Carrier 50Js Users Manual

50JS to the manual 6989d00c-3bee-46c9-9c46-0510a5127899

2015-01-24

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50JS,JX018-060
Single-Package Heat Pump Units
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Installation, Start-Up and Service Instructions
NOTE: Read the entire instruction manual before starting the
installation.
Index
SAFETY CONSIDERATIONS ...............................................1-4
General .................................................................................4
RECEIVING AND INSTALLATION..................................4-15
Check Equipment......................................................................4-5
Identify Unit..............................................................................4
Inspect Shipment.......................................................................5
Provide Unit Support...................................................................5
Roof Curb..................................................................................5
Slab Mount................................................................................5
Ground Mount...........................................................................5
Provide Clearances.......................................................................5
Rig and Place Unit....................................................................5-6
Select and Install Ductwork ....................................................6-8
Converting Horizontal Discharge Units to Downflow (Vertical)
Discharge...................................................................................6
Provide for Condensate Disposal ............................................6-8
Install Electrical Connections .....................................................8
High-Voltage Connections........................................................8
Routing Power Leads Into Unit ..........................................8-14
Connecting Ground Lead to Ground Lug..............................14
Special Procedures for 208-V Operation ...............................15
PRE-START-UP.........................................................................15
START-UP.............................................................................15-20
Check for Refrigerant Leaks ..................................................15
Unit Start-Up Adjustment .................................................15-20
MAINTENANCE ..................................................................20-23
SYSTEM INFORMATION.......................................................23
Time Delay Relay...................................................................23
Pressure Switches....................................................................23
Defrost Thermostat .................................................................23
TROUBLESHOOTING .......................................................24-25
START-UP CHECKLIST .........................................................25
NOTE TO INSTALLER — READ THESE INSTRUCTIONS
CAREFULLY AND COMPLETELY before installing this unit.
Also, make sure the Owner’s Manual and Service Instructions are
left with the unit after installation.
SAFETY CONSIDERATIONS
Installation and servicing of air-conditioning equipment can be
hazardous due to system pressure and electrical components. Only
trained and qualified personnel should install, repair, or service
air-conditioning equipment.
Untrained personnel can perform basic maintenance functions of
cleaning coils and filters. All other operations should be performed
by trained service personnel. When working on air-conditioning
equipment, observe precautions in the literature, tags and labels
attached to the unit, and other safety precautions that may apply.
Follow all safety codes. Wear safety glasses and work gloves. Use
quenching cloth for unbrazing operations. Have fire extinguisher
available for all brazing operations.

C99001

Fig. 1—Model 50JS/JX

Improper installation, adjustment, alteration, service, maintenance, or use can cause explosion, fire, electric shock, or
other occurrences, which could cause serious injury or death
or damage your property. Consult a qualified installer or
service agency for information or assistance. The qualified
installer or agency must use only factory-authorized kits or
accessories when modifying this product.
Recognize safety information. This is the safety-alert symbol .
When you see this symbol on the product or in instructions or
manuals, be alert to the potential for personal injury.
Understand the signal words — DANGER, WARNING, CAUTION, and NOTE. Danger identifies the most serious hazards,
which will result in severe personal injury or death. Warning
indicates a condition that could cause serious personal injury or
death. Caution is used to identify unsafe practices, which would
result in minor personal injury or product and property damage.
NOTE is used to highlight suggestions which will result in
enhanced installation, reliability or operation.
1. The power supply (volts, phase, and hertz) must correspond to
that specified on unit rating plate.
2. The electrical supply provided by the utility must be sufficient
to handle load imposed by this unit.
3. This installation must conform with local building codes and
with NEC (National Electrical Code). Refer to provincial and
local plumbing or waste water codes and other applicable local
codes.

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
PC 101
Catalog No. 565-057
Printed in U.S.A.
Form 50JS,JX-1SI
Pg 1
5-00
Replaces: 50JX-2SI
Tab 5a 5a

REQUIRED CLEARANCE TO COMBUSTIBLE MATL.

REQUIRED CLEARANCE FOR OPERATION AND SERVICING

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]
ELECTRIC HEAT PANEL .................................................................36.00 [914.4]

INCHES [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] *

NEC. REQUIRED CLEARANCES.

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

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 OTHER
GROUNDED SURFACES, POWER ENTRY SIDE.........................42.00 [1066.8]

C99007

UNIT

ELECTRICAL CHARACTERISTICS

50JS018

208/230-1-60

UNIT HEIGHT
IN. [MM]
"A"

283

128.4

37.02 [940.3]

UNIT WEIGHT

CENTER OF GRAVITY
IN. [MM]
X

19.5 [495.3]

16.8 [425.5]

15.0 [381.0]

50JS024

208/230-1-60

289

131.1

39.02 [991.1]

18.5 [469.9]

16.8 [425.5]

15.0 [381.0]

50JS030

208/230-1-60, 208/230-3-60

287

130.2

39.02 [991.1]

19.5 [495.3]

17.5 [444.5]

15.0 [381.0]

50JS036

208/230-1-60, 208/230-3-60, 460-3-60

291

132.0

37.02 [940.3]

19.5 [495.3]

17.8 [450.9]

13.0 [330.2]

50JS042

208/230-1-60, 208/230-3-60, 460-3-60

323

146.5

37.02 [940.3]

19.5 [495.3]

17.8 [450.9]

13.0 [330.2]

50JX024

208/230-1-60

299

135.6

41.02 [1041.9]

19.0 [482.6]

18.3 [463.6]

16.0 [406.4]

50JX030

208/230-1-60,208/230-3-60

320

145.2

37.02 [940.3]

20.0 [ 508]

19.3 [ 489.0]

17.6 [447.0]

50JX036

208/230-1-60,208/230-3-60, 460-3-60

328

148.8

37.02 [940.3]

20.0 [508]

19.0 [482.6]

16.5 [419.1]

Fig. 2—50JS018-042/50JX024-036 Unit Dimensions
2

REQUIRED CLEARANCE TO COMBUSTIBLE MATL.

REQUIRED CLEARANCE FOR OPERATION AND SERVICING

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

NEC. REQUIRED CLEARANCES.

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

C99006
CENTER OF GRAVITY
IN. [MM]

UNIT HEIGHT
IN. [MM]
"A"

160.1

38.98 [990.2]

20.5 [520.7]

20.6 [523.8]

17.0 [431.8]

189.6

38.98 [990.2]

19.5 [495.3]

19.8 [501.7]

17.0 [431.8]

158.8

40.98 [1040.9]

21.0 [533.4]

20.5 [520.7]

16.6 [421.6]

355

161.0

40.98 [1040.9]

20.0 [508.0]

21.3 [539.8]

18.0 [457.2]

428

194.1

42.98 [1091.7]

21.0 [533.4]

20.0 [508.0]

17.6 [447.0]

UNIT WEIGHT

UNIT

ELECTRICAL CHARACTERISTICS

lb
50JS048

208/230-1-60, 208/230-3-60, 460-3-60

353

50JS060

208/230-1-60, 208/230-3-60, 460-3-60

418

50JX042

208/230-1-60, 208/230-3-60, 460-3-60

350

50JX048

208/230-1-60, 208/230-3-60, 460-3-60

50JX060

208/230-1-60, 208/230-3-60, 460-3-60

Fig. 3—50JS048-060/50JX042-060 Unit Dimensions
3

SIDE PANEL

0.75"
BASE PAN
BOTTOM SUPPLY

3.0"

SUPPORT RIB(S)

4.0"

SEAL STRIP
(FACTORY SUPPLIED)
COUNTER FLASHING
(FIELD SUPPLIED)

NAILER

ROOFING FELT
(FIELD SUPPLIED)
INSULATION
(FIELD SUPPLIED)

CANT STRIP
(FIELD SUPPLIED)
ROOFING MATERIAL
(FIELD SUPPLIED)

A99340

C
46 3/16

17 3/8
TYP.

44 5/16

1 TYP.

7/8

3
13/16

SUPPORT B
A

B
SUPPORT A (2)
SIDE
(2)

END VIEW
END
(2)
DECK PAN (INSULATED)

UNIT SIZE
50JS018-042
50JS048-060

50JX024-036
50JX042-060

A99320
D
IN. [MM]

A
IN. [MM]

B
IN. [MM]

C
IN. [MM]

CPRFCURB006A00

8 [203]

11-27/32 [301]

30-5/8 [778]

CPRFCURB007A00

14 [356]

11-27/32 [301]

30-5/8 [778]

28-3/4 [730]

CPRFCURB008A00

8 [203]

15/27/32 [402]

42-18/ [1070]

40-1/4 [1022]

CPRFCURB009A00

14 [356]

15-27/32 [402]

42-1/8 [1070]

40-1/4 [1022]

ODS CATALOG NUMBER

28-3/4 [730]

Fig. 4—Roof Curb Dimensions
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 changed.
4. Insulated panels: 1-in. thick fiberglass 1 lb density.

shipped in a horizontal-discharge configuration for installation on
a ground-level slab. Standard units can be converted to downflow
(vertical) discharge configurations for rooftop applications.

Before performing service or maintenance operations on
system, turn off main power to unit. Turn off accessory heater
power switch if applicable. Electrical shock could cause
severe injury or death.

RECEIVING AND INSTALLATION
Step 1—Check Equipment

Step 1—General

IDENTIFY UNIT — The unit model number and serial number
are stamped on the unit identification plate. Check this information
against shipping papers.

The 50JS and 50JX heat pumps are fully self-contained and
designed for outdoor installation (See Fig. 1). Standard units are

corner or under an overhead obstruction. The minimum clearance
under a partial overhang (such as a normal house overhang) is 36
in. above the unit top. The maximum horizontal extension of a
partial over-hang must not exceed 36 in. For extended overhangs,
provide a minimum clearance of 36 in.

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. Manufacturer is not responsible for any
damage incurred in transit. Check all items against shipping list.
Immediately notify the nearest Carrier Air Conditioning office if
any item is missing. To prevent loss or damage, leave all parts in
original packages until installation.

IMPORTANT: Do not restrict outdoor airflow. An air restriction
at either the outdoor-air inlet or the fan discharge may be
detrimental to compressor life.
Do not place the unit where water, ice, or snow from an overhang
or roof will damage or flood the unit. Do not install the unit on
carpeting, tile, or other combustible materials. Slab-mounted units
should be at least 4 in. above the highest expected water and runoff
levels. Do not use unit if it has been under water.

Step 2—Provide Unit Support
ROOF CURB — Install accessory roof curb in accordance with
instructions shipped with curb (See Fig. 4). Install insulation, cant
strips, roofing, and flashing. Ductwork must be attached to curb.
IMPORTANT: The gasketing of the unit to the roof curb is critical
for a watertight seal. Install gasketing material supplied with the
roof curb. Improperly applied gasketing also can result in air leaks
and poor unit performance.

Step 4—Rig and Place Unit

Curb should be level to within 1/4 in. (See Fig. 5). This is
necessary for unit drain to function properly. Refer to accessory
roof curb installation instructions for additional information as
required.

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

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

When working with this equipment, observe precautions in the
literature, 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 work
gloves.

INSPECTION — Prior to initial use, and at monthly intervals, all
rigging brackets and straps should be visually inspected for any
damage, evidence of wear, structural deformation, or cracks.
Particular attention should be paid to excessive wear at hoist
hooking points and load support areas. Brackets or straps showing
any kind of wear in these areas must not be used and should be
discarded.

C
MAXIMUM ALLOWABLE
DIFFERENCE (in.)

A-B

B-C

A-C

1/4

1/4
C99065

INSTALLATION

Fig. 5—Unit Leveling Tolerances

1. Remove unit from shipping carton. Leave top shipping skid on
the unit as a spreader bar to prevent the rigging straps from
damaging the unit. If the wood skid is not available, use a
spreader bar of sufficient length to protect unit from damage.

SLAB MOUNT — Place the unit on a solid, level concrete pad
that is a minimum of 4 in. thick with 2 in. above grade (See Fig.
6). The slab should extend approximately 2 in. beyond the casing
on all 4 sides of the unit. Do not secure the unit to the slab except
when required by local codes.

OPTIONAL
RETURN
AIR
OPENING

2. Position the lifting bracket assembly around the base of the
unit. Be sure the strap does not twist.
3. Place each of the 4 metal lifting brackets into the handholds in
the composite pan.

OPTIONAL
SUPPLY
AIR
OPENING

4. Thread lifting bracket strapping around bottom perimeter of
unit as follows:
a. Open lever of tension buckle (ratchet type).
b. Feed strapping through tension buckle as shown in Fig. 7.
c. Pull strapping through tension buckle unit taut.

EVAP. COIL

d. Snap lever down to lock strap in tension buckle. To release
strapping, squeeze safety latch, lift lever, and pull webbing
outward.

COND. COIL

C99096

Fig. 6—Slab Mounting Detail
GROUND MOUNT — The unit may be installed either on a slab
or placed directly on the ground if local codes permit. Place the
unit on level ground prepared with gravel for condensate discharge.

HANDHOLD

Step 3—Provide Clearances
HOOK

The required minimum service clearances are shown in Figs. 2 and
3. Adequate ventilation and outdoor air must be provided. The
outdoor fan draws air through the outdoor coil and discharges it
through the top fan grill. Be sure that the fan discharge does not
recirculate to the outdoor coil. Do not locate the unit in either a

FEED
C99067

Fig. 7—Threading Belt
5

5. Tighten the tension buckle until it is taut. Lifting brackets
must be secure in the handholds.
For vertical supply and return units, tools or parts could drop
into ductwork and cause serious injury or death. Install a 90
degree turn in the return ductwork between the unit and the
conditioned space. If a 90 degree elbow cannot be installed,
then a grille of sufficient strength and density should be
installed to prevent objects from falling into the conditioned
space. Units with electric heaters require 90 degree elbow in
supply duct.

6. Attach field-supplied clevis or hook of sufficient strength to
hole in the lifting bracket (See Fig. 8).
7. Attach the 2 safety straps directly to the clevis or hook at the
4 rigging brackets. DO NOT attach the safety straps to the
lifting brackets (See Fig. 8).

914-137"
(36"-54")

“A”

1. All units should have field-supplied filters or accessory filter
rack installed in the return-air side of the unit. Recommended
sizes for filters are shown in Tables 1A and 1B.
2. Avoid abrupt duct size increases and reductions. Abrupt
change in duct size adversely affects air performance.

“B”

IMPORTANT: Use flexible connectors between ductwork and
unit to prevent transmission of vibration. Use suitable gaskets to
ensure weather tight and airtight seal. When electric heat is
installed, use fireproof canvas (or similar heat resistant material)
connector between ductwork and unit discharge connection. If
flexible duct is used, insert a sheet metal sleeve inside duct. Heat
resistant duct connector (or sheet metal sleeve) must extend 24-in.
from electric heater element.

DETAIL A
SCALE 0.250

TIGHTEN STRAPPING SECURELY
WITH TENSION BUCKLE

3. Size ductwork for cooling air quantity (cfm). The minimum
air quantity for proper electric heater operation is listed in
Tables 2A and 2B. Heater limit switches may trip at air
quantities below those recommended.

INSTALL SAFETY STRAPS TO
RIGGING CLEVIS AT 4 RIGGING BRACKETS
PLACE RIGGING BRACKET ASSEMBLY IN 4
HAND HOLES AND INSTALL TIE DOWN STRAP
AROUND PERIMETER OF UNIT AND THROUGH
SPACE IN BRACKET ASSEMBLY

SEE DETAIL A

C99075

UNIT

MAXIMUM WEIGHT

4. Seal, insulate and weatherproof all external ductwork. Seal,
insulate and cover with a vapor barrier all ductwork passing
through conditioned spaces. Follow latest Sheet Metal and Air
Conditioning Contractors National Association (SMACNA)
and Air Conditioning Contractors Association (ACCA) minimum installation standards for residential heating and air
conditioning systems.

Size

lb.

kg.

in.

mm.

in.

mm.

50JS018

305

138.4

19.5

495.3

16.75

425.5

50JS024

311

141.1

18.5

469.9

16.75

425.5

50JS030

309

140.2

19.5

495.3

17.50

444.5

50JS036

313

142.0

19.5

495.3

17.75

450.9

50JS042

345

156.4

19.5

495.3

17.75

450.9

50JS048

375

170.1

20.5

520.7

20.62

523.8

50JS060

440

199.6

19.5

495.3

19.75

501.7

50JX024

321

145.6

19.0

482.6

18.25

463.6

50JX030

342

155.2

20.0

508

19.25

489

50JX036

350

158.8

20.0

508

19.0

482.6

50JX042

372

168.8

21.0

533.4

20.5

520.7

50JX048

377

171.0

20.0

508

21.25

539.8

50JX060

450

204.2

21.0

533.4

20.0

508.0

5. Secure all ducts to building structure. Flash,weatherproof, and
vibration-isolate duct openings in wall or roof according to
good construction practices.
CONVERTING HORIZONTAL DISCHARGE UNITS TO
DOWNFLOW (VERTICAL) DISCHARGE UNITS

Before performing service or maintenance operations on
system, turn off main power to unit. Turn off accessory heater
power switch if applicable. Electrical shock could cause
serious injury or death.

Fig. 8—Suggested Rigging

1. Open all electrical disconnects before starting any service
work.

8. Position lifting point directly over the unit’s center of gravity.
9. Lift unit. When unit is directly over the roof curb, remove the
2 safety straps. Lower the equipment onto the roof curb.

2. Remove side duct covers to access bottom return and supply
knock outs.

Step 5—Select and Install Ductwork

3. Use a screwdriver and hammer to remove the panels in the
bottom of the base pan.

The design and installation of the duct system must be in
accordance with the standards of the NFPA for installation of
non-residence type air conditioning and ventilating systems, NFPA
90A or residence-type, NFPA 90B and/or local codes and ordinances.

4. Reinstall the side duct covers to block off the horizontal air
openings.
NOTE: These panels are held in place with tabs similar to an
electrical knockout.

Select and size ductwork, supply-air registers, and return air grilles
according to ASHRAE (American Society of Heating, Refrigeration, and Air Conditioning Engineers) recommendations.

NOTE: Avoid abrupt duct size increases and reductions. Abrupt
change in duct size adversely affects air performance.
Step 6—Provide for Condensate Disposal

The unit has duct flanges on the supply- and return-air openings on
the side of the unit.

NOTE: Ensure that condensate-water disposal methods comply
with local codes, restrictions, and practices.

When designing and installing ductwork, consider the following:

Table 1A—Physical Data
UNIT SIZE

50JS018

50JS024

50JS030

50JS036

50JS042

50JS048

NOMINAL CAPACITY (ton)

1-1/2

2-1/2

3-1/2

OPERATING WEIGHT (lb)

283

289

287

291

323

353

418

COMPRESSOR QUANTITY

50JS060

TYPE

RECIPROCATING COMPRESSOR

SCROLL COMPRESSOR

REFRIGERANT

R-22

REFRIGERANT METERING DEVICE

Accurater ®

Refrigerant (R-22) Quantity (lb.)

5.6

5.2

5.8

7.1

7.6

7.8

8.6

ORIFICE ID (in.)

0.053

0.061

0.068

0.078

0.088

0.093

ORIFICE OD (in.)

0.040

0.049

2@0.042

2@0.046

2@0.052

2@0.057

2@0.061

OUTDOOR COIL
Rows...Fins/in.
Face Area (sq ft)

1....17
10.2

1....17
12.0

2....17
10.3

2....17
11.6

OUTDOOR FAN
Nominal Airflow (CFM)
Diameter
Motor HP (RPM)

2400
22
1/8 (825)

2800
22
1/4 (1100)

2400
22
1/8 (825)

3300
22
1/4 (1100)

INDOOR COIL
Rows...Fins/in.
Face Area (Sq Ft)

2....15
3.7

3....15
3.7

4....15
3.7

3....15
4.7

4....15
4.7

INDOOR BLOWER
Nominal Airflow (CFM)
Size (in.)
Motor (HP)

700
10x10
1/8

800
10x10
1/4

1000
11x10
1/4

1200
11x10
1/2

1250
11x10
3/4

1600
11x10
3/4

2000
11x10
1

RETURN-AIR FILTERS (in.)
Throwaway

20x20x1

20x24x1

24x30x1

Table 1B—Physical Data
UNIT SIZE

50JX024

50JX030

50JX036

50JX042

50JX048

NOMINAL CAPACITY (ton)

2 1/2

3-1/2

OPERATING WEIGHT (lb)

299

320

328

350

355

420

COMPRESSOR QUANTITY

TYPE

SCROLL COMPRESSOR

REFRIGERANT

R-22

REFRIGERANT METERING DEVICE

Accurater ®

50JX060

Refrigerant (R-22) Quantity (lb.)

5.5

6.4

7.0

10.8

10.4

12.3

ORIFICE ID (in.)

0.065

0.073

0.076

0.080

0.088

0.0.93

ORIFICE OD (in.)

0.055

0.065

0.067

2@0.052

2@0.057

2@0.063

OUTDOOR COIL
Rows...Fins/in.
Face Area (sq ft)

1...17
14.6

2...17
10.9

2...17
14.4

2...17
16.4

OUTDOOR FAN
Nominal Airflow (CFM)
Diameter
Motor HP (RPM)

2350
22
1/8 (825)

2800
22
1/4 (1100)

2800
22
1/8 (825)

3300
22
1/4 (1100)

INDOOR COIL
Rows...Fins/in.
Face Area (Sq Ft)

3...15
3.7

4...15
3.7

4..15
4.7

4...15
4.7

4...15
5.7

INDOOR BLOWER
Nominal Airflow (CFM)
Size (in.)
Motor (HP)

800
10x10
1/4

1000
11x10
1/4

1200
11x10
1/2

1400
11x10
3/4

1600
11x10
3/4

2000
11x10
1

RETURN-AIR FILTERS (in.)
Throwaway

20x20x1

20x24x1

24x30x1

NOTE: Air filter pressure drop for non-standard filters must not exceed 0.08 in. wg.

Table 2A—Minimum Airflow for Reliable Electric Heater Operation (Cfm)
SIZE

50JS018

50JS024

50JS030

50JS036

50JS042

50JS048

50JS060

AIRFLOW (CFM)

650

800

1000*

1200

1400

1600

2000

Table 2B—Minimum Airflow for Reliable Electric Heater Operation (Cfm)
SIZE

50JX024

50JX030

50JX036

50JX042

50JX048

50JX060

AIRFLOW (CFM)

800

1000*

1200

1400

1600

2000

* The 030 size models must be run on medium or high speed when used in conjunction with 15 Kw electric heat accessory.

1” MIN.

INDOOR
THERMOSTAT

TRAP
OUTLET
RETURN
AIR

2” MIN.
FROM
POWER
SOURCE

TOP COVER

C99013

Fig. 11—Condensate Trap
DISCONNECT
PER NEC

Step 7—Install Electrical Connections

C99061

Fig. 9—Typical Installation

The unit cabinet must have an uninterrupted, unbroken
electrical ground to minimize the possibility of personal
injury if an electrical fault should occur. This ground may
consist of an electrical wire connected to the unit ground lug
in the control compartment, or conduit approved for electrical
ground when installed in accordance with NEC, ANSI/NFPA
American National Standards Institute/National Fire Protection Association (latest edition) (in Canada, Canadian Electrical Code CSA C22.1) and local electrical codes. Failure to
adhere to this warning could result in serious injury or death.

Failure to follow these precautions could result in damage to
the unit being installed:
1. Make all electrical connections in accordance with NEC
ANSI/NFPA (latest edition) and local electrical codes
governing such wiring. In Canada, all electrical connections must be in accordance with CSA standard C22.1
Canadian Electrical Code Part 1 and applicable local
codes. Refer to unit wiring diagram.
2. Use only copper conductor for connections between
field-supplied electrical disconnect switch and unit. DO
NOT USE ALUMINUM WIRE.
3. Be sure that high-voltage power to unit is within operating
voltage range indicated on unit rating plate. On 3-phase
units, ensure phases are balanced within 2%. Consult local
power company for correction of improper voltage and/or
phase imbalance.
4. Insulate low-voltage wires for highest voltage contained
within conduit when low-voltage control wires are in same
conduit as high-voltage wires.
5. Do not damage internal components when drilling through
any panel to mount electrical hardware, conduit, etc.

Accessory Duct Covers
C99030

Fig. 10—50JX with Duct Covers On
(Unit shown with optional louvered grille)
The units dispose of condensate through a 3/4 in. NPT female
fitting that exits on the compressor end of the unit. Condensate
water can be drained directly onto the roof in rooftop installations
(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 that the outlet of
the trap is at least 1 in. lower than the drain-pan condensate
connection to prevent the pan from overflowing. Prime the trap
with water. When using a gravel apron, make sure it slopes away
from the unit.
If the installation requires draining the condensate water away
from the unit, install a field-supplied 2 -in. trap at the condensate
connection to ensure proper drainage. Condensate trap is available
as an accessory or is field-supplied. Make sure that the outlet of the
trap is at least 1 in. lower than the unit drain-pan condensate
connection to prevent the pan from overflowing. Connect a drain
trough using a minimum of field-supplied 3/4 -in. PVC or
field-supplied 3/4 -in. copper pipe at outlet end of the 2 -in. trap
(See Fig. 11). Do not undersize the tube. Pitch the drain trough
downward at a slope of at least 1 in. every 10 ft of horizontal run.
Be sure to check the drain trough for leaks. Prime the trap at the
beginning of the cooling season start-up.

HIGH-VOLTAGE CONNECTIONS — The unit must have a
separate electrical service with a field-supplied, waterproof disconnect switch mounted at, or within sight from the unit. Refer to
the unit rating plate, NEC and local codes for maximum
fuse/circuit breaker size and minimum circuit amps (ampacity) for
wire sizing (See Tables 3A and 3B for electrical data).
The field-supplied disconnect may be mounted on the unit over the
high-voltage inlet hole (See Figs. 2-3).
If the unit has an electric heater, a second disconnect may be
required. Consult the Installation, Start-Up and Service Instructions provided with the accessory for electrical service connections.
Operation of unit on improper line voltage constitutes abuse and
may cause unit damage that could affect warranty.
ROUTING POWER LEADS INTO UNIT — Use only copper
wire between disconnect and unit. The high-voltage leads should

LEGEND
FIELD SPLICE
TERMINAL (MARKED)
TERMINAL (UNMARKED)
SPLICE
SPLICE (MARKED)
FACTORY WIRING
FIELD CONTROL WIRING
FIELD POWER WIRING
ACCESSORY OR OPTIONAL
WIRING
TO INDICATE COMMON
POTENTIAL ONLY:
NOT TO REPRESENT WIRING

AHA
C
CAP
CB
COMP
CTD
DB
DFT
DR
EQUIP
FU
GND
HR
HTR
IFM
LPS
OFM
QT
RVS
S.B.
TC
TDR
TH
TRAN

ADJUSTABLE HEAT ANTICIPATOR
CONTACTOR
CAPACITOR
CIRCUIT BREAKER
COMPRESSOR MOTOR
COMPRESSOR TIME DELAY
DEFROST BOARD
DEFROST THERMOSTAT
DEFROST RELAY
EQUIPMENT
FUSE
GROUND
HEATER RELAY
HEATER
INDOOR FAN MOTOR
LOW PRESSURE SWITCH
OUTDOOR FAN MOTOR
QUADRUPLE TERMINAL
REVERSING VALVE SOLENOID
SLOW BLOW FUSE
THERMOSTAT - COOLING
TIME DELAY RELAY
THERMOSTAT - HEATING
TRANSFORMER

NOTES:
1. IF ANY OF THE ORIGINAL WIRES FURNISHED ARE REPLACED, IT MUST BE
REPLACED WITH TYPE 90 DEGREE C WIRE OR IT’S EQUIVALENT.
2. SEE PRICE PAGES FOR THERMOSTAT AND SUBBASES.
3. USE 75 DEGREE COPPER CONDUCTORS FOR FIELD INSTALLATION.
4. FOR HIGH SPEED IFM, DISCONNECT RED
WIRE FROM TDR 3 AND CONNECT BLK WIRE FROM IFM.
FOR MEDIUM SPEED, DISCONNECT RED WIRE
FROM TDR 3 AND CONNECT BLU WIRE FROM IFM.
5. DEFROST TIMER TO BE SET AT 90 MINUTES EXCEPT FOR 50JS048, 060 MODELS
SET AT 50 MINUTES.

A00073

Fig. 12—Wiring Schematics
9

A00074

Fig. 13—Wiring Schematics

AHA
C
CAP
CB
COMP
CTD
DB
DFT
DR
EQUIP
GND
HR
HTR
IFM
LPS
OFM
OFR
QT
RVS
TC
TDR
TH
TRAN

ADJUSTABLE HEAT ANTICIPATOR
CONTACTOR
CAPACITOR
CIRCUIT BREAKER
COMPRESSOR MOTOR
COMPRESSOR TIME DELAY
DEFROST BOARD
DEFROST THERMOSTAT
DEFROST RELAY
EQUIPMENT
GROUND
HEATER RELAY
HEATER
INDOOR FAN MOTOR
LOW PRESSURE SWITCH
OUTDOOR FAN MOTOR
OUTDOOR FAN RELAY
QUADRUPLE TERMINAL
REVERSING VALVE SOLENOID
THERMOSTAT - COOLING
TIME DELAY RELAY
THERMOSTAT - HEATING
TRANSFORMER

A00075

Fig. 14—Wiring Schematics
11

Table 3A—Electrical Data—50JS
UNIT 50JS
SIZE

V-PH-HZ

VOLTAGE
RANGE
Min

Max

COMPRESSOR
RLA

LRA

ODFM

IDFM

ELECTRIC HEAT

POWER SUPPLY

FLA

Nominal KW*

FLA

MCA

Max Fuse or CRCT Breaker

MOCP

-/18.1/20.8
36.1/41.7

14.0/14.0
24.8/28.3
47.4/54.3

20/20
25/25
50/60

018

208/230-1-60

187

253

0.9

1.8

-/3.8/5
7.5/10

024

208/230-1-60

187

253

12.8

0.9

-/3.8/5
7.5/10

-/18.1/20.8
36.1/41.7

18.9/18.9
25.1/28.5
47.6/54.6

25/25
25/30
50/60

208/230-1-60

187

253

14.7

0.9

-/3.8/5
7.5/10
11.3/15

-/18.1/20.8
36.1/41.7
54.2/62.5

21.3/21.3
25.1/28.5
47.6/54.6
72.8/83.3

25/25
25/30
50/60
-

80/90

208/230-3-60

187

253

9.9

0.9

-/3.8/5
7.5/10
11.3/15

-/10.4/12
20.8/24.1
31.3/36.1

15.3/15.3
15.5/17.5
28.6/32.6
44.2/50.2

20/20
20/20
30/35
45/60

208/230-1-60

187

253

16.8

1.5

4.1

-/3.8/5
7.5/10
11.3/15

-/18.1/20.8
36.1/41.7
54.2/62.5

26.6/26.6
27.7/31.2
50.3/57.2
72.8/83.3

35/35
35/35
60/60
-

80/90

208/230-3-60

187

253

9.9

1.5

4.1

-/3.8/5
7.5/10
11.3/15

-/10.4/12
31.3/36.1
36.1/41.7

18.0/18.0
18.2/20.2
44.2/50.2
47.8/54.7

25/25
25/25
35/40
45/60

460-3-60

414

506

5.5

0.8

1.9

-/5
10
15

-/6.0
12.0
18.0

9.6
9.9
17.4
24.9

15
15
20
25

3.8

-/5
10
15
20

-/18.1/20.8
36.1/41.7
54.2/62.5
72.2/83.3

30.5/30.5
30.5/30.8
49.9/56.8
72.4/82.9
95.0/108.9

40/40
40/40
50/60
-

90.0
100/110

3.8

-/3.8/5
7.5/10
11.3/15
15/19.94

-/10.4/12
20.8/24.1
31.3/36.1
41.6/48

20.2/20.2
20.2/20.2
30.8/34.8
43.8/49.9
56.7/64.7

25/25
25/25
35/35
45/50
-

60/70

1.8

-/5
10
15
15-20

-/6.0
12.0
18.0
24.1

11.0
11.0
17.3
24.8
32.3

15
15
20
25
35

3.5

-/3.8/5
7.5/10
11.3/15
15/20

-/18.1/20.8
36.1/41.7
54.2/62.5
72.2/83.3

35.5/35.5
35.5/35.5
49.5/56.5
72.1/82.5
94.6/108.5

45/45
45/45
50/60
-

90.0
100/110

3.5

-/3.8/5
7.5/10
11.3/15
15/19.94

-/10.4/12
20.8/24.1
31.3/36.1
41.6/48.0

22.6/22.6
22.6/22.6
30.4/34.4
43.5/49.5
56.3/64.3

30/30
30/30
35/35
45/50
-

60/70

1.8

-/5
10
15
20

6.0
12.0
18.0
24.1

11.5
11.5
17.3
24.8
32.3

15
15
20
25
35

6.2

-/3.8/5
7.5/10
11.3/15
15/20

-/18.1/20.8
36.1/41.7
54.2/62.5
72.2/83.3

43.7/43.7
43.7/43.7
52.9/59.8
75.4/85.9
98.0/111.9

60/60
60/60
60/60
-

90.0
100/125

6.2

-/3.8/5
7.5/10
11.3/15
15/19.94

-/10.4/12
20.8/24.1
31.3/36.1
41.6/48.0

32.0/32.0
32.0/32.0
33.8/37.8
46.8/52.9
59.7/67.7

40/40
40/40
35/40
50/60
-

60/70

3.2

-/5
10
15
20

6.0
12.0
18.0
24.1

14.0
14.0
19.0
26.6
34.1

20
20
20
30
35

030

036

208/230-1-60

042

208/230-3-60

460-3-60

208/230-1-60

048

208/230-3-60

460-3-60

208/230-1-60

060

208/230-3-60

460-3-60

187

414

187

414

187

414

253

506

253

506

253

506

20.6

12.4

6.7

24.4

14.1

7.1

28.8

19.4

115

140

105

165

125

0.9

0.8

1.5

0.8

1.5

0.8

* Heater capacity (KW) based on heater voltage of 208v, 240v, and 480v. If power distribution voltage to unit varies from rated heater voltage, heater KW will vary
accordingly.

→Table 3B—Electrical Data—50JX
UNIT 50JX
SIZE

024

V-PH-HZ

VOLTAGE
RANGE
Min

Max

COMPRESSOR
RLA

LRA

ODFM

IDFM

ELECTRIC HEAT

FLA

Nominal KW*

FLA

MCA

Max Fuse or CRCT Breaker

MOCP

-/18.1/20.8
36.1/41.7

16.4/16.4
25.1/28.5
47.6/54.6

20/20
25/30
50/60

208/230-1-60

187

253.00

10.8

0.90

-/3.75/5.0
7.5/10

208/230-1-60

187

253

0.9

2.1

-/3.75/5.0
7.5/10
11.3/15

-/18.1/20.8
36.1/41.7
54.2/62.5

20.5/20.5
25.2/28.7
47.8/54.7
72.2/82.6

25/25
25/30
50/60
-

80/90

208/230-3-60

187

253

10.3

0.9

2.1

-/3.75/5.0
7.5/10
11.3/15

-/10.4/12.0
20.8/24.1
31.3/36.1

16.0/16.0
16.0/17.7
28.7/32.7
41.7/47.7

20/20
20/20
30/35
45/50

208/230-1-60

187

253

16.7

1.6

3.6

-/3.75/5.0
7.5/10
11.3/15

-/18.1/20.8
36.1/41.7
54.2/62.5

26.1/26.1
27.1/30.5
49.6/56.6
72.2/82.6

35/35
35/35
50/60
-

80/90

208/230-3-60

187

253

11.9

1.6

3.6

-/3.75/5.0
7.5/10
11.3/15

-/10.4/12.0
20.8/24.1
31.3/36.1

19.2/19.2
19.2/19.5
47.8/54.7
43.6/49.6

25/25
25/25
35/35
45/50

460-3-60

414

506

5.4

37.5

0.9

1.9

--/5
10
15

--/6
12
18

9.6
9.9
17.4
24.9

15
15
20
25

4.1

-/3.75/5.0
7.5/10
11.3/15
15.0/20.0

-/18.1/20.8
36.1/41.7
54.2/62.5
72.2/83.3

28.0/28.0
28.0/31.2
50.3/57.2
72.8/83.3
95.4/109.3

35/35
35/35
60/60
-

90.0
100/110

4.1

-/3.75/5.0
7.5/10
11.3/15
15.0/20.0

-/10.4/12.0
20.8/24.1
31.3/36.1
41.6/48.0

20.5/20.5
20.5/20.5
31.2/35.2
44.2/50.2
57.1/65.1

25/25
25/25
35/40
45/60
-

60/70

2.0

-/5
10
15
20

-/6
12
18
24

10.2
10.2
17.5
25.1
32.6

15
15
20
30
35

4.1

-/3.75/5.0
7.5/10
11.3/15
15.0/20.0

-/18.1/20
36.1/41.7
54.2/62.5
72.2/83.8

35.0/35.0
35.0/35.0
50.3/57.2
72.8/83.3
95.4/109.3

45/45
45/45
60/60
-

90.0
100/110

4.1

-/3.75/5.0
7.5/10
11.3/15
15.0/20.0

-/10.4/12.0
20.8/24.1
31.3/36.1
41.6/48

22.6/22.6
22.6/22.6
31.2/35.2
44.2/50.2
57.1/65.1

30/30
30/30
35/40
45/60
-

60/70

-/5
10
15
20

-/6
12
18
24

11.4
11.4
17.5
25.1
32.6

15
15
20
30
35

6.2

-/3.75/5.0
7.5/10
11.3/15
15.0/20.0

-/18.1/20.8
36.1/41.7
54.2/62.5
72.2/83.3

43.6/43.6
43.6/43.6
52.9/59.8
75.4/85.9
98.0/111.9

60/60
60/60
60/60
-

90.0
100/125

6.2

-/3.75/5.0
7.5/10
11.3/15
15.0/20.0

-/10.4/12.0
20.8/24.1
31.3/36.1
41.6/48.0

29.2/29.2
29.2/29.2
33.8/37.8
46.8/52.9
59.7/67.7

35/35
35/35
35/40
50/60
-

60/70

3.2

-/5
10
15
20

-/6
12
18
24

15.4
15.4
19.0
26.6
34.1

20
20
20
30
35

030

036

208/230-1-60

042

208/230-3-60

460-3-60

208/230-1-60

048

208/230-3-60

460-3-60

208/230-1-60

060

POWER SUPPLY

208/230-3-60

460-3-60

187

414

187

414

187

414

253

506

253

506

253

506

18.4

12.4

5.8

23.4

13.5

6.8

28.8

17.3

104

169

123

0.9

1.6

0.9

1.4

0.9

* Heater capacity (KW) based on heater voltage of 208v, 240v, and 480v. If power distribution voltage to unit varies from rated heater voltage, heater KW will vary
accordingly.

EXAMPLE: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v

LEGEND
FLA
LRA
MCA
MOCP
RLA

—
—
—
—
—

Full Load Amps
Locked Rotor Amps
Minimum Circuit Amps
Maximum Overcurrent Protection
Rated Load Amps

Average Voltage = 452 + 464 + 455
3
1371
=
3
= 457

NOTES:
1. In compliance with NEC (National Electrical Code) requirements
for multimotor and combination load equipment (refer to NEC
Articles 430 and 440), the overcurrent protective device for the
unit shall be Power Supply fuse . The CGA (Canadian Gas
Association) units may be fuse or circuit breaker.
2. Minimum wire size is based on 60 C copper wire. If other than
60 C wire is used, or if length exceeds wire length in table,
determine size from NEC.
3. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply voltage is greater than 2%. Use the following formula to determine
the percentage of voltage imbalance.

Determine maximum deviation from average voltage.
(AB) 457 452 = 5 v
(BC) 464 457 = 7 v
(AC) 457 455 = 2 v
Maximum deviation is 7 v.
Determine percent of voltage imbalance.
7
% Voltage Imbalance = 100 x
457
= 1.53%
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.

% Voltage imbalance
= 100 x

max voltage deviation from average voltage
average voltage

IMPORTANT: If the supply voltage phase imbalance is
more than 2%, contact your local electric utility company
immediately.

C99024

Fig. 15—Electrical Data Legend
CONNECTING GROUND LEAD TO GROUND LUG — Refer
to Fig. 17. Connect the ground lead to the chassis using the ground
lug in the wiring splice box.

be in a conduit until they enter the duct panel; conduit termination
at the duct panel must be watertight. Run the high-voltage leads
through the power entry knockout on the power entry side panel
(See Fig. 2 and 3 for location and size). When the leads are inside
the unit, run leads up the high-voltage raceway to the line wiring
splice box (See Fig. 12 through 14). For single-phase units,
connect leads to the black and yellow wires; for 3-phase units,
connect the leads to the black, yellow, and blue wires (See Fig.
17).

ROUTING CONTROL POWER WIRES — (24 V) — Form a
drip-loop with the thermostat leads before routing them into the
unit. Route the thermostat leads through grommeted, low-voltage
hole provided in unit into unit control power splice box (See Fig.
2 and 3). Connect thermostat leads to unit control power leads as
shown in Fig. 16.
The unit transformer supplies 24-v power for complete system
including accessory electrical heater. An automatic-reset circuit
breaker (See Fig. 18) is provided in the 24-v circuit; see the caution
label on the transformer or Fig. 19. Transformer is factory wired
for 230-v operation. If supply voltage is 208 v, rewire transformer
primary as described in Special Procedures for 208-V Operation
section.

BRN

ORN

R
RED

G
GRN

Y
YEL

E
WHT

W2
THERMOSTAT
AND SUBBASE

UNIT CONTROL POWER
SPLICE BOX

C99056

Fig. 16—Control Connections
GROUND LUG
(IN SLPICE BOX)
GROUND
LEAD

SINGLE-PHASE
CONNECTIONS
TO DISCONNECT
PER NEC

BLK

YEL

BLU
L3
3-PHASE
CONNECTIONS
NOTE: Use copper wire only.
LEGEND
NEC – National Electrical Code
Field Wiring
Splice Connections

24 V Circuit Breaker
24 Volt Compartment
C99070

Fig. 17—Line Power Connections

Fig. 18—Control Wiring Plate

C99057

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

TRANSFORMER CONTAINS A MANUAL
RESET OVERCURRENT PROTECTOR

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

IT WILL NOT AUTOMATICALLY RESET
DISCONNECT POWER PRIOR TO
SERVICING

4. Verify the following conditions:
a. Make sure that outdoor-fan blade is correctly positioned in
fan orifice.

THIS COMPARTMENT MUST BE CLOSED
EXCEPT WHEN SERVICING

Fig. 19—Transformer Label

b. Make sure that condensate drain pan and trap are filled
with water to ensure proper drainage.

C99058

c. Make sure that all tools and miscellaneous loose parts have
been removed.

SPECIAL PROCEDURES FOR 208-V OPERATION
1. Disconnect the yellow primary lead (w110) from the transformer. See unit wiring label (See Fig. 12 through 14).

5. Compressors are internally spring mounted. Do not loosen or
remove compressor hold-down bolts.

2. Connect the yellow primary lead (w110) to the transformer
terminal labeled 200v.

6. Each unit system has 2 Schrader-type ports, one low-side
Schrader fitting located on the suction line, and one high-side
Schrader fitting located on the compressor discharge line. Be
sure that caps on the ports are tight.

Indoor blower-motor speeds may need to be changed for 208-v
operation. Refer to indoor airflow and airflow adjustments section.
PRE-START-UP

FAN GRILLE

MOTOR

Failure to observe the following warnings could result in
serious personal injury or death:
1. Follow recognized safety practices and wear protective
goggles when checking or servicing refrigerant system.
2. Do not operate compressor or provide any electric power to
unit unless compressor terminal cover is in place and
secured.
3. Do not remove compressor terminal cover until all electrical sources are disconnected.
4. Relieve and recover all refrigerant from system before
touching or disturbing anything inside terminal box if
refrigerant leak is suspected around compressor terminals.
5. Never attempt to repair soldered connection while refrigerant system is under pressure.
6. Do not use torch to remove any component. System
contains oil and refrigerant under pressure.
To remove a component, wear protective goggles and
proceed as follows:
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 necessary. Oil can ignite when exposed to torch flame.

1/8" MAX BETWEEN
MOTOR AND FAN HUB

MOTOR SHAFT
C99009

Fig. 20—Fan Blade Clearance
START-UP
Using the Start-Up Checklist supplied at the end of this book,
proceed as follows:
Step 1—Check for Refrigerant Leaks
Locate and repair refrigerant leaks and charge the unit as follows:
1. Use both high- and low-pressure ports to relieve system
pressure and reclaim remaining refrigerant
2. Repair leak following accepted practices.
NOTE: Install a bi-flow filter drier whenever the system has
been opened for repair.
3. Check system for leaks using an approved method.
4. Evacuate refrigerant system and reclaim refrigerant if no
additional leaks are found.
5. Charge unit with R-22 refrigerant, using a volumetriccharging cylinder or accurate scale. Refer to unit rating plate
for required charge. Be sure to add extra refrigerant to
compensate for internal volume of filter drier.

Use the Start-Up Checklist supplied at the end of this book and
proceed as follows to inspect and prepare the unit for initial
start-up:

Step 2—Start-Up Adjustments
Complete the required procedures given in the Pre-Start-Up
section on this page before starting the unit. Do not jumper any
safety devices when operating the unit. Do not operate the unit in
Cooling mode when the outdoor temperature is below 40°F (unless
accessory low-ambient kit is installed). Do not rapid-cycle the
compressor. Allow 5 min. between ‘‘on’’ cycles to prevent
compressor damage.

1. Remove access panel.
2. Read and follow instructions on all DANGER, 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 broken
lines, loose parts, disconnected wires, etc.

CHECKING COOLING AND HEATING CONTROL OPERATION — Start and check the unit for proper control operation as
follows:

b. Inspect for oil at all refrigerant tubing connections and on
unit base. Detecting oil generally indicates a refrigerant
leak. Leak-test all refrigerant tubing connections using
electronic leak detector, or liquid-soap solution. If a refrigerant leak is detected, see following Check for Refrigerant
Leaks section.

1. Place room thermostat SYSTEM switch in OFF position.
Observe that blower motor starts when FAN switch is placed
in ON position and shuts down within 60 sec. when FAN
switch is placed in AUTO position.

INDOOR COIL

OUTDOOR COIL

LCS
COMPRESSOR

ACCUMULATOR

Bypass
Position

Metering
Position

LEGEND
LCS – Loss of Charge Switch
Accurater® Metering Device
Arrow indicates direction of flow
C99027
1. Hot gas from compressor flows through the 4-way valve and is directed to the indoor coil. It is then condensed and subcooled through the coil circuits and then leaves
the indoor coil by way of the ID Accurater in the bypass position to the liquid line.
2. The refrigerant then feeds the outdoor coil through the OD Accurater device in the metering position and distributes to each circuit.
3. Each circuit evaporates the refrigerant and the circuits are combined in the outdoor coil header.
4. The refrigerant then flows through the 4-way valve, accumulator, and back to the compressor.

Fig. 21—Typical Heat Pump Operation, Heating Mode

INDOOR COIL

OUTDOOR COIL

LCS
COMPRESSOR

ACCUMULATOR

Metering
Position

LEGEND
LCS – Loss of Charge Switch
Accurater® Metering Device
Arrow indicates direction of flow

Bypass
Position

C99028
1. Hot gas from compressor flows through the 4-way valve and is directed to the outdoor coil. It is then condensed and subcooled through the coil circuits. Refrigerant leaves
the outdoor coil by way of the OD Accurater in the bypass position to the liquid line.
2. The refrigerant then feeds the indoor coil through the ID Accurater device in the metering position and distributes to each circuit.
3. Each circuit evaporates the refrigerant and the circuits are combined in the indoor coil header.
4. The refrigerant then flows through the 4-way valve, accumulator, and back to the compressor.

Fig. 22—Typical Heat Pump Operation, Cooling Mode
16

Table 4A—Wet Coil Air Delivery
Unit 50JS 018-060 (Deduct 10% for 208v)*
UNIT

MOTOR SPEED
Low

018

Med
High
Low

024

Med
High
Low

Med
High

EXTERNAL STATIC PRESSURE (IN. WG)
0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Watts

214

191

170

1.0
-

Cfm

821

696

575

Watts

Cfm

Watts

283

274

267

Cfm

848

707

555

Watts

237

214

191

Cfm

971

821

696

Watts

368

366

365

360

Cfm

957

872

785

688

Watts

425

414

Cfm

891

735

Watts

295

292

289

Cfm

928

882

802

Watts

388

383

377

372

366

361

Cfm

1203

1120

1062

1004

930

838

Watts

469

458

449

442

Cfm

1141

1027

924

828

Watts

592

581

567

552

538

525

512

499

Cfm

1499

1421

1351

1281

1207

1125

1034

936

Watts

660

636

617

603

592

581

566

Cfm

1475

1371

1274

1186

1105

1024

928

Watts

776

761

744

725

706

689

Cfm

1452

1356

1254

1145

1030

910

Watts

606

596

586

575

563

550

537

Cfm

1464

1399

1341

1282

1218

1146

1066

Watts

680

665

649

635

622

611

600

590

Cfm

1608

1535

1461

1387

1316

1247

1180

1111

Watts

768

755

742

730

718

707

696

684

671

Cfm

1656

1576

1508

1447

1390

1331

1268

1198

1119

Watts

741

724

709

690

664

631

594

562

543

552

Cfm

1994

1937

1869

1797

1722

1645

1566

1480

1384

1269

Watts

773

744

715

687

662

640

625

Cfm

1957

1867

1787

1719

1653

1575

1463

Watts

799

782

773

756

704

Cfm

1914

1842

1774

1686

1538

Watts

742

723

698

666

629

591

559

540

Cfm

2197

2141

2103

2057

1988

1894

1783

1674

Watts

838

822

803

780

752

721

689

661

639

632

Cfm

2485

2406

2269

2127

2012

1937

1894

1855

1770

1571

Watts

934

913

891

866

837

806

776

750

735

Cfm

2483

2391

2283

2170

2061

1960

1868

1780

1687

* Air delivery values are based on operating voltage of 230 v or 460 v, wet coil, without filter or electric heater. Deduct filter and electric heater pressure drops to obtain
static pressure 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.
3. Deduct 10% for 208v.

IMPORTANT: Three-phase, scroll compressors are direction oriented. Unit must be checked to ensure proper compressor 3-phase
power lead orientation. If not corrected within 5 min., the internal
protector will shut off the compressor. The 3-phase power leads to
the unit must be reversed to correct rotation. When turning
backwards, scroll compressors emit elevated noise levels, and the
difference between compressor suction and discharge pressures
may be dramatically lower than normal.

2. Place SYSTEM switch in COOL position and FAN switch in
AUTO position. Set control below room temperature. Observe
that cooling cycle shuts down when control setting is satisfied.
3. Place system switch in HEAT position. Set control above
room temperature. Observe that compressor, outdoor fan, and
indoor blower motors start. Observe that heating cycle shuts
down when control setting is satisfied.
4. When using an automatic changeover room thermostat, place
both SYSTEM and FAN switches in AUTO positions. Observe that unit operates in Cooling mode when temperature
control is set to ‘‘call for Cooling’’ (below room temperature),
and unit operates in Heating mode when temperature control
is set to "call for Heating" (above room temperature).

CHECKING AND ADJUSTING REFRIGERANT CHARGE
— The refrigerant system is fully charged with R-22 refrigerant
and is tested and factory sealed.
NOTE: Adjustment of the refrigerant charge is not required
unless the unit is suspected of not having the proper R-22 charge.

Table 4B—Wet Coil Air Delivery
Unit 50JX 024-060 (Deduct 10% for 208v)*
UNIT

MOTOR SPEED
Low

024

Med
High
Low

Med
High

EXTERNAL STATIC PRESSURE (IN. WG)
0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Watts

275

273

271

270

1.0
-

Cfm

923

844

754

669

Watts

359

353

350

347

341

Cfm

941

876

814

737

622

Watts

447

439

431

423

Cfm

968

869

765

659

Watts

276

272

Cfm

963

929

781

Watts

375

377

371

362

354

350

Cfm

1202

1170

1079

976

884

807

Watts

469

449

435

428

Cfm

1174

988

828

718

Watts

462

451

431

411

394

381

Cfm

1374

1290

1205

1116

1020

916

Watts

523

506

490

471

449

426

Cfm

1500

1408

1301

1190

1082

977

Watts

645

628

610

595

584

575

Cfm

1474

1369

1267

1169

1069

962

Watts

620

600

586

574

562

548

530

510

487

462

439
1103

Cfm

1662

1621

1581

1540

1496

1447

1392

1331

1263

1186

Watts

686

661

634

606

577

547

517

Cfm

1722

1662

1594

1515

1427

1330

1227

Watts

757

730

704

682

Cfm

1669

1577

1486

1402
-

Watts

620

600

586

574

562

548

530

487

Cfm

1662

1621

1581

1540

1496

1447

1392

1331

1263

Watts

763

747

729

709

686

661

634

606

577

547

517
1227

Cfm

1917

1868

1822

1774

1722

1662

1594

1515

1427

1330

Watts

852

832

809

784

757

730

704

682

Cfm

1982

1914

1839

1757

1669

1577

1486

1402
-

Watts

597

592

578

526

460

452

445

Cfm

2265

2190

2101

2033

1974

1869

1614

Watts

754

730

707

687

671

658

646

630

603

558

486
1576

Cfm

2383

2282

2202

2134

2070

2005

1935

1858

1771

1667

Watts

901

876

856

836

813

785

755

723

696

681

687

Cfm

2480

2383

2301

2233

2175

2122

2066

1998

1910

1788

1619

met. Note that charging charts are different from type normally
used. Charts are based on charging the units to correct superheat
for the various operating conditions. Accurate pressure gage and
temperature sensing devices are required. Connect the pressure
gage to the service port on the suction line. Mount the temperature
sensing device on the suction line and insulate it so that the
outdoor ambient does not effect the reading. Indoor air CFM must
be within the normal operating range of the unit.

The charging label and the tables shown refer to system temperatures and pressures in cooling mode only. A refrigerant charging
label is attached to the outside of the service access door. If charge
level is suspect in Heating mode, reclaim all refrigerant and charge
to nameplate amount. (This information may be obtained from the
physical data table also.)
IMPORTANT: When evaluating the refrigerant charge, an indicated adjustment to the specified factory charge must always be
very minimal. If a substantial adjustment is indicated, an abnormal
condition exists somewhere in the cooling system, such as insufficient airflow across either coil or both coils.

TO USE COOLING CHARGING CHARTS — Take the outdoor
ambient temperature and read the suction pressure gage. Refer to
the chart to determine what the suction temperature should be.
NOTE: If the problem causing the inaccurate readings is a
refrigerant leak, refer to Check for Refrigerant Leaks section.

REFRIGERANT CHARGE — The amount of refrigerant charge
is listed on the unit nameplate and /or the physical data table. Refer
to the Refrigeration Service Techniques Manual, Refrigerants
Section.
NO CHARGE — Check for leak. Use standard evacuating techniques. After evacuating system, weigh in the specified amount of
refrigerant (refer to system data plate).
LOW CHARGE COOLING — Use Cooling Charging Charts
(Figs. 23-35). Vary refrigerant until the conditions of the chart are

OUTDOOR TEMP
°F
°C

551

483

414

345

115

105

758 110

80
75

70
55

620

551

483

414

207

276

-7

-1
4
10
16
SUCTION LINE TEMPERATURE (°C)

27
50JS500087

105

80.0

345

70.0

115

30.0
40.0
50.0
60.0
SUCTION LINE TEMPERATURE (°F)

125

689 100

276

20.0

OUTDOOR TEMP
°F
°C

(024) 60HZ CHARGING CHART

SUCTION LINE PRESSURE (PSIG)

620
SUCTION LINE PRESSURE (PSIG)

SUCTION LINE PRESSURE (KILOPASCALS)

689 100

125

SUCTION LINE PRESSURE (KILOPASCALS)

(018) 60HZ CHARGING CHART

20.0

30.0
40.0
50.0
60.0
SUCTION LINE TEMPERATURE (°F)

70.0

80.0

-7

-1
4
10
16
SUCTION LINE TEMPERATURE (°C)

27
50JS500088

C00026

C00027

Fig. 23—Cooling Charging Chart, 50JS 018 Units
OUTDOOR TEMP
°F
°C

483

414

345

SUCTION LINE PRESSURE (PSIG)

SUCTION LINE PRESSURE (KILOPASCALS)

551

115

105

95
85

35
29

75
65

24
18

689 100

276

207

30
20.0

30.0
40.0
50.0
60.0
SUCTION LINE TEMPERATURE (°F)

70.0

-7

-1
4
10
16
SUCTION LINE TEMPERATURE (°C)

125

115

105

80.0
27
50JS500089

C00028

620

551

483

414

345

90
SUCTION LINE PRESSURE (PSIG)

125
689 100

OUTDOOR TEMP
°F
°C

(036) 60HZ CHARGING CHART

SUCTION LINE PRESSURE (KILOPASCALS)

(030) 60HZ CHARGING CHART

620

Fig. 24—Cooling Charging Chart, 50JS 024 Units

276

207

30
20.0

30.0
40.0
50.0
60.0
SUCTION LINE TEMPERATURE (°F)

70.0

-7

-1
4
10
16
SUCTION LINE TEMPERATURE (°C)

80.0
27
50JS500090

C00029

Fig. 25—Cooling Charging Chart, 50JS030 Units

Fig. 26—Cooling Charging Chart, 50JS 036 Units
Airflow can be changed by changing the lead connection of the
blower motor.
Unit 50JS and JX three-speed motors (except sizes JS 018 and JX
030) are factory wired for low speed operation. Unit 50JX 030 is
factory wired for medium speed. Unit 50JS 018 has a two-speed
motor wired for low speed.
For 208/230-v Motors:—The motor leads are color-coded as
follows:
3-SPEED
Black = high speed
Blue = medium speed
Red = low speed

INDOOR AIRFLOW AND AIRFLOW ADJUSTMENTS

For heating and cooling operation, the recommended airflow
is 350 to 450 cfm for each 12,000 Btuh of rated cooling
capacity. for units with optional electric heat, the airflow must
not be reduced below the levels stated in Tables 2A and 2B.
Tables 4A and 4B shows both heating and cooling airflows at
various external static pressures. Refer to these tables to determine
the airflow for the system being installed.
NOTE: Be sure that all supply-and return-air grilles are open, free
from obstructions, and adjusted properly.

OUTDOOR TEMP
°F
°C

551

483

414

345

125
115
105

689 100

52
46
41

276

207

30
20.0

30.0
40.0
50.0
60.0
SUCTION LINE TEMPERATURE (°F)

70.0

-7

-1
4
10
16
SUCTION LINE TEMPERATURE (°C)

80.0
27
50JS500091

C00030

483

414

345

SUCTION LINE PRESSURE (PSIG)

SUCTION LINE PRESSURE (KILOPASCALS)

551

125
115
105
95

52
46
41
35

75
65

24
18

207

30
20.0

30.0
40.0
50.0
60.0
SUCTION LINE TEMPERATURE (°F)

70.0

-7

-1
4
10
16
SUCTION LINE TEMPERATURE (°C)

345

41
35

276

207

30
20.0

30.0
40.0
50.0
60.0
SUCTION LINE TEMPERATURE (°F)

70.0

-7

-1
4
10
16
SUCTION LINE TEMPERATURE (°C)

80.0
27
50JS500092

MAINTENANCE
To ensure continuing high performance, and to minimize the
possibility of premature equipment failure, periodic maintenance
must be performed on this equipment. This heat pump unit should
be inspected at least once each year by a qualified service person.
To troubleshoot unit, refer to Table 5.
NOTE TO EQUIPMENT OWNER: Consult your local dealer
about the availability of a maintenance contract.

276

414

105
95

To change the speed of the blower motor (BM), remove fan motor
speed lead from the blower relay (BR) and replace with the lead
for the desired blower motor speed. The motor speed lead is
attached to terminal BM. For low and medium speeds black must
be connected to the jumper wire. Insulate removed lead end to
avoid contact with chassis parts. To select high speed on 460-v GE
motors, separate the black female quick connect (QC) from the
jumper lead male quick connect (QC) and connect the black lead
to the BR. Insulate the jumper to avoid contact with any chassis
parts.

OUTDOOR TEMP
°F
°C

483

115

Fig. 28—Cooling Charging Chart, 50JS 048 Units

689 100

620

551

125

C00031

Fig. 27—Cooling Charging Chart, 50JS 042 Units
(060) 60HZ CHARGING CHART

620
SUCTION LINE PRESSURE (PSIG)

SUCTION LINE PRESSURE (KILOPASCALS)

689 100

OUTDOOR TEMP
°F
°C

(048) 60HZ CHARGING CHART

SUCTION LINE PRESSURE (KILOPASCALS)

(042) 60HZ CHARGING CHART

80.0

The ability to properly perform maintenance on this equipment requires certain expertise, mechanical skills, tools and
equipment. If you do not possess these, do not attempt to
perform any maintenance on this equipment, other than those
procedures recommended in the User’s Manual. FAILURE
TO HEED THIS WARNING COULD RESULT IN SERIOUS INJURY OR DEATH AND POSSIBLE DAMAGE TO
THIS EQUIPMENT.

27
50JS500093

C00032

Fig. 29—Cooling Charging Chart, 50JS 060 Units
To change the speed of the blower motor (BM), remove the fan
motor speed leg lead from the blower relay (BR). This wire is
attached to IGC terminal BM for single-phase and 3-phase units.
To change the speed, remove and replace with lead for desired
blower motor speed. Insulate the removed lead to avoid contact
with chassis parts.
For 460-v GE Motors—The motor leads are color coded as
follows:
3-SPEED
Black = high
Violet = jumper
Orange = medium
Red = low

OUTDOOR
TEMP

620

90.0

551

483

414

345

80.0
65

70.0
55

60.0

50.0

276

40.0

207

30.0
20.0

-7

30.0

40.0
50.0
60.0
SUCTION LINE TEMPERATURE (DEG. F)

70.0

80.0

-1

4
10
16
SUCTION LINE TEMPERATURE (DEG. C)

OUTDOOR
TEMP

(030) 60 Hz CHARGING CHART

C
52
46
41
35

125
115
105

52
46
41

60.0

50.0

689

100.0

620

90.0

551

483

414

345

SUCTION LINE PRESSURE (PSIG)

100.0

F
125
115
105
95

SUCTION LINE PRESSURE (KILOPASCALS)

689

SUCTION LINE PRESSURE (PSIG)

SUCTION LINE PRESSURE (KILOPASCALS)

(024) 60 Hz CHARGING CHART

80.0

70.0

276

40.0

207

30.0
20.0

-7

30.0

40.0
50.0
60.0
SUCTION LINE TEMPERATURE (DEG. F)

70.0

80.0

-1

4
10
16
SUCTION LINE TEMPERATURE (DEG. C)

50JX500219

50JX500220

C99031

C99032

Fig. 30—Cooling Charging Chart, 50JX 024 Units
OUTDOOR
TEMP

90.0

551

483

414

345

80.0

70.0

60.0

50.0

276

40.0

207

30.0
20.0

-7

30.0

40.0
50.0
60.0
SUCTION LINE TEMPERATURE (DEG. F)

70.0

80.0

-1

4
10
16
SUCTION LINE TEMPERATURE (DEG. C)

OUTDOOR
TEMP

(042) 60 Hz CHARGING CHART

C
52
46
41

689

100.0

620

90.0

551

483

414

345

SUCTION LINE PRESSURE (PSIG)

620

F
125
115
105

SUCTION LINE PRESSURE (KILOPASCALS)

100.0

SUCTION LINE PRESSURE (PSIG)

SUCTION LINE PRESSURE (KILOPASCALS)

(036) 60 Hz CHARGING CHART

689

Fig. 31—Cooling Charging Chart, 50JX 030 Units

80.0

F
125

C
52

115
105

46
41

85
75

29
24

70.0

60.0

50.0

276

40.0

207

30.0
20.0

-7

30.0

40.0
50.0
60.0
SUCTION LINE TEMPERATURE (DEG. F)

70.0

80.0

-1

4
10
16
SUCTION LINE TEMPERATURE (DEG. C)

50JX500221

50JX500222

C99033

C99034

Fig. 32—Cooling Charging Chart, 50JX036 Units
OUTDOOR
TEMP

90.0

551

483

414

345

80.0

C
52
46
41
35
29
24
18

70.0

60.0

50.0

276

40.0

207

30.0
20.0

-7

30.0

40.0
50.0
60.0
SUCTION LINE TEMPERATURE (DEG. F)

70.0

80.0

-1

4
10
16
SUCTION LINE TEMPERATURE (DEG. C)

OUTDOOR
TEMP

(060) 60 Hz CHARGING CHART

90.0

125
115
105
95

52
46
41
35

80.0

85
75

29
24

689

100.0

620

551

483

414

345

SUCTION LINE PRESSURE (PSIG)

620

F
125
115
105
95
85
75
65

SUCTION LINE PRESSURE (KILOPASCALS)

100.0

SUCTION LINE PRESSURE (PSIG)

SUCTION LINE PRESSURE (KILOPASCALS)

(048) 60 Hz CHARGING CHART

689

Fig. 33—Cooling Charging Chart, 50JX 042 Units

70.0

60.0

50.0

276

40.0

207

30.0
20.0

-7
50JX500223

30.0

40.0
50.0
60.0
SUCTION LINE TEMPERATURE (DEG. F)

70.0

80.0

-1

4
10
16
SUCTION LINE TEMPERATURE (DEG. C)

27
50JX500224

C99035

C99036

Fig. 34—Cooling Charging Chart, 50JX 048 Units

Fig. 35—Cooling Charging Chart,50JX 060 Units

results, spray condenser coil fins from inside to outside the unit.
On units with an outer and inner condenser coil, be sure to clean
between the coils. Be sure to flush all dirt and debris from the unit
base.

Failure to follow these warnings could result in serious injury
or death:
1. Turn off electrical power to the unit before performing any
maintenance or service on this unit.
2. Use extreme caution when removing panels and parts. As
with any mechanical equipment, personal injury can result
from sharp edges.
3. Never place anything combustible either on, or in contact
with, the unit.

Inspect the drain pan and condensate drain line when inspecting
the coils. Clean the drain pan and condensate drain by removing all
foreign matter from the pan. Flush the pan and drain trough with
clear water. Do not splash water on the insulation, motor, wiring,
or air filter(s). If the drain trough is restricted, clear it with a
‘‘plumbers snake’’ or similar probe device. Ensure that the
auxiliary drain port above the drain trough is also clear.
OUTDOOR FAN

Errors made when reconnecting wires may cause improper
and dangerous operation. Label all wires prior to disconnection when servicing.

Keep the condenser fan free from all obstructions to ensure
proper cooling operation. Never place articles on top of the
unit. Damage to unit may result.

The minimum maintenance requirements for this equipment are as
follows:

1. Inspect the fan blades for cracks or bends.

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

2. If fan needs to be removed, remove screws holding outdoor air
intake grille and remove grille.

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

3. Loosen the setscrew and slide the fan off the motor shaft.

3. Inspect blower motor and wheel for cleanliness each cooling
season. Clean when necessary.

4. When replacing fan blade, position blade so that the hub is 1/8
in. away from the motor end (1/8 in. of motor shaft will be
visible) (See Fig. 20).

4. Check electrical connections for tightness and controls for
proper operation each cooling season. Service when necessary.

5. Ensure that setscrew engages the flat area on the motor shaft
when tightening.
6. Replace grille.

AIR FILTER

ELECTRICAL CONTROLS AND WIRING — Inspect and check
the electrical controls and wiring annually. Be sure to turn off the
electrical power to the unit.

IMPORTANT: Never operate the unit without a suitable air filter
in the return-air duct system. Always replace the filter with the
same dimensional size and type as originally installed (See Tables
1A and 1B for recommended filter sizes).

Remove access panel to locate all the electrical controls and
wiring. Check all electrical connections for tightness. Tighten all
screw connections. If any smoky or burned connections are
noticed, disassemble the connection, clean all the parts, restrip the
wire end and reassemble the connection properly and securely.

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

After inspecting the electrical controls and wiring, replace all the
panels. Start the unit, and observe at least one complete cooling
cycle to ensure proper operation. If discrepancies are observed in
operating cycle, or if a suspected malfunction has occurred, check
each electrical component with the proper electrical instrumentation. Refer to the unit wiring label when making these checkouts.
NOTE: Refer to the Sequence of Operation section as an aid in
determining proper control operation.

INDOOR BLOWER AND MOTOR
NOTE: All motors are prelubricated. Do not attempt to lubricate
these motors.
For longer life, operating economy, and continuing efficiency,
clean accumulated dirt and grease from the blower wheel and
motor annually.

REFRIGERANT CIRCUIT — Inspect all refrigerant tubing connections and the unit base for oil accumulation annually. Detecting
oil generally indicates a refrigerant leak.

Disconnect and tag electrical power to the unit before
cleaning and lubricating the blower motor and wheel. Failure
to adhere to this warning could cause personal injury or death.
OUTDOOR COIL, INDOOR COIL, AND CONDENSATE
DRAIN PAN — Inspect the condenser coil, evaporator coil, and
condensate drain pan at least once each year.

System under pressure. Relieve pressure and recover all
refrigerant before system repair or final unit disposal to avoid
personal injury or death. Use all service ports and open all
flow-control devices, including solenoid valves.

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

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

Straighten bent fins with a fin comb. If coated with dirt or lint,
clean the coils with a vacuum cleaner, using the soft brush
attachment. Be careful not to bend the fins. If coated with oil or
grease, clean the coils with a mild detergent-and-water solution.
Rinse coils with clear water, using a garden hose. Be careful not to
splash water on motors, insulation, wiring, or air filter(s). For best

If no refrigerant leaks are found and low performance is suspected,
refer to Checking and Adjusting Refrigerant Charge section.
INDOOR AIRFLOW — The indoor airflow does not require
checking unless improper performance is suspected. If a problem

within a range of 15v to 30v and draws about 0.5 amps. If the
blower runs continuously instead of cycling off when the fan
switch is set on AUTO, the TDR is probably defective and must be
replaced.
LOSS OF CHARGE SWITCH — The loss of charge switch is a
protective device wired into control circuit (low voltage). It shuts
off the compressor if abnormally low pressures are present in the
refrigeration circuit.
NOTE: Because these switches are attached to refrigeration
system under pressure, it is not advisable to remove this device for
troubleshooting unless you are reasonably certain that a problem
exists. If switch must be removed, remove and recover all system
charge so that pressure gages read 0 psi. Never open system
without breaking vacuum with dry nitrogen.
CHECK DEFROST THERMOSTAT — There is a liquid header
with a brass distributor and feeder tube going into outdoor coil. At
the end of 1 of the feeder tubes, there is a 3/8-in. OD stub tube
approximately 3 in. long. (See Fig. 37.) The defrost thermostat
should be located on stub tube. Note that there is only 1 stub tube
used with liquid header, and on most units it is the bottom circuit.

C99097

Fig. 36—Refrigerant Circuit

DEFROST THERMOSTATS — Defrost thermostat signals heat

exists, be sure that all supply- and return-air grilles are open and
free from obstructions, and that the air filter is clean. When
necessary, refer to Indoor Airflow and Airflow Adjustments
section to check the system airflow.

FEEDER TUBE
STUB TUBE

METERING DEVICES — Refrigerant metering devices are fixed
orifices and are located in the inlet header to the indoor and
outdoor coils.
LIQUID LINE STRAINERS — The liquid line strainers (to protect metering devices) are made of wire mesh and are located in the
liquid lines on the inlet side of the metering devices.
DEFROST
THERMOSTAT

SYSTEM INFORMATION
TIME-DELAY RELAY — The Time-Delay Relay (TDR) is a
solid-state control, recycle delay timer which keeps indoor blower
operating for 60 sec. after thermostat is satisfied. This delay
enables blower to remove residual cooling in coil after compression shutdown, thereby improving efficiency of system. The
sequence of operation is that on closure of wall thermostat and at
end of a fixed on delay of 1 sec., fan relay is energized. When
thermostat is satisfied, an off delay is initiated. When fixed delay
of 60 ± 5 sec. is completed, fan relay is de-energized and fan motor
stops. If wall thermostat closes during this delay, TDR is reset and
fan relay remains energized. TDR is a 24-v device that operates

C99029

Fig. 37—Defrost Thermostat
pump that conditions are right for defrost or that conditions have
changed to terminate defrost. It is a thermally actuated switch
clamped to outdoor coil to sense its temperature. Normal temperature range is closed at 30˚ +/- 3˚F and open at 80˚ +/- 5˚F.
NOTE: The defrost thermostat must be located on the liquid side
of the outdoor coil on the bottom circuit and as close to the coil as
possible.

Table 5—Cooling and Heating Troubleshooting Chart
SYMPTOM

Compressor and outdoor fan will not start

Compressor will not start but condenser fan
runs

Three-phase scroll compressor (size 030060units) makes excessive noise, and there
may be a low pressure differential

Compressor cycles (other than normally satisfying thermostat)

CAUSE

Call power company

Fuse blown or circuit breaker tripped

Replace fuse or reset circuit breaker

Defective thermostat, contactor, transformer, control relay or defrost board

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 below room temperature

Units have a 5-min. time delay

DO NOT bypass this compressor time
delay—wait for 5 min. until time-delay relay is
deenergized

Faulty wiring or loose connections in compressor
circuit

Check wiring and repair or replace

Compressor motor burned out, seized, or internal
overload open

Determine cause
Replace compressor

Defective run capacitor, overload, or PTC (positive temperature coefficient) thermistor

Determine cause and replace

One leg of 3-phase power dead

Replace fuse or reset circuit breaker
Determine cause

Low input voltage (20% low)

Determine cause and correct

Scroll compressor is rotating in the wrong direction

Correct the direction of rotation by reversing the
3-phase power leads to the unit

Refrigerant overcharge or undercharge

Recover refrigerant, evacuate system, and recharge to capacities shown on nameplate

Defective compressor

Replace and determine cause

Insufficient line voltage

Determine cause and correct

Blocked outdoor coil

Determine cause and correct

Defective run/start capacitor, overload or start
relay

Determine cause and replace

Defective thermostat

Replace thermostat

Faulty outdoor-fan motor or capacitor

Replace

Damaged reversing valve

Determine cause and correct

Restriction in refrigerant system

Locate restriction and remove

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

Frosted coil with incorrect defrost operation

Check defrost time settings
Reset as necessary
Check defrost temperature switch
Replace as necessary

Air in system

Recover refrigerant, evacuate system, and recharge

Outdoor coil dirty or restricted

Clean coil or remove restriction

Dirty air filter

Replace filter

Compressor operates continuously

Excessive head pressure

Head pressure too low

Excessive suction pressure

REMEDY

Power failure

Dirty indoor or outdoor coil

Clean coil

Refrigerant overcharged

Recover excess refrigerant

Air in system

Recover refrigerant, evacuate system, and recharge

(Heat) Indoor air restricted or recirculating

Determine cause and correct

Indoor or outdoor air restricted or air short-cycling

Determine cause and correct

Low refrigerant charge

Check for leaks, repair and recharge

Compressor valves leaking

Replace compressor

Restriction in liquid tube

Remove restriction

(Heat) Outdoor coil frosted

Move timer on control board to 30 min. between
defrost cycles

(Cool) High Heat load

Check for source and eliminate

Compressor valves leaking

Replace compressor

Reversing valve hung up or leaking internally

Replace valve

Refrigerant overcharged

Recover excess refrigerant

Cooling and Heating Troubleshooting Chart (cont’d)
SYMPTOM
Suction pressure too low

CAUSE

REMEDY

(Cool) Dirty air filter

Replace filter

(Heat) Outdoor coil frosted

Move timer on control board to 30 min. between
defrost cycles

Low refrigerant charge

Check for leaks, repair and recharge

Metering device or low side restricted

Remove source of restriction

(Cool) Insufficient coil airflow

Increase air quantity
Check filter—replace if necessary

(Cool) Temperature too low in conditioned area

Reset thermostat

(Cool) Outdoor ambient below 40°F

Install low-ambient kit

Field-installed filter-drier restricted

Replace

Compressor runs but outdoor fan does not

NC (normally closed) contacts on defrost board
open

Check condition of relay on board
Replace if necessary

IFM does not run

Blower wheel not secured to shaft

Properly tighten blower wheel to shaft

Insufficient voltage at motor

Determine cause and correct

Power connectors not properly sealed

Connectors should snap easily; do not force

Motor programmed with a delay profile

Allow a few min. for motor to shut off

With thermostat in off state, the voltage on G,
Y1,Y, Y2, W with respect to common, should be
1/2 of actual low voltage supply

If measured voltage is more than 1/2, the thermostat is incompatible with motor
If voltage is less than 1/2, the motor has failed

Water dripping into motor

Verify proper drip loops in connector wires

Connectors not firmly sealed

Gently pull wires individually to be sure they are
crimped into the housing

IFM runs when it should be off

IFM operation is intermittent
IFM—Indoor Fan Motor

START-UP CHECKLIST
(REMOVE AND STORE IN JOB FILE)
I. PRELIMINARY INFORMATION
Model No...............................................................................................................................................................................................................
Serial No. ...............................................................................................................................................................................................................
Date ........................................................................................................................................................................................................................
Technician..............................................................................................................................................................................................................
II. PRE-START-UP
___ Verify that all packing materials have been removed from unit
___ Remove all shipping holddown bolts and brackets per installation instructions
___ 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 and propeller for location in housing and setscrew tightness
III. START-UP
Supply Voltage: L1-L2 __________ L2-L3 _________ L3-L1 __________
Compressor Amps: L1 __________ L2 _________ L3 __________
Indoor Fan Amps: __________
TEMPERATURE
Outdoor-Air Temperature: __________ DB
Return-Air Temperature: __________ DB __________ WB
Heat Pump Supply Air: __________
Electric Heater Supply Air: __________
PRESSURES
Refrigerant Suction __________ psig
Refrigerant Discharge __________ psig
___ Verify refrigerant charge using charging tables
___ Verify 3-phase scroll compressor is rotating in correct direction

50js1si

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
Tab 5a 5a
PC 101
Catalog No. 565-057
Printed in U.S.A.
Form 50JS,JX-1SI
Pg 28
5-00
Replaces: 50JX-2SI

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Modify Date                     : 2005:11:10 10:18:02-05:00
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Creator                         : Carrier Corporation
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Author                          : Carrier Corporation

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Carrier 50Js Users Manual

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