AC repair manual.pdf

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SONGZ User’s Manual of Exterior Overhead Air Conditioner

Company Profile

Established in June 2002 with total investment of USD 15.50 million, SHANGHAI SONGZ

AUTOMOBILE AIR CONDITIONING CO., LTD. is a solely foreign-funded enterprise

specialized in the research and development, manufacture and marketing of automobile air-conditioning system. The company’s headquarter is located in No. 4999, Huanning Road,

Xinzhuang Industrial Zone, Shanghai, covering an area of 110 mu. Now it has more than

2000 employees, among which there are over 300 specialists with middle or high professional

titles. In addition, it holds the shares of Xiamen SONGZ, Anhui SONGZ, Chongqing SONGZ,

Beijing SONGZ, Chengdu SONGZ, and Nanjing Boshilan. It passed ISO/TS 16949:2002Quality Management System Certification and Automobile Products Certification. In 2007,

it was awarded 'Outstanding Hi-tech Enterprise and Advanced Technical Foreign-funded

Enterprise'. In addition, with complete technical standards system, the company is one of the

key units that are designated to draft the national standards of air-conditioners for passenger

vehicle. Consecutively for many years, it has been crowned 'the Flagship Enterprise ofAir-conditioners for Passenger Vehicle' and 'the Best Manufacturer of Air-conditioners




Create healthy human living space2


Create healthy human living space 3

decker bus in China, and it also manufactured air-conditioners for Beijing Olympic new energy

bus and BRT bus.

In the future, SONGZ will seize the opportunity of fast development in automobile air-

conditioner industry by giving full devotion to its specialization and intensifying investment in

R&D, growing into an industry leader who boasts technology, brand and cost advantages and

give satisfaction to enterprise, staff, client and shareholder. In addition, it will make efforts on

the promotion of environmental and energy-efficient products, and assume social responsibility

to become an honored enterprise.

Contents

Notice to users 4

Chapter I Cautions 5

Chapter II Product Description 6

Chapter III Operation and maintenance of air conditioner 7

Chapter IV Operation and maintenance of contained air conditioning unit 17

Chapter V Fast diagnose and treatment of common faults 25

Common Used Circuit Diagram 34







Notice to users

Dear users,

Thank you very much for purchasing our bus air conditioning unit!

For your correct usage, maintenance and troubleshooting of the air conditioner, the Manual

describes in related details as your reference when necessary. The information included in the

Manual is applicable to the driver and mechanic who operate SONGZ bus air-conditioner.

Please hand over the Manual to the driver.

The Manual is used in conjunction with Product Quality Warranty Manual.

Please keep the Manual in vehicle for easy reference.

The Manual is for your reference only and subject to change without notice.

Please feel free to point out the inadequacy in the Manual if any.

Your opinions and suggestions on further improvement of the product

would be appreciated.

SONGZ reserves the right to modify the Manual from time to time without notice.

The Manual shall not be copied or printed in any form without SONGZ’s approval.

Chapter I Cautions

1.1 Safety Issues

1. Promptly switch off the air conditioner if fault alarm occurs.

2. Don’t touch the driving parts (fan, belt, belt pulley, etc) and high-temperature parts

(compressor and high pressure pipeline) of the system during operation or after shutdown of

the air conditioner.

3. The electrical part of the air conditioner shall work in dry.

4. To avoid accidents, the air conditioner shall only be dismounted by maintenance worker.

5. Following operations are not allowed.

a. Directly inflate the air conditioning system with nitrogen for pressurized leak detection

without installation of reducing valve.

b. Replace nitrogen with oxygen for pressurized leak detection.

c. Use refrigerant instead of vacuumizing device to evacuate the air inside the system.

d. Directly take oxygen weld when the system is yet complete decompressed.

e. Let the vehicle operation unchecked after the air conditioning system is pressurized and

during maintenance.

f. Fill R134a air conditioning system with other models of refrigerants such as R12, R407C,

R22.

g. Fill refrigerant oil that is not intended for the compressor of the system.

1.2 Suggestions on Operating Environment

1. Park the air conditioned bus in a shady and well-ventilated environment when stop.

2. During operation of air conditioner, please close the doors, windows and ventilation

equipment of the bus.

1.3 Rules on Customer Service

1. If any maintenance service is needed, please contact SONGZ customer service department,

service centers or service stations and show the Product Quality Warranty Manual.

2. We are not liable for any problems arising due to incorrect installation and improper use of

SONGZ products.







Chapter II Product Description

Typical overhead air-conditioner picture

(Figure 2-1)

Condenser

Evaporator

(Figure 2-2)

Chapter III Operation and

maintenance of air conditioner

3.1 Function of LED Numerical Control Manipulator

LED manipulator (Figure 3-1)

1. Power Switch

After the power switch of the vehicle is on, press to start up the air conditioner and press

again to shut down.

2. Operating Mode

Press MODE to select the operating mode of the air conditioner, i.e. refrigeration,

ventilation and heating.

When goes on, the air conditioner is “refrigerating” and “ventilating”.

When goes on, the air conditioner is “ventilating”.

When goes on, the air conditioner is “heating” (invalid for the product without heating

function).

When <AUTO> goes on, both the refrigerating condition of the air conditioner and the

lowest temperature to be reached in vehicle are automatically controlled by manipulator

based on the temperature inside the vehicle.

3. Fresh air

Press < Fresh Air> to select start-up or shutdown the fresh air device and ozone

generator. During operation, the corresponding green indicating light is on.

2.1 General

(1) The ultra-thin streamline design ensures an elegant appearance of the whole vehicle.

(2) Good component matching inside the product ensures high refrigerating efficiency of

the system.

(3) The selection of rational fresh air mechanism ensures a comfortable environment for the

clients (providing 10~20% fresh air).

(4) The product only uses green and environment-friendly refrigerant – HFC134a in hope of

a minimized environmental pollution.

(5) The product mainly consists of exterior overhead evaporator and condenser assembly,

compressor assembly, pipeline and manipulator, evaporator and condenser are installed

at top.

2.2 General Layout







When < > goes on, fresh air device starts to work with the vent opened for long term.

When <O3> goes on, ozone generator starts to work.

When <AUTO> goes on, fresh air supply is in auto-operation mode.

Note: the function is invalid for the air conditioner without functions of fresh air supply and

sterilization.

4. is a red nixie tube displays the temperature inside vehicle, defrosting temperature

and fault code.

5. Air volume control and air speed indication:

is an air speed control key to switch the fan in circulation from low speed to medium

speed to high speed.

Light beam: fan speed is showed by the illuminated LED on light beam.

3.2 How to Switch-on The Air Conditioner on LED Nnumerical Control

Manipulator

When the engine is started up, press the power button to activate evaporator fan. Since

manipulator has power-off memory function, the air condition simultaneously turns into the

running status that exists before shutdown, whereupon it is recommended to adjust the running

mode of the air conditioner and set its running parameter if required.

1. Press MODE to select running mode of the air conditioner, for example, when select

Refrigeration, the light shows green, and the air conditioner starts to refrigerate. The idle

speed boost will start to work as well if it is equipped in the engine.

2. Press or (hold on for more than 2s) to scroll the Defrosting 1 temperature – Defrosting

2 temperature - Setting temperature. When red nixie tube displays setting temperature, the

temperature to be reached inside vehicle can be set within 16°C~32°C. Press or once

to increase or decrease the setting value by 1°C, otherwise, if neither or is pressed

within 5s, it will automatically switch to the temperature inside vehicle display mode.

Note: Since human body’s comfortable temperature is 22°C~28°C, it is suggested to set

the temperature within this range. Once the temperature inside the vehicle is lower than the

setting value, sensor will promptly transmit the induction signal to manipulator whereby the

air conditioner will stop refrigerating.

3. Press to adjust the required air speed.

4. If you feel the air inside vehicle is turbid, press to drive the fresh air motor open the vent

in which fresh air flows into the vehicle. When shows green, the vent opens for long

time.

If AUTO shows green, fresh vent will open for 3 minutes and close for 27 minutes, and then

goes in this cycle.

If O3 shows green, the ozone generator is at work.

5. If you want to switch out refrigerating mode to auto-running mode, press MODE till AUTO

shows green, and then the refrigerating system will conduct auto-control based on actual in-

vehicle temeprature (During auto-operation, don’t press the key on manipulator, otherwise it

will exit the auto-mode.). The temperature set below AUTO mode is a conventional value.

(1) In AUTO mode, if the temperature inside vehicle is higher than 25°C and the temperature

outside vehicle exceeds 23°C, the air conditioner will turns into refrigerating status

where the conventional setting temperature is 25°C, i.e. Tset=25°C.

(2) In AUTO mode, if the temperature inside vehicle is within 21°C-24°C, the system will

operate in low-speed ventilating status.

Air speed indicating light (Figure 3-2)

Low speed Medium speed High speed

6. Browse buttons:

: increase temperature or page up the information;

: decrease temperature or page down the information.

7. Fault alarm indication:

: indicates air conditioner fault alarm if red LED flashes.

Note: MODE, Air Speed, Fresh Air and temperature setting buttons all

have power-off memory function!

Power-off memory function means that manipulator’s running mode, fresh air

working condition, in-vehicle setting temperature and air speed keep the same

as those before last shutdown.

After the fan starts up for 30 seconds and then the compressor will be

activated!







(3) In AUTO mode, if the temperature inside vehicle is lower than 20°C, the air conditioner

will turn into heating status where the conventional setting temperature is 20°C, i.e.

Tset=20°C.

6. Check the temperature inside vehicle

The temperature inside vehicle is displayed in default mode. When is switched on, the

nixie tube displays the temperature inside vehicle, which will change with the variation of

refrigerating time and thermal load of carriage.

The display of the temperature inside vehicle ranges from 0.0°C to 60.0°C (with accuracy

down to 0.5°C); ‘ Lo ’is displayed when the temperature inside vehicle is lower than 0.0°C,

and ‘ Hi ’is displayed the temperature inside vehiclee is higher than 60.0°C.

7. Check defrosting temperature

Press or and hold on for more than 2s to scroll Defrosting 1 temperature – Defrosting

2 temperature.

The display of defrosting temperature ranges from 0.0°C to 90.0°C (with accuracy down

to 0.5°C); ‘ Lo ’is displayed when defrosting temperature is lower than 0.0°C, and ‘ Hi ’is

displayed when defrosting temperature is higher than 90.0°C.

8. Check fault code

For some faults, we can analyze and determine their causes based on the display, receiving

and feedback commands on numerical control manipulator.

When fault indicating light goes on and the temperature inside vehicle is displayed, press

and the digital window will display fault codes in order of EP1, E 1, E 2, EU1; press

, the digital window will display fault codes in order of EU1, E 2, E 1, EP1; if related

alarm code is defaulted when scrolling, the displayed codes will move forward in order. See

Table 1.

Table 1 Air Conditioner Fault Codes Comparison

Fault Code Meaning of Fault Code Potential Cause

Fault code EP1 is displayed,

indicating unusual pressure–

electrical or system fault

Refrigerant leakage (low pressure

protection)

Fan of condenser malfunction (high

pressure protection)

System, dryer or expansion valve

blockage (low pressure protection)Pressure switch failure ( protection on

high pressure switch or low pressure

switch)

Fault code E 1 is displayed,

indicating that temperature

sensor is cut off.

Sensor is damaged

Sensor connection is loose

Fault code E 2 is displayed,

indicating the temperature

sensor of evaporator is cut

off (i.e. defrosting sensor isdisconnected)

Sensor is damaged

Sensor connection is loose

Fault code EU1 is displayed,

indicating voltage is too low (the

tested input supply voltage of

manipulator is less than 20V for

consecutive 13 seconds)

Generator speed is too slow

Belt is loose

Regulator fails

Generator stator winding or field

winding fails

Supplementary (notes!):

When (supply) voltage is higher than 32V for consecutive 13 seconds, power supply will

automatically cut off with ventilation, refrigeration and fresh air supply stopped working

while excitation will maintain effective and panel display will keep on.

When (supply) voltage is higher than 45V, power supply will automatically cut off with

ventilation, refrigeration and fresh air supply stopped working while excitation will

maintain effective, but panel display will keep off.







3.3 Cautions for Use of the Air Conditioner

1. Please keep the manipulator of air conditioner away

from water

Manipulator, an electrical subassembly, may lead to the malfunction of air conditioner if water

flows into it. Please pay special attention to:

After parking the bus, please close the doors and windows on right and left sides of the

cab to prevent rain soaking and damaging the manipulator.

When vehicle is under cleaning, please close the doors and windows on right and left

sides of the cab to prevent water inflow and damage to the manipulator.

In process of driving, driver’s teacup should be placed away from the manipulator to

avoid tea water splashing into the manipulator, causing in damage.

2. Air conditioner can only be switched on if engine is started up

If air conditioner is switched on before start of engine, clutch will pull in with the driving

disc of compressor, and the later start of engine will cause much friction between clutch

chuck and driving disc of the air conditioner because the instantaneous torque of engine

reaches to the peak. Such operation lasting for a long term will result in early wear-down

of the clutch. (With regard to the sudden shutdown due to the temperature inside vehicle

reaching set value, the instantaneous wear-down of chuck is normal.)

3. Don’t use the air conditioner when fault light or under-voltage light goes on.

4. In seasons when it is suitable to use air conditioner, engine’s idle speed can be appropriately

turned up and kept within 650~850rpm/min. In general, engine is equipped with special idle

speed boost for air conditioner. If it is found that the revolving speed of engine fails to greatly

increase after air conditioner starts refrigerating, it is necessary to check idle speed boost or

ECU for normal operation or notify the manufacturer of engine or passenger vehicle.

5. In out-of-service seasons, it is forbidden to remove the compressor and generator

transmission belts of air conditioner.

6. During operation of air conditioner, please close all the doors, windows and the air

interchangers (except fresh air device).

7. Do not close all air outlets of air conditioner and keep at least 1/3 outlets opened.

8. Generally, do not short-circuit the thermal control or defrosting protection (i.e. No forced

refrigeration).

9. Under no circumstance should the high/low pressure switch be short-circuited.

Correct usage ensures the best refrigerating effect of the air conditioner

with minimum faults and high reliability.

3.3 Maintenance of Air Conditioner

1. Avoid exposing the air conditioned vehicle in sunshine when parking in summer.

Exposure to sunlight will cause rapid increase of thermal load of the vehicle, which will

reduce refrigerating effect and cooling rate during the operation of air conditioner.

2. Check out the intensity of the belt and adjust it if necessary (see the Figure)

The intensity and wear rate of belt should be checked after 48-hour running of new vehicle

or every month. At present, in China it is common to control belt tension via hand-feel, i.e.

vertically pressing 10kg (about 98Newton) force onto the belt at center position between two

belt pulleys with deflection (offset) shown as follows:

(Figure 3 -4)

deflection per meter of

center distance

c e n t e r d i s t a n c e

e x t e r n

a l f o r c

e

10mm

Check the belt for wear rate and promptly replace the unqualified belt. (Note: two belts

should be the same during displacement.)

3. Check out the cleanness of filter screens of both return air grille and evaporator and regularly

clean the filter screens (there are three filter screens at each return air grille)

Generally, it is necessary to clean the city bus once or twice a week, and clean coach once

a week. In dusty area, the interval of cleaning can be shortened as appropriate.

Filter Screen at least cleaned once a month in out-of-service seasons

(Figurer 3-3)

Manipulator is installed on the left side of cab







Following cleaning methods are suggested:

Clean the surface of condenser and evaporator cores by high pressure water gun with

cleanser essence.

Blow the surface of condenser and evaporator cores with high pressure air gun.

Note: the high pressure water gun or air gun can be used only after being adjusted

to proper pressure, and the fins should not be beaten down; for specially dirty cores,

especially evaporator core with filter screen not being cleaned for so long that lots of

dust and dirt covered on fins, it is necessary to wash it with special fin leaner diluted with

water for air conditioner

7. Frequently check the compressor for any oil leakage or oil shortage:

Generally, coach air conditioner adopts piston compressor, of which the shaft is sealed via

the sliding seal surface of shaft seal, and the sealing property and lubrication of the shaft

seal all depend on refrigeration oil, so a little oil leakage (dropping) is normal. During actual

application, driver should examine the compressor as necessary, and promptly repair it once

oil leakage arises due to abnormal shaft seal.

Examining methods:

(1) The run-in period of compressor is 250 hours. The oil leakage during this period is normal,

and oiling is necessary only when a great deal of oil leakage occurs.

(2) The refrigerant level of compressor can be observed via sight glass: check the refrigerant

level 10-15 minutes after startup. Since the actual installation position of compressor is

different (oblique position), it’s better to examine the refrigerant level through two sight

glasses, at least through one sight glass. (Part of refrigerant flows into overhead section

during operation, and it should be verified repeatedly when debugging new vehicle).

It is every driver’s responsibility to regularly clean the filler screen of air

conditioner and keep a clean inside environment of the bus.

5. Check the amount of refrigerant and the dryer condition:

The dual cores should be cleaned at least once a year. The reversed fins found during

cleaning should be corrected with fin comb.

(Figure 3 -7)

Low of refrigerant inside Level Glass

(Figure 3 -6)

Level glass Dryer

(1) Check the moisture content of system via level glass of return air grille. If the color of

test paper goes green, it means the moisture content is normal. If the color of test paper

gradually becomes yellow, it means the moisture content is high and dryer fails where it

is necessary to replace the dryer.

(2) It is possible to judge if the refrigerant is enough by observing the movement of

refrigerant through level glass can help (See Figure 3-6).

No obvious but occas ional bubbles in liquid flow means refrigerant is enough, in contrast,

obvious and constant bubbles in liquid flow means refrigerant is not enough.

6. Check the heat exchange fins of evaporator and condenser cores for their cleanness:

Regularly cleaning heat exchanger (of evaporator, condenser) of the air conditioner ensures

the best refrigerating performance of air conditioner and avoids any faults of air conditioner

arising due to excessive dirt on the surface of heat exchanger.

Evaporator

core

Condenser

core

Figure 3 - 8

Detach the return air grille and clean the filler screen

Warning! If the filter screen is not cleaned regularly, the

heat exchange efficiency of evaporator may be seriously

impact for the case in which lots of dust and greasy

dirt enter into evaporator core, resulting in significant

decrease of refrigerating effect, and even causing

filter screen blockage, less air volume, or incomplete

evaporated fluid refrigerant entering into compressor to

give rise to “ liquid hammer” of the compressor.

(Figure 3 -5)







(3) When the air conditioner is not

running, it is suggested that the

oil level of one compressor be not

lower than 1/3 of the sight glass.

8. Inject lubricating grease for belt

pu lle y bea rin g and su ppo rt shaf t

sleeve of the air conditioner once

a year to ensure lubrication of the

bea ring . (2# lith ium base grea se is

suggested):

9. Regularly turn on the air conditioner

in winter:

Regularly turn on the air conditioner in winter to ensure its operation twice a month (running

for 5-10 minutes each time), so as to guarantee the lubrication of mechanism inside the

compressor.

Before start of vehicle, lock the clutch chuck of rotating compressor with hand or monkey

wrench to make the chuck of compress change from being heavy to being light (advisable),

then switch on the air conditioner for about 5 seconds, and switch it off. After this, switch

on the air conditioner once again for about 5-10s and switch it off as before. After above

procedure, the air conditioner can be normally started up.

For the users in north, the abovementioned operation procedure should be followed before

the first startup of air conditioner in spring.

10. Check the pipeline and joint

Frequently check the exposed rigid tube, flexible pipe and pipeline joint in case of any

interference, wear, extrusion and looseness. The broken pipeline and loose joint will cause

refrigerant leakage, resulting in decrease of refrigerating effect of the air conditioner and

even no refrigeration of the air conditioning system. The extruded pipeline will form stop-

flow of refrigerant, which will impact refrigerating effect of the air conditioner.

11. Check the wiring cluster

Frequently check the exposed wiring cluster and its connector assemblies in case of any

interference, wear and looseness.

Chapter IV Operation and maintenance of

contained air conditioning unit

4.1 Description of manipulator II’s Functions

Manipulator II (Figure 4-1)

1. Key switch

Key switch is set to start and stop the engine of power unit, and control the operation andshutdown of air conditioning system specialized generator.

2. Power indicating light

The power indicating light is set for power indication of power unit. When key switch is at

“On”, the power indicating light illuminates to power on, and at “off”, the power indicating

light extinguishes to power off.

3. Oil pressure alarm indicating light (see Figure 4-2)

Oil pressure alarm indicating light is set to warn the condition in which the lubricating oil

pressure of engine is too low, controlled by the switch-on/off

of oil-pressure in forced lubrication pipeline of engine. If the

alarm indicating light goes on, turn the key switch to “Off” to promptly stop engine’s operation, avoiding damage of engine,

and check machine oil level of the engine.

Note: During pre-startup of engine phrase, when key

switch is at “On”, the oil pressure indicating light

showing on is normal, and it will show off about 10s

after start up of engine.

4. Water temperature alarm indicating light (see Figure 4-3)

Water temperature alarm indicating light is set to warn the the condition in which water

(Figure 4 -2)

Sight glass

(Figure 3-9 )







temperature is too high, controlled by the switch-on/off of cooling water temperature switch

inside engine water cooling pump. If the alarm indicating light goes on, the engine will

automatically shutdown to avoid engine overheating.

When water temperature alarm indicating light

goes on, check if the level of engine water tank is

too low, air inlet passage is clear or the belt of water

pump is tensioned.

Note: When normal operation of engine or

after water temperature alarm indicating light

illuminates, please do not open the engine water

tank lid, to prevent operator being injured by the

cooling liquid.

5. See “Function description of manipulator I” in Chapter IV for other information about

manipulator.

4.2 How to switch on the air conditioner:

1. Startup of engine

(1) Before startup of engine, make sure the air conditioner is powered off and turn the key

switch clockwise to “Warm up” position (For the engine with different configuration, the

warm-up function probably doesn’t work, so the position can be skipped over) to prepare

the startup of engine. Warm-up time should not be more than 12s each time. (see Figure

4-4).

Note: If the engine fails to s tart while starting motor

has been running for 30 seconds, please re-start

the engine after one minute. If the engine fails to

start for three consecutive times, please check the

oil line, air line and electrical system, remove all

related faults if any, and re-start the engine.

(3) Turn key switch clockwise to “Start” position and

the engine will be started by the driving of starting

motor. (See Figure 4-6).

(4) When engine is started up, release the key switch,

which will automatically rebound to “On” position.

The engine operates at low speed to make preparation for switch-on of air conditioner.

Note: When passenger vehicle air conditioner is running, key switch

should keep at “On”.

2. Switch on the air conditioner (see How to switch on the air conditioner by manipulator I)

3. Introduction to timer function of manipulator

The manipulator has timer function, that is, the accumulative service time of the air

conditioner can be displayed and viewed through simple operation. If the manipulator is

changed in the midway, record the service time at the time of changing the manipulator. If it

is necessary to inquire the accumulative service time later, what we have to do is only to sum

the recorded service time and the current displayed service time.

Operation method: hold on both < >and< >for 5s, nixie tube will display the first 3

digits of service time of the system; within 10s, press < > to display the last 3 digits of

service time of the system, then press < >again to display the first 3 digits of service time

of the system; within 10s, there is no < >or< >pressed, it will automatically return to

<in-vehicle> temperature display.

The format of accumulative service time of air conditioner is in form of XXX, XXX. The

unit of first 5 digits is 1-hour, and the unit of last digit is 6-minute, with total statistic of 100

or 1000 hours.

4.3 Cautions for usage of air conditioner

1. See “Cautions for use of air conditioner” in Chapter III for other operations except engine.

2.The adjustment and maintenance are subject to the instruction for usage and related

regulations.

(1) Make sure the storage battery is fully charged, and check the terminals for cleanness and

(Figure 4-3)

(Figure 4 – 4) (Figure 4 – 5)

(2) Turn key switch to “On” position, then the “Power” and “Oil pressure” indicating lights

will illuminate. (see Figure 4-5)

(Figure 4-6)







check the connection for reliability.

(2) Prior to use of new engine, running-in according to regulations is necessary (see the Table

below), and the engine should not be suddenly accelerated.

(3) Please use the refrigerant that is prepared based on specified ratio and mixed with

antifreeze.

(4) The engine without supercharger should use CC class machine oil, while the engine with

supercharger should use CD class or above machine oil.

(5) The engine with supercharger should idle for 3-5 minutes after startup, and also idle for 3-5

minutes before stop.

(6) Machine oil pressure should be higher than 392KPa when it keeps at normal water

temperature (80~90°C) and medium vehicle speed, the normal

(7) The fuel of engine is 0# diesel (10# diesel is preferred in north in winter).

(8) During engine running, it is necessary to promptly shutdown and check malfunction if

any.

(9) Open the radiator cover at first before discharging the water in cooling system (don’

t open until water temperature decreases, otherwise the hot water that spouts out would

cause injury), then open the discharging plug screws at left bottom of radiator and left

side of cylinder.

Specification on running-in of new engine

(4) Re-fill machine oil and clean or replace filter element after vehicle travelling reaches to

1000 and 3000km.

4.3 Maintenance of Air Conditioner

1. Check Engine Machine Oil of Power Unit

Verify the oil level is between the highest and lowest scales of oil dipstick. (see Figure 4-7)

Cautions for running-in of new engine:

(1) Check the volume of machine oil, water and diesel and make sure the battery is charged,

and eliminate any leakage.

(2) Use torque wrench to turn engine crankshaft several rounds before starting engine.

(3) After engine is installed in vehicle, running-in should be done on Class 1 or Class 2 road.

No running-in is done on any poor road, especially on sands.

(Figure 4-7)

2. Check Cooling Open water tank lid to check the volume of cooling water. The rated volume

of cooling water is 9 liter (full).

(Figure 4-8)

3. Check the Air Filter of Engine

(1) Remove air filter element from the filter. (see Figure 4-9)

Mileage (Km) Load Vehicle speed

0 ~ 200 No load Less than 50% of the rated speed of the engine

> 200 ~ 800 Less than 50% of the rated load Less than 50% of the rated speed of the engine

> 800 ~ 1500 Less than 75% of the rated load Less than 75% of the rated speed of the engine

> 1500 ~ 2500 Full load Lower than the rated maximum speed







(2) Repeatedly blow with the compressed air.

(3) The replacement period of air filter should be based on the requirement specified in

instruction for use of engine.

(Figure 4-9)

ItemMaintenance

intervalStatus Contents and requirements

Air outlet Every dayBefore and after

startup

When air conditioner is running, it is necessary to keep 2/3 air

outlets opened to guarantee good circulation of airflow; Check if

the volume of air out at two sides is similar.

Filter screen of

return air grilleEvery week Before startup

Wash the filter screen (sponge block) of return air grille with

water, and the washing can be earlier if vehicle runs in dusty area.

Filter screen ofevaporator core

Every month Before startup Wash the filter screen of evaporator core with water, and thewashing can be earlier if vehicle operates in dusty area.

Condensate pipe Every day After star tup

After air conditioner has operated for 1 hour, check the

condensate pipe for any discharge of condensate water. In South

or coastal area with high humidity or in rainy season, there is

large amount of water discharge.

Transmission belt

Every week Before startupCheck the belt for its intensity and wear, and adjust or replace it

if necessary. Vertically apply 10kg force (about 98 Newton) with

thumb to the belt between two belt pulley, its deflection should be

as follows: the deflection of center distance per meter is 10mm.Every month Before startup

Compressor oil

level

Every day or

every week

Before and after

startup

Check the compressor for its oil level. The refrigerating machine

oil level of compressor can be observed through sight glass: over

4∕5 30minutes after stop of the air conditioner, and 1∕4~3∕4 in

working condition. If the level is lower than above criteria during

250-hour running-in period, it is necessary to replace felt and

add refrigeration oil; if the level is lower than above criteria afterrunning-in time, the shaft seal should be replaced.

Electromagnetic

clutchEvery day

Before and after

startup

Prior to power-on, check the clutch bearing for any abnormal

sound; after power-on, check if the electromagnetic clutch can

promptly pull in /separate, and slip.

Compressor

Every year Before startup Check the bolt of fixed support of compressor for any looseness.

Every week After startup

During non-use of compressor, check different components for

normality by operating it once every week, several minutes each

time

Fan Every year After star tup Check if there is any abnormal sound dur ing operation.

Dryer Every year After startup

Replace the dryer (note: if the test paper of sight glass fails to

become y ellow, and refrigeration of the system is normal and

the sight glass is clear and transparent, the dryer may not be

replaced).

Socket connector,

terminal Every month Before startup

Check if the cable of compressor clutch and the terminals of

generator are loose.

Fuse Every month Before startup

Check if the master fuse of 150A power supply, the fuse of 50A

fan, and the 5A, 7.5A, 10A inserting type fuses are intact, and if

the retaining screw at both sides and base are loose.

Transition wheel Half a year Before startup Refill lubricating grease (may inject it from “grease fitting”.)

Support shaft

sleeveHalf a year Before startup

Refill lubricating grease (may inject it from “grease fitting”.)

Refill lubricating grease (may inject it from “grease fitting”

Instruction Table for Driver’s Routine Operation and Maintenance

See SONGZ User’s Manual of Passenger Vehicle Air Conditioner for the rules on operation and maintenance by

professional technician (Version No.: JS-2010-01& by Zhong Huawei).

If any fault occurs, please inmmediately contact SONGZ service center or service station.







secured, and check if the socket connectors of manipulator and compressor coil are properly

connected, because poor connection will cause high current, resulting in fuse heating and

burnout.

No refrigeration due to the loose socket connector of engine clutch coil: it is generally

caused by excessively tightened wiring harness or poor connection of socket connector. Please

re-insert the socket connector and secure firmly the two ends of wiring harness.

No refrigeration due to refrigerant leak: in this case, the “fault light” of manipulator flashes

red. At this moment, the “Refrigeration” should be switched off promptly. Check the engine

chamber, flexible pipe and copper pipe inside air passage for any leakage. In case of slight

leakage, there is refrigerant stain at connector or weld; in case of fast leakage, we can hear the

sound of leakage. Report the check results to SONGZ service center, where the professional

technician will treat the problem.

2. Poor refrigerating effect of air conditioner

Closing most of air outlets will cause poor

refrigerating effect and less air volume. Sine

the temperature of front part of the vehicle is

higher than that of rear part due to direct solar

radiation, sometimes the driver would adjust

the temperature inside vehicle according to own

feeling, resulting in some passengers feeling “too

cold” and closing the air outlets. However, the

more air outlets closed, the less air supplied. If

the defrosting sensor fails, it will even cause evaporator core icing, lead to “short circuit” of

in-vehicle return air inlet and circulating air flow, resulting in “fault” of poor refrigerating

effect of the air conditioner. To solute such problems, please set the temperature inside

vehicle at the value for passengers’ comfort, and open all air outlets.

Poor refrigerating effect due to bad carriage seal. The solution is: close all doors and

windows.

Poor refrigerating effect due to shortage of refrigerant. In order to determine this case,

the first is to check via sight glass if the refrigerant is enough (see Item 5 of 3.3 for

related standard), and notify SONGZ service center to solve the problem.

3. Less air volume or no air supply from the air conditioner

The connection of generator is loose

or broken, causing no air supply

of air conditioner. In this case, it is

necessary to check the connection

of output, grounding and excitation

of generator terminals in the air

conditioner. To solute such problems,

pl ea se re -c on ne ct or cr im p th e

terminals.

No air supply is caused by fuse

burnout, generally due to the damaged fuse of main power source 150A or evaporator fan. In

general, 150A main power supply is equipped with spare fuse that can be used to solve the

problem on spot. If the fuse of fan is damaged, the problem can only be solved by SONGZ

service station.

The broken speed regulation resistance of evaporator causes less air volume on both sides or

on one side. On this occasion, please contact the SONGZ service station.

4. Less air volume and significant decrease of refrigerating effect

If it happens during normal running of air conditioning system, it is often due to extremely

dirty filter screen of air conditioner. Especially, for the air conditioner that was used last

summer and re-used next spring and summer, the refrigerating effect of the air conditioner

is obviously worse than the previous year. What should be done is to dismantle the filter

screen of return air grille and filter screen of evaporator, and wash them. For preventing

such problem, it is necessary to regularly wash filter screen of the air conditioner according

to user’s manual. See aforesaid Item 4 of 3.3 for detailed requirements.

5. Abnormal sound of clutch

The fault is often related with bearing and behaviors as follows: when the engine starts up

while air conditioner is shutdown, the clutch makes abnormal sound, and after switch-on of

air conditioner, the abnormal sound disappears. Before pull-in of clutch, the bearing is in “full

working condition” when the load is the maximum. When the problem arises for the first

time, please contact SONGZ service center as soon as possible.

6. See User’s Manual for common troubleshooting of engine.

Air outlet

Fuse of

evaporator fan

Control box of return air inlet







Appendix: Fault analysis table of air conditioner for passenger vehicle

Fault analysis table: power-down of air conditioner

Fault Symptom Potential Cause Measure

Power-

down of air

conditioner

No air supply, no refrigeration,

and no panel display

No power input at Pin D+

on the manipulator of the air

conditioner

Check vehicle key switch

for the introduced power

supply

10A fuse of manipulator

damaged

Replace the fuse after

removing short circuit

and poor contact

Master fuse of power supply

burnt out, resulting in dead

power supply of electrical

load.

Same as

Manipulator fai lure Replace manipulator

No air supply and no

refrigeration

Generator failure (inside

regulator and generator)

Replace manipulator or

generator

Ineffective refrigerating output,

ineffective ventilating output,

effective excitation, ineffectivefresh air/ sterilization/heating,

and on the panel, only the low-

speed light keeps on.

(Supply) voltage higher than

+32VDC for consecutive13s, resulting in too high

voltage of vehicle generator.

Check and replaceregulator or generator

Ineffective refrigerating

output, ineffective ventilating

output, ineffective excitation,

ineffective fresh air/ steriliza-

tion/heating, no display on the

panel, and noisy fan

The interior part of vehicle

generator or regulator

damaged when higher than

+45VDC

Check and replace

regulator or generator

Fault analysis table: no air supply or less air volume


No air supply or

less air volume

Evaporator fan fails

Poor grounding of fan Check circuit

Loose socket connectors Re-connect and fix

Broken fuse Replace fuse

Broken relay Replace relay

Broken speed regulation

resistance

Replace speed regulation

resistance

Broken evaporator fan Replace evaporator fan

Less air volume of air

outlet

Extremely dirty filter screen

of evaporator Wash filter screen

Air pipe fallen off, causing

air leakage

Check the tightness of air

pipe

Electric brush of evaporator

fan seriously worn down

Replace carbon brush or

evaporator fan

Air volume has no change

when adjusting air volume

level

Manipulator failureCheck and replace

manipulator

The ventilation of

air conditioner is not

controlled by manipulator:

after switch-off of the air

conditioner, there is still air

supply from the air outlet.

Relay of the fan burnt out

with pins 30, 87 closed

Note: the fault always

occurs on the vehicle where

air conditioner and vehicle

share one generator.

Check and replace relay







Fault analysis table: no refrigeration


No refrigeration, only

natural wind supply

Compressor and condenser fan

fail

Carriage temperature is too

high or too low, i.e. higher

than 60°C or lower than 16°C

It is normal, with no need of

repair

The output voltage of

generator lower than 20V

Find the reason of low

pressure and treat the fault


fail, fault light shows red, and

high/low pressure is on the

low side.

Refrigerant in extremely low

volume

Check air leakage position and

add right amount of refrigerant


fail, fault light shows red, and

it’s difficult to set high/low

pressure

Refrigerant fully leakedCheck air leakage position and

add right amount of refrigerant


fail, fault light shows red, low

pressure is unusually low, and

filter pipe of receiver dryer is

condensed.

Receiver dryer blockage (by

dirt)

Dismantle and check the

component


fail, and fault light shows red

Return air temperature sensor

(temperature sensor) breakage

(open circuit)

Replace the sensors after

verifying the sensor is

defective.

Defrosting sensor breakage

(open circuit)Same as above

Pressure switch defection

Replace the pressure switch

after verifying the switch is

defective

Compressor and condenser

fan fail, fault light shows red,

and high pressure is unusually

high.

Condenser fan breakageRepair or replace the

condenser fan

Fuse of condenser fan burnt

out

Replace the fuse of condenser

fan

Compressor fails

Loosen socket connector of

electromagnetic clutch

Re-connect the cable of

compressor

Fuse of electromagnetic clutch

burnt out

Remove the reason of fuse

burnt out and replace the fuse

Control relay ofelectromagnetic clutch

breakage

Replace the relay

Electromagnetic clutch

breakage

Repair or replace


Overly wider air gap of


Adjust air gap or replace the

clutch

Interior parts of compressor

damagedReplace compressor

Loosen or broken transmission

beltAdjust or replace the belt


intermittentrefrigerationof airconditioner(cooling airis just blownout everynow andthen)

No pull-in of clutchsometimes

Loose wire terminals ofelectromagnetic clutch

Reconnect the wire, and replacethe electromagnetic clutch afterverifying the clutch is defective.

Defective Sensor (return airtemperature sensor and defrostingsensor)

Replace the sensor after verifyingthe sensor is defective.

Defective pressure switch that starts

to work under abnormal pressure

Replace the pressure switch after

verifying the switch is defective. No closing of relaysometimes

Relay of electromagnetic clutch breakage

Replace the replay

The sensitivity of return airtemperature sensor or defrostingsensor decreases or they installed inincorrect position.

Adjust installation position of thesensor; replace the sensor.

Insufficientcooling air

Low pressure is unusuallylow, or evaporator frostingand air inlet of compressorfrosting may occur at thesame time.

The air flow passage in evaporator blockage

Remove the blocking

Filter screen of return air grille ofevaporator blockage by dust or dirt.

Wash filter screen and remove the blocking

Dirt in evapora to r core Remove the di rt on evapor ator core

Exhaust pressure isunusually high, andcompressor is unusuallyheating.

Dirt in condenser core, causing blockage of air flow passage incondenser

Wash out and remove the dirt oncondenser with compressed air orwater

The exhaust pressureand suction pressure atcompressor side is high

Condenser fan failureRemove the fault causing the fandoesn’t work

The revolving speed ofcondenser fan is slow, andexhaust/suction pressure ishigh.

Carbon brush seriously damaged Replace carbon brush or fan

Poor grounding of condenser fan Re-grounding

High/low pressure is onlow side, refrigerant isnot enough, and there areobvious bubbles in sightglass.

Refrigerant leakage Repair position with refrigerantleakage, and then fill refrigerant tillto specified amount.Leakage of system pipeline

Insufficient filling-up of refrigerant Fill refrigerant

High/low pressure is onhigh side, there are bubblesin sight glass, compressor

is noisy, and compressor isunusually heating

Incondensable gas in the system: air,hydrogen, nitrogen, etc. All the gasescirculate in system with refrigerant,and don’t condense with refrigerant,and don’t produce refrigeratingeffect. Generally it is because ofincomplete vacuation, with some airleft in system.

Exhaust the incondensable gases,and completely vacuate prior to

filling-up of refrigerant.

Compressor is noisy

The refrigerant oil is too much in thesystem (note: refrigerant oil involvesin the circulation, but is not used asheat exchange medium).

Check and adjust oil level of thecompressor

High pressure is low whilelow pressure is high,high/low pressure rapidlykeeps balanced after closingrefrigeration, compressoris noisy and compressor isunusually heating.

Compressor valve damaged andexistsing displacing valve leakage(blowing between high and low pressure cylinders)

Replace valve plate or compressor

Sealing gasket of valve plate breakage (blowing between high andlow pressure cylinders)

Replace sealing gasket

Fault analysis table: insufficient cooling air







Fault analysis table: abnormal noise


Noise of actuating

device

After switch-on of air

conditioner, abnormal

noise comes out ofactuating part.

Sound from transition wheel

or tense bearing

Replace the transition

wheel or bearing

Sound from clutch bearing Replace clutch or bearing

Engine surges: Overly low

idle speed

Increase the idle speed of

engineLoose support screw of

compressor Adjust screw torsion

Belt slipped due to being

looseAdjust belt intensity

Abnormal noise of

compressor

High/low pressure

is unusually high,

compressor is

unusually heating, and

compressor is noisy.

Too much refrigerant filled inDischarge right amount of

refrigerant

Refrigerant oil is too

much

Too much refrigerant oil in

the system

Reduce the level of

compressor refrigerant oil

and make adjustment

Compressor is

unusually noisy

Liquid refrigerant flowed into

the compressor

See “Fault analysis table:

cooling air is not enough”

Interior of compressor

damagedReplace compressor

Clutch slips on friction

surface

Excessive gap of clutch

Overly low voltage of

generator

See “Fault analysis table:

No refrigeration, but

normal ventilation”

Sound of fan Fan makes sound Sound from Fan bea ring Replace the fan


Insufficientcooling air

High/low pressure difference isreduced

Overly large friction loss between the parts insidecompressor, resulting in actualair displacement much less thantheoretical one.

Repair or replace compressor

Low pressure is too low, andobvious temperature differenceexists between the pipelines at

both sides, with drop of water onthe pipelines.

Receiver dryer inlet blockage Wash or replace drying filter

The displacing valve ofcompressor breakage withfragments entered into high

pressure end, resulting in slight blocking.

Remove the fragments

Suction pressure is unusuallylow, expansion valve frosts, thelow-pressure side sometimes becomes vacuum, refrigerationis intermittent or there is norefrigeration at times, and pointerof pressure gage jitters.

The water entering the systemiced at expansion valve nozzle,stopping the circulation, but whenthe ice is melted, the systemrecovers its normal operation.Generally, the problem arisesfrom the dryer in saturate statusand system moisture out of limit.

Clean or replace component, andthe dryer should be replaced.

Suction pressure is unusually low,expansion valve frosts, and airinlet of compressor frosts.

Damage or breakage in therefrigerant pipeline betweenthermal bulb of expansion valveand the expansion valve

Check and replace expansionvalve and pipeline

Low pressure is high, or at thesame time, evaporator frosts, airinlet of compressor frosts and

compressor becomes noisy.

Expansion valve overly opened.

Check if thermal bulb is fit withoutlet pipe of evaporator, and ifthe installation position is correct.

Replace it as necessary.

The pressure on low pressure sideis low

Expansion valve overly closed:interior balance pipe (thermal bulb) breakage; dirty interior ofthe valve.

Replace the thermal bulb orexpansion valve; wash theexpansion valve.

The pressure of low pressure pipeis unusually high, evaporatorfrosts, compressor frosts, andcompressor become noisy.

Expansion valve failure withacicular corrosion or breakage.

Replace the expansion valve

Cooling air is not enough

The air flow of air outlets andreturn air inlet shorted.

Block the air outlets on both sidesof return air inlet

Poor seal of evaporator box.

Cooling air is not enough Overly low speed of engineIncrease the speed of engine toappropriate range

Cooling air is not enoughPolluted interior of system caused by impure refrigerant

Replace refrigerant and refrigerantoil

The temperature inside vehicle isset too high.

Misuse: stop refrigeration beforehuman comfortable temperatureis reached.

Re-set temperature

Air outlets are too few, and the airsupply in carriage is too less.

Problems due to unreasonable air passage structure with insufficientair supply area.

Increase the number of air outlets

Heat insulation of platform flooris poor

Metal floor without installationof plastic board or PVC artificialleather.

Install floor leather

There is no heat preservation pasted in air passage.

Poor seal of air supply pipe. paste heat preservation

Air leakage exists in air passage.Air pipe fallen off or the hotairflow from outside entered intothe air passage.

Check and take appropriatesealing measure







Common Used Circuit Diagram

1. The circuit diagrams in the Manual that represent part of products’ typical circuit diagrams.

2. Instruction for usage of circuit diagrams:

The circuit diagram SZC provided below is applicable to the maintenance of CPP, BBP, LUX

series. The so-called circuit difference between SZC-II, II/F, III, III/F, IV, IV/F, V, V/F, VI

series is just due to the variation of coil quantity of relay, evaporator fan, condenser fan and

compressor with same control principles.

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