does not rise above 40°C.

kThe high-pressure gas is in the refrigerantcan. If the can is stored in a hot place, itsinside pressure rises and it may burst andcan cause injury, frostbite, loss of sight, etc.

q Never throw or hit the refrigerant can. (Do not roughly handle the package of the refrig-erant can, either.)

q If the refrigerant can has a flow, bruise, etc., do not use it.

kThe high-pressure gas is in the refrigerantcan. If the can is handled wrongly, it mayburst or the refrigerant may leak, and thatcan cause injury, frostbite, loss of sight, etc.

q Do not put the refrigerant can in fire.

kDo not bring refrigerant in contact with flame.If refrigerant touches flame, it will be decom-posed and poisonous gas will be produced.

q Keep the refrigerant can off children.

Quantity of refrigerant

Part No.

200g 583200-0600

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3. Control of compressor oil (ZXL-100PG: ForHFC134a)Compressor oil does not need to be checked or added so frequently as engine oil. Insufficiency or excess of compressor oil can cause the fol-lowing troubles, however.Accordingly, compressor oil must be supplied to the specified level, similarly to refrigerant.Check compressor oil in the following cases, and then add new oil if necessary.q At the beginning of the 2nd season.q When much refrigerant is discharged

because of leakage.q When the compressor is troubled and

replaced.q When a cycle parts such as the condenser,

receiver drier, evaporator unit, etc. is replaced.

4. Procedure for checking (adding, replacing)oil level1) Perform the oil return operation.2) Collect refrigerant in the air conditioner

cycle. [* 1]3) Remove the compressor.4) Check the oil level.5) Add or replace oil.6) Install the compressor.7) Charge the air conditioner cycle with refriger-

ant. [* 2][* 1] [* 2] TAKAHASHI WORKS CO., LTD., see page 52 - 3 to 15.

kSince refrigerant is high-pressuregas, it must be handled by onlydesignated persons.

kIf refrigerant gets in your eyes,you may lose your sight. (Put onprotective goggles.)

5. Oil return operationCompressor oil is circulated in the air conditioner cycle together with refrigerant while the air con-ditioner is in operation.When checking the oil level or replacing a cycle part, you are required to return compressor oil in the piping and each component part to the com-pressor to minimize the quantity of oil lost during the replacement work. For this purpose, perform the "oil return operation" shown at right.a If it is impossible to perform the oil return

operation (because of seizure, breakage, etc.), install a new compressor (link part, etc.) and perform the oil return operation. Then, remove the compressor again and drain the excessive oil.

• Quantity of oil to be added when cycle part is replaced

<Oil return operation>

Condition Contents

Insufficiency of oil Lubrication trouble andseizure of compressor

Excess of oilCooling trouble (Excessive oil stick to parts and lower heat exchange performance)

Air conditioner part Quantity to be added (cm3)

Evaporator Approx. 50

Condenser Approx. 30

Receiver drier Approx. 50

Hose/Pipe Approx. 10

Item Condition value

Doors Open all doors (OPEN)

Engine speed Approx. 1,000 rpm

Blower fan motor HI (Max. speed)

Air conditioner switch ON (Operate compressor)

Operating time Approx. 20 min



6. Draining and adding compressor oil1) Draining oil.

Prepare an oil pan and drain oil. Measure the quantity of the drained oil with a measuring cylinder and set it as the 16quantity to be added.

a The type (ZXL-100PG) and additional quan-tity of compressor oil are printed on the label stuck to the compressor.

2) Adding oilAdd oil of the specified quantity (quantity measured with the measuring cylinder) through the port in the reverse order to drain-ing.

a If oil for CFC-12 (R-12) is used, lubrication trouble will occur and the compressor may be broken or seized.Be sure to use the specified oil (ZXL-100PG).

a Oil for HFC-134a absorbs moisture very eas-ily. Accordingly, fit the cap immediately after using oil to stop the atmosphere.Store the oil can in a dry and ventilated place.

a Precautions for using oilOil for HFC-134a (ZXL-100PG in particular) may dissolve acrylic resin and polystyrene (excluding baked polystyrene paint film). Accordingly, do not stick oil to those plastics.

7. Compressor oil for applying pipingWhen connecting a pipe or hose, apply oil (ZXL-100PG) to its O-ring to prevent refrigerant leak-age.

kWhen discarding a can which still has someoil in it, make a hole on it to discharge gasand oil.

2186(2)

2187(2)

2188(2)

2189(2)

TESTING AND ADJUSTING PRECAUTIONS FOR CONNECTING AIR CONDITIONER PIPING


PRECAUTIONS FOR CONNECTING AIR CONDITIONER PIPING

q When connecting the piping, apply compressor oil to the O-rings. (See the previous page.)Do not apply oil to the threads of a nut or union, however.

q Once an O-ring is used, it is deformed and dete-riorated. Accordingly, do not reuse it. When removing it, use a soft tool (such as a toothpick) so that the piping will not be damaged.

q Push in each pipe to the stopper (until it clicks) and tighten the nut fully with your fingers.

q Be sure to use 2 wrenches to tighten each nut (Apply a torque wrench to the tightening side). Fix 1 wrench and tighten the nut with another wrench to the specified torque.

a Tightening torque for pipes of O-ring type (Standard value)

Outside diameter of pipe

(mm)

Tightening torque Nm kgm

End face seal Cylindrical face seal

ø 8, ø 9 9.8 – 201.0 – 2.0

9.8 – 201.0 – 2.0

ø 12 15 – 251.5 – 2.5

15 – 251.5 – 2.5

ø 16 20 – 292.0 – 3.0

29 – 343.0 – 3.5

ø 19 25 – 342.5 – 3.5

34 – 493.5 – 4.0


TROUBLESHOOTING


Troubleshooting procedure...................................................................................................................... 73- 2

Block diagram and circuit diagram of control system .............................................................................. 73- 3Detail of air conditioner unit ..................................................................................................................... 73- 5Arrangement of connector pins ............................................................................................................... 73- 6Arrangement of connectors and how to disconnect control unit connectors ........................................... 73- 7How to inspect electric parts.................................................................................................................... 73- 8Troubleshooting chart .............................................................................................................................. 73- 10Troubleshooting table ...............................................................................................................................73- 11Troubleshooting for electrical system (E mode) ...................................................................................... 73- 13

E-1 Air conditioner does not operate............................................................................................ 73- 14E-2 Air is not cooled ..................................................................................................................... 73- 16E-3 Air does not come out or air flow is abnormal........................................................................ 73- 18E-4 Temperature cannot be adjusted ........................................................................................... 73- 20E-5 Air outlet cannot be changed ................................................................................................. 73- 22E-6 Intake cannot be changed ..................................................................................................... 73- 25

Troubleshooting with gauge pressure...................................................................................................... 73- 26


TROUBLESHOOTING TROUBLESHOOTING PROCEDURE

The air conditioner has a self-diagnosis function for inspecting the main component parts. With this function,you can inspect the operations of each sensor (which is not installed to the air conditioner having only the man-ual mode), each actuator, and fan motor system.If a troubled section is detected, every part of that section must be inspected.

TROUBLESHOOTING PROCEDURE

1. Find out the troubled section according to the detected trouble of the air conditioner.2. Find out the troubled section with the self-diagnosis function (See TESTING AND ADJUSTING, Inspection

with self-diagnosis).If the air conditioner unit or control unit does not operate at all, however, check that the power supply up tothe control unit is normal.If any part of the air conditioner unit or control unit operates, the power supply does not need to bechecked.

3. After finding out the troubled section, inspect the component parts in that section and repair the troubledpart.

Basic flow of troubleshooting

* 1: See TESTING AND ADJUSTING

Occurrence of trouble

Check of battery voltage (24 V)

Does any part of air conditioner unit or control unit operate?

Inspection with self-diagnosis function (* 1)

Troubleshooting with troubleshooting chart

Troubleshooting with gauge pressure

End

E-1 Air conditioner does not operate

Inspection of troubled part

Inspection with troubleshooting table

Inspection of troubled part

Repair

Repair

Repair

Repair

No

No

No

No

YES

OK

OK

OK


TROUBLESHOOTING BLOCK DIAGRAM AND CIRCUIT DIAGRAM OF CONTROL SYSTEM

BLOCK DIAGRAM AND CIRCUIT DIAGRAM OF CONTROL SYSTEM

* 1. The internal air sensor, water temperature sensor, external air sensor, and AUTO SW AUTO LED are not installed to the air conditioner having only the manual mode. The external air sensor is not installed to theautomatic air conditioner of PC78US-6, either.

6267

TROUBLESHOOTING


BLOCK DIAGRAM AND CIRCUIT DIAGRAM OF CONTROL SYSTEM

6268


TROUBLESHOOTING DETAIL OF AIR CONDITIONER UNIT

DETAIL OF AIR CONDITIONER UNIT

* 1. The internal air sensor and external air sensor are not installed to the air conditioner having only the man-ual mode.

6269


TROUBLESHOOTING ARRANGEMENT OF CONNECTOR PINS

ARRANGEMENT OF CONNECTOR PINS

* 1. The water temperature sensor, internal air sensor, sunlight sensor, and external air sensor are notinstalled to the air conditioner having only the manual mode.The external air sensor is not installed to the automatic air conditioner of PC78US-6, either.

a For the wiring harness connectors of M26, M84, and M85 on the air conditioner unit side, see Detail of airconditioner unit

6270

6271


TROUBLESHOOTINGARRANGEMENT OF CONNECTORS AND HOW TO DISCONNECT CONTROL UNIT CONNECTORS

ARRANGEMENT OF CONNECTORS AND HOW TO DISCONNECTCONTROL UNIT CONNECTORS

a The following is the explanation for PC78US-6and PC128/138US-2.

1. Arrangement of connector1) Connectors M26, M84, and M85 are

installed under the rear part of the operator'sseat.

2) Connector M87 is in cover (1) under the rightrear part of the operator's cab.

a Connector M88 of the mode duct is described inthe text (See TESTING AND ADJUSTING,Inspecting selection of air outlet (Mode door andmode actuator)).

2. How to disconnect control unit connectors1) Unhook claw (N) under left console bellows

(B) and remove plate (P).2) Remove tray (T) and screw (S), and then lift

up cover (C) and control unit and disconnectconnectors M80 and M81.

AJS01466

AJS01477

9JS02170


TROUBLESHOOTING HOW TO INSPECT ELECTRIC PARTS

HOW TO INSPECT ELECTRIC PARTS

kWhen removing each electric part, turn the start-ing switch OFF.

a See Detail of air conditioner unita Even if the water temperature sensor, internal air

sensor, and thermostat are normal, if a clip isremoved by vibration and the sensor is sepa-rated from the object, the system does not work.

1. Water temperature sensor and internal air sensor* Not installed to the air conditioner having only

manual mode.a Remove the air conditioner unit to inspect

these sensors.• Measure the resistance between the terminals.

2. External air sensor* Not installed to the air conditioner having only

manual mode.Not installed to the automatic air conditionerof PC78US-6, either.

a On PC128/138US-2, this sensor is installed tothe battery relay bracket.

• Measure the resistance between the terminals.(The characteristics of this sensor are thesame as those of the internal air sensor.)

3. Sunlight sensor (1)* Not installed to the air conditioner having only

manual modea Since the current is small (several 10 µA), it

cannot be checked with a circuit tester.a On PC78US-6 and PC128/138US-2, this sen-

sor is installed on the monitor panel.

4. Thermostata The thermostat unit cannot be inspected in the

field (since 24V power source is necessaryand the ON/OFF range is 1.5 - 6 °C)

a Inspect the thermostat without removing itfrom the machine (See E-2 Air is not cooled)

a Removal: Remove the air conditioner unit,and then remove the thermostat

5. Pressure switch(See STRUCTURE AND OPERATION, Outlineof main parts, 6.4)

6272

6273

9JS02205


TROUBLESHOOTING HOW TO INSPECT ELECTRIC PARTS

a Before performing the following work (6. - 10.),remove the cover under the seat.

6. Resistor(1) Remove connector [N] from the resistor.(2) Measure the resistance between terminal L

and terminal Mo. Resistance between L andMo: 7.3 za The resistance has effects on the opera-

tion when the fan speed (air flow) is at theminimum.

a Before performing the following work,remove the cover under the seat.

7. Power transistor(1) Disconnect connector [L] of the power tran-

sistor.(2) Check the continuity between the terminals

on the power transistor.a The power transistor has effects on the

lowest 3 levels of the fan speed (air flow)control.

8. MAX HI relay(1) Disconnect connector [M] from the MAX HI

relay.(2) Check the continuity between the terminals

on the MAX HI relay side.a This relay is turned ON when the fan

speed (air flow) is set to the maximum(MAX HI).

9. A/C (Air conditioner) relay(1) Disconnect connector [H] from the air condi-

tioner relay.(2) Check the continuity between the terminals

on the air conditioner relay.a Turn the compressor OFF.

10. OFF relay(1) Disconnect connector [K] from the OFF relay.(2) Check the continuity between the terminals

on the OFF relay side.a This relay is used to turn the fan (all air-

flow) OFF.

6274

6275

6276

6277


TROUBLESHOOTING TROUBLESHOOTING CHART

TROUBLESHOOTING CHART

The numbers in the boxes are the item Nos. in the troubleshooting table.1. Cooling trouble

2. Heating trouble

Cooling trouble

Check of spurting air temperature

Air flow is insufficient or air does not come out

Check of operation of blower fan motor

1 Blower fan motor does not revolve or its speed is different from set value

2 Blower fan motor is normal but air flow is insufficient

Air flow is normal

Check or revolution of compressor

3 Compressor operates normally

4 Compressor does not revolve at all or its speed is low

Both high pressure and low pressure are low

Both high pressure and low pressure are high

High pressure is high and low pressure is low

High pressure is low and low pressure is high

Heating trouble

Check of spurting air temperature

Air flow is insufficient or air does not come out

Check of operation of blower fan motor

1 Blower fan motor does not revolve or its speed is different from set value

5 Blower fan motor is normal but air flow is insufficient

Air flow is normal but air temperature is low

6 Check of hot water


TROUBLESHOOTING TROUBLESHOOTING TABLE

TROUBLESHOOTING TABLE

1. Blower fan motor does not revolve or its speed is different from set value.a See the troubleshooting for the electrical system "E-3 Air does not come out or air flow is abnormal"

2. Blower fan motor is normal but air flow is insufficient.

3. Air flow is normal or compressor operates normally.

Possible cause Check method RemedyDefective OFF relay See check of relay ReplaceDisconnection of wire or defective connection

Check ground wire and connector of blower fan motor for disconnection

Repair broken parts and connect correctly

Defective blower motor Check 2 lead wires of motor with circuit tester. If there is not continuity, motor is defective Replace

Resistor trouble Check continuity with circuit tester (If there is not continuity, resistor is defective) Replace

Defective power transistor or defective MAX HI relay

Move fan switches in order and check fan speed. See section of check of relay Replace

Possible cause Check method RemedyAir leakage Check fitting condition of air conditioner unit case ReplaceObstacle on suction side of evaporator Check evaporator for stain and obstacle Remove obstacle and clean

Defective amplifier of elec-tronic thermostat or defective contact of electronic thermo-stat sensor

Evaporator is frozen. Check sensor clip. Check sensor for dirt

Repair or replace

Possible cause Check method Remedy

Excessive or insufficient refrigerant

If HFC-134a is used as refrigerant, its quantity cannot be checked through sight glass.Accordingly, check by connecting gauge mani-fold. Purpose of sight glass is to check refrigerant flow

Collect refrigerant, then charge with proper quan-tity of refrigerant again

Insufficient refrigerantRepair leaking part, then charge with proper quan-tity of refrigerant again

Overcharge with refrigerantCollect refrigerant, then charge with proper quan-tity of refrigerant again

Judgment by pressure at inlet/outlet of compressor

Normal pressure rangeLow pressure: Approx. 0.13 - 0.2 MPa1.3 - 2.0 kg/cm2High pressure: Approx. 1.5 - 1.7 MPa 15 - 17 kg/cm2These values are for following condition, however.Temperature in cab: 30 - 35 °CEngine speed: Approx. 1500 r/min

See Troubleshooting with gauge pressure

TROUBLESHOOTING TROUBLESHOOTING TABLE


4. Compressor does not revolve at all or its speed is low.

a See "E-2 Air is not cooled"

5. Blower fan motor is normal but air flow is insufficient.

6. Check of hot water

7. Other items

Troubled part Possible cause Check method Remedy

Belt Loosened belt Vibration amplitude of belt is large Adjust tension

Compressor Trouble in compressor Slip of belt Repair or replace

Magnet clutch

Low battery voltage Slip of clutch Charge battery

Layer short circuit in coil Slip of clutch Replace magnet clutch

Oil on clutch surface Magnet clutch is dirty and slips Clean clutch surface or replace clutch

Too large clearance between drive plate and pulley

Measure clearance between clutch plate and clutch wheel with feeler gaugeProper clearance: (0.3 - 0.6 mm)

Repair

Disconnection of coil Inspect with circuit tester Replace

Disconnection in wiring or defective connection of ground wire

When clutch is turned ON, magnet does not attract. Check ground wire and connections

Repair


Large duct resistance Check duct for crushing and clogging Repair

Air leakage through duct joints Check duct joints for defective duct seal and discon-nection of duct Repair

Clogging of heat core fins Check heater core fins for clogging Repair


Low engine coolant tempera-ture

Warm up engine, and then check engine coolant tem-perature

Find out cause

Low engine coolant level Check coolant level in radiator Add coolant

Insufficient circulation of engine coolant

Check engine coolant piping for clogging (Hose, pipe, and core) Bleed air and repair

Possible cause Check method

Temperature cannot be adjusted See Troubleshooting for electrical system, E-4

Air outlet cannot be changed See Troubleshooting for electrical system, E-5

Intake cannot be changed See Troubleshooting for electrical system, E-6

TROUBLESHOOTING TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)


TROUBLESHOOTING FOR ELECTRICAL SYSTEM (E MODE)

Information in troubleshooting tablea The following information is summarized in the troubleshooting table and the related electrical circuit dia-

gram.Before carrying out troubleshooting, understand that information fully.

a Grounding fault, short circuit with power source, and short circuit are not described since they are commonto all items. After checking all of the shown possible causes, if you still cannot detect the cause, check forthe above troubles.

a If a wiring harness is burnt, replace it.• Grounding fault

Wiring harness which is not connected to chassis ground circuit is in contact with chassis ground circuit.• Short circuit with power source

Wiring harness which is not connected to power source (24V) circuit is in contact with power source (24V)circuit.

• Short circuitIndependent wiring harnesses are in contact with each other abnormally.

Related circuit diagramThis is a circuit diagram of the part related to troubleshooting• The circuit diagram shows the connector Nos. and pin Nos.• See "Arrangement of connector pins" and "Arrangement of connectors and how to disconnect

control unit"• The circuit diagram shows the size and colors of wires. W: White, B: Black, R: Red, G: Green, Y: Yellow, L: Blue, V: Purple, P: Pink, O: Orange, Br: Brown,

Gr: Gray, Sb: Sky blue, Lg: Light green, Dg: Dark green, Ch: Dark browna When there are 2 colorsExample: WY: Yellow line on white backgrounda The number before the wire color indicates the wire size.

• N.C.: Normally closed (Normally turned ON)a Sockets (of relays, resistors, power transistors, etc.) are omitted.

Trouble Phenomenon that appears on machine

Related information Information related to the detected trouble or troubleshooting

Possible causes andstandard value in nor-mal state

Cause Standard value in normal state/Remarks on trouble-shooting

1

Possible causes of trouble (Given numbers are refer-ence numbers, which do not indicate priority. Perform troubleshooting according to these num-bers, however.)

<Contents of description>• Standard value in normal state to judge possible

causes• Remarks on judgment

<Troubles in wiring harness>• Disconnection

Connector is connected imperfectly or wiring har-ness is disconnected

<Precautions for troubleshooting>(1) Entry order of pin Nos. and handling of circuit

tester leadsConnect positive (+) lead and negative (-) lead ofcircuit tester as explained below for troubleshoot-ing, unless otherwise specified• Connect positive (+) lead to pin No. or wiring har-

ness entered on front side• Connect negative (-) lead to pin No. or wiring har-

ness entered on rear side(2) Example of troubleshooting by inspection of mul-

tiple itemsa Normal in 1 but abnormal in 2At this time "- defective" shown at left is applied

2

3 - defective



E-1 Air conditioner does not operate

Trouble The air conditioner does not operate

Phenomenon that appears on

machine• The LED on the control panel does not light up• The compressor and fan motor do not revolve, either

Related informationCheck that the fuse is not broken and the engine starts normally in advanceThe ground wire of the air conditioner is connected to the chassis ground inside the chassis wiring harness together with other electric parts (relay, valve, etc.)

Possible causes and stan-dard value in normal state


1 Defective ground wire

1) Turn starting switch OFF 2) Disconnectground terminal of battery3) Lift up left console cover and control unit as 1 unit 4) Disconnect connector M80Between terminal 10 of connector M80 and chassis ground

Resis-tance Max.1z

2Defective wiring har-ness or defective con-trol unit

1) Turn starting switch OFF 2) Disconnect ground terminal of battery3) Lift up left console cover and control unit as 1 unit4) Disconnect connector M80 5) Connect ground terminal of battery6) Turn starting switch ONBetween terminal 2 of connector M80 and chassis ground Voltage 24V

Between terminal 11 of connector M80 and chassis ground Voltage 24V

3 Defective control unit a Normal in 1 and 2

4

Disconnection in wir-ing harness• Intermediate wiring

harness

a When abnormal in 1 or 2, find out which wiring harness is discon-nected (Perform after 2)

1) Turn starting switch OFF 2) Disconnect connector M85 (without connecting connector M80)Female terminal of connector M80 and female ter-minal of M85 (See circuit diagram) Continuity Made

5

Disconnection in wir-ing harness• Attached to air condi-

tioner unit

a When abnormal in 1 or 2, find out which wiring harness is discon-nected (Perform after 2 or 4)

1) Turn starting switch OFF 2) Disconnect connector M26 and M85 (without connecting connector M80)Male terminal of connector M26 and male terminal of M85 (See circuit diagram) Continuity Made

6

Disconnection in wir-ing harness• Wiring harness on

machine

a When (abnormal in 1 or 2) and normal in 4 and 5, perform followingdirectly

1) Turn starting switch OFF 2) Disconnect ground terminal of battery3) Disconnect connector M26Between female terminal of connector M26 and chassis ground Continuity Made

Female terminal of connector M26 and fuse 25A terminal (See circuit diagram) Continuity Made



Related circuit diagram

6278



E-2 Air is not cooled

Trouble Air is not cooled

Phenomenon that appears on machine The compressor does not operate

Related information See TESTING AND ADJUSTING, Inspecting relay(Remove the cover under the seat for troubleshooting)

Possible causes and standard value in nor-mal state


1 Defective compressor

1) Turn starting switch OFF 2) Disconnect compressor connector3) Turn starting switch ON 4) Turn air conditioner switch ONBetween connector terminal (there is on 1 pin) and chassis ground Voltage 24V

2 Defective air conditioner relay

1) Turn starting switch ON 2) Turn air conditioner switch ON/OFFAir conditioner relay makes ON/OFF sounda See TESTING AND ADJUSTING, Inspecting relay

3 Defective pressure switch

1) Turn starting switch OFF 2) Disconnect connector IBetween terminals of connector I on air conditionerunit side Continuity Made

a While pressure switch operates normally, continuity is may not be made.Accordingly, measure gauge pressure. For pressure range, see STRUC-TURE AND OPERATION. For connecting method, see 42-11 "Connectingservice tool"

kWhen replacing pressure switch, collect refrigerant gas in advance

4Defective control unit or disconnection in inter-mediate wiring harness (between M81 and M84)

1) Turn starting switch OFF 2) Disconnect connector M84 3) Turn starting switch ON4) Turn air conditioner switch ONBetween female terminal of connector M84 and chas-sis ground Resistance Max. 1z

5Disconnection in wiring harness• Intermediate wiring har-ness

1) Turn starting switch OFF 2) Lift up left console cover and control unit as 1 unit 3) Disconnect connectors M81 and M84Female terminal of connector M81 and female termi-nal of M84 Continuity Made

6 Defective control unit a Abnormal in 4 and normal in 5 –

7

Defective thermostat or wiring harness (Air conditioner unit does not need to be removed)

1) Turn starting switch OFF 2) Disconnect connector I 3) Disconnect connector M84Between 0.3GY on wiring harness side of connector and male pin

25 (0.3GW) of connector M84 Continuity Made

8 Defective thermostat

Set cooling level to maximum to freeze evaporator (Set air flow to minimum) Compressor

Turned OFF before

freezinga Protective circuit of thermostat turns operation OFF when temperature is 1.5

- 6°C. Accordingly, if protective circuit operates normally, compressor maynot revolve. Check again before judging thermostat defective

9Disconnection in wiring harness• Attached to air

conditioner unit

1) Turn starting switch OFF 2) Disconnect connectors M84, M85, M26, and I and air conditioner relayReferring to circuit diagram, check continuity Continuity Madea To check around thermostat, air conditioner unit must be removed and dis-

assembled




6279

9JS02181



E-3 Air does not come out or air flow is abnormalTrouble Air does not come out or air flow is abnormal

Phenomenon that appears on machine

• The fan motor does not operate• Air flow is different from the setting of the control panel

Related information See TESTING AND ADJUSTING, Inspecting relay (Remove the cover under the seat for troubleshoot-ing.) See How to inspect electric parts

Possible causes and standard value in normal state


1 Defective OFF relay1) Turn starting switch ON 2) Turn air conditioner switch ON/OFF. OFF relay makes ON/OFF sound

When air does not come out at any of 4 levels

–a See TESTING AND ADJUSTING, Inspecting relay

2 Defective fan motor1) Turn starting switch OFF 2) Disconnect connector O Between terminals of connector O on air conditioner unit side Continuity Made

3 Defective MAX HI relay* 1

1) Turn starting switch ON 2) Turn air conditioner switch ON 3) Set air flow to MAX HI and medium alternatelyAir flow changes (MAX HI relay makes ON/OFF sound)a See TESTING AND ADJUSTING, Inspecting relay. If air flow cannot be set to maximum (relay is

kept turned OFF) or it is kept at maximum regardless of setting of air flow (relay is kept turnedON), replace MAX HI relay

4Defective power transis-tor* 1

1) Turn starting switch ON 2) Turn air conditioner switch ON 3) Set air flow to lower 3 levelsAir flow is increased as level is increase to 2 and 3a If air flow is kept at minimum (power transistor is kept turned OFF) or at level 3 (power tran-

sistor is kept turned ON) regardless of setting of air flow, replace power transistor

5 Defective resister

1) Turn starting switch ON 2) Turn air conditioner switch ON 3) Set air flow to minimumAir flows out a little (a If air does not flow out only when setting is at minimum, replace resistor)1) Turn starting switch OFF 2) Disconnect connector NBetween resistor terminals MO and L (See 6. How to inspect elec-tric parts) Resistance Approx.

7z

6Defective control unit or intermediate wiring har-ness (between M81 and M84)

1) Turn starting switch OFF 2) Disconnect connector M84 3) Turn starting switch ON 4) Turn air conditioner switch ONBetween female terminal 23 of connector M84 and chassis ground Resistance Max.1z

1) Turn starting switch OFF 2) Disconnect connector M84 3) Turn starting switch ON 4) Turn air conditioner switch ON 5) Set air flow to maximumBetween female terminal 31 of connector M84 and chassis ground Resistance Max.1z

1) Turn starting switch OFF 2) Disconnect connector M84 3) Turn starting switch ON 4) Turn air conditioner switch ON 5) Set air flow to intermediate level 2Between female terminal 22 of connector M84 and chassis ground Voltage 1 - 5V

7Disconnection in wiring harness• Intermediate wiring har-ness

1) Turn starting switch OFF 2) Lift up left console cover and control unit as 1 unit 3) Disconnect connectors M81 and M84Female terminal of connector M81 and female terminal of connectorM84 (See circuit diagram) Continuity Made

8 Defective control unit a Abnormal in 6 and normal in 7 –

9Disconnection in wiring harness• Attached to air condi-tioner unit

1) Turn starting switch OFF 2) Disconnect connectors M84 M26, L, N, and O, OFF relay, and MAX HI relay

Referring to circuit diagram, check continuity Continuity Made



* 1. When either of the MAX HI relay (kept turned ON) or power transistor (kept turned ON) is broken, it is difficult to see which one is broken. In this case, check them according to the following procedure.1) Turn the starting switch OFF and remove the MAX HI relay.2) Turn the starting switch and air conditioner switch ON and set the air flow to lower 3 levels to see if the

air flow is normal (changed).Normal o MAX HI relay is defective, Abnormal o Power transistor is defective


6280

9JS02180



E-4 Temperature cannot be adjusted

Trouble Temperature cannot be adjusted

Phenomenon that appears on machine The mix door does not move. (Normal: Operates to 8 levels according to setting of temperature)

Related informationSee TESTING AND ADJUSTING, Inspecting temperature adjustment (Air mix door and mix actuator)(In air conditioner unit: Remove the cover under the seat for troubleshooting.)



1

Defective link mecha-nism between mix actuator and mix door (Removal of rod (3), etc.)

As temperature setting is changed from left end to right end, levers (1) and (2) operates in 3 levels. (Since there are 2 doors, there are 2 levers and 2 rods.)

Repair

2 Locked air mix doorSame as above• Mix actuator tries to move (motor sounds and

vibrates) but cannot move

Remove, disassemble, and repair

3Defective mix actuator• Potentiometer• Motor coil

1) Turn starting switch OFF 2) Disconnect connector DBetween terminals 19 and 20 and between 8 and 20 ofmix actuator connector on air conditioner unit side Resistance Max.approx.4

Kz

Between terminals 27 and 35 of mix actuatorconnector D on air conditioner unit side

Continuity Made

Diode range

4

Defective control unit or wiring harness• Potentiometer• Motor drive

1) Turn starting switch OFF 2) Disconnect connector D 3) Turn starting switch ON 4) Turn air conditioner switch ONBetween terminals 20 and 19 of mix actuator connec-tor D on wiring harness side (regardless of setting oftemperature control switch)

Voltage 5V

–

Between terminals 27 and 35 of mix actuator connec-tor D on wiring harness side (Change of setting of tem-perature control switch: Left end - Right end)

Voltage - 21 to + 21Va Several seconds after

switch setting is changed

a If abnormal in 4, perform 5 and 6 to see which of wiring harness andcontrol unitis defective

5

Disconnection in wir-ing harness• Attached to air

conditioner unit

1) Turn starting switch OFF 2) Disconnect connectors D, M84, and M85Terminal of connector D on wiring harness side and male terminal of M84 (See circuit diagram) Continuity Made

Terminal of connector D on wiring harness side and male terminal of M85 (See circuit diagram) Continuity Made

6

Disconnection in wir-ing harness• Intermediate wiring

harness

1) Turn starting switch OFF 2) Lift up left console cover and control unit as 1 unit 3) Disconnect connectors M81, M84, M80, and M85Female terminal of connector M81 and female termi-nal of M84 (See circuit diagram) Continuity Made

Female terminal of connector M80 and female termi-nal of M85 (See circuit diagram) Continuity Made

a If M85 (or M80) is disconnected, power is not supplied to control unit. Accord-ingly, M85 and M80 cannot be inspected by checking voltage similarly to 4.Inspect them by checking continuity

7 Defective control unit a Abnormal in 4 and normal in 5 and 6 –




6281

9JS02169



E-5 Air outlet cannot be changed

Trouble The air outlet cannot be changedPhenomenon that

appears on machine Mode door (4) does not move

Related information See TESTING AND ADJUSTING, Inspecting selection of air outlet (Mode door and mode actua-tor). (Carry out troubleshooting for mode duct (5).)

Possible causes and standard value in nor-mal state


1Defective mode actuator• Motor coil

1) Turn starting switch OFF 2) Disconnect connector M88

Terminals 28 and 36 of mode actuator connector M88 onmode duct side

Continuity Madea Diode range

a Since direction troubleshooting for mode door position sensor is impossible, carryout troubleshooting indirectly by 3 and 4

2 Locked mode door (4)

Mode actuator tries to move (motor sounds andvibrates) but cannot move Mode door

Revolution (Visual check)

3

Defective controlunit or wiring har-ness• Motor drive• Mode door position

sensor

1) Turn starting switch OFF 2) Disconnect connector M88 3) Turn starting switch ON 4) Turn air conditioner switch ON

Between terminals 28 and 36 of mode actuator connec-tor M88 on wiring harness side (Change of setting ofmode switch: Left end - Right end)

Voltage - 21 to + 21Va Several seconds after

switch setting is changed

5) Mode switch position: Left (Vent/Def)Between terminals 4 and 20 of M88 on wiring harness side Voltage 0V

Between terminals 14-A (14-B) and 20 of M88 on wiring harness side Voltage 0V


6) Mode switch position: Center (Bi-level)

Between terminals 4 and 20 of M88 on wiring harness side Voltage 5V



7) Mode switch position: Right (Foot)Between terminals 4 and 20 of M88 on wiring harnessside Voltage 5V

Between terminals 14-A (14-B) and 20 of M88 on wiringharness side Voltage 0V

Between terminals 5-A (5-B) and 20 of M88 on wiringharness side Voltage 5V

a If abnormal in 3, perform 4 to see which of wiring harness and control unit isdefective (Keep M88 disconnected.)

4Disconnection in wir-ing harness(Inspect 3 pieces together)

1) Turn starting switch OFF 2) Lift up left console cover and control unit as 1 unit 3) Disconnect connectors M81 and M80Female terminal of connector M81 and female terminalof M88 (See circuit diagram) Continuity Made

Female terminal of connector M89 and female terminalof M88 (See circuit diagram) Continuity Made

a If M85 (or M80) is disconnected, power is not supplied to control unit. Accordingly,wiring between M85 and M80 (wiring on position sensor side) cannot be inspectedby checking voltage. Inspect it by checking continuity

a If abnormal in 4, perform 5 to see which wiring harness is defective. (Keep M80,M81, and M88 disconnected.)



• Move right console (2) inward, and then remove covers (1) and (3).

a (4) is the mode doora There is the mode actuator in mode duct (5).a If duct joint A is moved, you can replace mode duct (5).



5

Disconnection in wiring harness• Intermediate wiring

harness• Attached to air

conditioner unit• Wiring harness on

machine

1) Turn starting switch OFF 2) Disconnect connectors M84, M85, and M87Female terminal of connector M81 and female terminal of M84 (See circuit diagram) Continuity Made

Female terminal of connector M80 and female terminal of M85 (See circuit diagram) Continuity Made

Male terminal of connector M84 and female terminal of M87 (See circuit diagram) Continuity Made



6 Defective control unit a Abnormal in 3 and normal in 47 Defective mode duct a Normal in 3

AJS01468

6282



• Connector M87: Remove cover (1) at the right rear of the operator's cab to find.

AJS01477



E-6 Intake cannot be changed


Trouble The intake cannot be changedPhenomenon that

appears on machine The intake door does not move

Related information See TESTING AND ADJUSTING, Inspecting selection of intake (Intake door and intake actuator) (Remove the intake duct for troubleshooting)



1 Locked intake door

• Intake actuator tries to move (motor sounds and vibrates) but cannot move Intake door

Revolution (Visual check)

2Defective intake actuator, control unit, or wiring har-ness

1) Turn starting switch OFF 2) Disconnect connector M833) Turn starting switch ON 4) Turn air conditioner switch ON5) Press intake switch to select external/internal air

Between terminals 32 and 24 of intake actuator connector M83 on wiring harness side

Voltage ±21Va Reversal of polarity

(Several seconds after switch setting is changed)

3Disconnection in wiring harness• Intermediate wir-

ing harness

1) Turn starting switch OFF 2) Lift up left console cover and control unit as 1 unit 3) Disconnect connectors M81, M80, and M83Female terminal of connector M81 and female terminal of M83 (See circuit diagram) Continuity Made

Female terminal of connector M80 and female terminal of M83 (See circuit diagram) Continuity Made

4 Defective intake actuator a Normal in 2 and 3

5 Defective control unit

a Abnormal in 2 and normal in 3, or perform fol-lowing directly

1) Turn starting switch OFF 2) Lift up left console cover and control unit as 1 unit 3) Disconnect connectors M81 (Connect M80) 4) Turn starting switch ON 5) Turn air conditioner switch ON6) Press intake switch to select external/internal air

Between terminals 32 and 24 of connector M81 on control unit side

Voltage ±21Va Reversal of polarity

(Several seconds after switch setting is changed)

6283


TROUBLESHOOTING TROUBLESHOOTING WITH GAUGE PRESSURE

TROUBLESHOOTING WITH GAUGE PRESSURE

Connect the gauge manifold ( * 1 ) and carry out trou-bleshooting by reading the high and low gauge pres-sures of the cooling cycle.

a The gauge pressure varies largely with the weather condition and operating condition of themachine. Take care.

<Measurement condition for pressure>

* 1. See page 42-11 "Connecting service tool"* 2. kWhen replacing a cooling cycle part, collect refrigerant, and then charge the air conditioner system with

refrigerant again. See page 52-14 "Procedure for collecting refrigerant gas" and page 42-32 "Charging with refrigerant"

Item Condition value Atmospheric tempera ture 30 - 35 °C Engine speed 1500rpm Air conditioner switch ON Fan switch HI Set temperature Full cool

Indicated gauge pressure Cause Check method Remedy

<Pressure is normal>Air conditioner cycle is operating normallyIf there is any trouble (cooling trouble), there is another cause

High pressure: Approx. 1.5 -1.7 MPa 15 -17 kg/cm2Low pressure: Approx. 0.13 - 0.2 MPa 1.3 - 2.0 kg/cm2

<Both high pressure and low pressure are low>Low pressure becomes vacuum

Insufficient refrigerantConnect gauge manifold

(* 1)

Collect refrigerant, then charge with proper quantity ofrefrigerant again

(* 2)

Clogging of receiver drierThere is temperature difference between inlet and outlet pipes of receiver drierTank is frosty

Replace (* 2)

Clogging of expansion valve Expansion valve is frosty Clean or replace (* 2)

Refrigerant leakage through thermometer tube of expansion valve (Blocking of valve passage)

Opening side of expansion valve is not cold (• Low gauge pressure becomes vacuum)

Replace

(* 2)Defective electronic thermometer (thermometer amplifier) or defective contact of sensor (removal of fixing clip)

Evaporator is frozen Adjust or replace

Clogging or flattening of piping

Piping between receiver drier and compressor is clogged or flattened. If clogged com-pletely, low gauge pressure becomes vacuum

Clean or replace (* 2)

<Both high pressure and low pressure are high>

Overcharging with refrigerantConnect gauge manifold (* 1)

Collect refrigerant, then charge with proper quantity ofrefrigerant again

(* 2)

Defective cooling of condenserStain of condenser, clogging or crushing of fins, or defec-tive revolution of cooling fan

Clean, repair fins, or repair or replace

condenser (* 2)

Defective adjustment of expan-sion valve or defective installa-tion of thermometer tube (Valve is opened too wide)

Defective adjustment of refrigerant flow rate Thermometer tube is not in contact with evaporator pipe

Repair or replace (* 2)

Air in cycle –Evacuate and then charge with proper quantity of refriger-

ant again (* 2)

<High pressure is high and low pressure is low>

Clogging or flattening of piping between compressor and con-denser

There is remarkable temper-ature difference between before and after clogged part

Clean inside of cycle or replace

(* 2)<High pressure is low and low pressure is high>

Defective compressor valve or gasket (Compression trouble of compressor)

Both high pressure and low pressure are balanced while compressor is in operation

Replace(* 2)

DISASSEMBLY AND ASSEMBLY DISASSEMBLY, ASSEMBLY OF CONTROL PANEL


Aire Acondicionado SEBD036406

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