50SDSingle Packaged Electric Cooling Units

Installation, Start-Up, and Operating InstructionsSizes 024-060

NOTE: Read the entire instruction manual before starting theinstallation.

This symbol → indicates a change since the last issue.

TABLE OF CONTENTSSAFETY CONSIDERATIONS .....................................................1

RULES FOR SAFE INSTALLATION AND OPERATION.......2

INTRODUCTION..........................................................................2

RECEIVING AND INSTALLATION ..........................................2Check Equipment......................................................................2

IDENTIFY UNIT ................................................................2INSPECT SHIPMENT........................................................2

Provide Unit Support ................................................................2ROOF CURB.......................................................................2SLAB MOUNT ...................................................................2GROUND MOUNT ............................................................2

Provide Clearances....................................................................2Field Fabricate Ductwork .........................................................2Rig and Place Unit....................................................................2

INSPECTION ......................................................................4INSTALLATION ................................................................4

Connect Condensate Drain .......................................................7Install Duct Connections ..........................................................7

CONFIGURING UNITS FOR DOWNFLOW (VERTI-CAL) DISCHARGE............................................................7

Install Electrical Connection ....................................................9HIGH-VOLTAGE CONNECTIONS..................................9SPECIAL PROCEDURES FOR 208-V OPERATION .....9CONTROL VOLTAGE CONNECTIONS.........................9STANDARD CONNECTION ..........................................10TRANSFORMER PROTECTION....................................12

PRE-START-UP ..........................................................................12

START-UP ...................................................................................12CHECK FOR REFRIGERANT LEAKS..........................12START UP COOLING SECTION AND MAKE ADJUST-MENTS..............................................................................12CHECKING COOLING CONTROL OPERATION .......12CHECKING AND ADJUSTING REFRIGERANTCHARGE ...........................................................................12INDOOR AIRFLOW AND AIRFLOW ADJUST-MENTS..............................................................................14For 208/230V.....................................................................14COOLING SEQUENCE OF OPERATION.....................14

MAINTENANCE.........................................................................14AIR FILTER......................................................................15EVAPORATOR BLOWER AND MOTOR.....................15CONDENSER COIL, EVAPORATOR COIL, AND CON-DENSATE DRAIN PAN..................................................16CONDENSER FAN ..........................................................16ELECTRICAL CONTROLS AND WIRING ..................16REFRIGERANT CIRCUIT...............................................16EVAPORATOR AIRFLOW .............................................17METERING DEVICE — ACCURATER........................17

TROUBLESHOOTING ...............................................................17

START-UP CHECKLIST............................................................17

NOTE TO INSTALLER — Before the installation, READ THESEINSTRUCTIONS CAREFULLY AND COMPLETELY. Also,make sure the User’s Manual and Replacement Guide are left withthe unit after installation.

SAFETY CONSIDERATIONS

Installation and servicing of air-conditioning equipment can behazardous due to system pressure and electrical components. Onlytrained and qualified personnel should install, repair, or serviceair-conditioning equipment.

Untrained personnel can perform basic maintenance functions ofcleaning coils and filters. All other operations should be performedby trained service personnel. When working on air-conditioningequipment, observe precautions in the literature, tags, and labelsattached to the unit, and other safety precautions that may apply.

Follow all safety codes. Wear safety glasses and work gloves. Usequenching cloth for unbrazing operations. Have fire extinguisheravailable for all brazing operations. Consult a qualified installer orservice agency for information or assistance. The qualified in-staller or agency must use only factory-authorized kits or acces-sories when modifying this product.

Fig. 1—Model 50SD

C99001

Visit www.carrier.com

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.Book 1 6Tab 6 8

PC 101 Printed in U.S.A. Catalog No. 50SD-1SI Pg 1 8-05 Replaces: New

ELECTRICAL SHOCK HAZARDFailure to follow this warning could result in personal injuryor death.Before performing service or maintenance operations onsystem, turn off power to unit. Turn off accessory heaterpower switch, if applicable.

RULES FOR SAFE INSTALLATION AND OPERATION

Recognize safety information. This is the safety-alert symbol .When you see this symbol in instructions or manuals, be alert tothe potential for personal injury.

Understand the signal words DANGER, WARNING, CAUTION,and NOTE. These words are used with the safety-alert symbol.DANGER identifies the most serious hazards which will result insevere personal injury or death. WARNING signifies a hazardwhich could result in personal injury or death. CAUTION is usedto identify unsafe practices which may result in minor personalinjury or product and property damage. NOTE is used to highlightsuggestions which will result in enhanced installation, reliability,or operation.

These instructions cover minimum requirements and conform toexisting national standards and safety codes. In some instances,these instructions exceed certain local codes and ordinances,especially those that may not have kept up with changing residen-tial construction practices. We require these instructions as aminimum for a safe installation.

INTRODUCTION

The 50SD unit (see Fig. 1) is fully self-contained, and designed foroutdoor installation. See Figs. 2 and 3 for unit dimensions. All unitsizes have discharge openings for both horizontal and downflowconfigurations, and are factory shipped with all downflow ductopenings covered . The unit may be installed either on a rooftop,ground-level cement slab, or directly on the ground if local codespermit. (See Fig. 4A for roof curb dimensions.)

RECEIVING AND INSTALLATION

Step 1—Check Equipment

IDENTIFY UNIT

The unit model number and serial number are stamped on the unitidentification plate. Check this information against shipping pa-pers.

INSPECT SHIPMENT

Inspect for shipping damage while unit is still on shipping pallet.If unit appears to be damaged or is torn loose from its anchorage,have it examined by transportation inspectors before removal.Forward claim papers directly to transportation company. Manu-facturer is not responsible for any damage incurred in transit.Check all items against shipping list. Immediately notify thenearest Carrier Air Conditioning office if any item is missing. Toprevent loss or damage, leave all parts in original packages untilinstallation.

Step 2—Provide Unit Support

ROOF CURB

Install accessory roof curb in accordance with instructions shippedwith curb (See Fig. 4A). Install insulation, cant strips, roofing, andflashing. Ductwork must be attached to curb.

IMPORTANT: The gasketing of the unit to the roof curb is criticalfor a watertight seal. Install gasketing material supplied with theroof curb. Improperly applied gasketing also can result in air leaksand poor unit performance.

Curb should be level to within 1/4 in. (See Fig. 5A). This isnecessary for unit drain to function properly. Refer to accessoryroof curb installation instructions for additional information asrequired.

SLAB MOUNT

Place the unit on a solid, level concrete pad that is a minimum of4 in. thick with 2 in. above grade (See Fig. 5B). The slab shouldextend approximately 2 in. beyond the casing on all 4 sides of theunit. Do not secure the unit to the slab except when required bylocal codes.

GROUND MOUNT

The unit may be installed either on a slab or placed directly on theground if local codes permit. Place the unit on level groundprepared with gravel for condensate discharge.

Step 3—Provide Clearances

The required minimum service clearances are shown in Fig. 2 & 3.Adequate ventilation and outdoor air must be provided. Theoutdoor fan draws air through the outdoor coil and discharges itthrough the top fan grille. Be sure that the fan discharge does notrecirculate to the outdoor coil. Do not locate the unit in either acorner or under an overhead obstruction. The minimum clearanceunder a partial overhang (such as a normal house overhang) is 36in. above the unit top. The maximum horizontal extension of apartial overhang must not exceed 48 in. For extended overhangs,provide a minimum clearance of 48 in.

IMPORTANT: Do not restrict outdoor airflow. An air restrictionat either the outdoor-air inlet or the fan discharge may bedetrimental to compressor life.

Do not place the unit where water, ice, or snow from an overhangor roof will damage or flood the unit. Do not install the unit oncarpeting or other combustible materials. Slab-mounted unitsshould be at least 4 in. above the highest expected water and runofflevels. Do not use unit if it has been under water.

Step 4—Field Fabricate Ductwork

Secure all ducts to roof curb and building structure on verticaldischarge units. Do not connect ductwork to unit. For horizontalapplications, unit is provided with flanges on the horizontalopenings. All ductwork should be secured to the flanges. Insulateand weatherproof all external ductwork, joints, and roof openingswith counter flashing and mastic in accordance with applicablecodes.

Ducts passing through an unconditioned space must be insulatedand covered with a vapor barrier. If a plenum return is used on avertical unit, the return should be ducted through the roof deck tocomply with applicable fire codes. A minimum clearance is notrequired around ductwork. Cabinet return-air static shall notexceed -.25 in. wg.

Step 5—Rig and Place Unit

Rigging and handling of this equipment can be hazardous for manyreasons due to the installation location (roofs, elevated structures,etc.)

Only trained, qualified crane operators and ground support staffshould handle and install this equipment.

When working with this equipment, observe precautions in theliterature, on tags, stickers, and labels attached to the equipment,and any other safety precautions that might apply.

Follow all applicable safety codes. Wear safety shoes and workgloves.

2

Fig. 2—50SD024-030 Unit Dimensions

UNIT ELECTRICAL CHARACTERISTICSUNIT WEIGHT UNIT HEIGHT

IN. (MM)”A”

CENTER OF GRAVITYIN. (MM)

lb. kg X Y Z50SD024 208/230-1-60 343 156 39.02 (991) 20.0 (508) 19.3 (490) 17.6 (447)50SD030 208/230-1-60 366 166 41.02 (1042) 20.0 (508) 14.0 (356) 13.0 (330)

C99007

REQUIRED CLEARANCE FOR OPERATION AND SERVICINGINCHES [mm]

EVAP. COIL ACCESS SIDE............................................................36.00 [914.0]POWER ENTRY SIDE....................................................................42.00 [1066.8](EXCEPT FOR NEC REQUIREMENTS)UNIT TOP .......................................................................................48.00 [1219.2]SIDE OPPOSITE DUCTS ..............................................................36.00 [914.0]DUCT PANEL .................................................................................12.00 [304.8] *

*MINIMUM DISTANCES: IF UNIT IS PLACED LESS THAN 304.8 [12.00] FROM WALL SYSTEM, THEN SYSTEM PERFORMANCE MAYBE COMPROMISE.

REQUIRED CLEARANCE TO COMBUSTIBLE MATL.

INCHES [mm]TOP OF UNIT...................................................................................14.00 [355.6]DUCT SIDE OF UNIT.........................................................................2.00 [50.8]SIDE OPPOSITE DUCTS ................................................................14.00 [355.6]BOTTOM OF UNIT .............................................................................0.50 [12.7]

NEC. REQUIRED CLEARANCES.INCHES [mm]

BETWEEN UNITS, POWER ENTRY SIDE ....................................42.00 [1066.8]UNIT AND UNGROUNDED SURFACES, POWER ENTRY SIDE .36.00 [914.0]UNIT AND BLOCK OR CONCRETE WALLS AND OTHERGROUNDED SURFACES, POWER ENTRY SIDE.........................42.00 [1066.8]

(Refer to Maximum Operating Clearances)

3

UNIT FALLING HAZARDFailure to follow this warnig could result to personal injury ordeath. Never stand beneath rigged units or lift over people.Never exceed 200 lbs. per bracket lifting force.

UNIT FALLING HAZARDFailure to follow this warning could result to personal injuryor death.Accessory lifting kit is only to be used with Small Packagedunits which have a composite base pan with molded riggingholds.

INSPECTION

Prior to initial use, and at monthly intervals, all rigging bracketsand straps should be visually inspected for any damage, evidence

Fig. 3—50SD036–060 Unit Dimensions

UNIT ELECTRICAL CHARACTERISTICSUNIT WEIGHT UNIT HEIGHT

IN. (MM)”A”

CENTER OF GRAVITYIN. (MM)

lb. kg X Y Z50SD036 208/230-1-60 433 196 42.98 (1092) 21.0 (533) 20.5 (520) 16.6 (422)50SD042 208/230-1-60 460 209 46.98 (1193) 21.0 (533) 20.5 (520) 17.1 (434)50SD048 208/230-1-60 480 218 46.98 (1193) 21.0 (533) 20.0 (508) 17.4 (442)50SD060 208/230-1-60 492 223 46.98 (1193) 21.0 (533) 20.0 (508) 17.6 (447)

A05126

REQUIRED CLEARANCE FOR OPERATION AND SERVICINGINCHES [mm]

EVAP. COIL ACCESS SIDE............................................................36.00 [914.0]POWER ENTRY SIDE....................................................................42.00 [1066.8](EXCEPT FOR NEC REQUIREMENTS)UNIT TOP .......................................................................................48.00 [1219.2]SIDE OPPOSITE DUCTS ..............................................................36.00 [914.0]DUCT PANEL .................................................................................12.00 [304.8] *

*MINIMUM DISTANCES: IF UNIT IS PLACED LESS THAN 304.8 [12.00] FROM WALL SYSTEM, THEN SYSTEM PERFORMANCE MAYBE COMPROMISE.

REQUIRED CLEARANCE TO COMBUSTIBLE MATL.

INCHES [mm]TOP OF UNIT...................................................................................14.00 [355.6]DUCT SIDE OF UNIT.........................................................................2.00 [50.8]SIDE OPPOSITE DUCTS ................................................................14.00 [355.6]BOTTOM OF UNIT .............................................................................0.50 [12.7]

NEC. REQUIRED CLEARANCES.INCHES [mm]

BETWEEN UNITS, POWER ENTRY SIDE ....................................42.00 [1066.8]UNIT AND UNGROUNDED SURFACES, POWER ENTRY SIDE .36.00 [914.0]UNIT AND BLOCK OR CONCRETE WALLS AND OTHERGROUNDED SURFACES, POWER ENTRY SIDE.........................42.00 [1066.8]

(Refer to Maximum Operating Clearances)

4

of wear, structural deformation, or cracks. Particular attentionshould be paid to excessive wear at hoist hooking points and loadsupport areas. Brackets or straps showing any kind of wear in theseareas must not be used and should be discarded.

INSTALLATION

1. Position the lifting bracket assembly around the base of theunit. Leave the top shipping skid on the unit to act as aspreader bar. Be sure the strap does not twist.

2. Place each of the four (4) metal lifting brackets into therigging holds in the composite pan.

3. Tighten the ratchet strap unit tight. Lifting brackets should besecure in the rigging holds.

4. Attach the clevis or hook of sufficient strength to hole in thelifting bracket (See Fig. 6).

Fig. 4A—Roof Curb Dimensions

UNIT SIZE ODS CATALOGNUMBER

AIN. (MM)

BIN. (MM)

CIN. (MM)

DIN. (MM)

EIN. (MM)

FIN. (MM)

GIN. (MM)

50SD024-030CPRFCURB006A00 8 (203) 11(279) 16-1/2 (419) 28-3/4 (730) 30-3/8 (771) 44-5/16 (1126) 45-15/16 (1167)CPRFCURB007A00 14 (356) 11(279) 16-1/2 (419) 28-3/4 (730) 30-3/8 (771) 44-5/16 (1126) 45-15/16 (1167)

50SD036-060CPRFCURB008A00 8 (203) 16-3/16 (411) 17-3/8 (441) 40-5/16 (1022) 41-15/16 (1065) 44-7/16 (1129) 46-1/16 (1169)CPRFCURB009A00 14 (356) 16-3/16 (411) 17-3/8 (441) 40-5/16 (1022) 41-15/16 (1065) 44-7/16 (1129) 46-1/16 (1169)

NOTES:1. Dimensions in ( ) are in millimeters.2. Roof curb is made of 16-gage steel.3. Table lists only the dimensions per part number that have changed4. Insulated panels: 1-in. thick fiberglass 1 lb. density.

A05165

Gask et aroundouter edge

Insulateddeck pan

Gask et aroundduct

S/AR/A

HVAC unitbase

*Gask etingouter flange

Flashing fieldsupplied

Roofing materialfield supplied

Cant str ipfield supplied

*Provided with roofcurb

Roof

Duct wo rkfield supplied

Insulation (fieldsupplied)

Roofcurb*

Wood nailer*

Gask etinginner flange*

Scre w(NO TE A)

Roof Curb for Small Cabinet

Note A: When unit mounting scre w is used,retainer bra cke t must also be used.

HVAC unitbase

*Gask etingouter flange

Flashing fieldsupplied

Roofing materialfield supplied

Cant str ipfield supplied

*Provided with roofcurb

Roof

Duct wo rkfield supplied

Insulation (fieldsupplied)

Roofcurb*

Wood nailer*

Gask etinginner flange*

Scre w(NOTE A)

Roof Curb for Large Cabinet

Note A: When unit mounting scre w is used,retainer bra cket must also be used.

A

B Typ.

Supply opening(B x C)

LongSupport

D

F

Return opening(B X C)

Insulateddeck pan

ShortSupport

C Typ.

G

E

F

G

DE

5

5. Attach safety straps directly to the field supplied rigging strapsor clevis clip. Do not attach the safety straps to the liftingbrackets.

6. Use the top of the unit as a spreader bar to prevent the riggingstraps from damaging the unit. If the wood top is not available,use a spreader bar of sufficient length to not damage the unit.

UNIT FALLING HAZARDFailure to follow this warning could result to personal injuryor death.Lifting point should be directly over the center of gravity forthe unit.

Step 6—Connect Condensate DrainNOTE: When installing condensate drain connection be sure tocomply with local codes and restrictions.

Model 50SD disposes of condensate water through a 3/4 in. NPTfitting which exits through the base on the evaporator coil accessside. See Fig. 2 & 3 for location.

Condensate water can be drained directly onto the roof in rooftopinstallations (where permitted) or onto a gravel apron in ground-level installations. Install a field-supplied condensate trap at end of

condensate connection to ensure proper drainage. Make sure thatthe outlet of the trap is at least 1 in. lower than the drainpancondensate connection to prevent the pan from overflowing (SeeFig. 7). When using a gravel apron, make sure it slopes away fromthe unit.

Connect a drain tube using a minimum of 3/4 -in. PVC or 3/4 -in.copper pipe (all field-supplied) at the outlet end of the 2-in. trap.Do not undersize the tube. Pitch the drain tube downward at aslope of at least 1-in. for every 10 ft. of horizontal run. Be sure tocheck the drain tube for leaks. Prime trap at the beginning of thecooling season start-up.

Step 7—Install Duct Connections

The unit has duct flanges on the supply- and return-air openings onthe side and bottom of the unit. For downshot applications theductwork can be connected to the roof curb. See Fig. 2 & 3 forconnection sizes and locations.

IMPORTANT: Use flexible connectors between ductwork andunit to prevent transmission of vibration. Use suitable gaskets toensure weathertight and airtight seal. When electric heat isinstalled, use fire proof canvas (or similar heat resistant material)connector between ductwork and unit discharge connection. Ifflexible duct is used, insert a sheet metal sleeve inside duct. Heat

Fig. 4B—50SD Unit Corner Weights (in Pounds)

CORNER #50SD

024 030 036 042 048 060

1 69 74 87 93 97 99

2 53 57 68 72 74 76

3 83 88 104 111 116 119

4 138 147 174 184 193 198

TOTAL WEIGHT 343 366 433 460 480 492

C00071

1 2

4 3x

y

Fig. 5A—Unit Leveling Tolerances

C99065

A

B

CMAXIMUM ALLOWABLE

DIFFERENCE (in.)

A-B B-C A-C

1/4 1/4 1/4

6

resistant duct connector (or sheet metal sleeve) must extend 24-in.from the unit discharge connection flange into the ductwork.

CONFIGURING UNITS FOR DOWNFLOW (VERTICAL) DIS-CHARGE

ELECTRICAL SHOCK HAZARDFailure to follow this warning could result in personal injuryor death.Before performing service or maintenance operations on thesystem, turn off main power to unit and install lockout tag.

1. Open all electrical disconnects and install lockout tag beforestarting any service work.

2. Remove return duct cover located on duct panel by breakingfour (4) connecting tabs with screwdriver and a hammer. (Fig.8 & 9)

3. To remove supply duct cover, break front and right sideconnecting tabs with a screwdriver and a hammer. Push louverdown to break rear and left side tabs. (Fig. 8 & 9)

4. If unit ductwork is to be attached to vertical opening flangeson the unit composite base (jackstand applications only), do soat this time. Collect ALL screws that were removed. Do notleave screws on rooftop as permanent damage to the roof mayoccur.

5. It is recommended that the unit base insulation around theperimeter of the vertical return-air opening be secured to theunit base with aluminum tape. Applicable local codes may

Fig. 5B—Slab Mounting Detail

C99096

OPTIONALRETURN

AIROPENING

OPTIONALSUPPLY

AIROPENING

EVAP. COIL COND. COIL

2"

Fig. 6—Suggested Rigging

SIZEMAXIMUM WEIGHT A B

lb. kg in. mm. in. mm.UNIT 50SD

024 372 169 20.0 508.0 19.3 490.2030 395 179 20.0 508.0 14.0 355.6036 462 210 21.0 533.4 20.5 520.7042 489 222 21.0 533.4 20.5 520.7048 509 231 21.0 533.4 20.0 508.0060 521 236 21.0 533.4 20.0 508.0

C99066

DETAIL A

7

require aluminum tape to prevent exposed fiberglass.

6. Cover both horizontal duct openings with the duct covers fromthe accessory duct cover kit. Ensure opening is air-andwatertight.

7. After completing unit conversion, perform all safety checksand power up unit.

NOTE: The design and installation of the duct system must be inaccordance with the standards of the NFPA for installation ofnonresidence-type air conditioning and ventilating systems, NFPA90A or residence-type, NFPA 90B; and/or local codes andordinances.Adhere to the following criteria when selecting, sizing, andinstalling the duct system:

8. Units are shipped for side shot installation.

9. Select and size ductwork, supply-air registers, and return-airgrilles according to American Society of Heating, Refrigera-tion and Air Conditioning Engineers (ASHRAE) recommen-dations.

10. Use flexible transition between rigid ductwork and unit toprevent transmission of vibration. The transition may bescrewed or bolted to duct flanges. Use suitable gaskets toensure weathertight and airtight seal.

11. All units must have field-supplied filters or accessory filterrack installed in the return-air side of the unit. Recommendedsizes for filters are shown in Table 1.

12. Size all ductwork for maximum required airflow (eitherheating or cooling) for unit being installed. Avoid abrupt ductsize increases or decreases or performance may be affected.

13. Adequately insulate and weatherproof all ductwork locatedoutdoors. Insulate ducts passing through unconditioned space,and use vapor barrier in accordance with latest issue of SheetMetal and Air Conditioning Contractors National Association(SMACNA) and Air Conditioning Contractors of America(ACCA) minimum installation standards for heating and airconditioning systems. Secure all ducts to building structure.

14. Flash, weatherproof, and vibration-isolate all openings inbuilding structure in accordance with local codes and goodbuilding practices.

Table 1—Physical Data—Unit 50SD

UNIT SIZE 024 030 036 042 048 060NOMINAL CAPACITY (ton) 2 2-1/2 3 3-1/2 4 5OPERATING WEIGHT (lb.) 343 366 433 460 480 492

COMPRESSOR ScrollREFRIGERANT (R-22)

Quantity (lb.) 7.8 8.4 10.9 10.9 12.3 12.0

REFRIGERANT METERING DEVICEOrifice ID (in.)

Accurater0.065 0.070 0.080 0.088 0.088 0.101

CONDENSER COILRows...Fins/in.

Face Area (sq. ft.)

2...2111.9

2...2113.6

2...2115.5

2...2119.4

2...2119.4

2...2119.4

CONDENSER FANNominal CfmDiameter (in.)

Motor Hp (Rpm)

270022

1/8 (825)

270022

1/8 (825)

280022

1/8 (825)

280022

1/8 (825)

330022

1/4 (1100)

330022

1/4 (1100)

EVAPORATOR COILRows...Fins/in.

Face Area (sq. ft.)

3...173.7

3...173.7

3...174.7

3...174.7

3...175.6

4...175.6

EVAPORATOR BLOWERNominal Airflow (Cfm)

Size (in.)Motor Hp (RPM)

80010x10

1/3 (1050)

100010x10

1/3 (1050)

120011x10

1/2 (1000)

140011x10

1/2 (1075)

160011x10

1/2 (1075)

175011x10

1.0 (1040)

RETURN-AIR FILTERS (in.)*Throwaway 20x24x1 20x24x1 24x36x1 24x36x1 24x36x1 24x36x1

*Required filter sizes shown are based on the larger of the ARI (Air Conditioning and Refrigeration Institute) rated cooling airflow or the heating airflow velocity of 300ft./min. for throwaway type. For permanent filters, follow filter manufacturer’s recommendations for filter size based on allowable face velocity. Air filter pressure drop fornon-standard filters must not exceed 0.08 in. wg.

Fig. 7—Condensate Trap

C99013

1” (25mm) MIN.

2” (50mm) MIN.

TRAPOUTLET

Fig. 8—Supply and Return Duct Opening

C99011

SUPPLYDUCTOPENING

RETURNDUCTOPENING

8

Step 8—Install Electrical Connection

ELECTRICAL SHOCK HAZARDFailure to follow this warning could result in personal injuryor death.The unit cabinet must have an uninterrupted, unbrokenelectrical ground to minimize the possibility of personalinjury if an electrical fault should occur. This ground mayconsist of an electrical wire connected to the unit groundscrew in the control compartment, or conduit approved forelectrical ground when installed in accordance with NEC(National Electrical Code) ANSI/NFPA (latest edition) andlocal electrical codes. In Canada, follow Canadian ElectricalCode CSA (Canadian Standards Association) C22.1 and localelectrical codes.

INSTALLATION REQUIREMENTSFailure to follow these precautions may result in damage tothe unit being installed:1. Make all electrical connections in accordance with NEC

ANSI/NFPA (latest edition) and local electrical codesgoverning such wiring. In Canada, all electrical connec-tions must be in accordance with CSA standard C22.1Canadian Electrical Code Part 1 and applicable localcodes. Refer to unit wiring diagram.

2. Use only copper conductor for connections betweenfield-supplied electrical disconnect switch and unit. DONOT USE ALUMINUM WIRE.

3. Be sure that high-voltage power to unit is within operatingvoltage range indicated on unit rating plate.

4. Do not damage internal components when drilling throughany panel to mount electrical hardware, conduit, etc.Consult local power company for correction of impropervoltage.

HIGH-VOLTAGE CONNECTIONS

The unit must have a separate electrical service with a field-supplied, waterproof, disconnect switch mounted at, or withinsight from, the unit. Refer to the unit rating plate for maximumfuse/circuit breaker size and minimum circuit amps (ampacity) forwire sizing. See Table 3 for electrical data.

The field-supplied disconnect switch box may be mounted on theunit over the high-voltage inlet hole when the standard power andlow-voltage entry points are used. See Fig. 2 & 3 for acceptablelocation.

See unit wiring label and Fig. 10 for reference when making highvoltage connections. Proceed as follows to complete the high-voltage connections to the unit.

Single phase units:

1. Run the high-voltage (L1, L2) and ground leads into thecontrol box.

2. Connect ground lead to chassis ground connection.

3. Connect L1 to pressure lug connection 11 of the compressorcontactor.

4. Connect L2 to pressure lug connection 23 of the compressorcontactor.

SPECIAL PROCEDURES FOR 208-V OPERATION

ELECTRICAL SHOCK HAZARDFailure to follow this warning could result in personal injuryor death.Make sure that the power supply to the unit is switched OFFand lockout tag installed before making any wiring changes.

CONTROL VOLTAGE CONNECTIONS

NOTE: Do not use any type of power-stealing thermostat. Unitcontrol problems may result.

Use no. 18 American Wire Gage (AWG) color-coded, insulated(35 C minimum) wires to make the control voltage connections

Table 2—Minimum Airflow for Safe Electric HeaterOperation (Cfm)

SIZE 024 030 036 042 048 060Cfm 800 1000 1200 1400 1600 1750

Fig. 9—Vertical Duct Cover Removed

C99012

DUCT COVERS REMOVED

9

Table 3—Electrical Data—50SD

UNITSIZE V-PH-HZ

VOLTAGERANGE COMPRESSOR OFM IFM ELECTRIC HEAT

(SINGLE POINT CONNECTION) POWER SUPPLY

Min Max RLA LRA FLA FLA Nominal Kw* FLA MCAMax Fuse

orCkt Bkr

MOCP

024 208/230–1–60 187 253 10.9 54.0 0.9 2.0

-/-3.8/5.07.5/10.05.4/7.2

-/-18.1/20.836.1/41.726.0/30.0

16.5/16.525.1/28.547.6/54.635.0/40.0

20/2030/3050/6035/40

————

030 208/230–1–60 187 253 14.0 72.5 0.9 2.0

-/-3.8/5.07.5/10.011.3/15.05.4/7.2

-/-18.1/20.836.1/41.754.2/62.526.0/30.0

20.4/20.425.1/28.547.6/54.670.2/80.635.0/40.0

25/2525/3050/60

—35/40

———

80/90—

036 208/230–1–60 187 253 16.0 88.0 0.9 3.1

-/-3.8/5.07.5/10.011.3/15.05.4/7.2

-/-18.1/20.836.1/41.754.2/62.526.0/30.0

24.0/24.026.4/29.949.0/56.071.6/82.036.4/41.4

30/3030/3050/60

—40/45

———

80/90—

042 208/230–1–60 187 253 18.4 104.0 0.9 4.1

-/-3.8/5.07.5/10.011.3/15.015.0/20.05.4/7.2

-/-18.1/20.836.1/41.754.2/62.572.2/83.326.0/30.0

28.0/28.028.0/31.250.3/57.272.8/83.395.4/109.337.6/42.6

35/3535/3560/60

——

40/45

———

80/90100/110

—

048 208/230–1–60 187 253 18.3 109.0 1.5 4.1

-/-3.8/5.07.5/10.011.3/15.015.0/20.05.4/7.2

-/-18.1/20.836.1/41.754.2/62.572.2/83.326.0/30.0

28.5/28.528.5/31.250.3/57.272.8/83.395.4/109.337.6/42.6

35/3535/3560/60

——

40/45

———

80/90100/110

—

060 208/230–1–60 187 253 25.0 148.0 1.5 6.2

-/-3.8/5.07.5/10.011.3/15.015.0/20.05.4/7.2

-/-18.1/20.836.1/41.754.2/62.572.2/83.326.0/30.0

39.0/39.039.0/39.052.9/59.875.4/85.998.0/111.940.2/45.3

50/5050/5060/60

——

50/50

———

80/90100/125

—

(See legend following Electrical Data charts)

A05108

LEGEND

FLA — Full Load AmpsLRA — Locked Rotor AmpsMCA — Minimum Circuit AmpsMOCP — Maximum Overcurrent ProtectionRLA — Rated Load Amps

NOTES:1. In compliance with NEC (National Electrical Code) requirements

for multimotor and combination load equipment (refer to NECArticles 430 and 440), the overcurrent protective device for theunit shall be Power Supply fuse . The CGA (Canadian GasAssociation) units may be fuse or circuit breaker.

2. Minimum wire size is based on 60 C copper wire. If other than60 C wire is used, or if length exceeds wire length in table,determine size from NEC.

®

Fig. 10—High- and Control-Voltage Connections

C99010

POWERSUPPLY

FIELD-SUPPLIEDFUSED DISCONNECT

HIGH VOLTAGEPOWER LEADS(SEE UNIT WIRINGLABEL)

GND

CONTROL BOX

SPLICE BOX

LOW-VOLTAGEPOWER LEADS(SEE UNITWIRING LABEL)

Y

G

R

C

YEL(Y)

GRN(G)

RED(R)

BRN(C)

THERMOSTAT(TYPICAL)

LEGENDField Control-Voltage WiringField High-Voltage Wiring

NOTE: Use blue wire for 3-phase units only.

10

between the thermostat and the unit. If the thermostat is locatedmore than 100 ft. from the unit (as measured along the controlvoltage wires), use no. 16 AWG color-coded, insulated (35 Cminimum) wires.

STANDARD CONNECTION

Remove knockout hole located in the electric heat panel adjacentto the control access panel. See Fig. 2 & 3. Remove the rubbergrommet from the installer’s packet (included with unit) and installgrommet in the knockout opening. Provide a drip loop beforerunning wire through panel.

Run the low-voltage leads from the thermostat, through the inlethole, and into unit low-voltage splice box.

Locate five 18-gage wires leaving control box. These low-voltageconnection leads can be identified by the colors red, green, yellow,brown, and white (See Fig. 10). Ensure the leads are long enoughto be routed into the low-voltage splice box (located below rightside of control box). Stripped yellow wire is located in connectionbox. Route leads through hole in bottom of control box and makelow-voltage connections (See Fig. 10). Secure all cut wires, so thatthey do not interfere with operation of unit.

TRANSFORMER PROTECTION

The transformer is of the energy-limiting type. It is set towithstand a 30-second overload or shorted secondary condition.

PRE-START-UP

FIRE, EXPLOSION, ELECTRICAL SHOCK HAZARDFailure to observe the following warnings could result inserious personal injury:1. Follow recognized safety practices and wear protective

goggles when checking or servicing refrigerant system.2. Relieve and recover all refrigerant from system before

touching or disturbing anything inside terminal box ifrefrigerant leak is suspected around compressor terminals.

3. Never attempt to repair soldered connection while refrig-erant system is under pressure.

4. Do not use torch to remove any component. Systemcontains oil and refrigerant under pressure. To remove acomponent, wear protective goggles and proceed as fol-lows:a. Shut off electrical power to unit.b. Relieve and reclaim all refrigerant from system using

both high- and low-pressure ports.c. Cut component connecting tubing with tubing cutter and

remove component from unit.d. Carefully unsweat remaining tubing stubs when neces-

sary. Oil can ignite when exposed to torch flame.

Proceed as follows to inspect and prepare the unit for initialstartup:

1. Remove access panel.

2. Read and follow instructions on all WARNING, CAUTION,and INFORMATION labels attached to, or shipped with, unit.

3. Make the following inspections:

a. Inspect for shipping and handling damages such as brokenlines, loose parts, disconnected wires, etc.

b. Inspect for oil at all refrigerant tubing connections and onunit base. Detecting oil generally indicates a refrigerantleak. Leak test all refrigerant tubing connections usingelectronic leak detector, halide torch, or liquid-soap solu-tion. If a refrigerant leak is detected, see Check forRefrigerant Leaks section.

c. Inspect all field- and factory-wiring connections. Be surethat connections are completed and tight.

d. Ensure electrical wiring does not contact refrigerant tubesor sharp metal edges.

e. Inspect coil fins. If damaged during shipping and handling,carefully straighten fins with a fin comb.

Verify the following conditions:

a. Make sure that condenser-fan blade is correctly positionedin fan orifice. Leading edge of condenser-fan blade shouldbe 1/2 in. maximum from fan orifice (See Fig. 11).

b. Make sure that air filter(s) is in place.

c. Make sure that condensate drain trap is filled with water toensure proper drainage.

d. Make sure that all tools and miscellaneous loose parts havebeen removed.

START-UPCHECK FOR REFRIGERANT LEAKS

Proceed as follows to locate and repair a refrigerant leak and tocharge the unit:

1. Locate leak and make sure that refrigerant system pressure hasbeen relieved and reclaimed from both high- and low-pressureports.

2. Repair leak following accepted practices. NOTE: Install afilter drier whenever the system has been opened for repair.

3. Add a small charge of R-22 refrigerant vapor to system andleak-test unit.

4. Recover refrigerant from refrigerant system and evacuate to500 microns if no additional leaks are not found.

5. Charge unit with R-22 refrigerant, using a volumetric-charging cylinder or accurate scale. Refer to unit rating platefor required charge. Be sure to add extra refrigerant tocompensate for internal volume of filter drier.

START UP COOLING SECTION AND MAKE ADJUST-MENTS

EQUIPMENT DAMAGE HAZARDFailure to follow this caution may result in unit componentdamage.Complete the required procedures given in the Pre-Start- Upsection before starting the unit. Do not jumper any safetydevices when operating the unit. Do not operate the compres-sor when the outdoor temperature is below 40°F (unlessaccessory low-ambient kit is installed). Do not rapid-cycle thecompressor. Allow 5 minutes between “on” cycles to preventcompressor damage.

CHECKING COOLING CONTROL OPERATION

Start and check the unit for proper cooling control operation asfollows:

Fig. 11—Fan Blade Clearance

C99009

FAN GRILLEMOTOR

1/8" MAX BETWEENMOTOR AND FAN HUB MOTOR SHAFT

1/2˝

11

Fig. 12—Wiring Diagram (208/230-60-1)

A05112

12

1. Place room thermostat SYSTEM switch in OFF position.Observe that blower motor starts when FAN switch is placedin ON position and shuts down after 30 second fan time delayexpires when FAN switch is placed in AUTO position.

2. Place SYSTEM switch in COOL position and FAN switch inAUTO position. Set cooling control below room temperature.Observe that compressor, condenser fan, and evaporatorblower motors start. Observe that compressor and outdoor fanshut down when control setting is satisfied and that indoorblower shuts down after 30 second fan time delay expires.

3. When using an auto-changeover room thermostat, place bothSYSTEM and FAN switches in AUTO positions. Observe thatunit operates in heating mode when temperature control is setto “call for heating” (above room temperature) and operates incooling mode when temperature control is set to “call forcooling” (below room temperature).

IMPORTANT:

CHECKING AND ADJUSTING REFRIGERANT CHARGE

The refrigerant system is fully charged with R-22 refrigerant,tested, and factory-sealed.

NOTE: Adjustment of the refrigerant charge is not requiredunless the unit is suspected of not having the proper R-22 charge.

A superheat charging chart is attached to the outside of the serviceaccess panel. The chart includes the required suction line tempera-ture at given suction line pressures and outdoor ambient tempera-tures (See Fig. 13).

An accurate superheat, thermocouple- or thermistor-type ther-mometer, and a gauge manifold are required when using thesuperheat charging method for evaluating the unit charge. Do notuse mercury or small dial-type thermometers because they are notadequate for this type of measurement.

NOTE: Allow system to operate in the cooling mode for aminimum of 10 minutes before checking or adjusting refrigerantcharge.

EQUIPMENT DAMAGE HAZARDFailure to follow this caution may result in unit componentdamage.When evaluating the refrigerant charge, an indicated adjust-ment to the specified factory charge must always be veryminimal. If a substantial adjustment is indicated, an abnormalcondition exists somewhere in the cooling system, such asinsufficient airflow across either coil or both coils.

Proceed as follows:

1. Remove caps from low- and high-pressure service fittings.

2. Using hoses with valve core depressors, attach low- andhigh-pressure gauge hoses to low- and high-pressure servicefittings, respectively.

3. Start unit in Cooling mode and let unit run until systempressures stabilize.

4. Measure and record the following:

a. Outdoor ambient-air temperature (°F db).

b. Suction-tube temperature (°F) at low-side service fitting.

c. Suction (low-side) pressure (psig).

5. Using “Cooling Charging Charts” compare outdoor-air tem-perature (°F db) with the suction line pressure (psig) todetermine desired system operating suction line temperature.(See Fig. 13.)

6. Compare actual suction-tube temperature with desiredsuction-tube temperature. Using a tolerance of ±3°F, addrefrigerant if actual temperature is more than 3°F higher thanproper suction-tube temperature, or remove refrigerant ifactual temperature is more than 3°F lower than requiredsuction-tube temperature.

NOTE: If the problem causing the inaccurate readings is arefrigerant leak, refer to Check for Refrigerant Leaks section.

INDOOR AIRFLOW AND AIRFLOW ADJUSTMENTS

For cooling operation, the recommended airflow is 350 to 450cfm for each 12,000 Btuh of rated cooling capacity.

Table 5 shows cooling airflows at various external static pressures.Refer to these tables to determine the airflow for the system beinginstalled.

NOTE: Be sure that all supply- and return-air grilles are open,free from obstructions, and adjusted properly.

ELECTRICAL SHOCK HAZARDFailure to follow this warning could result in personal injuryor death.Disconnect electrical power to the unit and install lockout tagbefore changing blower speed.

Airflow can be changed by changing the lead connections of theblower motor.

All 50SD units are factory wired for low speed, except sizes 030and 048 which are wired for medium speed.

FOR 208/230V

For color coding on the 208/230V motor leads, see Table 4.

To change the speed of the indoor fan motor (IFM), remove the fanmotor speed leg lead from the time delay relay (TDR). This wireis attached to terminal–3 of TDR. To change the speed, removeand replace with lead for desired blower motor speed. Insulate theremoved lead to avoid contact with chassis parts.

COOLING SEQUENCE OF OPERATION

With the room thermostat SYSTEM switch in the COOL positionand the FAN switch in the AUTO position, the cooling sequenceof operation is as follows:

When the room temperature rises to a point that is slightly abovethe cooling control setting of the thermostat, the thermostatcompletes the circuit between thermostat terminal R to terminals Yand G. These completed circuits through the thermostat connectcontactor coil (C) (through unit wire Y) and time delay relay(TDR) (through unit wire G) across the 24-v secondary oftransformer (TRAN).

The normally open contacts of energized contactor (C) close andcomplete the circuit through compressor motor (COMP) to con-denser (outdoor) fan motor (OFM). Both motors start instantly.

The set of normally open contacts of energized relay TDR closeand complete the circuit through evaporator blower (indoor) fanmotor (IFM).

Table 4—Color Coding for 208/230–V Motor Leads

BLACK = HIGH SPEEDBlue = Medium Speed

Red = Low Speed

13

NOTE: Once the compressor has started and then has stopped, itshould not be started again until 5 minutes have elapsed.

The cooling cycle remains “on” until the room temperature dropsto a point that is slightly below the cooling control setting of theroom thermostat. At this point, the thermostat “breaks” the circuitbetween thermostat terminal R to terminals Y and G. These opencircuits deenergize contactor coil C and relay coil TDR. Thecondenser and compressor motors stop. After a 30-second delay,the blower motor stops. The unit is in a “standby” condition,waiting for the next “call for cooling” from the room thermostat.

MAINTENANCE

To ensure continuing high performance, and to minimize thepossibility of premature equipment failure, periodic maintenancemust be performed on this equipment. This cooling unit should beinspected at least once each year by a qualified service person. Totroubleshoot heating or cooling of units, refer to tables at the backof the book.

NOTE TO EQUIPMENT OWNER: Consult your local dealerabout the availability of a maintenance contract.

FIRE, EXPLOSION, ELECTRICAL SHOCK HAZARDFailure to follow this warning could result in personal injury,death or property damage.The ability to properly perform maintenance on this equip-ment requires certain expertise, mechanical skills, tools, andequipment. If you do not possess these, do not attempt toperform any maintenance on this equipment other than thoseprocedures recommended in the User’s Manual.

FIRE, EXPLOSION, ELECTRICAL SHOCK, CUT HAZ-ARDFailure to follow these warnings could result in seriouspersonal injury:1. Turn off electrical power to the unit and install lockout tag

before performing any maintenance or service on the unit.2. Use extreme caution when removing panels and parts. As

with any mechanical equipment, personal injury can resultfrom sharp edges, etc.

3. Never place anything combustible either on, or in contactwith, the unit.

Fig. 13—Cooling Charging ChartA05109

14

EQUIPMENT DAMAGE HAZARDFailure to follow this caution may result in unit componentdamage.Errors made when reconnecting wires may cause improperand dangerous operation. Label all wires prior to disconnec-tion when servicing.

The minimum maintenance requirements for this equipment are asfollows:

1. Inspect air filter(s) each month. Clean or replace whennecessary.

2. Inspect indoor coil, drain pan, and condensate drain at leasteach cooling season for cleanliness. Clean when necessary.

3. Inspect blower motor and wheel for cleanliness and checklubrication each heating and cooling season. Clean whennecessary.

4. Check electrical connections for tightness and controls forproper operation each heating and cooling season. Servicewhen necessary.

5. Ensure electric wires are not in contact with refrigerant tubingor sharp metal edges.

AIR FILTER

EQUIPMENT DAMAGE HAZARDFailure to follow this caution may result in unit componentdamage.Never operate the unit without a suitable air filter in thereturn-air duct system. Always replace the filter with the samedimensional size and type as originally installed. See Tables1 and 2 for recommended filter sizes.

Inspect air filter(s) at least once each month and replace(throwaway-type) or clean (cleanable-type) at least twice duringeach heating and cooling season or whenever the filter(s) becomesclogged with dust and lint.

EVAPORATOR BLOWER AND MOTOR

NOTE: All motors are prelubricated. Do not attempt to lubricatethese motors.

For longer life, operating economy, and continuing efficiency,clean accumulated dirt and grease from the blower wheel andmotor annually.

ELECTRICAL SHOCK HAZARDFailure to follow this warning could result in personal injuryor death.Disconnect and tag electrical power to the unit beforecleaning the blower motor and wheel.

To clean the blower motor and wheel:

1. Remove and disassemble blower assembly as follows:

a. Remove unit access panel.

b. Disconnect motor lead from time delay relay (TDR).Disconnect yellow lead from terminal L2 of the contactor.

c. On all units remove blower assembly from unit. Removescrews securing blower to blower partition and slideassembly out. Be careful not to tear insulation in blowercompartment.

d. Ensure proper reassembly by marking blower wheel andmotor in relation to blower housing before disassembly.

e. Loosen setscrew(s) that secures wheel to motor shaft,remove screws that secure motor mount brackets to hous-ing, and slide motor and motor mount out of housing.

2. Remove and clean blower wheel as follows:

a. Ensure proper reassembly by marking wheel orientation.

b. Lift wheel from housing. When handling and/or cleaningblower wheel, be sure not to disturb balance weights (clips)on blower wheel vanes.

c. Remove caked-on dirt from wheel and housing with abrush. Remove lint and/or dirt accumulations from wheeland housing with vacuum cleaner, using soft brush attach-ment. Remove grease and oil with mild solvent.

d. Reassemble wheel into housing.

e. Reassemble motor into housing. Be sure setscrews aretightened on motor shaft flats and not on round part ofshaft.

f. Reinstall unit access panel.

3. Restore electrical power to unit. Start unit and check forproper blower rotation and motor speeds during heating andcooling cycles.

CONDENSER COIL, EVAPORATOR COIL, AND CONDEN-SATE DRAIN PAN

Inspect the condenser coil, evaporator coil, and condensate drainpan at least once each year.

The coils are easily cleaned when dry; therefore, inspect and cleanthe coils either before or after each cooling season. Remove allobstructions, including weeds and shrubs, that interfere with theairflow through the condenser coil.

Straighten bent fins with a fin comb. If coated with dirt or lint,clean the coils with a vacuum cleaner, using the soft brushattachment. Be careful not to bend the fins. If coated with oil orgrease, clean the coils with a mild detergent-and-water solution.Rinse coils with clear water, using a garden hose. Be careful not tosplash water on motors, insulation, wiring, or air filter(s). For bestresults, spray condenser coil fins from inside to outside the unit.On units with an outer and inner condenser coil, be sure to cleanbetween the coils. Be sure to flush all dirt and debris from the unitbase.

Inspect the drain pan and condensate drain line when inspectingthe coils. Clean the drain pan and condensate drain by removing allforeign matter from the pan. Flush the pan and drain tube withclear water. Do not splash water on the insulation, motor, wiring,or air filter(s). If the drain tube is restricted, clear it with a“plumbers snake” or similar probe device. Ensure that the auxiliarydrain port above the drain tube is also clear

CONDENSER FAN

UNIT OPERATIONAL HAZARDFailure to follow this caution may result in damage to unitcomponents.Keep the condenser fan free from all obstructions to ensureproper cooling operation. Never place articles on top of theunit.

1. Remove 6 screws holding condenser grille and motor to topcover.

15

Table 5—Wet Coil Air Delivery (Deduct 10 percent for 208v)*Horizontal and Downflow Discharge

Unit 50SD024-060

230 VOLT

Unit MotorSpeed

External Static Pressure (in. wg)0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

024

LowWatts 311 309 304 301 286 — — — — —Cfm 935 885 820 757 686 — — — — —

MedWatts — — — — 379 357 357 345 327 —Cfm — — — — 957 868 769 647 365 —

HighWatts — — — — — — 447 435 421 —Cfm — — — — — — 970 853 712 —

030

LowWatts 311 309 304 301 — — — — — —Cfm 935 885 820 757 — — — — — —

MedWatts 411 405 398 390 379 357 357 — — —Cfm 1195 1155 1100 1028 957 868 769 — — —

HighWatts — — — — 477 467 447 435 — —Cfm — — — — 1185 1088 970 853 — —

036

LowWatts 437 433 424 417 403 391 379 362 — —Cfm 1353 1318 1283 1235 1187 1123 1059 975 — —

MedWatts — — — 531 516 496 478 459 435 —Cfm — — — 1489 1437 1362 1289 1208 1099 —

HighWatts — — — — — — — 629 602 —Cfm — — — — — — — 1470 1357 —

042

LowWatts 625 606 586 571 550 534 509 483 457 —Cfm 1539 1496 1466 1437 1387 1330 1264 1183 1093 —

MedWatts — 741 715 694 669 645 610 573 544 —Cfm — 1738 1698 1653 1604 1538 1457 1362 1271 —

HighWatts — — — — — 798 772 738 700 —Cfm — — — — — 1720 1648 1540 1414 —

048

LowWatts 627 617 607 584 567 548 528 503 — —Cfm 1550 1530 1493 1461 1414 1361 1320 1250 — —

MedWatts 771 755 734 711 690 665 639 607 572 —Cfm 1798 1771 1734 1687 1645 1595 1530 1449 1355 —

HighWatts — — 908 887 858 827 804 767 748 —Cfm — — 2000 1994 1876 1811 1735 1647 1555 —

060

LowWatts 786 769 754 736 722 705 684 658 — —Cfm 2027 1960 1901 1821 1759 1693 1616 1513 — —

MedWatts 873 849 833 815 798 782 763 748 — —Cfm 2095 2026 1962 1887 1817 1748 1679 1583 — —

HighWatts 1012 993 981 963 948 927 904 886 — —Cfm 2184 2109 2036 1963 1886 1812 1729 1647 — —

* Air delivery values are based on operating voltage of 230v wet coil, without filter or electric heater. Deduct filter and electric heater pressure drops to obtain staticpressure available for ducting.

NOTES:1. Do not operate the unit at a cooling airflow that is less than 350 cfm for each 12,000 Btuh of rated cooling capacity. Evaporator coil frosting may occur at airflows below

this point.2. Dashes indicate portions of table that are beyond the blower motor capacity or are not recommended.

16

2. Turn motor/grille assembly upside down on top cover toexpose the fan blade.

3. Inspect the fan blades for cracks or bends.

4. If fan needs to be removed, loosen the setscrew and slide thefan off the motor shaft.

5. When replacing fan blade, position blade so that the hub is 1/8in. away from the motor end (1/8 in. of motor shaft will bevisible).

6. Ensure that setscrew engages the flat area on the motor shaftwhen tightening

7. Replace grille.

ELECTRICAL CONTROLS AND WIRING

Inspect and check the electrical controls and wiring annually. Besure to turn off the electrical power to the unit and install lockouttag.

Remove access panel to locate all the electrical controls andwiring. Check all electrical connections for tightness. Tighten allscrew connections. If any smoky or burned connections arenoticed, disassemble the connection, clean all the parts, restrip thewire end and reassemble the connection properly and securely.

After inspecting the electrical controls and wiring, replace theaccess panel. Start the unit, and observe at least one completeheating cycle and one complete cooling cycle to ensure properoperation. If discrepancies are observed in either or both operatingcycles, or if a suspected malfunction has occurred, check eachelectrical component with the proper electrical instrumentation.Refer to the unit wiring label when making these checkouts.

NOTE: Refer to the heating and/or cooling sequence of operationin this publication as an aid in determining proper controloperation

REFRIGERANT CIRCUIT

Inspect all refrigerant tubing connections and the unit base for oilaccumulations annually. Detecting oil generally indicates a refrig-erant leak.

EXPLOSION, PERSONAL INJURY HAZARDFailuire to follow this warning could result in personal injury,death, or property damage.System under pressure. Relieve pressure and recover allrefrigerant before system repair or final unit disposal. Use allservice ports and open all flow-control devices, includingsolenoid valves.

If oil is detected or if low cooling performance is suspected,leak-test all refrigerant tubing using an electronic leak-detector,halide torch, or liquid-soap solution. If a refrigerant leak isdetected, refer to Check for Refrigerant Leaks section.

If no refrigerant leaks are found and low cooling performance issuspected, refer to Checking and Adjusting Refrigerant Chargesection.

EVAPORATOR AIRFLOW

The heating and/or cooling air-flow does not require checkingunless improper performance is suspected. If a problem exists, besure that all supply- and return-air grilles are open and free fromobstructions, and that the air filter is clean. When necessary, referto Indoor Airflow and Airflow Adjustments section to check thesystem airflow.

METERING DEVICE — ACCURATER PISTON

This metering device is a fixed orifice and is contained in a brassbody in the liquid line feeding the indoor coil.

TROUBLESHOOTING

Use the Troubleshooting–Cooling guide (see Table 6) if problemsoccur with these units.

START-UP CHECKLIST

Use the Start-Up checklist to ensure proper start-up procedures arefollowed.

17

Table 6—Troubleshooting—Cooling

SYMPTOM CAUSE REMEDY

Compressor and condenser fan will not start.

Power Failure Call power company

Fuse blown or circuit breaker tripped Replace fuse or reset circuit breaker

Defective thermostat, contractor, transformer, orcontrol relay Replace component

Insufficient line voltage Determine cause and correct

Incorrect or faulty wiring Check wiring diagram and rewire correctly

Thermostat setting too high Lower thermostat setting belowroom temperature

Compressor will not start but condenser fanruns.

Faulty wiring or loose connections in compressorcircuit Check wiring and repair or replace

Compressor motor burned out, seized, or internaloverload open

Determine causeReplace compressor

Defective run/start capacitor, overload, start relay Determine cause and replace

Compressor cycles(other than normally satisfying thermostat).

Refrigerant overcharge or undercharge Recover refrigerant, evacuate system, and re-charge to capacities shown on nameplate

Defective compressor Replace and determine cause

Insufficient line voltage Determine cause and correct

Blocked condenser Determine cause and correct

Defective run/start capacitor, overload or startrelay Determine cause and replace

Defective thermostat Replace thermostat

Faulty condenser-fan motor or capacitor Replace

Restriction in refrigerant system Locate restriction and remove

Compressor operates continuously.

Dirty air filter Replace filter

Unit undersized for load Decrease load or increase unit size

Thermostat set too low Reset thermostat

Low refrigerant charge Locate leak, repair, and recharge

Leaking valves in compressor Replace compressor

Air in system Recover refrigerant, evacuate system, and re-charge

Condenser coil dirty or restricted Clean coil or remove restriction

Excessive head pressure.

Dirty air filter Replace filter

Dirty condenser coil Clean coil

Refrigerant overcharged Recover excess refrigerant

Air in system Recover refrigerant, evacuate system, and re-charge

Condenser air restricted or air short-cycling Determine cause and correct

Head pressure too low.

Low refrigerant charge Check for leaks, repair and recharge

Compressor valves leaking Replace compressor

Restriction in liquid tube Remove restriction

Excessive suction pressure.

High heat load Check for source and eliminate

Compressor valves leaking Replace compressor

Refrigerant overcharged Recover excess refrigerant

Suction pressure too low.

Dirty air filter Replace Filter

Low refrigerant charge Check for leaks, repair, and recharge

Metering device or low side restricted Remove source of restriction

Insufficient evaporator airflow Increase air quantityCheck filter- replace if necessary

Temperature too low in conditioned area Reset thermostat

Outdoor ambient below 40°F Install low-ambient kit

Field-installed filter-drier restricted Replace

18

START-UP CHECKLIST(REMOVE AND STORE IN JOB FILE)

I. PRELIMINARY INFORMATIONModel No .............................................................................................................................................................Serial No ..............................................................................................................................................................Date .....................................................................................................................................................................Technician ...........................................................................................................................................................Job/ Location...............................................................................................................................................

II. PRE-START-UP____ Verify that all packing materials have been removed from unit____ Verify that condensate connection is installed per installation instructions____ Check all electrical connections and terminals for tightness____ Check that indoor (evaporator) air filter is clean and in place____ Verify that unit installation is level____ Check fan wheel propeller for location in housing and setscrew tightness

III. START-UPSupply Voltage: L1-L2(C-S) __________Compressor Amps: L1(C) __________Indoor (Evaporator) Fan Amps: __________

TEMPERATUREOutdoor (Condenser) Air Temperature: __________ DBReturn-Air Temperature: __________ DB __________ WBCooling Supply Air: __________ DB __________ WB

PRESSURESRefrigerant Suction __________ psigSuction Line Temp*__________Refrigerant Discharge __________ psigDischarge Temp† ______________ Verify Refrigerant charge using charging tables

* Measured at suction inlet to compressor

† Measured at liquid line leaving condenser

19

Copyright 2005 CARRIER Corp. • 7310 W. Morris St. • Indianapolis, IN 46231

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.Book 1 6Tab 6 8

PC 101 Printed in U.S.A. Catalog No. 50SD-1SI Pg 20 8-05 Replaces: New