Bryant R 22 Users Manual

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2015-02-02

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Application Guide and
Service Manual
AIR CONDITIONERS AND HEAT PUMPS
USING R-22 REFRIGERANT
Cancels:

NOTE: Read the entire instruction manual before starting the
installation.

AP01-3, SM01,02-4

SM01,02-5
10-00

Fan Motors ..............................................................................21
Service Alarm Control Board.................................................21
Outdoor Thermostat(s)............................................................22
Compressor Plug.....................................................................24
Low-Voltage Terminals ..........................................................25
RECIPROCATING COMPRESSOR ..........................................25
Mechanical Failures ................................................................25
Electrical Failures ...................................................................26
System Cleanup After Burnout ..............................................27
Compressor Removal And Replacement ...............................27
COPELAND SCROLL COMPRESSOR ....................................28
Features ...................................................................................28
Troubleshooting ......................................................................28
Discharge Thermostat .............................................................28
Discharge Solenoid Valve ......................................................28
MILLENNIUM SCROLL COMPRESSOR ................................29
Features ...................................................................................29
Compressor Protection............................................................29
Troubleshooting ......................................................................29
Scroll Compressor, 3–Phase Monitor.....................................29
TWO-SPEED SYSTEM ..............................................................29
Cautions and Warnings...........................................................29
System Functions ....................................................................29
Factory Defaults......................................................................33
Major Components..................................................................33
LED Function/Malfunction Lights .........................................34
Troubleshooting ......................................................................34
REFRIGERATION SYSTEM .....................................................35
Refrigeration Cycle.................................................................35
Leak Detection ........................................................................35
Brazing ....................................................................................37
Service Valves ........................................................................38
Check-Flo-Rater™ (Bypass-Type) Heat Pumps Only...........39
Reversing Valve......................................................................39
Thermostatic-Expansion Valves (TXV).................................40
Thermostatic-Expansion Valve (Bi-Flow TXV)....................41
Coil Removal ..........................................................................41
Liquid-Line Strainer (Heat Pumps Only) ..............................41
Accumulator ............................................................................43
Contaminant Removal ............................................................43
System Charging.....................................................................43
Checking Charge.....................................................................43
CARE AND MAINTENANCE...................................................45

This symbol → indicates a change since the last issue.
TABLE OF CONTENTS
SAFETY CONSIDERATIONS .....................................................1
INTRODUCTION ..........................................................................2
INSTALLATION GUIDELINE ....................................................2
Residential New Construction ..................................................2
Add-On Replacement (Retrofit) ...............................................2
Seacoast (For Air Conditioners Only) .....................................2
ACCESSORY DESCRIPTIONS ...................................................2
Compressor Crankcase Heater..................................................2
Evaporator Freeze Thermostat..................................................2
Winter Start Control .................................................................2
Compressor Start Assist—PTC ................................................2
Compressor Start Assist Capacitor/Relay ................................2
Low-Ambient Controller ..........................................................2
MotorMaster™ Control ............................................................2
Low-Ambient Pressure Switch.................................................2
Wind Baffle...............................................................................3
Coastal Filter.............................................................................3
Support Feet ..............................................................................3
Liquid-Line Solenoid Valve .....................................................3
Thermostatic-Expansion Valve.................................................3
Isolation Relay ..........................................................................3
LOW-AMBIENT GUIDELINE.....................................................3
LONG-LINE GUIDELINE............................................................3
Approved Systems ....................................................................3
Interconnecting Tubing Sizing .................................................3
Metering Device Sizing ............................................................6
Liquid-Line Solenoid And Tubing Configuration ...................7
Charging Information................................................................8
2–Speed Applications ...............................................................8
UNIT IDENTIFICATION .............................................................8
Product Number Stamped on Unit-Rating Plate......................8
Serial Number Identification ....................................................9
CABINET.....................................................................................10
Remove Top Cover—Before 1/1/92 ......................................10
Remove Fan-Motor Assembly—Before 1/1/92 .....................10
Information Plate—Reliant Products......................................10
Control-Box Cover—Cube Products......................................10
Remove Top Cover— After 1/1/92 .......................................10
Remove Fan-Motor Assembly—After 1/1/92........................11
ELECTRICAL..............................................................................12
Aluminum Wire ......................................................................12
Contactors................................................................................13
Capacitors................................................................................14
Cycle Protector........................................................................15
Crankcase Heater ....................................................................16
Time-Delay Relay...................................................................16
Pressure Switches....................................................................17
Defrost Thermostats................................................................18
Defrost-Control Board ............................................................18

SAFETY CONSIDERATIONS
Service and repair of these units should be attempted only by
trained service technicians familiar with Bryant standard service
instructions and training manual.
All equipment should be installed in accordance with accepted
practices and unit Installation Instructions, and in compliance with
all national and local codes.
Power should be turned off when servicing or repairing electrical
components. Extreme caution should be observed when troubleshooting electrical components with power on. Observe all warning notices posted on equipment.
—1—

Refrigeration system contains refrigerant under pressure. Extreme
caution should be observed when handling refrigerants. Wear
safety glasses and gloves to prevent personal injury. During
normal system operation, some components are hot and can cause
burns. Rotating fan blades can cause personal injury. Appropriate
safety considerations are posted throughout this manual where
potentially dangerous techniques are addressed.
It is important to recognize safety information. This is the
. When you see this symbol on the unit and
safety-alert symbol
in instructions or manuals, be alert to the potential for personal
injury.
Understand the signal words DANGER, WARNING, and CAUTION. These words are used with the safety-alert symbol. DANGER identifies the most serious hazards which will result in severe
personal injury or death. WARNING signifies hazards which
could result in 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.

6. If suction-line filter drier was installed for system clean up,
operate system for 10 hr. Monitor pressure drop across
drier. If pressure drop exceeds 3 psig, replace suction-line
and liquid-line filter driers. Be sure to purge system with
dry nitrogen and evacuate when replacing filter driers.
Continue to monitor pressure drop across suction-line filter
drier. After 10 hr of run time, remove suction-line filter
drier and replace liquid-line filter drier. Never leave
suction-line filter drier in system longer than 72 hr
(actual time).
7. Charge system. (See unit information plate.)
III. SEACOAST (FOR AIR CONDITIONERS ONLY)
Installation of these units in seacoast locations requires the use of
a coastal filter. (See section on cleaning.)
ACCESSORY DESCRIPTIONS
Refer to Table 1 for an Accessory Usage Guide for Air Conditioners and Heat Pumps. See Model-specific product literature for
any kit part number. Refer to the appropriate section below for a
description of each accessory and its use.
I. COMPRESSOR CRANKCASE HEATER

WARNING: Improper installation, adjustment, alteration, service, maintenance, or use can cause explosion,
fire, electrical shock, or other conditions which may
cause personal injury, death, or property damage. Consult
a qualified installer, service agency, or your distributor or
branch for information or assistance. The qualified installer or agency must use factory-authorized kits or
accessories when modifying this product.

An electric heater which mounts to base of compressor to keep
lubricant warm during off cycles. Improves compressor lubrication
on restart and minimizes chance of refrigerant slugging and oil
pumpout. The crankcase heater may or may not include a
thermostat control. For units equipped with crankcase heaters,
apply power for 24 hr before starting compressor.
II. EVAPORATOR FREEZE THERMOSTAT
An SPST temperature-activated switch stops unit operation when
evaporator reaches freeze-up conditions.
III. WINTER START CONTROL
An SPST delay relay which bypasses the low-pressure switch for
approximately 3 minutes to permit startup for cooling operation
under low-load conditions.
IV. COMPRESSOR START ASSIST—PTC
Solid-state electrical device which gives a ″soft″ boost to the
compressor at each start.
V. COMPRESSOR START ASSIST CAPACITOR/RELAY
Start capacitor and start relay gives ″hard″ boost to compressor
motor at each start. Required with Liquid-Line Solenoid or
hard-shutoff TXV for all equipment.

INTRODUCTION
This service manual enables a service technician to service, repair,
and maintain a family of similar air conditioners and heat pumps.
It covers standard single-speed products and 2–speed products
only. For variable-speed products, refer to the respective service
manuals.
INSTALLATION GUIDELINE
I. RESIDENTIAL NEW CONSTRUCTION
Specifications for this unit in the residential, new-construction
market require the outdoor unit, indoor unit, refrigerant-tubing
sets, metering device, and filter drier listed in Product Data Sheet
(PDS). DO NOT DEVIATE FROM PDS. Consult unit Installation
Instructions for detailed information.

VI. LOW-AMBIENT CONTROLLER
Low-ambient controller is a cycle-control device activated by a
temperature sensor mounted on a header tube of the outdoor coil.
It is designed to cycle the outdoor fan motor in order to maintain
condensing temperature within normal operating limits (approximately 100°F high, and 60°F low). The control will maintain
working head pressure at low-ambient temperatures down to 0°F
when properly installed.
VII. MOTORMASTER™ CONTROL

II. ADD-ON REPLACEMENT (RETROFIT)
Specifications for this unit in the add-on replacement/retrofit
market require change-out of outdoor unit, metering device, and all
capillary-tube coils. Change-out of indoor coil is recommended.
There can be no deviation.
1. If system is being replaced due to compressor electrical
failure, assume acid is in system. If system is being replaced
for any other reason, use approved acid test kit to determine
acid level. If even low levels of acid are detected, install
factory-approved, suction-line filter drier in addition to the
factory-supplied, liquid-line filter drier. Remove the
suction-line filter drier as soon as possible, with a maximum
of 72 hr.

A fan speed-control device activated by a temperature sensor. It is
designed to control condenser fan-motor speed in response to the
saturated, condensing temperature during operation in cooling
mode only. For outdoor temperature down to -20°F, it maintains
condensing temperature at 100°F ± 10°F. Requires a ball-bearing
fan motor.
VIII. LOW-AMBIENT PRESSURE SWITCH
A long-life pressure switch which is mounted to outdoor unit
service valve. It is designed to cycle the outdoor fan motor in
response to condenser pressure in cooling mode in order to
maintain head pressure within normal operating limits (approximately 100 psig to 225 psig). The control will maintain working
head pressure at low-ambient temperatures down to 0°F when
properly installed.

2. Drain oil from low points or traps in suction-line and
evaporator if they were not replaced.
3. Change out indoor coil or verify existing coil is listed in the
Product Data Sheets.
4. Replace outdoor unit.
5. Install liquid-line filter drier.
—2—

TABLE 1—REQUIRED FIELD-INSTALLED ACCESSORIES FOR AIR CONDITIONERS AND HEAT PUMPS
ACCESSORY
Crankcase Heater
Evaporator Freeze Thermostat
Winter Start Control
Accumulator
Compressor Start Assist
Capacitor and Relay
Low Ambient Controller,
MotorMaster™ Control,
or
Low-Ambient Pressure Switch
Wind Baffle
Coastal Filter
Support Feet
Liquid-Line Solenoid Valve
or
Hard-Shutoff TXV
Ball-Bearing Fan Motor
Isolation Relay

REQUIRED FOR
LOW-AMBIENT
APPLICATIONS
(BELOW 55°F)
Yes
Yes
Yes†
No

REQUIRED FOR
LONG-LINE
APPLICATIONS*
(OVER 50 FT)
Yes
No
No
No

REQUIRED FOR
SEA COAST
APPLICATIONS
(WITHIN 2 MILES)
No
No
No
No

Yes

See Low-Ambient Instructions
No
Recommended

No
No
No
See Long-Line
Application
Guideline
No
No

No
Yes
Recommended

No
Yes‡
Yes**

No
No
No

*For tubing line sets between 50 and 175 ft, refer to Residential Split-System Long-Line Application Guideline.
†Only when low-pressure switch is used.
‡Required for Low-Ambient Controller (full modulation feature) and MotorMaster™ control only.
** Required on Heat Pumps only.

IX. WIND BAFFLE
A field-fabricated sheet-metal cover used to stop prevailing winds
or where outdoor ambient temperature is less than 55°F during unit
operation of cooling mode.

LONG-LINE GUIDELINE
This Long-Line Application Guideline applies to all Bryant
residential air conditioner and heat pump split systems that have a
nominal capacity of 18,000 to 60,000 Btuh. This guideline
provides required system changes and accessories necessary for
any residential product having piping requirements greater than 50
ft or installations where indoor unit is located above outdoor unit.
This guideline is intended to cover applications outside the
standard Installation Instructions. This guideline is for standard,
single-speed products. For applications involving 2-speed products, refer to Section VI first.

X. COASTAL FILTER
A mesh screen inserted under top cover and inside base pan to
protect condenser coil from salt damage without restricting airflow.
XI. SUPPORT FEET
Four adhesive plastic feet which raise unit 4 in. above mounting
pad. This allows sand, dirt, and other debris to be flushed from unit
base; minimizes corrosion.

NOTE: The presale literature for outdoor unit must be referred to
in conjunction with this guideline.

XII. LIQUID-LINE SOLENOID VALVE
An electrically operated shutoff valve to be installed at outdoor or
indoor unit (depending on tubing configuration) which stops and
starts refrigerant liquid flow in response to compressor operation.
Maintains a column of refrigerant liquid ready for action at next
compressor-operation cycle and prevents liquid migration during
the off cycle.

I. APPROVED SYSTEMS
Any residential indoor/outdoor unit combination listed in the
outdoor unit presale literature is an approved system, EXCEPT the
following:

XIII. THERMOSTATIC-EXPANSION VALVE
A modulating flow-control device which meters refrigerant flow
rate into the evaporator in response to the superheat of the
refrigerant gas leaving the evaporator. Only use factory-specified
TXV’s.

•

Indoor coils with capillary-metering devices

•

All equipment less than nominal 18,000 Btuh

•

All 1/4-in. and 5/16–in. liquid-line applications

•

Any indoor furnace coil/fan coil not listed in outdoor unit
presale literature

• Any application which has interconnecting tubing with an
equivalent length greater than 175 ft

XIV. ISOLATION RELAY
A DPDT relay which switches the low-ambient controller out of
the outdoor fan-motor circuit when the heat pump switches to
heating mode.

II. INTERCONNECTING TUBING SIZING
Table 4 lists recommended interconnecting vapor-line diameters
for equivalent total-line lengths. All residential split systems
installed in long-line applications must use only 3/8-in. liquid
lines. Equivalent line length equals the linear length (measured) of
interconnecting vapor tubing plus losses due to elbows. (See Table
5 and Fig. 3.) Liquid lines larger than 3/8-in. OD greatly increase
charge quantity of the system. Excessive charge increases risk of
migration and compressor damage. Table 4 provides the estimated
percentage of nominal cooling-capacity losses based on the standard, required vapor line size versus what is selected for the
long-line application. Since the vapor line is the discharge line in
heating mode, losses are minimal.

LOW-AMBIENT GUIDELINE
The minimum operating temperature for these units in cooling
mode is 55°F outdoor ambient without additional accessories. This
equipment may be operated in cooling mode at ambient temperatures below 55°F when the accessories listed in Table 1 are
installed. Wind baffles are required when operating in cooling
mode at ambients below 55°F. Refer to Fig. 1 or 2 and Table 2 or
3 for wind baffle construction details.
—3—

4″

x 3/8″ (5.56 x 9.53) SLOT

4 REQ'D
1/ ″ (3.45) DIA HOLE
8
2 REQ'D

H
8″

5 5/16″
(151.5)

4″

(9.6)

(5.56) DIA HOLE 2 REQ'D

2″

SUPPORT

(12.7)
TYP

MAT'L: 18 GA STEEL

16″

(11.6)

A
1/ ″
2
(12.7)

1/ ″ (3.45) DIA HOLE
8
1 REQ'D

K
B

16″

(11.6)

1/ ″ (5.56) DIA HOLE
4
3 REQ'D

6″
(152.4)

1/ ″
4

8″

(6.3)

(9.6)

D
1/ ″ x 2″
4
(5.56 x 50.8) SLOT

BAFFLE
MAT'L: 20 GA STEEL
SCREW
10 REQ'D

SUPPORT
4 REQ'D

BAFFLE
2 REQ'D

OUTDOOR
UNIT

BAFFLE ASSEMBLY
A95445

Fig. 1—Wind Baffle Construction for Reliant Units
—4—

Calculate the linear length of vapor tube required, adding any
losses for the total number of elbows for application. (See Table
5.) Using this equivalent length, select desired vapor-line size from
Table 4. Subtract the nominal percentage loss from outdoor-unit
presale-literature Detailed Cooling Capacities data for the given
indoor/outdoor combination. Reference all notes of Table 4.

All standard accessory-tubing kits are supplied with 3/8-in. insulation on vapor line.
For minimal capacity loss in long-line application, 1/2-in. insulation should be specified.

NOTE: When specifying vapor-line insulation, be aware of the
following standard practice:
TABLE 2—WIND BAFFLE DIMENSIONS FOR RELIANT UNITS WITH AEROQUIET-SYSTEM TOP (IN.)
UNIT SIZE

Small

26-3/16

Medium

Large

42-1/16

UNIT HEIGHT
23-13/16
27-13/16
33-13/16
27-13/16
33-13/16
39-13/16
33-13/16
39-13/16

A
17-1/4
17-1/4
17-1/4
21
21
21
25-5/16
25-5/16

7 7/8″
(200.0)

B
24-5/16
24-5/16
24-5/16
30-5/8
30-5/8
30-5/8
39-3/4
39-3/4

C
10-1/4
10-1/4
10-1/4
10-1/4
10-1/4
10-1/4
10-1/4
10-1/4

3/ ″
16

D
19-3/4
23-3/4
29-3/4
23-3/4
29-3/4
35-3/4
29-3/4
35-3/4

E
20-1/2
24-1/2
30-1/2
24-1/2
30-1/2
36-1/2
30-1/2
36-1/2

1/ ″ (3.45) DIA
8
2 REQ'D

(4.6)

G
19-5/8
23-5/8
29-5/8
23-5/8
29-5/8
35-5/8
29-5/8
35-5/8

J
19-5/8
23-5/8
29-5/8
23-5/8
29-5/8
35-5/8
29-5/8
35-5/8

K
0
0
0
17-1/8
17-1/8
17-1/8
21-11/16
21-11/16

L
0
11-7/8
14-7/8
11-7/8
14-7/8
17-7/8
14-7/8
17-7/8

5 3/64″
(128.0)

2″

1/
1/ ″
4

H
20-3/8
24-3/8
30-3/8
24-3/8
30-3/8
36-3/8
30-3/8
36-3/8

E
C

F
34-1/2
34-1/2
34-1/2
42
42
42
50-9/16
50-9/16

(12.7)

(6.4)
5 3/64″
(128.0)

64″

13/

7 7/8″
(199.9)

25/

64″

(10.0)

(5.4)
TYP
1 21/32″ (42.1)

BAFFLE - LEFT
MAT'L: 20 GA STEEL

2″

7 29/32″ (200.8)

(12.7)
TYP

BAFFLE - RIGHT
MAT'L: 20 GA STEEL

4″

(5.56) DIA
2 REQ'D

2 1/2″
(63.5)

A
2 1/2″
(63.5)

1/ ″ x 3/ ″ (5.56 x 9.53) SLOT
4
8
6 REQ'D
1/ ″ (5.56) DIA
4
4 REQ'D

1 21/32″ (42.1)
1/ ″
4

x 3/8″ (5.56 x 9.53) SLOT

25⁄ ″
64

6 REQ'D

(10.0)

4 9/64″ (105.2)
45°
TYP

23/

64″

(9.2)

LEFT
SIDE

2 5/64″
(52.6)

8 5/64″ (205.3)
TYP

1/ ″
4

(6.4)

1/ ″ (12.7)
2
TYP
23/ ″ (9.2)
64

SCREW
14 REQ'D

4″ (5.56) DIA
2 REQ'D
1/

4 57⁄64″
(124.2) TYP

RIGHT
SIDE

OUTDOOR
UNIT

SUPPORT
3 REQ'D

SUPPORT
MAT'L: 18 GA STEEL

1/ ″ (3.45) DIA.
8
4 REQ'D

BAFFLE ASSEMBLY

A95446

Fig. 2—Wind Baffle Construction for Cube Units
—5—

TABLE 3—WIND BAFFLE DIMENSIONS FOR CUBE UNITS (IN.)
UNIT SIZE

Small

Medium

22-1/2

Large

UNIT HEIGHT
21-15/16
23-15/16
25-15/16
27-15/16
29-15/16
31-15/16
33-15/16
21-15/16
23-15/16
25-15/16
27-15/16
29-15/16
31-15/16
33-15/16
35-15/16
37-15/16
25-15/16
27-15/16
29-15/16
31-15/16
33-15/16
35-15/16
37-15/16
39-15/16

A
19-7/8
21-7/8
23-7/8
25-7/8
27-7/8
29-7/8
31-7/8
19-7/8
21-7/8
23-7/8
25-7/8
27-7/8
29-7/8
31-7/8
33-7/8
35-7/8
23-7/8
25-7/8
27-7/8
29-7/8
31-7/8
33-7/8
35-7/8
37-7/8

B
13-3/4
13-3/4
13-3/4
13-3/4
13-3/4
13-3/4
13-3/4
18-5/16
18-5/16
18-5/16
18-5/16
18-5/16
18-5/16
18-5/16
18-5/16
18-5/16
25-3/4
25-3/4
25-3/4
25-3/4
25-3/4
25-3/4
25-3/4
25-3/4

C
28-1/8
28-1/8
28-1/8
28-1/8
28-1/8
28-1/8
28-1/8
32-5/8
32-5/8
32-5/8
32-5/8
32-5/8
32-5/8
32-5/8
32-5/8
32-5/8
40-1/8
40-1/8
40-1/8
40-1/8
40-1/8
40-1/8
40-1/8
40-1/8

D
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16
10-11/16

E
20-1/4
20-1/4
20-1/4
20-1/4
20-1/4
20-1/4
20-1/4
24-3/4
24-3/4
24-3/4
24-3/4
24-3/4
24-3/4
24-3/4
24-3/4
24-3/4
32-1/4
32-1/4
32-1/4
32-1/4
32-1/4
32-1/4
32-1/4
32-1/4

F
11-11/16
11-11/16
11-11/16
11-11/16
11-11/16
11-11/16
11-11/16
16-3/16
16-3/16
16-3/16
16-3/16
16-3/16
16-3/16
16-3/16
16-3/16
16-3/16
23-11/16
23-11/16
23-11/16
23-11/16
23-11/16
23-11/16
23-11/16
23-11/16

G
3-13/16
3-13/16
3-13/16
3-13/16
3-13/16
3-13/16
3-13/16
8-1/4
8-1/4
8-1/4
8-1/4
8-1/4
8-1/4
8-1/4
8-1/4
8-1/4
15-13/16
15-13/16
15-13/16
15-13/16
15-13/16
15-13/16
15-13/16
15-13/16

H
19-13/16
21-13/16
23-13/16
25-13/16
27-13/16
29-13/16
31-13/16
19-13/16
21-13/16
23-13/16
25-13/16
27-13/16
29-13/16
31-13/16
33-13/16
35-13/16
23-13/16
25-13/16
27-13/16
29-13/16
31-13/16
33-13/16
35-13/16
37-13/16

J
17-13/16
19-13/16
21-13/16
23-13/16
25-13/16
27-13/16
29-13/16
17-13/16
19-13/16
21-13/16
23-13/16
25-13/16
27-13/16
29-13/16
31-13/16
33-13/16
21-13/16
23-13/16
25-13/16
27-13/16
29-13/16
31-13/16
33-13/16
35-13/16

TABLE 4—ESTIMATED PERCENTAGE OF NOMINAL COOLING-CAPACITY LOSSES*
UNIT
NOMINAL
SIZE
(BTUH)
18,000
24,000
30,000
36,000

42,000

48,000

60,000

LONG-LINE
VAPOR-LINE
DIAMETER
(IN.)†
5/8
3/4
5/8
3/4
5/8
3/4
3/4
7/8
3/4
7/8
1-1/8
3/4
7/8
1-1/8
7/8
1-1/8

EQUIVALENT LINE LENGTH (FT)
50

100

125

150

175

5
1
6
0
6
2
7
2
7
3
0
10
4
0
7
1

7
3
9
1
8
3
10
4
10
4
0
14
6
0
9
2

9
4
13
1
10
4
14
6
13
6
1
18
7
1
11
2

12
5
16
2
13
5
17
8
17
7
1
22
9
1
14
3

12
5
19
3
15
6
21
10
20
8
2
N/R
11
2
16
3

14
7
22
4
17
7
N/R
11
23
10
2
N/R
13
2
19
4

*The estimated percentage of cooling capacity that must be subtracted from the Detailed Cooling Capacities data specified in outdoor unit-presale literature for any given
indoor/outdoor combination.
†Vapor-line diameter that may be selected for a long-line application. If smaller vapor lines are selected but not specified within the table, large capacity losses will occur
and defrost capabilities will be reduced. If larger vapor lines are selected but not specified within the table, refrigerant oil return will be impaired due to velocity losses.
N/R—Not recommended due to excessive loss of capacity.

For reference only, the close cell insulation material specified for
accessory tubing kits is a compound of vinyl, neoprene, or nitrile
blends of these polymers. Performance requirements include
thermal range of 0° F to 200°F (-17.8° C to 93° C) and a maximum
thermal conductivity of 0.28.
NOTE: Special consideration must be given to isolating interconnecting tubing from building structure. Isolate tubing so that
vibration or noise is not transmitted into structure.

lines and installed system design (indoor coil above or below
outdoor unit.) The piston or TXV provides such flexibility.
The piston should be changed for both indoor coil and outdoor heat
pump unit, depending on system configuration and line length.
Tables 6 and 7 provide necessary changes for a given application.
Use Tables 6 and 7 when selecting correct piston size. Outdoorunit presale literature must be consulted to determine metering
devices specified for standard applications. After determining
standard application piston size(s), refer to Tables 6 and 7 as they
relate to system design (outdoor unit above or below indoor unit)
per equivalent length of tubing.

III. METERING DEVICE SIZING
The metering device for a long-line application must be flexible
enough to compensate for frictional losses due to long refrigerant
—6—

EXAMPLE:
An 042 size heat pump is 75 ft above an 042 size fan coil.
The 042 size heat-pump presale literature specifies a size
80 indoor piston and size 63 outdoor piston.
To establish correct indoor piston size for a 75 ft vertical
separation, refer to Table 6. For a 75 ft equivalent line
length, the piston change is -5. Therefore subtract 5 from
the original indoor piston size of 80:
80 – 5 = 75
Table 8 provides common piston sizes. In this instance, 75
is not listed, therefore round DOWN to next piston size,
which would be 74.
To establish correct outdoor piston size for a 75 ft vertical
separation, refer to Table 7. For a 75 ft equivalent line
length, the piston change is +4. Therefore add 4 to the
original outdoor piston size of 63:
63 + 4 = 67
Since 67 is listed in Table 8, that is the piston which should
be used. If a 67 size piston were not listed, it would be
necessary to round UP to next piston size.

90° STD

TXVs may be used instead of pistons for indoor-metering devices.
Some fan coils are equipped with a hard-shutoff, bi-flow TXV
standard, and no change is required. When sizing an accessory
TXV for long-line applications, TXV should be the same nominal
tonnage as outdoor unit. Refer to presale literature for kit part
numbers.

90° LONG RAD

TABLE 6—CALCULATION OF INDOOR PISTON NO.
OUTDOOR UNIT ABOVE INDOOR
FT
PISTON CHANGE
0-25
0
26-50
-3
51-75
-5
76-100
-7
101-125
-9
126-150
-10
OUTDOOR UNIT BELOW INDOOR
FT
PISTON CHANGE
0-25
0
26-50
+4

45° STD

A92498

Fig. 3—Tube Bend Losses
TABLE 7—CALCULATION OF OUTDOOR PISTON NO.

TABLE 5—FITTING LOSSES IN EQUIVALENT FT
TUBE SIZE OD
(IN.)
5/8
3/4
7/8
1-1/8

OUTDOOR UNIT ABOVE INDOOR
FT
PISTON CHANGE
0-50
0
51-75
+4
76-100
+6
101-125
+8
126-150
+10
OUTDOOR UNIT BELOW INDOOR
FT
PISTON CHANGE
0-50
0

REFERENCE DIAGRAM IN FIG. 1
A
B
C
1.6
1.0
0.8
1.8
1.2
0.9
2.0
1.4
1.0
2.6
1.7
1.3

NOTE: If total equivalent horizontal length is 100 ft or longer,
both indoor and outdoor pistons must be increased 1 full piston
size, in addition to changes required by Tables 6 and 7.

IV. LIQUID-LINE SOLENOID AND TUBING CONFIGURATION
There are 2 types of liquid-line solenoids: 1 for single-flow
applications and the other for bi-flow applications. The purpose of
having 2 solenoids is to minimize the valve internal-pressure drop
in accordance with refrigerant flow direction and liquid migration
to the compressor. The bi-flow solenoid is designed to have
minimal refrigerant-pressure drop in either flow direction, which
makes it suitable for heat pump usage. Refer to Table 9 for
liquid-line solenoid kit part numbers.

After finding appropriate change in piston size, add or subtract the
change from original piston number. If piston size is decreased,
round new piston number down to nearest common piston number
found in Table 8. If piston size is increased, round new piston
number up to nearest common piston number found in Table 8.

—7—

TABLE 8—COMMON PISTON SIZES
CHECK-FLORATER™
—
—
35
—
—
38
—
40
—
42
—
—
46
—
49
51
52
—
55
57
59
61
—
63

CHATLEFF
32
33
35
36
37
38
39
40
41
42
43
45
—
47
49
51
52
53
55
57
59
61
62
63

CHECK-FLORATER™
65
67
—
70
—
73
—
76
78
80
—
82
84
86
88
—
90
—
93
96
98
101
104
109

EXAMPLE:
To calculate additional charge required for a 25–ft line set:
25 ft – 15 ft = 10 ft X 0.6 oz/ft = 6 oz of additional charge

CHATLEFF
65
67
68
70
71
73
74
76
78
80
81
82
84
86
88
89
90
92
93
96
98
101
104
—

The rating-plate charge of a given outdoor unit is for a standard
application of 15 ft of interconnecting tubing. The rating-plate
charge can be found on outdoor unit-rating plate or in outdoor
unit-presale literature. Long-line applications do not require additional oil charge.
VI.

Outdoor units may be connected to indoor section using accessory
tubing package or field-supplied refrigerant grade tubing of correct
size and condition. In long–line applications, 2–speed units are
handled basically the same way as the single-speed units. There are
2 major differences:
1. For tubing up to 100 ft:
Liquid tube diameters and refrigerant connection diameters
for all sizes are 3/8 in.
Vapor tube diameter for the 036 and 048 is 7/8 in.; 060 is
1–1/8 in.
Vapor refrigerant connection diameter for all sizes is 7/8 in.
DO NOT INSTALL EQUIVALENT INTERCONNECTING TUBING LENGTHS GREATER THAN 100 FT.
2. Do not increase or decrease tubing sizes.
For other applications see the previous sections under Long-Line
Guidelines.
UNIT IDENTIFICATION
I. PRODUCT NUMBER STAMPED ON UNIT-RATING
PLATE
The unit product number has 16 positions containing groups of
numbers and letters that indicate specific information about the
unit. Listed below is the breakdown of the 16 positions.
Positions 1, 2, and 3—Product Series
Example:
A 500–series number indicates a split-system condensing unit and
a 600–series number indicates a split-system heat pump.
Position 4—Model Letters
New models are introduced with the letter A, and subsequent
model changes are identified by changing to the next letter, as B,
then C, and so forth.
Position 5—Electrical Characteristics
Example:
J—208–230, 1 Phase, 60 Hertz
N—208/230, 208/240, 1 Phase, 60 Hertz
P—208/230, 208/240, 3 Phase, 60 Hertz
E—460, 3 Phase, 60 Hertz
Q—220, 3 Phase, 50 Hertz
S—220/240, 1 Phase, 50 Hertz
Z—380/415, 3 Phase, 50 Hertz
Position 6—Fuel and Controls
Not applicable on condensing units or heat pumps, so the letter ’X’
is used to signify ’none.’
Positions 7, 8, and 9—Nominal Cooling Capacity (in thousands
Btuh)
Example: 036 = 36,000 Btuh or 3–ton capacity.
Positions 10, 11, and 12—Not applicable on condensing units or
heat pumps, so the number ’zero’ is used to signify ’none.’
Position 13—Brand Name
Example:
A—Common unit —U.S.A. Only
Position 14—Unit Series
New units are introduced with the letter A, and subsequent major
component variations, such as in compressor, fan motor, coil
circuitor size, etc., are identified by changing to the next letter, as
B, then C, and so forth.

NOTE: When installing a liquid-line solenoid, the system may
require a minimum 60va low-voltage transformer.
Each type of solenoid has an indicator flow arrow stamped on the
valve body. When solenoid is closed (not energized) and pressure
is applied in direction of flow arrow, complete shutoff occurs. If
pressure is applied against direction of flow arrow, leakage
through valve occurs. When determining proper installation of
valve within liquid line, 2 considerations must be made:
1. Direction of flow arrow
2. Where solenoid is installed in system.
TXVs can only be substituted for liquid-line solenoids in singleflow air conditioning systems. Bi-flow TXVs allow liquid migration to coldest point during off cycles, which could allow liquid
into compressor.
Fig. 4 through 7 detail proper installation of liquid-line solenoid
and provide applications where TXVs may be substituted. Reference all notes of the appropriate figures.
TABLE 9—LIQUID-LINE SOLENOID KIT PART NUMBERS
TYPE OF VALVE
Single Flow
Bi-Flow

2–SPEED APPLICATIONS

PART NO.
KAALS0101LLS
KHALS0401LLS

CHARGING INFORMATION

Weigh in appropriate refrigerant charge, then use the standard
practices of superheat-charging method for piston applications and
subcooling-charging method for TXV applications to confirm
correct charge. The standard charging methods can be found on
outdoor unit-information plate, in unit Installation Instructions, or
in the Service Manual. Since total system charge is increased for
long-line applications, it may be necessary to calculate the
additional refrigerant charge. Since long-line applications only
involve 3/8-in. liquid lines, the additional refrigerant charge
required is 0.6 oz of Refrigerant 22 (R-22) per ft of 3/8-in. liquid
line over 15 ft.
—8—

Positions 15 and 16—Product Variations
Example:
AA—Standard unit
Other letters—For product variations from standard

52—Last week of a year
Positions 3 and 4—Year of Manufacture
Example:
94—1994
Position 5—Manufacturing Site
Example:
A–Indianapolis
E–Collierville
Positions 6 through 10—Serial Number

II. SERIAL NUMBER IDENTIFICATION
The unit serial number has 10 positions containing groups of
numbers and a letter that indicate specific information about the
unit. Listed below is the breakdown of the 10 positions.
Positions 1 and 2—Week of Manufacture
Example:
01—First week of a year

175' MAX.

GROUND LEVEL

BASEMENT

A90074

Fig. 4—Application with Air Conditioner Installed in a Horizontal Configuration

175' MAX.

GROUND LEVEL

BASEMENT

A90075

Fig. 5—Application with Heat Pump Installed in a Horizontal Configuration
—9—

TRAP

50' MAX.

HEAT PUMP ONLY

GROUND LEVEL

A90076

Fig. 6—Application with Air Conditioner or Heat Pump Installed with Indoor Unit Above Outdoor Unit
CABINET
Certain maintenance routines and repairs require removal of
cabinet panels. There are 4 basic cabinet designs for air conditioners and heat pumps. (See Fig. 8.) The horizontal discharge unit will
be discussed in a separate section of this manual. Note that
separate sections apply according to date of manufacture.

III. INFORMATION PLATE—RELIANT PRODUCTS
The information plate is secured to the front of the control box and
provides a cover for it. (See Fig. 9.) This plate also provides a
surface to attach the wiring schematic, superheat-charging tables
with instructions, and warning labels. The plate has 2 tabs on the
top edge that are bent down at slightly more than 90°. When the
information plate is removed, these tabs can be inserted into 2
mating slots in the bottom-front edge of the control box, and the
plate will hang down, forming a lower front panel. (See Fig. 10.)
This is convenient where access to the controls is required while
the unit is operating. The information plate on the small size casing
completely covers the opening below the control box. On larger
models, the information plate may not cover the entire opening. In
this instance, the top cover can be removed and placed on its side
to cover the additional space.

I. REMOVE TOP COVER—BEFORE 1/1/92
NOTE: This section applies to all Reliant products made prior to
January 1, 1992.
1. Turn off all power to outdoor and indoor units.
2. Remove screws holding top cover to coil grille and corner
posts.
3. Remove access panel.

IV. CONTROL-BOX COVER—CUBE PRODUCTS
This panel contains much of the same information as the information plate mentioned previously, but is designed only to cover the
control box.
V. REMOVE TOP COVER— AFTER 1/1/92
NOTE: The section applies to all Reliant Products made after
January 1, 1992.
1. Turn off all power to outdoor and indoor units.
2. Remove 5 screws holding top cover to coil grille and coil
tube sheet.
3. Remove 2 screws holding control-box cover.
4. Remove 2 screws holding information plate.
5. Disconnect fan motor wires, cut any wire ties, and move
wires out of control box and through tube clamp on back of
control box.

4. Remove information plate.
5. Disconnect fan motor wires, cut wire ties, and remove wire
ties from control box. Refer to unit-wiring label.
6. Lift top cover from unit.
7. Reverse sequence for reassembly.
II.

REMOVE FAN-MOTOR ASSEMBLY—BEFORE 1/1/92

NOTE: This section applies to all Reliant products made prior to
January 1, 1992.
1. Perform items 1 through 6 above.
2. Remove nuts holding fan-motor top cover.
3. Remove motor and fan blade assembly.
4. Reverse sequence for reassembly.
5. Prior to applying power, check that fan rotates freely.
—10—

HEAT PUMP ONLY

150' MAX.

A90077

Fig. 7—Application with Air Conditioner or Heat Pump Installed Above Indoor Unit

6. Lift top cover from unit.
7. Reverse sequence for reassembly.
VI.

REMOVE FAN-MOTOR ASSEMBLY—AFTER 1/1/92

NOTE: This section applies to all Reliant products made after
January 1, 1992
1. Perform items 1, 3, 4, and 5 above. (Note item 2 is not
required.)
2. Remove 4 screws holding wire basket to top cover.
3. Lift wire basket from unit.
4. Remove nuts holding fan motor to wire basket.
5. Remove motor and fan blade assembly.
6. Pull wires through wire raceway to change motor.
7. Reverse sequence for reassembly.
8. Prior to applying power, check that fan rotates freely.

—11—

A94003

Fig. 8—Basic Cabinet Designs

ELECTRICAL
WARNING: Exercise extreme caution when working on
any electrical components. Shut off all power to system
prior to troubleshooting. Some troubleshooting techniques require power to remain on. In these instances,
exercise extreme caution to avoid danger of electrical
shock. ONLY TRAINED SERVICE PERSONNEL
SHOULD PERFORM ELECTRICAL TROUBLESHOOTING.

ALUMINUM WIRE
CAUTION: Aluminum wire may be used in the branch
circuit (such as the circuit between the main and unit
disconnect), but only copper wire may be used between
the unit disconnect and the unit on Bryant systems.

Whenever aluminum wire is used in the branch-circuit wiring with
this unit, adhere to the following recommendations.
Connections must be made in accordance with the National
Electrical Code (NEC), using connectors approved for aluminum
wire. The connectors must be UL-approved (marked Al/Cu with
the UL symbol) for the application and wire size. The wire size
selected must have a current capacity not less than that of the
copper wire specified and must not create a voltage drop between
the service panel and the unit in excess of 2 percent of the
unit-rated voltage.
To prepare the wire before installing the connector, all aluminum
wire must be ″brush scratched″ and coated with a corrosion
inhibiter such as Pentrox A. When it is suspected that the

Troubleshooting charts for air conditioning and heat pump units
are provided in the back of this manual. They enable the service
technician to use a systematic approach to locate the cause of a
problem and correct system malfunctions.

—12—

II.

CONTACTORS

NOTE: The section applies to single-speed models only.
The contactor provides a means of applying power to unit using
low voltage (24v) from transformer in order to power the contactor
coil. (See Fig. 11.) Depending on unit model, you may encounter
single-, double-, or triple-pole contactors to break power. One side
of the line may be electrically energized, so exercise extreme
caution when troubleshooting.

SEFL JOSD
J SEFL
JOSDJ
SEFL JOSD
J SEFL
JOSDJ
SEFL JOSD
J SEFL
JOSDJ

SEFL JOSDJ
SEFL JOSDJ SEFL JOSDJ
SEFL JOSDJ SEFL JOSDJ PAASFLDLKREW
ATC
SEFL JOSDJ SEFL JOSDJ
UTUHD
SEFL JOSDJ SEFL JOSDJC
SEFL JOSDJ SEFL JOSDJH MD
SEFL JOSDJ R ITYALK

The contactor coil for residential air-conditioning units and heat
pumps is powered by 24vac. If contactor does not operate:
1. With power off, check whether contacts are free to move.
Check for severe burning or arcing on contact points.
2. With power off, use ohmmeter to check for continuity of
coil. Disconnect leads before checking. A low-resistance
reading is normal. Do not look for a specific value, as
different part numbers have different resistance values.
3. Reconnect leads and apply low-voltage power to contactor
coil. This may be done by leaving high-voltage power to
outdoor unit off, and turning thermostat to heat or cool.
Check voltage at coil with voltmeter. Reading should be
between 20v and 30v. Contactor should pull in if voltage is
correct and coil is good. If contactor does not pull in,
change contactor.

A88411

Fig. 9—Information Plate
connection will be exposed to moisture, it is very important to
cover the entire connection completely to prevent an electrochemical action that will cause the connection to fail very quickly. Do
not reduce the effective size of wire, such as cutting off strands so
that the wire will fit a connector. Proper size connectors should be
used. Check all factory and field electrical connections for
tightness. This should also be done after the unit has reached
operating temperatures, especially if aluminum conductors are
used.

SEFL
JOSD
J SE
FL JO
SEFL
SDJ
JOSD
J SE
FL JO
SEFL
SDJ
JOSD
J SE
FL JO
SDJ

4. With high-voltage power off and contacts pulled in, check
for continuity across contacts with ohmmeter. A very low or
zero resistance should be read. Higher readings could
indicate burned or pitted contacts which may cause future
failures.

SEFL
JOSD
J SE
FL JO
SEFL
SDJ
JOSD
J SE
FL JO
SEFL
SDJ
JOSD
J SE
FL JO
SDJ

SEFL
JOSDJ
SEFL
JOSDJ SEFL JOS
SEFL
JOSDJ SEFL JOSDJ PAASFLD
SEFL
LKREW
JOSDJ SEFL JOSDJ ATC
SEFL
JOSDJ SEFL JOSDJ UTUHD
SEFL
JOSDJ SEFL JOSDJC MD
DJH
SEFL
JOSDJ R ITYALK

SEFL
JOSDJ
SEFL
JOSDJ SEFL JOS
SEFL
JOSDJ SEFL JOSDJ PAASFL
SEFL
DLKREW
JOSDJ SEFL JOSDJ ATC
SEFL
JOSDJ SEFL JOSDJ UTUHD
SEFL
JOSDJ SEFL JOSDJC MD
DJH
SEFL
JOSDJ R ITYALK

A88412
A88413

Fig. 10—Information Plate Removed/Installed Below Control Box
—13—

A91455

Fig. 12—Capacitors

A88350

Use the following formula to calculate capacitance:
Capacitance (mfd) = (2650 X amps) divided by (volts)

Fig. 11—Contactor
III.

CAPACITORS

3. Remove any capacitor that shows signs of bulging, dents, or
leaking. Do not apply power to a defective capacitor as it
may explode.
START CAPACITORS AND PTC DEVICES
Sometimes under adverse conditions, a standard run capacitor in a
system is inadequate to start compressor. In these instances, a
start-assist device is used to provide an extra starting boost to
compressor motor. The first device is called a positive-temperature
coefficient (PTC) or thermistor. (See Fig. 13.) It is a resistor wired
in parallel with the run capacitor. As current flows through the
PTC at start-up, it heats up. As it heats up, its resistance increases
greatly until it effectively lowers the current through it to an
extremely low value. This, in effect, removes it from the circuit.

CAUTION: Capacitors can store electrical energy when
power is off. Electrical shock can result if you touch the
capacitor terminals and discharge the stored energy.
Exercise extreme caution when working near capacitors.
With power off, discharge stored energy by shorting
across the capacitor terminals with a 15,000-ohm, 2-watt
resistor.

NOTE: If bleed resistor is wired across start capacitor, it must be
disconnected to avoid erroneous readings when ohmmeter is
applied across capacitor. (See Fig. 12.)
CAUTION: Always check capacitors with power off.
Attempting to troubleshoot a capacitor with power on can
be dangerous. Defective capacitors may explode when
power is applied. Insulating fluid inside is combustible
and may ignite, causing burns.

12.5-22.5 OHMS

12.5 OHM
(BEIGE COLOR)

Capacitors are used as a phase-shifting device to aid in starting
certain single-phase motors. Check capacitors as follows.

25-45 OHMS

20-36 OHMS

1. After power is off, discharge capacitors as outlined above.
Disconnect capacitor from circuit. Put ohmmeter on R X
10k scale. Using ohmmeter, check each terminal to ground
(use capacitor case). Discard any capacitor which measures
1/2–scale deflection or less. Place ohmmeter leads across
capacitor and place on R X 10k scale. Meter should jump to
a low-resistance value and slowly climb to higher value.
Failure of meter to do this indicates an open capacitor. If
resistance stays at zero or a low value, capacitor is internally shorted.

BLUE
20 OHM
(BLUE COLOR)

25 OHM
(BLUE COLOR)
A88414

Fig. 13—PTC Devices
After system shutdown, resistor cools and resistance value returns
to normal until next time system starts. If indoor coil does not have
a bleed-type expansion device, it may be necessary to remove start
thermistor and replace with accessory start capacitor and relay.
Consult pre-sale literature for application of start kits. Thermistor
device is adequate for most conditions; however, in systems where
off-cycle is short, device cannot cool fully and becomes less
effective as a start device. It is an easy device to troubleshoot.

2. Capacitance testers are available which read value of
capacitor. If value is not within ± 10 percent value stated on
capacitor, it should be changed. If capacitor is not open or
shorted, the capacitance value is calculated by measuring
voltage across capacitor and current it draws.
WARNING: Exercise extreme caution when taking
readings while power is on. Electrical shock can cause
personal injury or death.

1. Shut off all power to system.
2. Check thermistor with ohmmeter as described below.
3. Shut off all power to unit.
—14—

4. Remove PTC from unit. Wait at least 10 minutes for PTC to
cool to ambient temperature.

CAUTION: Do not check winding at compressor terminals with pressure in the system. Check resistance by
removing wires attached at the compressor contactor and
run capacitor.

5. Measure resistance of PTC with ohmmeter as shown in
Fig.13.
The cold resistance (RT) of any PTC device should be approximately 100 – 180 percent of device ohm rating.
12.5–ohm PTC = 12.5–22.5 ohm resistance — beige color
25–ohm PTC = 25–45 ohm resistance — blue color
20–ohm PTC = 20–36 ohm resistance — blue color
If PTC resistance is appreciably less than rating or more than 200
percent higher than rating, device is defective.
If thermistor is good and compressor does not start:
1. Disconnect thermistor from starting circuit.
2. Give compressor a temporary capacitance boost (see next
section).
3. Run compressor for 10 minutes, shut off, and allow system
pressure to equalize.

3. Obtain a start capacitor in the range of
150–180µF[@0330] volts rating. Connect 8–gauge wires
with insulated clips or terminals to the H and C terminals of
the run capacitor.
4. Turn power on to unit. If compressor starts, immediately
remove start-capacitor wires from H and C terminals of run
capacitor, using a pair of insulated, needle-nose pliers. DO
NOT leave start capacitor attached to run capacitor for more
than 3 seconds, even if compressor doesn’t start.
5. Discharge start capacitor by using a pair of insulated,
needle-nose pliers and shorting a 15,000 ohm, 2 watt
resistor across terminals.

4. Reconnect start thermistor.
5. Try restarting compressor without boost capacitor. If after 2
attempts compressor does not start, remove thermistor. Add
an accessory start-capacitor relay package.
TEMPORARY CAPACITANCE BOOST

NOTE: Some start capacitors already have a bleed resistor
attached. If so, it will discharge itself over a short period of time.
6. Run compressor 10 minutes. Stop and allow unit to sit idle
for 5 minutes.
7. Check system pressure equalization.

WARNING: Do not under any circumstances attach a
temporary boost capacitor directly to the compressor
terminals. Serious personal injury can result. Exercise
extreme caution with this procedure when high-voltage
power is on.

8. Attempt to restart without capacitance boost.
If PTC thermistor device is inadequate as start device, a start
capacitor and relay may be added to system to ensure positive start.
Capacitor is wired in parallel with run capacitor through normally
closed set of contacts on a device called start relay. The relay coil
is wired across start and common terminals of compressor. The
added capacitance gets the compressor started. As compressor
comes up to speed, voltage across start and common terminals
increases to a value high enough to cause start relay to energize.
This opens normally closed contacts and removes start capacitor
from circuit. In actual practice, this occurs in a fraction of a
second.
NOTE: If bleed resistor is wired across start capacitor, it must be
disconnected to avoid erroneous readings when ohmmeter is
applied across capacitor.
To check start relay and capacitor:

There are times when a temporary capacitance boost is needed to
get compressor started. (See Fig. 14.) If compressor motor does not
start, it may be due to low-line voltage, improper pressure
equalization, weak run capacitor, or a seized compressor. Check
each possibility and attempt capacitance boost before adding
auxiliary start capacitor and relay.
220-V FROM UNIT
CONTACTOR

1. Turn off all power to unit.
2. Discharge start and run capacitors as outlined earlier.
COMP. RUN
CAPACITOR

Fig. 14—Capacitance Boosting

3. Most start capacitors will have a 15,000 ohm, 2 watt bleed
resistor. Disconnect these devices from system.
Start capacitor can be inspected visually. It is designed for short
duration or intermittent duty. If left in circuit for prolonged period,
start capacitor blows through a specially designed bleed hole. If it
appears blown, check for welded contacts in start relay. Start
capacitor can be checked by ohmmeter method discussed earlier.
Start relay is checked with ohmmeter. Check for continuity across
coil of relay. You should encounter a high resistance. Since relay
contacts are normally closed, you should read low resistance
across them. Both PTC device and capacitor-relay start system are
standard equipment on some of these units. They are also available
as accessories and may be field-installed.

1. Turn off all power to unit. There may be more than one
power source to condensing unit.
NOTE: If a PTC is already installed, remove it from the system
by pulling PTC wires from H and C terminals on run capacitor.
2. Check compressor for ground or open windings. If winding’s resistance is within manufacturer’s recommendations,
proceed. (See Reciprocating Compressor Section IIElectrical Failures for proper compressor-winding check.)

IV. CYCLE PROTECTOR
Solid-state cycle-protector device protects unit compressor by
preventing short cycling. After a system shutdown, cycle protector
provides for a 5 ± 2-minute delay before compressor restarts. On
normal start-up, a 5-minute delay occurs before thermostat closes.
After thermostat closes, cycle protector device provides a 3-sec
delay on HN67PA025, HN67ZA003, and HN67ZA008. (See Fig.
15, 16, and 17.)

START (BOOST)
CAPACITOR

A88349

—15—

T2
T1
T3

T2
T3

HN67ZA002
A91438

HN67ZA008
A94005
T3 BLK
T1 YEL

T2 VIO
T3 BLK

HN67PA025

HN67ZA003

A91440

A91439

Fig. 15—Cycle-Protector Device
Cycle-protector device is simple to troubleshoot. Only a voltmeter
capable of reading 24v is needed. Device is in control circuit;
therefore, troubleshooting is safe with control power (24v) on and
high-voltage power off.
With high-voltage power off, attach voltmeter leads across T1 and
T3 and set thermostat so that Y terminal is energized. Make sure
all protective devices in series with Y terminal are closed.
Voltmeter should read 24v across T1 and T3. With 24v still
applied, move voltmeter lead from T1 terminal to T2 terminal
across T2 and T3. After 5 ± 2 minutes, voltmeter should read 24v,
indicating control is functioning normally. If no time delay is
encountered or device never times out, change control.
V.

no circuit through the crankcase heater because both leads are
connected to the same side of the line. This allows the heater to
operate when the system is not calling for heating/cooling. The
heater does not operate when the system is calling for
heating/cooling. On units with 2 or 3 pole contactors, the crankcase heater is connected to the line side of the contactor and is not
controlled by the contactor contacts.
The crankcase heater is powered by high-voltage power of unit.
Use extreme caution troubleshooting this device with power on.
The easiest method of troubleshooting is to apply voltmeter across
crankcase heater leads to see if heater has power. Do not touch
heater. Carefully feel area around crankcase heater. If warm,
crankcase heater is probably functioning. Do not rely on this
method as absolute evidence heater is functioning. If compressor
has been running, the area will still be warm.
With power off and heater leads disconnected, check across leads
with ohmmeter. Do not look for a specific resistance reading.
Check for resistance or an open circuit. Change heater if an open
circuit is detected. Some crankcase heaters in this series of units
are equipped with a crankcase-heater switch. This energy-saving
device shuts off power to heater when temperatures are high
enough that heater is not needed. Be sure this switch is functioning
normally before condemning crankcase heater.
VI. TIME-DELAY RELAY
The time-delay relay (TDR) is a solid-state-controlled, recycledelay timer which keeps the indoor blower operating for 90 sec
after thermostat is satisfied. This delay enables the blower to
remove residual cooling in the coil after compression shutdown,

CRANKCASE HEATER

Crankcase heater is a device for keeping compressor oil warm. By
keeping oil warm, refrigerant does not migrate to and condense in
compressor shell when the compressor is off. This prevents
flooded starts which can damage compressor.
Crankcase heaters come in 2 basic types: wraparound-(bellyband)
type that is wrapped externally around compressor shell, and
insertion-type that is inserted into compressor oil well in shell of
compressor. Both types are used in outdoor units.
On units that have a single-pole contactor, the crankcase heater is
wired parallel with the contactor contacts and in series with the
compressor. (See Fig. 18.) When the contacts are open, a circuit is
completed from the line side of the contactor, through the
crankcase heater, through the run windings of the compressor, and
to the other side of the line. When the contacts are closed, there is
—16—

OPERATING
TIME

3
SEC

5 MIN

T1
_

OPERATING
TIME

5 MIN

BLK DENOTES CLOSED CONTACTS

HN67PA025, HN67ZA003, HN67ZA008

HN67ZA002
A91436

A91437

Fig. 16—Cycle-Protector Sequence
CUT YELLOW WIRE
BETWEEN CONTACTOR AND
LOW-PRESSURE SWITCH

YEL

SAFETY
CONTROL

YEL

TERMINAL
BOARD
CONNECTION

BRN

TERMINAL
BOARD
CONNECTION

VIO

LOGIC

BLK

A88415

Fig. 17—Cycle-Protector Wiring
TDR is reset, and the fan relay remains energized. The TDR is a
24v device that operates within a range of 15 to 30v and draws
about 0.5 amps.

DSV

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.

VII.

PRESSURE SWITCHES

Pressure switches are protective devices wired into control circuit
(low voltage). They shut off compressor if abnormally high or low
pressures are present in the refrigeration circuit. Depending on unit
model, you may find a low- and/or high-pressure switch in system.

LOW-PRESSURE SWITCH
Located on suction line of condensing unit only, the low-pressure
switch protects against low-suction pressures caused by such
events as loss of charge, low airflow across indoor coil, dirty
filters, etc. It opens on a pressure drop at about 27 psi. If system
pressure is above this, switch should be closed. To check switch,
turn off all power to unit, disconnect leads on switch, and apply
ohmmeter leads across switch. You should have continuity on a
good switch. 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.

A91426

Fig. 18—Wiring for Single-Pole Contactor
thereby improving the efficiency of the system. The sequence of
operation is that on closure of the wall thermostat and at the end of
a fixed on-delay of 1 sec, the fan relay is energized. When the
thermostat is satisfied, an off-delay is initiated. When the fixed
delay of 90 ± 20 sec is completed, the fan relay is de-energized and
fan motor stops. If the wall thermostat closes during this delay, the
—17—

2. Remove control-box cover for access to electrical components and defrost-control board.

CAUTION: Wear safety glasses and gloves when working with refrigerants.

3. Disconnect defrost-thermostat leads from control board and
connect to ohmmeter. Thermostat leads are the black,
insulated wires connected to DFT and R terminals on
control board. Resistance reading may be zero (indicating
closed defrost thermostat) or infinity (∞ for open thermostat) depending on outdoor temperature.

Apply heat with torch to solder joint and remove switch. Wear
safety glasses when using torch. Have quenching cloth available.
Oil vapor in line may ignite when switch is removed. Braze in
1/4-in. flare fitting and screw on replacement pressure switch.
HIGH-PRESSURE SWITCH
Located on discharge line, the high-pressure switch protects
against high-discharge pressures caused by such events as overcharge, condenser-fan motor failure, system restriction, etc. It
opens on pressure rise at about 435 psi. If system pressures go
above this setting during abnormal conditions, the switch opens.
Do not attempt to simulate these system abnormalities as high
pressures pose a serious safety hazard. High-pressure switch is also
checked with an ohmmeter similar to checking low-pressure
switch. If system pressure is below 435 psi, the switch shows
continuity. It is replaced in the same manner as low-pressure
switch. Observe all safety precautions.
LIQUID-LINE PRESSURE SWITCH
Located on liquid line of heat pump only, the liquid-line pressure
switch functions similar to conventional low-pressure switch.
Because heat pumps experience very low suction pressures during
normal system operation, a conventional low-pressure switch
cannot be installed on suction line. This switch is installed in liquid
line instead and acts as loss-of-charge protector. The liquid line is
the low side of the system in heating mode. It operates identically
to low-pressure switch except it opens at 7 psi when the heating
piston is in the liquid valve or 27 psi when the heating piston is in
the liquid line. Troubleshooting and removing this switch is
identical to procedures used on other switches. Observe same
safety precautions.

4. Jumper between DFT and R terminals on control board as
shown in Fig. 19.
5. Disconnect outdoor fan motor lead from OF2. Tape lead to
prevent grounding.
6. Turn on power to outdoor unit.
7. Restart unit in heating, allowing frost to accumulate on
outdoor coil.
8. After a few minutes in heating, liquid-line temperature at
defrost thermostat should drop below closing set point of
defrost thermostat of approximately 30°F. Using ohmmeter,
check resistance across defrost-thermostat leads. Resistance
of zero indicates defrost thermostat is closed and operating
properly.
9. Remove protective cover from TP1 and TP2 speed-up
terminals. Install jumper wire on speed-up terminals. This
reduces the timing sequence to 1/60 of original time. (See
Fig. 20.) Since Fig. 20 shows timing cycle set at 30 minutes,
unit initiates defrost within approximately 30 sec; if setting
is at 50 minutes, within 50 sec; 90 minutes, within 90 sec.
When you hear the reversing valve change position, remove
protective cover/jumper. Otherwise, control will terminate
normal 10-minute defrost cycle in approximately 10 sec.
CAUTION: Exercise extreme caution when shorting
speed-up pins. If pins are accidentally grounded, damage
to the control board will occur.

VIII. DEFROST THERMOSTATS
Defrost thermostat signals heat 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.
IX.

10. Unit is now operating in defrost mode. Using voltmeter,
check between C and W2 as shown in Fig. 21. Reading on
voltmeter should indicate 24v. This step ensures defrost
relay contacts have closed, energizing supplemental heat
(W2) and reversing valve solenoid (O).

DEFROST-CONTROL BOARD

11. Unit should remain in defrost no longer than 10 minutes.
Actual time in defrost depends on how quickly speed-up
jumper is removed. If it takes 3 sec to remove speed-up
jumper after unit has switched to defrost, only 7 minutes of
defrost cycle remains.

Solid-state defrost boards used on heat pumps replace electromechanical timer and defrost relay found on older defrost systems.
The defrost-control board can be field-set to check need for defrost
every 30, 50, or 90 minutes of operating time by connecting the
jumper (labeled W1 on the circuit board) to the terminal for the
defrost time desired. The board is set at factory for 90 minutes. The
defrost period is field-selectable, depending upon geographic areas
and defrost demands. Two types of defrost boards are used, and
functions are described in the sections to follow.
Troubleshooting defrost control involves a series of simple steps
that indicate whether or not board is defective.
NOTE: This procedure allows the service technician to check
control board and defrost thermostat for defects. First troubleshoot
to make sure unit operates properly in heating and cooling modes.
This ensures operational problems are not attributed to the defrostcontrol board.
HK32FA003, 006 DEFROST CONTROL
This control board utilizes screw terminals for the low-voltage
field wiring. The board has a feature that allows the heat pump to
restart in defrost if room thermostat is satisfied during defrost. To
troubleshoot the board, perform the following items.
1. Turn thermostat to OFF. Shut off all power to outdoor unit.

12. After a few minutes in defrost (cooling) operation, liquid
line should be warm enough to have caused defrostthermostat contacts to open. Check resistance across defrost
thermostat. Ohmmeter should read infinite resistance, indicating defrost thermostat has opened at approximately 80°F.
13. Shut off unit power and reconnect fan lead.
14. Remove jumper wire from speed-up terminal and reinsert
cover on speed-up terminals. Failure to remove jumper
causes unit to speed up operating cycles continuously.
15. Remove jumper between DFT and R terminals. Reconnect
defrost thermostat leads.
16. Replace control-box cover. Restore power to unit.
If defrost thermostat does not check out following above items or
incorrect calibration is suspected, check for a defective thermostat
as follows.
1. Follow items 1-5 above.
—18—

OF2 OF1
OF2

OF1

E
W2

L
W3

DFT

TI DFT

TEST 30 50 90

O
R
W2
Y

30 50

CES0110063,
CES0130024

HK32FA003/HK32FA006

A91442
A88402

Fig. 19—Jumper DFT and R Terminals
2. Using thermocouple temperature-measuring device, route
4. Jumper between DFT and R terminals on control board as
sensor or probe underneath coil (or other convenient locashown in Fig. 21.
tion). Attach to liquid line near defrost thermostat. Insulate
5. Disconnect outdoor fan-motor lead from OF2. Tape lead to
for more accurate reading.
prevent grounding.
6. Turn on power to outdoor unit.
3. Turn on power to outdoor unit.
7. Restart unit in heating mode, allowing frost to accumulate
4. Restart unit in heating mode.
on outdoor coil.
5. Within a few minutes, liquid-line temperature drops within
8. After a few minutes in heating mode, liquid-line temperaa range causing defrost thermostat contacts to close. Temture at defrost thermostat should drop below closing set
perature range is from 33°F to 27°F. Notice temperature at
point of defrost thermostat of approximately 30°F. Check
which ohmmeter reading goes from ∞ to zero ohms.
resistance across defrost thermostat leads using ohmmeter.
Thermostat contacts close at this point.
Resistance of zero indicates defrost thermostat is closed and
6. Remove protective cover from TP1 and TP2 speed-up
operating properly.
terminals, and install jumper wire on the speed-up termi9. Short between the speed-up terminals using a thermostat
nals.
screwdriver. This reduces the timing sequence to 1/256 of
7. Unit changes over to defrost within 90 sec (depending on
original time. (See Fig. 20 and Table 10.)
timing cycle setting). Liquid-line temperature rises to range
NOTE: Fig. 20 shows timing cycle set at 30 minutes; however,
where defrost thermostat contacts open. Temperature range
for the CES30110063 board the timing cycle will be set for 90 min
is from 75°F to 85°F. Resistance goes from zero to ∞ when
and unit initiates defrost within approximately 21 sec. When you
contacts open.
hear the reversing valve change position, remove screwdriver
immediately. Otherwise, control will terminate normal 10-minute
8. If either opening or closing temperature does not fall within
defrost cycle in approximately 2 sec.
above ranges or thermostat sticks in 1 position, replace
thermostat to ensure proper defrost operation.
CAUTION: Exercise extreme caution when shorting
CES0110063 DEFROST CONTROL
speed-up pins. If pins are accidentally shorted to other
Some heat pumps built in 1991 and later incorporate a new defrost
terminals, damage to the control board will occur.
control. The screw terminals found on the previous control board
have been replaced by a connector plug with stripped-wire leads.
This control board also contains the feature that allows the heat
10. Unit is now operating in defrost mode. Check between C
pump to restart in defrost if the room thermostat is satisfied during
and W2 using voltmeter as shown in Fig. 21. Reading on
defrost. The board also contains a 5-minute cycle protector that
voltmeter should indicate 24v. This step ensures defrostprevents the unit from short cycling after it cycles off or after a
relay contacts have closed, energizing supplemental heat
power interruption. To troubleshoot the board, perform the follow(W2) and reversing valve solenoid (O).
ing items.
11. Unit should remain in defrost no longer than 10 minutes.
1. Turn thermostat to OFF. Shut off all power to outdoor unit.
Actual time in defrost depends on how quickly speed-up
2. Remove control-box cover for access to electrical compojumper is removed. If it takes 2 sec. to remove speed-up
nents and defrost-control board.
jumper after unit has switched to defrost, the unit will
switch back to heat mode.
3. Disconnect defrost-thermostat leads from control board,
12. After a few minutes in defrost (cooling) operation, liquid
and connect to ohmmeter. Thermostat leads are the black,
line should be warm enough to have caused defrostinsulated wires connected to DFT and R terminals on
thermostat contacts to open. Check resistance across defrost
control board. Resistance reading may be zero (indicating
thermostat. Ohmmeter should read infinite resistance, indiclosed-defrost thermostat), or infinity (∞ for open thermocating defrost thermostat has opened at approximately 80°F.
stat) depending on outdoor temperature.
—19—

OF1 OF2
G

OF2
OF1

L
G

TI DFT

TEST 30 50 90

DFT
O
R

50 90

Y
C

HK32FA003/HK32FA006

CES0110063,
CES0130024

A88404

A91444

Fig. 20—Inserting Jumper Wire

OF2 OF1

OF2
OF1

E
W2

L
W3

G C

DFT

TI DFT

TEST 30 50 90

30 50

W1
O

HK32FA003/HK32FA006

R
W2

A88403

Y
C

CES0110063,
CES0130024
A91443

Fig. 21—Checking Between C and W2
13. Shut off unit power and reconnect fan lead.

TABLE 10—DEFROST CONTROL SPEED-UP TIMING SEQUENCE FOR CES0110063/CES0130024

14. Remove jumper between DFT and R terminals. Reconnect
defrost-thermostat leads. Failure to remove jumper causes
unit to switch to defrost every 30, 50, or 90 minutes and
remain in defrost for full 10 minutes.
15. Replace control-box cover. Restore power to unit.
If defrost thermostat does not check out following above items or
incorrect calibration is suspected, check for a defective thermostat
as follows.
1. Follow items 1-5 above.

PARAMETER

MINIMUM

MAXIMUM

30-minute cycle
50-minute cycle
90-minute cycle
10-minute cycle
5 minutes

27
45
81
9
4.5

33
55
99
11
5.5

SPEED-UP
(NOMINAL)
7 sec
12 sec
21 sec
2 sec
1 sec

4. Restart unit in heating.
5. Within a few minutes, liquid-line temperature drops within
a range causing defrost-thermostat contacts to close. Temperature range is from 33°F to 27°F. Notice temperature at
which ohmmeter reading goes from ∞ to zero ohms.
Thermostat contacts close at this point.

2. Route sensor or probe underneath coil (or other convenient
location) using thermocouple temperature-measuring device. Attach to liquid line near defrost thermostat. Insulate
for more accurate reading.
3. Turn on power to outdoor unit.
—20—

6. Short between the speed-up terminals using a small, slotted
screwdriver.

3. Restart unit in heating mode, allowing frost to accumulate
on outdoor coil.

7. Unit changes over to defrost within 21 sec (depending on
timing-cycle setting). Liquid-line temperature rises to range
where defrost-thermostat contacts open. Temperature range
is from 75°F to 85°F. Resistance goes from zero to ∞ when
contacts open.

4. After a few minutes in heating mode, liquid-line temperature should drop below closing point of defrost thermostat
(approximately 30° F.
NOTE: Unit will remain in defrost until defrost thermostat
reopens at approximately 80° F coil temperature at liquid line or
remainder of defrost cycle time.

8. If either opening or closing temperature does not fall within
above ranges or thermostat sticks in 1 position, replace
thermostat to ensure proper defrost operation.

5. Turn off power to outdoor unit and reconnect fan-motor
lead to OF2 on control board after above forced-defrost
cycle.
Compressor Shut Down
This control has the option of shutting down the compressor for 30
seconds while going into and out of defrost modes. This is
accomplished by turning DIP switch 3 to the ON position. See Fig.
22 for switch position. Factory default is in the OFF position.
Five-Minute Time Delay
This control has a 5–minute time delay on startup. The speedup
terminals can be used to bypass this delay. Momentary shorting
across the speedup terminals will, upon release, bypass 5–minute
time delay. Do not short out the speedup terminals for more than
5 seconds, or defrost mode will be initiated.
Troubleshooting
Troubleshooting this control is done in the same manner as the
CES0130063 control with the exceptions listed above.
DEFROST THERMOSTAT LOCATION
On most residential, outdoor heat-pump models, the defrost
thermostat is located on the return-bend side of the coil. The 5/16
OD feeder tube from the header will enter a 1–1/2 in. to 2–in. long
3/8 OD stub prior to entering the coil. There is only one stub tube
per coil. All other feeder tubes enter the coil directly. The defrost
thermostat attaches to this stub tube. (See Fig. 23.)

CES0130024 DEFROST CONTROL
Some heat pumps built in 1993 and later incorporated a new
defrost control similar to the CES0110063 except the 5-minute
cycle protector has been removed. This control is used on heat
pump units with reciprocating compressors where short-cycle
protection is not required.
Troubleshooting this control will be the same as the CES0110063
control except for the cycle-protector function. The CES0130024
control is identical to the CES0110063 except the T2 terminal and
cycle-protector logic have been removed.
CES0130076 DEFROST CONTROL
This defrost control is the same size as the CES0130063 control
but is not backwards-compatible. (See Fig. 22.) To upgrade to the
new control, you must have replacement-defrost thermostat and
harness kit. See your replacement-component representative for kit
part number.
Defrost Settings
The defrost control is a time/temperature control which includes a
field-selectable time period (DIP switch 1 and 2 on board, see
Table 11) between defrost cycles of 30, 60, 90, and 120 minutes
(factory-set at 90 minutes).

X. FAN MOTORS
Fan motor rotates the fan blade that either draws or blows air
through outdoor coil to perform heat exchange. Motors are totally
enclosed to increase reliability. This also eliminates need for rain
shield. For the correct position of the fan blade assembly, see Fig.
24 and Table 12.

TABLE 11—DEFROST TIMER SETTINGS
SW1
On
Off
Off
On

SW2
Off
On
Off
On

SW3
30
60
90
120

WARNING: Turn off all power to unit before servicing
or replacing fan motor. Be sure unit main power switch is
turned off. Failure to do so may result in electric shock,
death, or injury from rotating fan blade.

To initiate a forced defrost, two options are available, depending
on the status of the defrost thermostat.
If defrost thermostat is closed, speedup pins (J1) must be shorted
by placing a Flathead screwdriver in between for 5 seconds and
releasing, to observe a complete defrost cycle. When the Quiet
Shift switch is selected, compressor will be turned off for two,
30–second intervals during this complete defrost cycle. When
Quiet Shift switch is in factory-default OFF position, a normal and
complete defrost cycle will be observed.
If defrost thermostat is in open position and speedup pins are
shorted (with a Flathead screwdriver) for 5 seconds and released,
a short defrost cycle will be observed (actual length is dependent
upon the selected Quiet Shift position). When Quiet Shift switch is
in ON position, the length of defrost is 1 minute (30 seconds
compressor-off period followed by 30 seconds of defrost with
compressor operation). On return to heat operation, compressor
will again turn off for an additional 30 seconds and the fan for 40
seconds. When the Quiet Shift is in OFF position, only a brief
30–second cycle will be observed.
If it is desirable to observe a complete defrost in warmer weather,
the thermostat must be closed as follows.

The bearings are permanently lubricated; therefore, no oil ports are
provided.
For suspected electrical failures, check for loose or faulty electrical
connections, or defective fan-motor capacitor. Fan motor is
equipped with thermal overload device in motor windings which
may open under adverse operating conditions. Allow time for
motor to cool so device can reset. Further checking of motor can
be done with an ohmmeter. Set scale on R X 1 position; check for
continuity between 3 leads. Replace motors that show an open
circuit in any of the windings. Place 1 lead of ohmmeter on each
motor lead. At same time, place other ohmmeter lead on motor
case (ground). Replace any motor that shows resistance to ground,
signs of arcing, burning, or overheating.
XI.

SERVICE ALARM CONTROL BOARD

NOTE: If the proper night-setback thermostat is not used, the
service-alarm control will work, but there will be no light
indication on thermostat.
The service-alarm control provides immediate warning when
outdoor heat pump requires servicing. It turns on indoor
thermostat-malfunction light if compressor does not operate for

1. Turn off power to outdoor unit.
2. Disconnect outdoor fan-motor lead from OF2 on control
board. (See Fig. 22.) Tape to prevent grounding.
—21—

OF1

DFT

OF2

T2 C C O
T1
Y

O R W2 Y C

P1
30

120

DFT

QUIET
SHIFT

90
INTERVAL TIMER OFF

SPEEDUP

Speedup
Pins

CESO130076–00
Quiet
Shift

Defrost interval
DIP switches
A99442

Fig. 22—Defrost Control
either heating or cooling. This enables owner to obtain timely
heat-pump service during heating season, reducing supplementary
electric heat costs, and during cooling season, reducing period of
heat discomfort.
The service alarm is an accessory device. Service alarm locks out
compressor under certain adverse operating conditions. System is
manually reset by shutting it off at thermostat subbase, then
turning it back on. If adverse condition is corrected, system
restarts.
One example of an adverse condition would be a system located in
a desert climate where high operating temperatures may cause
system to shut down on the high-pressure switch or on the
compressor internal overload.
Connect service alarm to outdoor-unit control-circuit-terminal
board. (See Fig. 25 and wiring diagram on unit.)
Connect all field line-power wires to unit in usual manner. Route
1 field line-power supply wire through metallic loop on bottom of
service alarm then to normal unit connection. Units with RLA of
less than 14 amps will require 2 passes through the metallic loop.
Refer to Fig. 25 or 26 for wiring connections for service alarm or
service alarm with solid-state cycle-protector accessories, when
used.
NOTE: The wire from the X terminal on the service alarm to L on
the outdoor terminal board, indoor terminal board, and thermostat
subbase is field-supplied and wired when using defrost controls
HK32FA003 or HK32FA006. When defrost control CES0110063
or CES0130024 is used, field-supplied wire from X terminal on
service alarm to L on indoor thermostat subbase is required.

Service alarm requires 2 inputs.
1. It must sense a 24v input from thermostat. As thermostat
calls for heating or cooling, it supplies 24v to service-alarm
device.
2. A current transformer (or induction loop) similar to a
clamp-on ammeter senses current draw in the compressor
lead. Induction loop must sense a minimum current draw
when thermostat is calling for heating or cooling.
NOTE: On a single-phase compressor, induction loop senses
current in common leg. On a 3-phase compressor, induction loop
senses current in any 1 of the phases.
WARNING: If service alarm needs replacing, shut off
all power to unit before attempting removal. Electrical
shock can cause personal injury or death.

Troubleshooting service-alarm device is easy. With thermostat
calling for heating or cooling and compressor running, indoor
thermostat light should be off. If on, check for wiring errors or
replace the service alarm.
To check for correct operation, shut off circuit breaker or disconnect switch to outdoor unit while it is running. Signal light on
thermostat should light. If this does not occur, check for wiring
errors or replace the service alarm.
XII. OUTDOOR THERMOSTAT(S)
The outdoor thermostat(s) is installed in the control box. The
sensing bulb(s) remain in the control box. Outdoor thermostat
brings on stages of electric heat as outdoor temperature and
—22—

TABLE 12—FAN POSITION
AEROQUIET SYSTEM AND AEROMAX TOP
Fan Motor Part No.

Fan Blade Part No.

HC29GE208
HC31GE230/231
HC33GE208
HC33GE232
HC34GE231
HC34GE460
HC35GE208
HC35GE232
HC37GE208
HC37GE230
HC38GE221
HC39GE232

HC39GE234

HC39GE461
HC40GE230
HC40GE461

Dimension A (In.)

LA01EB023
LA01EC019
LA01EA026
LA01RA015
LA01EW049
LA01RA015

Brookside
4–5/32
5–1/8
4–5/8
4–7/8
5–1/4
4–29/32

Revcor
—
—
—
4–5/8
—
4–17/32

LA01RA015

5–5/32

4–25/32

LA01EW048
LA01EA025
LA01RA024
LA01RA026
LA01EA025
LA01EW046
LA01EA031
LA01EC018
LA01RA026
LA01EA036
LA01EA024
LA01EC018
LA01EA036
LA01EC018
LA01RA026
LA01EA024
LA01EA024

4–15/16
5–7/8
5–11/32
5–9/16
6–1/8
6–5/32
7–25/32
5–11/16
5–1/2
5–9/16
5–3/32
5–1/2
6–1/16
6–1/4
6–1/16
5–9/32
5–27/32

—
—
5–3/32
4–11/16
6–1/8
6–1/8
—
—
4–3/4
—
4–27/32
—
—
—
5–7/32
5–11/32
5–19/32

FEEDER TUBE
STUB TUBE

DEFROST
THERMOSTAT

A97517

Fig. 23—Defrost Thermostat Location

BASKET TOP
A91428

Fig. 24—Fan Position
—23—

HIGH AND/OR LOW PRESSURE
AND/OR DISCHARGE TEMPERATURE
SWITCH (IF USED)
DTS

24-VOLT WIRING

HPS
C

LPS

BRN

BLU

BLU YEL
YEL

C
THERMOSTAT
SUBBASE

INDOOR
UNIT
TERMINAL
BOARD

BLK

ORN

YEL

RED

OUTDOOR
UNIT
TERMINAL
BOARD
1

SERVICE ALARM
PASS SUPPLY WIRE THROUGH
METALLIC LOOP TWICE ON
UNITS WITH NAMEPLATE
RLA OF 14 AMPS OR LESS.
*METALLIC
LOOP

ONE FIELD
LINE VOLTAGE
SUPPLY WIRE

A88340

Fig. 25—Service Alarm Wiring Connections
FIELD LINE VOLTAGE SUPPLY WIRE

YEL

CYCLE PROTECTOR
T1 T2 T3

SERVICE ALARM
X
3
2
1

HIGH AND/OR LOW PRESSURE
AND/OR DISCHARGE TEMPERATURE
SWITCH (IF USED)

VIO BLK
ORN
Y

DTS
L

YEL

BLK

BRN

YEL
LPS

BLU

HPS
BRN
A88339

THERMOSTAT INDOOR OUTDOOR
UNIT
SUBBASE
UNIT
TERMINAL TERMINAL
BOARD
BOARD
C

COMMON POTENTIAL
FACTORY WIRING (FIELD CONNECTED)
FIELD-SUPPLIED WIRING
CONTACTOR
A88339

Fig. 26—Wiring Connections for Service Alarm and Cycle Protector
XIII. COMPRESSOR PLUG
The compressor electrical plug provides a quick-tight connection
to the compressor terminals. The plug completely covers the
compressor terminals, and the mating female terminals are completely encapsulated in the plug. Therefore, the terminals are
isolated from any moisture so corrosion and resultant pitted or
discolored terminals are reduced. The plug is oriented to the relief
slot in the terminal box so the cover cannot be secured if wires are
not positioned in slot, assuring correct electrical connection at the
compressor. The plug can be removed by simultaneously pulling
while ″rocking″ the plug. However, these plugs are specialized and
vary in terminal orientation in the plug. Therefore, plugs can be
used on only the specific compressor or group as shown in Fig. 27.
For the Carlyle and Bristol compressors in Fig. 27, the triangle
formed by the fusite terminals points down, and the plug is
likewise oriented. The fusite terminals and plug-terminal orienta-

heat-pump output drops. Setting at which thermostat closes is
variable, depending on design of system. It is set at time of
installation and should not be changed without cause. Up to 2
outdoor thermostats may be installed. Some systems may not have
any thermostat. An outdoor thermostat can also be used to lock out
compressor operation at low ambients in condensing unit not
equipped with low-ambient control.
Although these devices are installed in control circuit (24v), turn
off all power to unit before attempting to troubleshoot thermostat.
Use a standard ohmmeter to check for continuity through thermostat. If you suspect thermostat is out of calibration, use calibrated
electronic thermometer to determine correct outdoor temperature.
Turn thermostat dial knob until switch closes. Observe this using
ohmmeter across switch. Read temperature setting when switch
closes. It should be close to reading observed using electronic
thermometer. Any setting within ± 5°F is acceptable.
—24—

tion shown for the Tecumseh compressor is shown with the
triangle formed by the terminals pointing toward the top. The
configuration around the fusite terminals is the outline of the
terminal covers used on the specific compressors. The slot through
which the wires of the plug are routed is oriented on the bottom or
slightly to the left or right. The correct plug can be connected
easily to the compressor terminals and plug wires routed easily
through the slot in the terminal cover. Therefore, if a Carlyle or
Bristol compressor is substituted for a Tecumseh compressor, a
new plug must be installed. If the plug is not changed, proper
connection and routing of the plug wires through the terminal
cover will be impossible.

G—Energizes blower circuit from indoor thermostat.
E—Energizes emergency-heat relay.
W2—Energizes first-stage supplemental heat through defrost relay
(wht).
L—Energizes light on thermostat with service alarm.
W3—Energizes second- or third-stage supplemental heat.
R—Energizes 24v power from transformer (red).
Y—Energizes contactor for first-stage cooling or first-stage heating for heat pumps (yel).
O—Energizes reversing valve on heat pumps (orn).
C—Common side of transformer (blk).
RECIPROCATING COMPRESSOR

BRISTOL
COPELAND

LEAD 3
BLUE

CARLYLE

C S
R

The compressor is the heart of the refrigeration system. It pumps
refrigerant through the system. If it malfunctions, system capacity
and efficiency could be negatively affected.

CAUTION: The compressor is an electrical (as well as
mechanical) device. Exercise extreme caution when
working near compressors. Power should be shut off, if
possible, for most troubleshooting techniques. Refrigerants in system present other safety hazards. Always wear
safety glasses and gloves when handling refrigerants.

LEAD 2
YEL.

LEAD 1
BLK.

TECUMSEH
C
C

Compressor failures are classified in 2 broad failure categories:
mechanical and electrical. Both types are discussed below.

LEAD 1
BLK.

I. MECHANICAL FAILURES
A compressor is a mechanical pump driven by an electric motor
contained in a welded or hermetic shell. In a mechanical failure,
motor or electrical circuit appears normal, but compressor does not
function normally.

LEAD 2
YEL.

LEAD 3
BLUE

TECUMSEH

LEAD 1
BLK.

CAUTION: Exercise extreme caution when reading
compressor currents when high-voltage power is on.
Correct any of the problems described below before
installing and running a replacement compressor. Wear
safety glasses and gloves when handling refrigerants.

LEAD 3
BLUE

C
C

LOCKED ROTOR

In this type of failure, compressor motor and all starting components are normal. When compressor attempts to start, it draws
locked-rotor current and cycles off on the internal protection.
Locked-rotor current is measured by applying a clamp-on ammeter
around common (blk) lead of the compressor on a single-phase
compressor, or any 1 of the leads on a 3-phase compressor. Current
drawn when it attempts to start is then measured. LRA (lockedrotor amp) value is stamped on compressor nameplate.

LEAD 2
YEL.

MILLENNIUM

If compressor draws locked-rotor amps and all other external
sources of problems have been eliminated, compressor must be
replaced. Because compressor is a sealed unit, it is impossible to
determine exact mechanical failure. However, complete system
should be checked for abnormalities such as incorrect refrigerant
charge, restrictions, insufficient airflow across indoor or outdoor
coil, and so forth, which could be contributing to the failure.

LEAD 1
BLK.

C
R S

LEAD 3
BLUE

RUNS, DOES NOT PUMP

LEAD 2
YEL.

In this type of failure, compressor motor runs and turns compressor, but compressor does not pump the refrigerant. A clamp-on
ammeter on common leg of a single-phase compressor, or any 1
lead of a 3-phase compressor, shows a very low current draw,
much lower than RLA (rated load amps) value stamped on
compressor nameplate. Because no refrigerant is being pumped,
there is no return gas to cool compressor motor. It eventually
overheats and shuts off on its internal protection.

A94002

Fig. 27—Compressor Plug
XIV. LOW-VOLTAGE TERMINALS
The low-voltage terminal designations, along with descriptions
and/or functions, are used on all split-system condensers and heat
pumps:

RUNS, DOES NOT PUMP, HIGH-TO-LOW SIDE LEAK
—25—

(EXAMPLE)
TO DETERMINE INTERNAL CONNECTIONS OF SINGLEPHASE MOTORS (C,S,R) EXCEPT SHADED-POLE

?
?

DEDUCTION:

POWER OFF!
?

(GREATEST RESISTANCE)
5.8Ω (OHM)

RUN WINDING (R)
START WINDING (S)

OHMMETER
0-10Ω SCALE

(SMALLEST RESISTANCE)
0.6Ω

2 IS COMMON (C)
BY ELIMINATION

(REMAINING RESISTANCE)
5.2Ω

2 IS COMMON,
THEREFORE, 1 IS

1
5.2Ω

1
2
0.6Ω

5.8Ω

START WINDING (S)

2
3

3
3 IS RUN WINDING (R)

A88344

Fig. 28—Identifying Internal Connections
2. Remove and recover all refrigerant from system so that
gage pressures are 0 psi.
3. Clean area around leak to bare metal.
4. Apply flux and repair joint with silver solder. Do not use
low-temperature solder such as 50-50.
5. Clean off excess flux, check for leaks, and apply paint over
repaired area to prevent corrosion.
Do not use this method to repair a compressor leak due to severe
corrosion. Never attempt to repair a compressor leaking at electric
terminals. This type of failure requires compressor replacement.
II. ELECTRICAL FAILURES
The compressor mechanical pump is driven by an electric motor
within its hermetic shell. In electrical failures, compressor does not
run although external electrical and mechanical systems appear
normal. Compressor must be checked electrically for abnormalities.
Before troubleshooting compressor motor, review this description
of compressor motor-terminal identification.
SINGLE-PHASE MOTORS
To identify terminals C, S, and R:
1. Turn off all unit power.
2. Short the run and start capacitors to prevent shock.
3. Remove all wires from motor terminals.
4. Read resistance between all pairs of terminals using an
ohmmeter on 0-10 ohm scale.
5. Determine 2 terminals that provide greatest resistance
reading.
Through elimination, remaining terminal must be common (C).
Greatest resistance between common (C) and another terminal
indicates start winding because it has more turns. This terminal is
start (S). Remaining terminal will be run winding (R). (See Fig.
28.)
NOTE: If compressor is hot, allow time to cool and internal line
break to reset. There is an internal line-break protector which must
be closed.
THREE-PHASE MOTORS
Resistance readings between all 3 sets of windings should be the
same.
All compressors are equipped with internal motor protection. If
motor becomes hot for any reason, protector opens. Compressor
should always be allowed to cool and protector to close before
troubleshooting. Always turn off all power to unit and disconnect
leads at compressor terminals before taking readings.

In this type of failure, compressor motor runs and turns compressor, and compressor is pumping. Usually, an internal problem such
as blown head gasket or broken internal-discharge line causes
compressor to pump hot discharge gas back into its own shell
rather than through system.
Using pressure gages on service valves shows high suction and
low discharge pressure readings. Motor currents are lower than
normal. Because hot gas is being discharged into shell, the shell
becomes hot. The hot gas causes compressor motor to cycle off on
its internal protection.
RUNS AND PUMPS, LOW CAPACITY
This failure type is difficult to pinpoint because extent of damage
varies. Compressor is a pump with internal valves that enable
compressor to pump properly. The cylinder has a set of suction and
discharge valves. Any of these parts may become damaged or
broken, causing loss in pumping capacity. Severity of damage
determines amount of capacity loss. Use pressure gages to find any
abnormal system pressures if system charge and other conditions
are normal.
An owner may complain that a unit is not handling the building’s
heating or cooling load. The compressor current draw may be
abnormally low or high. Although this type of failure does occur,
all other possible causes of capacity loss must be eliminated before
condemning compressor.
NOISY COMPRESSOR
Noise may be caused by a variety of internal problems such as
loosened hardware, broken mounting springs, etc. System problems such as overcharged compressor (especially at start-up) or too
much oil in compressor may also cause excessive noise. Excess oil
in compressor is normally encountered only after a replacement
compressor has been added without purging oil from previous
compressor. As new compressor pumps, excess oil in system
returns and adds to volume already present, causing noise.
COMPRESSOR LEAKS
CAUTION: Use safety glasses and gloves when handling refrigerants.

Sometimes a leak is detected at weld seam around girth of
compressor or a fitting that joins compressor shell. Many of these
leaks can be repaired and the compressor saved if correct procedure is followed.
1. Turn off all power to unit.
—26—

Most common motor failures are due to either an open, grounded,
or short circuit. Directions below are specifically for single-phase
units, however, they also apply to 3-phase compressors. When a
single-phase compressor fails to start or run, 3 tests can help
determine the problem. First, all possible external causes should be
eliminated, such as overloads, improper voltage, pressure equalization, defective capacitor(s), relays, wiring, and so forth. Compressor has internal line-break overload, so be certain it is closed.
OPEN CIRCUIT
To determine if any winding has a break in the internal wires and
current is unable to pass through:

4. Motor must be dry or free from direct contact with liquid
refrigerant.
MAKE THIS CRITICAL TEST
(Not advisable unless above conditions are met.)
1. Be sure all power is off.
2. Discharge all capacitors.
3. Remove wires from terminals C, S, and R.
4. Place instrument probes together and determine probe and
lead wire resistance.
5. Check resistance readings from C-R, C-S, and R-S.

1. Be sure all power is off.

6. Subtract instrument probe and lead resistance from each
reading.
If any reading is within ± 20 percent of known resistance, motor is
probably normal. Usually a considerable difference in reading is
noted if a turn-to-turn short is present.

2. Discharge all capacitors.
3. Remove wires from terminals C, S and R.
4. Check resistance from C-R, C-S and R-S using an ohmmeter on 0-1000 ohm scale.
Because winding resistances are usually less than 10 ohms, each
reading appears to be approximately 0 ohm. If resistance remains
at 1000 ohms, an open or break exists, and compressor should be
replaced.

III.

SYSTEM CLEANUP AFTER BURNOUT
CAUTION: Turn off all power to unit before proceeding. Wear safety glasses and gloves when handling
refrigerants. Acids formed as a result of motor burnout
can cause burns.

CAUTION: Be sure internal line-break overload is not
temporarily open.

NOTE: To analyze level of suspected contamination from compressor burnout, use Total Test. See your distributor/branch.
Some compressor electrical failures can cause motor to overheat.
When this occurs, by-products, which include sludge, carbon, and
acids, can contaminate system. If burnout is severe enough, system
must be cleaned before replacement compressor is installed. The 2
types of motor burnout are classified as mild or severe.
In mild burnout, there is little or no detectable odor. Compressor
oil is clear or slightly discolored. An acid test of compressor oil
will be negative. This type of failure is treated the same as
mechanical failure. Liquid-line strainer should be removed and
liquid-line filter drier installed.
In a severe burnout, there is a strong, pungent, rotten-egg odor.
Compressor oil is very dark. Evidence of burning may be present
in tubing connected to compressor. An acid test of compressor oil
will be positive. Complete system must be reverse flushed with
refrigerant. Check-Flo-Rater™ or TXV must be cleaned or replaced. In a heat pump, accumulator and reversing valve are
replaced. These components are also removed and bypassed during
reverse-flushing procedure. Remove and discard liquid-line
strainer. After system is reassembled, install liquid-line and
suction-line filter driers. Run system for 2 hrs. Discard both driers
and install new liquid-line drier only.

GROUND CIRCUIT
To determine if a wire has broken or come in direct contact with
shell, causing a direct short to ground:
1. Be sure all power is off.
2. Discharge all capacitors.
3. Remove wires from terminals C, S, and R.
4. On hermetic compressors, allow crankcase heaters to remain on for several hours before checking motor to ensure
windings are not saturated with refrigerant.
5. Use an ohmmeter on R X 10,000 ohm scale. A megohmmeter may be used in place of ohmmeter. Follow manufacturer’s instructions.
6. Place 1 meter probe on ground or on compressor shell.
Make a good metal-to-metal contact. Place other probe on
terminals C, S, and R in sequence.
7. Note meter scale.
8. If reading of zero or low resistance is obtained, motor is
grounded. Replace compressor.
A 1 ton or less capacity compressor is probably grounded if
resistance is below 1 million ohms. On larger-sized, single-phase
compressors, resistance to ground should not be less than 1000
ohms per volt of operating voltage.
Example:
230 volts X 1000 ohms/volt = 230,000 ohms minimum.
SHORT CIRCUIT
To determine if any wires within windings have broken through
their insulation and made contact with other wires, thereby
shorting all or part of the winding(s), be sure the following
conditions are met:

IV. COMPRESSOR REMOVAL AND REPLACEMENT
Once it is determined that compressor has failed and the reason
established, compressor must be replaced.
CAUTION: Wear safety glasses and gloves when handling refrigerants and when using brazing torch.

1. Shut off all power to unit.

1. Correct motor-winding resistances must be known before
testing, either from previous readings or from manufacturer’s specifications.
2. Temperature of windings must be as specified, usually
about 70°F.
3. Resistance-measuring instrument must have an accuracy
within ± 5 to 10 percent. This requires an accurate ohmmeter, such as a Wheatstone bridge or null balance-type
instrument.

2. Remove and recover all refrigerant from system until
pressure gages read zero psi. Use all service ports.
3. Disconnect electrical leads from compressor. Disconnect or
remove crankcase heater and remove compressor-holddown
bolts.
4. Cut compressor from system with tubing cutters. Do not use
brazing torch for compressor removal. Oil vapor may ignite
when compressor is disconnected.
—27—

5. Scratch matching marks on stubs in old compressor. Make
corresponding marks on replacement compressor.
6. Use torch to remove stubs from old compressor and to
reinstall them in replacement compressor.

Scroll Gas Flow

7. Use copper couplings to tie compressor back into system.

Compression in the scroll is
created by the interaction of
an orbiting spiral and a
stationary spiral. Gas enters
an outer opening as one of the
spirals orbits.

8. Evacuate system, recharge, and check for normal system
operation.

9. Copeland CR-6 and scroll compressors have copper-plated,
steel-suction ports. Excess heat during brazing will burn off
copper plating. See Brazing section for additional information.
COPELAND SCROLL COMPRESSOR
I. FEATURES
The scroll compressor pumps refrigerant through the system by the
interaction of a stationary and an orbiting scroll. (See Fig. 29.) The
scroll compressor has no dynamic suction or discharge valves, and
it is more tolerant of stresses caused by debris, liquid slugging, and
flooded starts. Due to the design of the scroll compressor, the
internal compression components unload (equalize pressure) on
shutdown. The white oil (Sontex 200LT) used in the scroll is
compatible with 3GS oil, which can be used if additional oil is
required. (See Table 13 for oil recharge requirements.)

2
The open passage is sealed off
as gas is drawn into the spiral.

TABLE 13—COMPRESSOR OIL RECHARGE
RECHARGE
COMPRESSOR MODEL
(FL. OZ.)
Carlyle/Scroll
″J″ Type
44
SC, SRD450AC
34
SR
52
SRH482, SRY482
68
SRH602, SRY602
70
Copeland
CRG3, CRH3, CRJ3, CRK3, CRL3
51
CRN5, CRP5, CRT5, CTH1, CTL1
66
CRC4, CRZ4
36
CR16K6 THROUGH CR42K6
42
*ZR18K1
19
*ZR23K1, ZR28K1
24
*ZR34K1
30
*ZR40K1
34
*ZR49K1-PFV
56
*ZR49K2-TF5, ZR49K2-TFD
56
*ZR61K2-PFV
56
*ZR61K2-TF5, ZR61K2-TFD
66
Tecumseh
AV55
50
AW55
30
AG
60
Bristol
H23A
52
H23B
37
H24A3, H24A4
47
H24A5
52
H25A, H26A
62
H25B, H26B, H29B
32

4
By the time the gas arrives at
the center port, discharge
pressure has been reached.

OIL TYPE

As the spiral continues to orbit,
the gas is compressed into an
increasingly smaller pocket.

5
Actually, during operation, all
six gas passages are in various
stages of compression at all
times, resulting in nearly continuous suction and discharge.

Suniso 3GS
Zerol 150
w/3 percent
Syn-O-Ad

A90198

Fig. 29—Scroll Compressor Refrigerant Flow
vacuum. If a pumpdown procedure is used, the scroll compressor
is capable of pumping into a vacuum very quickly, which could
cause fusite arcing and compressor failure. See Step IV of
Reciprocating Compressor section for removal and replacement.
III. DISCHARGE THERMOSTAT
Some scroll compressors have a discharge thermostat that reciprocating compressors do not have. This thermostat is mounted in a
well in the top of the compressor shell to sense if the discharge
temperature reaches 290°F and shuts down the compressor to
prevent damage to it. When the temperature of the thermostat
reaches 140°F, power is restored to the compressor.
To determine if the thermostat is operating properly, either attach
the thermocouple of an electronic thermometer to the dome of the
compressor near the thermostat, or remove the thermostat and
place the thermocouple inside the well. The electronic thermometer must be capable of reading at least 300°F. Start the unit and let
it run for at least 15 minutes to obtain normal operating conditions.
Watch the thermometer to see if it is approaching 270°F. If the
thermocouple is located on the dome near the discharge thermostat, there could be a 20° difference between well and dome
temperatures. If the temperature approaches 270°F, repair system
problem, such as low charge, blocked condenser coil, and so forth.
If the temperature does not approach 270°F, replace discharge
thermostat.
Replacing Discharge Thermostat
To replace the discharge thermostat, refer to the Installation
Instructions packaged with the replacement discharge thermostat
kit. (See Fig. 30.)
IV. DISCHARGE SOLENOID VALVE
Some larger units equipped with scroll compressors contain a
solenoid valve that is piped between the discharge tube and suction
tube of the compressor. The purpose of the solenoid valve is to

Suniso 3GS

*Copeland scrolls are charged initially with Sontex 200LT white oil. Since this
oil is not commercially available, use 3GS.

II.

TROUBLESHOOTING

Troubleshooting mechanical or electrical problems in a scroll
compressor is the same as for a reciprocating compressor, except
that a scroll compressor should never be allowed to pump into a
—28—

The scroll compressor is capable of pumping into a vacuum very
quickly, which could cause fusite arcing and compressor failure.
See Step IV of Reciprocating Compressor section for removal and
replacement.

PLASTIC CAP

IV.
BLUE SEALANT

SCROLL COMPRESSOR, 3–PHASE MONITOR

CES0130075 — PHASE MONITOR

PRONG

This control is factory-installed on all 3–phase, scroll compressor
models. (See Fig. 31 and 32.) On start-up, the control will energize
the pilot relay for 2 seconds. The monitor will check for correct
compressor rotation. If rotation is correct, unit will continue to run.
If rotation is incorrect, the control will break the 24vac power at
the contactor and an LED light on the control will flash. If LED is
flashing, turn off power, reverse L1 and L3 field-power leads, and
restart unit. This control will check incoming power at every
restart.

GROMMET

TWO-SPEED SYSTEM
I.

THERMAL GREASE

CAUTIONS AND WARNINGS
CAUTION: For proper unit operation and reliability, the
2-speed units must be installed with the factory-supplied
balance port, hard shutoff TXV. Do not install with
indoor coils having piston or capillary-tube metering
devices.

THERMOSTAT

A90198

CAUTION: Do not install equivalent interconnecting
tubing lengths greater than 100 ft. Do not decrease or
increase interconnecting tubing diameters.

Fig. 30—Location of Discharge Thermostat
cause a rapid pressure equalization around the compressor, thus
reducing the normal shutdown sound created by reverse rotation of
the scroll. The solenoid valve is normally closed and is wired
across high-voltage line 1 to load terminals of the contactor. (See
Fig. 18.) The solenoid-valve assembly also requires a check valve
piped in the discharge tube between the solenoid-valve tee and the
condenser coil, or reversing valve on heat pumps. The purpose of
the check valve is to prevent refrigerant from bypassing through
the solenoid valve into the suction tube when the unit cycles off.

CAUTION: To avoid electrical shock, bleed resistor
must be connected across run capacitor. Replace if
missing or damaged.

CAUTION: Contactor is mechanically interlocked. Do
not disable mechanical interlock. Compressor damage
may occur.

MILLENNIUM SCROLL COMPRESSOR
I. FEATURES
The scroll compressor pumps refrigerant through the system by the
interaction of a stationary and an orbiting scroll. (See Fig. 29.) The
scroll compressor has no dynamic suction or discharge valves, and
it is more tolerant of stresses caused by debris, liquid slugging, and
flooded starts. The Millennium scroll varies from the Copeland
scroll in that the Millennium has a shutdown flapper valve located
between the scroll plates and the discharge head, whereas the
Copeland has a check device at the discharge connection after the
discharge head. The Copeland discharge head unloads when the
compressor shuts down. The scroll plate actually runs backwards
while it unloads. A 1 to 3 second unloading of refrigerant occurs.
The Millennium flapper valve eliminates the refrigerant unloading
by not allowing the discharge head to run backwards because of its
location. The Millennium scroll compressor uses Zerol 150 oil
with 3 percent Syn-O-Ad and is the only oil recommended for oil
recharge. See Table 13 for recharge requirements.

WARNING: Contactor control voltage is 240vac.

WARNING: Do not attempt to operate this equipment
below 55°F outdoor ambient temperature.

NOTE: Sections that follow describe the 598A Series B and
698A Series B products, which started production March, 1994.
For 598A Series A and 698A Series A products, refer to the
Split-System Service Manual dated 3–1–94, Catalog No. BDP
3356–115.
II. SYSTEM FUNCTIONS
COOLING OPERATION
The 2-speed products utilize a 2-stage-cooling indoor thermostat.
With a call for first-stage cooling (Y1), the outdoor fan and
low-speed compressor are energized. If low speed cannot satisfy
the cooling demand, high speed will be energized (Y1 and Y2) by
the second stage of the indoor thermostat. The thermostat has a 2°
differential between first and second stages. After second stage is
satisfied, the unit returns to low-speed operation, until first stage is
satisfied, or until second stage is again required.

II. COMPRESSOR PROTECTION
Millennium scroll compressors are protected by an internal linebreak mounted on the motor windings. Internal protectors respond
to overcurrent and high temperature. These protectors are
automatic-reset devices containing a snap-action, bi-metal switch.
III. TROUBLESHOOTING
Troubleshooting mechanical and electrical problems in a scroll
compressor is similar to a reciprocating compressor, except that a
scroll compressor should never be allowed to pump into a vacuum.
—29—

A00010

Fig. 31—CES0130075 3–Phase Monitor Board
L2

L1
COMP
CONT
EQUIP
GND

L3
11

*CH

CONT

CAP
23

OFM

LOGIC
CESO130075
CONT

CONT
*HPS

*LPS

T2
LOGIC
T1
*LLS

T3
CTD

Y
IFR
G
R

R
INDOOR
THERMOSTAT

EXTERNAL POWER SUPPLY 24 V
A00011

Fig. 32—CESO130075 3–Phase Monitor Wiring Diagram
—30—

HEATING OPERATION (HEAT PUMP ONLY)
The 2-speed products utilize a 2-stage-heating indoor thermostat.
The first stage of heating is heat-pump operation (Y1). Auxiliary
backup heat is controlled by second stage (W2). There is a 2°
differential between first and second stage. The control board
determines the compressor speed based on ambient temperature.
See Table 14 for ambient temperatures at which speed changes
occur. When high-speed, heat-pump heating is required, the
control provides a Y2 (24vac) signal back to the thermostat to
energize high-speed-indicator LED.

LM1 LM2

DFT1 DFT2 T1

OFF

15
10

ZONE

CRANKCASE-HEATER OPERATION
The 2-speed control energizes the crankcase heater during the
unit’s off cycle when the outdoor ambient is below 75°F.
OUTDOOR FAN-MOTOR OPERATION
The 2-speed control energizes the outdoor fan any time the
compressor is operating. The outdoor fan remains energized during
the 1-minute, speed-change time delay and if a pressure switch or
compressor PTC overload should trip.
If the outdoor fan motor won’t run, check the header-pin housing.
(See Fig. 37.) There should be NO jumper wire between Terminals
15 and 16.
Heat Pumps
After the termination of a defrost cycle, the outdoor fan delays
come on for 20 sec. This allows the refrigeration system to recover
the outdoor coil heat and minimize the ″steam cloud″ effect.
SECOND-STAGE LATCHING
When low-speed cooling operation no longer satisfies the first
stage of the indoor thermostat, the indoor temperature will increase
by 2° until second stage is energized. After high-speed cooling
satisfies second stage, it returns to low-speed cooling operation. If
desired, the installer may select to have high-speed cooling by
energizing Y1. High speed will stay energized until Y1 is satisfied.
This eliminates the temperature drop between the first and second
stages of indoor thermostat, holding room temperature closer to set
point.
To utilize this function, the unit capacity should be plotted versus
the heat gain of the structure, which provides the system’s balance
point when the structure requires high-speed capacity. (See Fig.
35.)
Second-stage latching can be selected by rotating the potentiometer (POT) to the desired outdoor second-stage latching temperature (See Fig. 34.) The temperatures that can be selected are 85°,
90°, 95°, 100°, and 105°F. The POT is factory set at 105°F.
ZONE SELECTION
If the stage–2 latch POT is set to ZONE position, the compressor
operating speed in either heat or cool mode is determined by the
Y1 and/or Y2 inputs. The system operates in low speed with a Y1
input and high speed with Y2 or Y1-and-Y2 input. This allows the
multistage-zoning system to determine what speed is needed
regardless of outdoor temperature or switchover point.
DEFROST TIME SELECTION
The defrost interval can be field selected, depending on local or
geographic requirements. It is factory set at 90 minutes and can be
changed to either 30 or 50 minutes by rotating the defrost-time
POT. (See Fig. 34.)

PW2 PW1

K7
FURN INT
OFF

Fig. 34—Speedup Terminals

C
1

DFT1 DFT2 T1

LM1 LM2
O

A93568

LOW VOLTAGE

ODF

CCH

105 OFF

100

STAGE 2 DEFROST BALANCE
LATCH
TIME
POINT

LED FUNCTION LIGHTS
When using the factory-authorized indoor thermostats with the
2-speed outdoor units, there are 2 locations where system-function
LED-indicator lights are available. The indoor thermostat provides
indicator lights for high- and low-speed operation, system malfunction, and auxiliary heat for heat pumps. The 2-speed control
board has an LED which provides signals for several system
operations. See Table 15 for LED functions, indicator locations,
and definitions. Table 15 also provides the order of signal
importance if more than 1 signal should occur. The signal to the
indoor thermostat is supplied by the low-voltage ″L″ lead.
THREE-SECOND TIME DELAY
Any time the control receives a 24v input, such as Y1 or Y2, there
is a 3-sec time delay before the control function is initiated. This
helps prevent nuisance trips and thermostat ″jiggling.″
ONE-MINUTE SPEED-CHANGE TIME DELAY
When the compressor changes speeds from high to low or low to
high, there is a 1-minute time delay before the compressor restarts.
The outdoor fan motor remains running.
FIVE-MINUTE TIME DELAY
The 2-speed-control logic contains a 5-minute time delay that
prevents the unit from short cycling after a thermostat-off cycle or
power interruption. The unit can be forced to operate immediately
by momentarily touching a jumper between the speed-up terminals
of the control board. (See Fig. 33 and 34.) The speed-up feature
will not bypass any other function or time delay.

FURN INT

AMBIENT TEMPERATURE (°F)
High Speed
Low Speed
30 or less
31 or greater
33 or less
34 or greater
40 or less
41 or greater

HIGH VOLTAGE

PW2 PW1

SPEED-UP

036
048
060

TABLE 14—AMBIENT TEMPERATURE FOR HIGH- AND
LOW-SPEED OPERATION
UNIT
SIZE

SPEED-UP

STAGE 2 DEFROST BALANCE
LATCH
TIME
POINT

LED 1

A93569

Fig. 33—Two-Speed Control Board
TWO-MINUTE LOW-SPEED MINIMUM
If the unit has not operated within the past 30 minutes, the unit
operates for a minimum of 2 minutes in low speed upon the next
thermostat high or low demand.
—31—

TABLE 15—FUNCTION LIGHT CODE AND DISPLAY LOCATION
CODE
Constant flash
No pause
1 flash
w/pause
2 flashes
w/pause
3 flashes
w/pause
4 flashes
w/pause

T’STAT

UNIT

—

DEFINITION
No demand
Stand by

POSSIBLE CAUSE

—

Low-speed operation

—

High-speed operation

—

Ambient thermistor failure

—

Coil thermistor failure

—

3 flashes
pause
4 flashes

Thermistor out of range**

5 flashes
w/pause

X‡

Pressure switch trip
(LM1/LM2)

6 flashes
w/pause†

Compressor PTCs out of limit

Constant light
No pause
No flash

Board failure

Thermistor drift, wrong location
Incorrect wiring
Incorrect refrigerant charge
Dirty indoor/outdoor coil
Dirty outdoor coil
Refrigerant overcharge
Wrong indoor coil
Low refrigerant charge
Compressor mechanical problem
Dirty indoor/outdoor coil
Equipment or electrical service
not grounded

*Function light signals order of importance; in case of multiple-signal request, 1 is most important.
†Signal at thermostat will occur after 3 consecutive attempted restarts and lockout has occurred.
‡Will be energized if pressure switch remains open for 1 hr.
**Check both thermistors to determine which is faulty.

FIELD-INITIATED FORCED DEFROST
By placing a jumper across the speedup terminals for a minimum
of 5 sec and then removing it, the unit initiates a defrost cycle. (See
Fig. 34.) The cycle occurs only if the outdoor ambient is less than
50°F, regardless of outdoor coil temperature. The cycle terminates
when the coil thermistor reaches 80°F ( ± 5) or the defrost period
reaches a maximum of 10 minutes.
FURNACE INTERFACE
This feature provides a heat-pump lockout upon a demand for
auxiliary heat (W2) and must be used when interfacing a heat
pump with a gas/oil furnace. Field selection of the furnaceinterface option is done by connecting the factory-supplied jumper
to the ON position of the 3 terminal connectors. (See Fig. 33.)
When the option is selected, the heat pump will be locked out of
operation any time there is a thermostat demand for W2 or the
outdoor ambient is below the balance-point POT-setting selection.
(See Fig. 34.) When the unit requires defrost, auxiliary heat (W2)
energizes the furnace. After defrost is terminated, the heat pump
shuts down and the furnace satisfies the thermostat. To utilize this
function, the economic and/or thermal balance point must be
determined. See the appropriate heat pump balance-point worksheet available from your distributor or branch.
BALANCE POINT
This feature can be used in 2 different options: furnace interface or
electric-heat staging. Refer to the Furnace Interface section for its
application. If the heat pump is installed with a fan coil with
multistages of electric heat, this option can be used to stage the
banks of heat by outdoor ambient. This eliminates the need for
accessory outdoor thermostats.
When using this option to stage electric heat, first stage is
energized by a W2 demand, and second stage is energized by a W3
demand. Select the W3 desired temperature by rotating the
balance-point POT. (See Fig. 34.) Temperatures that may be
selected are 10°, 15°, 20°, 25°, 30°, 35°, 40°, and 45°F. The POT
is factory set at 45°F.
LOW-SPEED HEATING WITH AUXILIARY HEAT
If the system is operating in low-speed heating and there is a
demand for auxiliary heat (W2), the system changes to high-speed
operation. W2 is energized unless the low-voltage control wiring is
configured as described in Fig. 36.

HIGH

SPEE

50
BTU (1000'S)

HIGH SPEED
BALANCE POINT

D CA

PACIT

40
LOW S

PEED

CAPA

STRUCTURE
BALANCE POINT

CITY

20
LOW SPEED
BALANCE POINT
10

100

110

120

TEMPERATURE (°F)
A91282

Fig. 35—Typical Cooling Balance Points
DEFROST
The 2-speed control logic for the defrost function is the standard
time and temperature initiated, time or temperature terminated.
Defrost occurs only at outdoor temperatures less than 50°F. The
control initiates defrost when the outdoor coil thermistor is 30°F (±
2) or less, and the selected defrost time (interval) has been
accumulated during unit operation. Termination occurs when the
coil thermistor reaches 80°F (± 5) or the defrost period reaches a
maximum of 10 minutes.
Defrost always occurs in high speed unless the stage–2 latch POT
is set at ZONE. During defrost the unit operates in high speed,
energizes the reversing valve (O) and auxiliary heat (W2), and
de-energizes the outdoor fan. Upon termination, there is a 20-sec
delay in the outdoor fan being energized. If the stage–2 latch POT
is set to ZONE and the heat pump is in low speed, it defrosts in low
speed.
—32—

TWO SPEED
THERMOSTAT

FAN
COIL

TWO SPEED
HEAT PUMP

PRESSURE SWITCH PROTECTION
The outdoor unit is equipped with high- and low-pressure
switches, wired in series. If a pressure switch opens, the control
provides a 5-minute time delay in outdoor unit operation with the
outdoor fan running. A malfunction signal appears on the control
when a pressure switch opens. If the switch remains open for 1 hr
or longer, a malfunction signal is provided at the L terminal of the
indoor thermostat.

CONTROL
LOGIC

W3
W3

A93572

III. FACTORY DEFAULTS
Factory defaults have been provided in the event of failure of the
ambient thermistor, outdoor-coil thermistor, and/or furnace interface jumper. Refer to Table 17 for default and function.

Fig. 36—Low-Voltage Control Wiring
AUXILIARY HEAT (W2) LOCKOUT
In some areas, it is necessary to disable the auxiliary heat, except
for defrost, until the outdoor ambient is less than the structure’s
balance point. This is accomplished by using the low-voltage
wiring as shown in Fig. 36. Wire the 24vac W2 signal from the
indoor thermostat to W3 of the control, and W2 of the control to
W2 of the indoor unit. When the outdoor ambient is less than the
setting of the balance-point POT, the 24vac signal energizes the
auxiliary heat (W2) of the indoor unit.
EMERGENCY HEAT
If the 2-speed control receives a call for auxiliary heat (W2)
without a heat-pump heating (Y1) call, the second auxiliary stage
(W3) is energized. This ensures all available heat is energized if
the indoor thermostat is switched to emergency heat.
COMPRESSOR PTC-OVERLOAD PROTECTION
The control senses the resistance of the compressor internal
positive-temperature coefficient (PTC) overloads. If the resistance
of the PTCs is out of range, the control shuts off the unit until the
resistance range is acceptable. See Table 16 for compressor PTC
ranges.

IV. MAJOR COMPONENTS
TWO-SPEED CONTROL
The 2-speed control board controls the following functions:
• High- and low-compressor contactor operation
• Outdoor fan-motor operation
• Crankcase-heater operation
• Compressor protection
• Pressure-switch monitoring
• Second-stage latching
• Time delays
• 5-minute time-delay speedup (bypass)
Heat pumps:
• Time/temperature defrost
• Defrost-interval selection
• Furnace interface
• Electric-heat staging
HEADER-PIN HOUSING
The header-pin housing is the plastic assembly which holds the
stripped-lead ends for field connections. The 2-speed control
receives the 24vac low-voltage control-system inputs through the
housing/pins. The housing also contains jumpers which the control
uses for system configuration, such as heat pump versus air
conditioner. See Fig. 37 for header-pin housing configurations.
TWO-SPEED COMPRESSOR
The 2-speed compressor contains motor windings that provide
low-speed, 4–pole (1750 rpm) and high-speed, 2–pole (3500 rpm)
operation. Refer to Fig. 38 to determine which windings are
energized at each speed. Refer to Compressor Winding-Check
section under Troubleshooting and Table 18 for appropriate
winding resistances.
The 2-speed compressor is also protected by an internal-pressure
relief (IPR), which relieves discharge gas into the compressor shell
(low side) when the differential between suction and discharge

TABLE 16—COMPRESSOR PTC RANGES
COMPRESSOR INTERNAL-PTC RESISTANCE
Safe Range (77°F)
1.5k to 7.8k ohms
To trip
26k to 34k ohms
To reset
8.4k to 10k ohms

When the control turns off the outdoor unit due to out-of-range
PTCs, the unit remains off for 15 minutes with the outdoor fan
running. After 15 minutes, the control checks the resistance every
5 minutes until it reaches the reset range. During this time, a
malfunction signal appears on the control board. If this happens,
remove the wires on control board at S1 and S2 and measure the
resistance across the leads. When the resistance reaches 8,400 to
10,000 ohms, system operation may be resumed. If the resistance
remains outside this range, a quick check of the leads at the
compressor should be made. Loose connections can cause inaccurate readings. If a PTC trip occurs 3 times, the control will lock out
the outdoor-unit operation and provide malfunction signals at both
the control and indoor thermostat.

TABLE 17—FACTORY DEFAULTS
FAILED COMPONENT

FUNCTION
Crankcase Heater
Second-Stage Latching
Furnace Interface

Ambient Thermistor

Heating Switchover Speed Point
Defrost Initiation
Outdoor Thermostat for
Auxiliary Heat

Outdoor Coil Thermistor

Defrost Initiation and Termination

Furnace Interface Jumper

Furnace Interface

—33—

DEFAULT
Energized during any off cycle
Does not function
Balance point does not function, but
interface still energizes furnace and
locks out heat pump with a call for W2
Unit only runs in highcompressor speed
Defrost is initiated based on coil
temperature only
Anytime there is a call for W2,
W3 is also energized.
Defrost occurs at each time interval,
but terminates after 5 minutes
Does not function

C - TRANSFORMER COMMON

R - TRANSFORMER LINE

pressures exceeds 500 psi. The compressor is also protected by 3
PTC devices attached to the motor windings. The PTC’s resistance
is sensed by the 2-speed control board. See Table 16 for resistance
ranges.
MECHANICALLY INTERLOCKED CONTACTORS
The 2-speed products are equipped with mechanically interlocked
contactors. Each contactor has interconnecting linkage, providing
independent interlocks.
The 2-speed control provides the electrical interlock. The contactors are supplied with 240v coils, which reduce the va requirements of the low-voltage (24vac) control system.
TEMPERATURE THERMISTORS
Thermistors are electronic devices which sense temperature. As
the temperature increases, the resistance decreases. Two thermistors are used to sense temperature: one senses outdoor ambient,
and the other senses coil temperature (heat pump only). Refer to
Fig. 39 for resistance values versus temperature.
If the outdoor ambient thermistor should fail, a malfunction signal
appears on the indoor thermostat and 2-speed control. The control
does not initiate second-stage latching, crankcase heater is turned
on during all off-cycles, heating defaults to high speed, and defrost
initiates on demand from coil thermistor. (See Table 17.)

3
4
5

W2 - FIRST STAGE AUXILIARY HEAT

O - REVERSING VALVE

Y2 - SECOND STAGE COOLING/HEAT PUMP

Y1 - FIRST STAGE COOLING/HEAT PUMP

W3 - SECOND STAGE AUXILIARY HEAT

L - MALFUNCTION LIGHT

4 - TON

IF NO JUMPER IS
INSTALLED, DEFAULT
IS 3 - TON

5 - TON

14
15
16
17

JUMPER FOR
HEAT PUMP ONLY

A93576

THERMISTOR CURVE

Fig. 37—Header-Pin Housing
T3 T8

RESISTANCE (KOHMS)

EXTERNAL MAIN

70
60
50
40
30
20
10
0
0

MAIN WINDING

40
60
80
TEMPERATURE (DEG. F)

100

120

A91431

Fig. 39—Resistance Values Versus Temperature

4 POLE START

If the outdoor coil thermistor should fail, a malfunction signal
appears on the indoor thermostat and 2-speed control. The control
defrosts every 90 minutes of heating operation and terminates in 5
minutes. (See Table 17.)
V. LED FUNCTION/MALFUNCTION LIGHTS

2 POLE START
HIGH SPEED
(L1) T1 + T7
(L2) T2 + T3

LOW SPEED
(L1) T1
(L2) T7 + T8

The 2-speed control is equipped with an LED function/ malfunction light.
NOTE: Only malfunction signal appears at thermostat. Both
function and malfunction signals appear at control board. (See Fig.
33 for LED location.) Table 15 provides the function/malfunction
code, location, and definition.
VI. TROUBLESHOOTING

A92015

Fig. 38—Energizing Windings

NOTE: Troubleshooting charts for air conditioning and heat
pump units are provided in the back of this manual — see Fig. 52,
53, and 54.
COMPRESSOR WINDING CHECK
The 2-speed compressor is nothing more than 2 single-phase
motors within 1 compressor shell. When the compressor fails to
start or run, there are 3 tests that can be made: open, ground, or
short. This compressor has no internal line-break overload; however, it does have PTC motor protectors. See Compressor PTCOverload Protection section for PTC overload information.

TABLE 18—TWO-SPEED COMPRESSOR
(WINDING RESISTANCE AT 70°F ± 2°)
WINDING
T1-T2
T1-T3
T1-T7
T1-T8

3 TON
0.80
3.20
1.30
3.10

4 TON
0.70
2.20
1.00
2.20

5 TON
0.60
1.80
1.00
2.00

—34—

NOTE: To ensure accurate ohm measurements, place ohmmeter
probes on flat surface of compressor-terminal tabs, not the brass
mounting screw.
Open
To determine if a winding has an actual break in the internal wires
and current is unable to pass through:

2. Discharge all capacitors.

24v power. If the fault clears, check to ensure the indoor and
outdoor unit and electrical service are properly grounded. If the
entire system is grounded, the control board should be replaced, as
the control is not field reparable. If the control-board light is
flashing, see LED and Table 15 for function/malfunction definition. Cycling 24 vac to control board resets previous error
messages and any lockouts which have occurred. See Table 19 for
more information regarding control-board operation.
CONTROL-BOARD POWER INPUTS AND OUTPUTS

3. Remove wires from terminals T1, T2, T3, T7, and T8.

See Fig. 33 and 37 for inputs and outputs.

1. Be sure all power is off.

BLEED RESISTOR
The bleed resistor is a 150k, 2–watt resistor across the compressorrun capacitor to protect service technician from injury by electrical
shock. Capacitor will bleed-off approximately 1 minute after
power to outdoor unit is turned off. If run capacitor is changed out,
be sure to place bleed resistor on new capacitor. If bleed resistor is
damaged, replace resistor.
START CAPACITOR AND RELAY

4. Use an ohmmeter on 0-1000 ohm scale to check resistance.
(See Fig. 38, 40, and 41 and Table 18.)
Because winding resistances are usually less than 10 ohm, each
reading will appear to be approximately zero ohm. If during any
check the resistance remains at 1000 ohm, an open or break exists,
and the motor or compressor should be replaced.
Ground
To determine if any wire has broken and come in direct contact
with the housing or shell, causing a direct short to ground:

The 2-speed system has a second start relay in the control box. One
start relay is for low-speed start, and the second is for high-speed
start. Both start relays use a common-start capacitor. When
servicing this equipment, be certain system starts in both low- and
high-speed operation.

1. Be sure all power is off.
2. Discharge all capacitors.
3. Remove wires from T1, T2, T3, T7, and T8.

REFRIGERATION SYSTEM

4. Allow crankcase heater to remain on for several hrs before
checking motor to ensure that windings are not saturated
with refrigerant.

1. Be sure all power is off.

I. REFRIGERATION CYCLE
In a refrigeration system, refrigerant moves heat from one place to
another. It is useful to understand flow of refrigerant in a system.
In a straight cooling system, compressed hot gas leaves compressor and enters condensing coil. As gas passes through condenser
coil, it rejects heat and condenses into liquid. The liquid leaves
condensing unit through liquid line and enters metering device at
indoor coil. As it passes through metering device, it becomes a
gas-liquid mixture. As it passes through indoor coil, it absorbs heat
and refrigerant and is again compressed to a hot gas. The cycle
then repeats.
In a heat pump, the basic cycle is the same. (See Fig. 42.)
Reversing valve in system decides which coil, indoor or outdoor,
becomes evaporator or condenser. It rejects heat into the home
after heat is absorbed by outdoor evaporator coil, thus the home is
heated.
In cooling cycle, the indoor coil becomes the evaporator. It absorbs
heat from the home and rejects it through the outdoor condenser
coil, thus the home is cooled.
A unique feature of the heat pump is that metering devices are
designed to meter refrigerant in one direction of flow and allow
refrigerant to pass unhindered in the other direction. If indoormetering device is metering refrigerant, the outdoor device bypasses refrigerant and vice versa. This allows both coils to serve a
dual function.

2. Discharge all capacitors.

II.

5. Using an ohmmeter on R X 10,000 ohm scale, place 1 meter
probe on ″ground″ motor or compressor frame. Make a
good metal-to-metal contact. Place other probe on terminals
T1, T2, T3, T7, and T8 in sequence. Note meter scale.
If any reading of zero or low resistance is obtained, the motor is
grounding. Replace the compressor.
Short
NOTE: This is an extremely critical test and is not advised unless
the following conditions are met.
The correct motor-winding resistances must be known before
testing. See Table 18 for cold-motor winding resistance.
The temperature of the windings must be specified, 70°F ± 2°F.
The resistance-measuring instrument must have an accurate ohmmeter (such as a Wheatstone bridge or null balance-type instrument).
The motor must be dry or free from direct contact with liquid
refrigerant.
To determine if any wires have broken through their insulation and
come in direct contact with each other, thereby ″shorting″ all or
part of the winding(s):

3. Remove wires from terminals T1, T2, T3, T7, and T8.

LEAK DETECTION
CAUTION: Always wear safety glasses and gloves
when handling refrigerants.

4. Subtract instrument probe and lead resistance from each
reading. If any reading is within ± 20 percent of the known
resistance from Table 18, the motor probably does not have
a short. Usually a considerable difference will be noted if a
turn-to-turn short is present.
CONTROL BOARD FAILURE
The control board continuously monitors its own operation and the
operation of the system. The diagnostic feature allows easy
troubleshooting of the control and system in the field. If a failure
occurs, the LED light on the control will flash a failure code. If the
failure is internal to the control board, the light will stay on
continuously (no flash). Before replacing control board, reset the

New installations should be checked for leaks prior to complete
charging.
If a system has lost all or most of its charge, system must be
pressurized again, up to approximately 150 lb minimum. This can
be done by adding refrigerant using normal charging procedures,
or it may be pressurized with nitrogen (less expensive than
refrigerant). Nitrogen also leaks faster than R-22 and is not
absorbed by refrigeration oil. Nitrogen cannot, however, be
detected by a leak detector. (See Fig. 43.)
—35—

SCHEMATIC DIAGRAM
(LADDER FORM)

L1
C1

L2
C2

T7
27

COMP
MAIN

T2
EXT
MAIN

LOW
START

HIGH
START

EQUIP
GND

HS
SR

1
16

CAP
F

26
C1

22
C1

5
LS
SR

1
13

23
A91446

Fig. 40—Low-Speed Windings

SCHEMATIC DIAGRAM
(LADDER FORM)

L2
C2

T7
27

COMP
MAIN

EXT
MAIN

LOW
START

T1
HIGH
START

EQUIP
GND

H
BR

2
HS
SR

1
CAP

26
C1

5
LS
SR

1
13

23
A91445

Fig. 41—High-Speed Windings
—36—

In all instances, when a leak is found, system charge must be bled
down and leak repaired before final charging and operation. After
leak testing or leak is repaired, evacuate system, and recharge with
correct refrigerant charge.

COOLING CYCLE
REVERSING VALVE
(ENERGIZED)
OUTDOOR FAN

INDOOR
FAN

INDOOR COIL
ACCUMULATOR

SUCTION SERVICE
PORT AT SERVICE
VALVE (CLG CYCLE)

COMP
STRAINER

OUTDOOR
COIL

STRAINER
SUCTION
SERVICE
PORT
(BYPASSING)

(METERING)

HEAT PUMP
ACCESSORY
FILTER DRIER
(DUAL FLOW)

LIQUID LINE
PRESSURE SWITCH

LIQUID LINE SERVICE PORT
AT SERVICE VALVE (CLG CYCLE)

A88400

Fig. 42—Heat Pump Refrigerant-Flow Diagrams
CAUTION: Due to the high pressure of nitrogen, it
should never be used without a pressure regulator on the
tank.

Leaks in a system pressurized with refrigerant can be spotted with
a leak detector that detects extremely small refrigerant leaks. This
discussion assumes that system is pressurized with either all
refrigerant or a mixture of nitrogen and refrigerant.
If system has been operating for some time, make first check for
a leak visually. Since refrigerant carries a small quantity of oil,
traces of oil at any joint or connection are an indication that
refrigerant is leaking at that point.
A simple and inexpensive method of testing for leaks is to use soap
bubbles. Any solution of water and soap may be used. Soap
solution is applied to all joints and connections in system. A small
pinhole leak is located by tracing bubbles in soap solution around
leak.
Use electronic leak detector to check for leaks. This unquestionably is the most efficient and easiest method for checking leaks.
There are various types of electronic leak detectors. Generally
speaking, they are all portable, and most are lightweight, consisting of a box with several switches and a probe or sniffer. Detector
is turned on and probe is passed around all fittings and connections
in system. Leak is detected by either a movement of a pointer on
detector dial, by a buzzing sound, or a light.

A88401

Fig. 43—Leak Detector
III. BRAZING
When brazing is required in the refrigeration system, certain basics
should be followed:
1. Clean joints make the best joints. To clean:
a. Remove all oxidation from surfaces to a shiny finish
before brazing.

TABLE 19—24V PIN CONNECTION TROUBLESHOOTING
MODE OF OPERATION
18-PIN CONNECTOR
All
Low-speed Cooling
High-speed Cooling
Low-speed Heating

TERMINAL
DESIGNATION
R-C
Y1,0-C
Y1, Y2, 0-C
Y1-C
Y1-C

LOCATION ON
CONTROL BOARD
2-1
8,6-1
8,7,6-1
8-1
8-1

VOLTAGE
PATH
Input
Input
Input
Input
Input

VOLTAGE
REQUIRED
24
24
24
24
24

Y2-C

7-1

Output

Y1-C

8-1

Input

Y2, W2, 0-C

7,5,6-1

Output

Second Stage of
Auxiliary Heat

Y1, W2-C
W3, Y2-C

7,5-1
9,8-1

Input
Output

24
24

Cooling Secondstage Latching

Y1, Y2, 0-C

8,7,6-1

Input

High-speed Heating

Defrost

—37—

POSSIBLE SOURCE
OF PROBLEM
Check transformer (secondary)
Check thermostat
Check thermostat
Check thermostat
Check thermostat
Outdoor temperature below
speed; change temperature
Check thermostat
Outdoor temperature below 50°F;
Coil temperature less than 30°F
Check thermostat
Check balance-point setting
Ambient thermistor failure;
Check second-stage POT

SERVICE PORT
W/SCHRADER
CORE

STEM

FIELD
SIDE
STEM

SERVICE PORT
W/SCHRADER CORE
FIELD
SIDE
SEAT
SEAT

BAR STOCK FRONT SEATING VALVE
FORGED FRONT SEATING VALVE
A91447
A91448

Fig. 44—Service Valves
b. Remove all flux residue with brush and water while
material is still hot.

pressurized. To pressurize the service port, this valve must be
moved off the back-seating position. This valve does not contain a
Schrader fitting. Both types of service valves are designed for
sweat connection to the field tubing.
The service valves in the outdoor unit come from the factory
front-seated. This means that the refrigerant charge is isolated from
the line-set connection ports. Some heat pumps are shipped with
sweat-adapter tube. This tube must be installed on the liquidservice valve. After connecting the sweat adapter to the liquidservice valve of a heat pump, the valves are ready for brazing. The
interconnecting tubing (line set) can be brazed to the service valves
using either silver-bearing or non-silver-bearing brazing material.
Consult local codes.
Before brazing the line set to the valves, the belled ends of the
sweat connections on the service valves must be cleaned so that no
brass plating remains on either the inside or outside of the bell
joint. To prevent damage to the valve and/or cap ″O″ ring, use a
wet cloth or other acceptable heat-sinking material on the valve
before brazing. To prevent damage to the unit, use a metal barrier
between brazing area and unit.
After the brazing operation and the refrigerant tubing and evaporator coil have been evacuated, the valve stem can be turned
counterclockwise until it opens or back-seats, which releases
refrigerant into tubing and evaporator coil. The system can now be
operated.
Back-seating service valves must be back-seated (turned counterclockwise until seated) before the service-port caps can be removed and hoses of gage manifold connected. In this position,
refrigerant has access from and through outdoor and indoor unit.
The service valve-stem cap is tightened to 20 ± 2 ft/lb torque and
the service-port caps to 9 ± 2 ft/lb torque. The seating surface of
the valve stem has a knife-set edge against which the caps are
tightened to attain a metal-to-metal seal. If accessory pressure
switches are used, the service valve must be cracked. Then, the
knife-set stem cap becomes the primary seal.
The service valve cannot be field-repaired; therefore, only a
complete valve or valve stem and service-port caps are available
for replacement.

2. Use ″sil-fos″ or ″phos-copper″ for copper-to-copper only.
No flux is required.
3. Silver solder is used on copper-to-brass, copper-to-steel, or
copper-to-copper. Flux is required when using silver solder.
4. Fluxes should be used carefully. Avoid excessive application and do not allow fluxes to enter into the system.
5. Proper brazing temperature of copper is when it is heated to
a dull red color.
This section on brazing is not intended to teach a technician how
to braze. There are books and classes that teach and refine brazing
techniques. The basic points above are listed only as a reminder.
IV.

SERVICE VALVES
WARNING: Never attempt to make repairs to existing
service valves. Unit operates under high pressure. Damaged seats and o-rings should not be replaced. Replacement of entire service valve is required. Tampering with
damaged valves can cause personal injury or death.
Service valve must be replaced by properly trained
service technician.

Service valves provide a means for holding original factory charge
in outdoor unit prior to hookup to indoor coil. They also contain
gage ports for measuring system pressures and provide shutoff
convenience for certain types of repairs. (See Fig. 44.)
Two types of service valves are used in outdoor residential
equipment. The first type is a front-seating valve, which has a
service port that contains a Schrader fitting. The service port is
always pressurized after the valve is moved off the front-seat
position.
The second type is a combination front-seating/back-seating valve,
which has a metal-to-metal seat in both the open and closed
positions. When it is fully back-seated, the service port is not
—38—

PISTON BODY

PISTON
(ORIENT AS SHOWN)
BRASS
HEX NUT

FEEDER
TUBES

STRAINER

PISTON
PISTON RETAINER

PISTON
RETAINER

TEFLON
SEAL

FLARE ADAPTER

BRASS
HEX
BODY

INTERNAL STRAINER

A91138

PRODUCTION
EXCEPT 1992

Fig. 45—Check-Flo-Rater™ Components
If the service valve is to be replaced, a metal barrier must be
inserted between the valve and the unit to prevent damaging the
unit exterior from the heat of the brazing operations.

A94004

5. Slide piston out by inserting a small, soft wire with small
kinks through metering hole. Do not damage metering hole,
sealing surface around piston cones, or fluted portion of
piston.
6. Clean piston refrigerant-metering hole.
7. Install a new retainer O-ring or retainer assembly before
reassembling bypass-type Check-Flo-Rater™.
RELIANT AND CUBE PRODUCTS PRODUCED IN 1992
1. Shut off power to unit.
2. Reclaim outdoor-unit refrigerant.
3. Loosen brass hex nut and remove line from brass hex body.
4. Slide piston out by inserting a small, soft wire with small
kinks through metering hole. Do not damage metering hole,
sealing surface around piston cones, or fluted portion of
piston.
5. Clean piston refrigerant-metering hole.
6. Always replace Teflon seal with new seal. Never try to
reuse old seals.
7. Reassemble brass nut and brass hex body. Be sure orientation is as shown in Fig. 45.
VI. REVERSING VALVE
In heat pumps, changeover between heating and cooling modes is
accomplished with a valve that reverses flow of refrigerant in
system. (See Fig. 46.) This reversing-valve device is easy to
troubleshoot and replace. The reversing-valve solenoid can be
checked with power off with an ohmmeter. Check for continuity
and shorting to ground. With control-circuit (24v) power on, check
for correct voltage at solenoid coil. Check for overheated solenoid.
With unit operating, other items can be checked, such as frost or
condensate water on refrigerant lines.
The sound made by a reversing valve as it begins or ends defrost
is a ″whooshing″ sound, as the valve reverses and pressures in
system equalize. An experienced service technician detects this
sound and uses it as a valuable troubleshooting tool.
Using a remote measuring device, check inlet and outlet line
temperatures. DO NOT touch lines. If reversing valve is operating
normally, inlet and outlet temperatures on appropriate lines should
be close. Any difference would be due to heat loss or gain across
valve body. Temperatures are best checked with a remote-reading,
electronic-type thermometer with multiple probes. Route thermocouple leads to inside of coil area through service-valve mountingplate area underneath coil. Fig. 47 and 48 show test points (TP) on
reversing valve for recording temperatures. Insulate points for
more accurate reading.

CAUTION: Wear safety glasses and gloves when handling refrigerants.

Pumpdown Procedure
Service valves provide a convenient shutoff valve useful for
certain refrigeration-system repairs. System may be pumped down
to make repairs on low side without losing complete refrigerant
charge.
1. Attach pressure gage to suction service-valve gage port.
2. Front seat liquid-line valve.
3. Start unit in cooling mode. Run until suction pressure
reaches 5 psig (35kPa). Do not allow compressor to pump
to a vacuum.
4. Shut unit off. Front seat suction valve.
NOTE: All outdoor unit coils will hold only factory-supplied
amount of refrigerant. Excess refrigerant, such as in long-line
applications, may cause unit to relieve pressure through internal
pressure-relief valve (indicated by sudden rise of suction pressure)
before suction pressure reaches 5 psig (35kPa). If this occurs, shut
off unit immediately, front seat suction valve, and recover remaining pressure.
V. CHECK-FLO-RATER™
(BYPASS-TYPE)
HEAT
PUMPS
ONLY
REFRIGERANT-METERING
HOLE
THROUGH IT. THE RETAINER FORMS A STOP FOR
PISTON IN REFRIGERANT-BYPASS MODE AND A SEALING SURFACE FOR LIQUID-LINE FLARE CONNECTION.
(SEE FIG. 45.) TO CHECK, CLEAN, OR REPLACE PISTON:
RELIANT PRODUCTS EXCEPT 1992 PRODUCTION
1. Shut off power to unit.
2. Pump unit down using pumpdown procedure described in
this service manual.
3. Loosen nut and remove liquid-line flare connection from
Check-Flo-Rater™.
4. Pull retainer out of body, being careful not to scratch
flare-sealing surface. If retainer does not pull out easily,
carefully use locking pliers to remove it.
—39—

NEW SOLENOID COIL

3 PORT DESIGN
A91457

4TH PORT

4 PORT DESIGN
A91456

Fig. 46—Reversing Valve
If valve is defective:

5. Use slip couplings to install new valve with stubs back into
system. Even if stubs are long, wrap valve with a wet rag to
prevent overheating.

1. Shut off all power to unit and remove all charge from
system.

6. After valve is brazed in, check for leaks. Evacuate and
charge system. Operate system in both modes several times
to be sure valve functions properly.

2. Check valve design. If valve is of the 3-port design and new
replacement is of the 4-port design, replacement of the
solenoid coil and wire leads is necessary. Valve bodies are
interchangeable, but solenoid and wires are not. Three-port
reversing valve and solenoid coil with leads must be used
together. New solenoid coil cannot be used on a 3-port
valve.
Four-port reversing valve uses solenoid with quick-connect
terminals for leads connection. Old solenoid coil cannot be
used on 4-port reversing valve. If for any reason a new wire
cord is not available, cut the leads on the old solenoid coil
as close to the coil as possible. Terminate the leads with 2
female 1/4-in. quick-connects. Connect terminals to new
solenoid and tape connection to insulate and provide
moisture barrier. Replace these wires as soon as wire cord
is available. See RCD (Replacement Component Catalog)
for proper cord part number.

FROM INDOOR COIL VIA
SERVICE VALVE ON
OUTDOOR COIL

TO OUTDOOR
COIL
TO
ACCUMULATOR

TP-4

TP-3

TP-2

TP-1

3. Remove solenoid coil from valve body. Remove valve by
cutting it from system with tubing cutter. Repair person
should cut in such a way that stubs can be easily rebrazed
back into system. Do not use hacksaw. This introduces
chips into system that cause failure. After defective valve is
removed, wrap it in wet rag and carefully unbraze stubs.
Save stubs for future use. Because defective valve is not
overheated, it can be analyzed for cause of failure when it
is returned.

FROM COMPRESSOR
DISCHARGE LINE

A88342

Fig. 47—Reversing Valve (Cooling Mode or Defrost
Mode, Solenoid Energized)
VII. THERMOSTATIC-EXPANSION VALVES (TXV)
The types of TXVs used in condensing-unit and heat-pump
systems are as follows:

4. Braze new valve onto used stubs. Keep stubs oriented
correctly. Scratch corresponding matching marks on old
valve and stubs and on new valve body to aid in lining up
new valve properly. When brazing stubs into valve, protect
valve body with wet rag to prevent overheating.

Rapid-Pressure Balance (RPB)—Has a special bleed port that
allows rapid bleed-through of pressure after system shutdown until
pressure equalization occurs within approximately 1 to 2 minutes.
—40—

TABLE 20—TXV SUPERHEAT SETTING AT OUTLET OF EVAPORATOR COIL
INSTALLATION
Field Accessory
Field Accessory
Field Accessory/Factory-Installed
Factory-Installed
Factory-Shipped/Field-Installed

FROM
OUTDOOR
COIL

TP-4

TO
ACCUMULATOR

TP-3

INSULATE FOR
ACCURATE
READING

TXV TYPE
RPB/HSO
RPB/HSO
HSO
HSO
HSO

PRODUCT USAGE
Air Conditioner Indoor Unit
Heat Pump Indoor Unit
Indoor Fan Coil Unit
2-Speed Heat Pump Outdoor Unit
2-Speed Indoor Unit

increased leaving evaporator pressure, which is transferred
via the equalizer tube to the underside of the diaphragm.
This tends to cause the pin-Bryant spring pressure to close
the valve. The refrigerant flow is effectively stabilized to
the load demand with negligible change in superheat. The
bi-flow TXV is used on split-system heat pumps. In the
cooling mode, the TXV operates the same as the standard
TXV previously explained. (See Fig. 49.)
However, when the system is switched to the heating mode
of operation, the refrigerant flow is reversed. The bi-flow
TXV has an additional internal-check valve and external
tubing. (See Fig. 50.) These additions allow the refrigerant
to bypass the TXV when refrigerant flow is reversed with
only a 1- to 2-psig pressure drop through the device. When
the heat pump switches to the defrost mode, the refrigerant
flows through a completely open (unthrottled) TXV, and
the bulb senses the residual heat of the outlet tube of the coil
that had been operating in the heating mode (about 85°F
and 155 psig). This temporary, unthrottled valve decreases
the indoor-pressure drop, which in turn increases the
refrigerant-flow rate, decreases overall defrost time, and
enhances defrost efficiency.

TO INDOOR COIL
VIA SERVICE VALVE
ON OUTDOOR COIL

INSULATE
FOR
ACCURATE
READING

SUPERHEAT SETTING
10°
6°
6°
4°
4°

TP-2

TP-1

FROM COMPRESSOR
DISCHARGE LINE
ELECTRONIC
THERMOMETER

A88341

Fig. 48—Reversing Valve (Heating Mode, Solenoid DeEnergized)

IX. COIL REMOVAL
Coils on this family of units are easy to remove, if required for
compressor removal or replacement coil.

Hard Shutoff (HSO)—Has no bleed port and allows no bleedthrough after system shutdown. No pressure equalization occurs.
Because of unequalized system pressures, a start capacitor and
relay must be installed on single-phase reciprocating compressors
to start the compressor.
See Table 20 for TXV superheat settings. These settings are
factory set and are not field adjustable. Table 17 settings are for
Bryant-approved accessories and factory-installed TXVs only.

CAUTION: Wear safety glasses and gloves when handling refrigerants.

To remove or replace coil:
1. Shut off all power to unit.

VIII. THERMOSTATIC-EXPANSION VALVE (BI-FLOW
TXV)
The standard TXV is a metering device that is used in condensing
and heat pump systems to adjust to changing load conditions by
maintaining a preset superheat temperature at the outlet of the
evaporator coil. The volume of refrigerant metered through the
valve seat is dependent upon:

2. Remove and recover refrigerant from system through service valves.
3. Remove top cover. (See Remove Top Cover section.)
4. Remove screws in base pan to coil grille.
5. Remove coil grille from unit.
6. Remove screws on corner-post (Reliant) service-valve
panel (Cube unit) holding coil-tube sheet.

1. Superheat temperature sensed by cap-tube sensing bulb on
suction tube at outlet of evaporator coil. As long as this bulb
and cap tube contains some liquid refrigerant, this temperature is converted into suction pressure pushing downward
on the diaphragm, which tends to open the valve via the
pushrods.

CAUTION: Cut tubes to reduce the possibility of fire
and personal injury.

2. The suction pressure at the outlet of the evaporator coil is
transferred via the external equalizer tube to the underside
of the diaphragm.

7. Use midget-tubing cutter to cut liquid and vapor lines at
both sides of coil. Cut in convenient location for easy
reassembly with copper-slip couplings.

3. The needle valve on the pin Bryant is spring-loaded, which
also exerts pressure on the underside of the diaphragm via
the pushrods, which tends to close the valve. Therefore,
bulb pressure equals evaporator pressure (at outlet of coil)
plus spring pressure. If the load increases, the temperature
increases at the bulb, which increases the pressure on the
topside of the diaphragm, which pushes the pin Bryant
away from the seat, opening the valve and increasing the
flow of refrigerant. The increased refrigerant flow causes

8. Lift coil vertically from basepan. Place aside carefully.
9. Reverse procedure to reinstall coil.
X. LIQUID-LINE STRAINER (HEAT PUMPS ONLY)
The liquid-line strainer is upstream of the heating piston. The
strainer catches debris in the liquid line during heating mode. If it
becomes plugged, system operation and pressure become abnormal, and the compressor may become hot and cycle off on the
overloads or pressure relief.
—41—

CAPILLARY TUBE

DIAPHRAGM
BYPASS TXV

PUSHRODS
FEEDER TUBES
INLET
COIL

OUTLET
NEEDLE
VALVE
SPRING
DISTRIBUTOR

BULB

CHECK VALVE
(CLOSED)

EXTERNAL EQUALIZER TUBE

BYPASS TUBE

A88406

Fig. 49—TXV in Cooling Mode

CAPILLARY TUBE

DIAPHRAGM
BYPASS TXV

PUSHRODS
FEEDER TUBES
INLET
COIL

OUTLET
NEEDLE
VALVE
SPRING

BULB

DISTRIBUTOR
CHECK VALVE
(OPEN)

EXTERNAL EQUALIZER TUBE

BYPASS TUBE

A88405

Fig. 50—TXV in Heating Mode
—42—

If the strainer must be replaced, shut off all power to the unit. See
Fig. 49 for strainer location.
XI. ACCUMULATOR
The accumulator is a device always found in heat pumps and found
in some condensing-unit models. Under some light-load conditions on indoor coils and on outdoor coil with heat pump in heating
mode, some liquid refrigerant is present in suction gas returning to
compressor. The accumulator stores liquid and allows it to boil off
into a vapor so it can be safely returned to compressor. Since a
compressor is designed to pump refrigerant in its gaseous state,
introduction of liquid into it could cause severe damage or total
failure of compressor.
The accumulator is a passive device which seldom needs replacing. Occasionally, its internal oil-return orifice or bleed hole may
become plugged. Some oil is contained in refrigerant returning to
compressor. It cannot boil off in accumulator with liquid refrigerant. The bleed hole allows a small amount of oil and refrigerant to
enter the return line where velocity of refrigerant returns it to
compressor. If bleed hole plugs, oil is trapped in accumulator, and
compressor will eventually fail from lack of lubrication. If bleed
hole is plugged, accumulator must be changed. Bleed hole is so
tiny that cleaning efforts are usually not successful. The accumulator has a fusible element located in the bottom-end bell. (See Fig.
51.) This fusible element melts at 430°F and vents the refrigerant,
if this temperature is reached either internal or external to the
system. If fuse melts, the accumulator must be replaced.
To change accumulator:
1. Shut off all power to unit.
2. Remove and reclaim all refrigerant from system.
NOTE: Coil may be removed for access to accumulator. Refer to
appropriate sections of service manual for instructions.

430° FUSE
ELEMENT
A88410

Fig. 51—Accumulator
1. Pump the system down to 28 in. of mercury vacuum and
allow pump to continue to operate for additional 15
minutes.
2. Close service valves and shut off vacuum pump.
3. Connect a refrigerant cylinder to the system and open until
system pressure is 2 psig.
4. Close the service valve.
5. Allow system to stand for 1 hr, during which time the dry
refrigerant will be able to diffuse throughout the system,
absorbing moisture.
This procedure is repeated 3 times, after which the system will be
free of any contaminants and water vapor.

CAUTION: Wear safety glasses and gloves when working on refrigerants and when using brazing torch.

XIII. SYSTEM CHARGING
For all approved combinations, system must be charged correctly
for normal system operation and reliable operation of components.

3. When accumulator is exposed, remove it from system with
tubing cutter.
4. Scratch matching marks on tubing stubs and old accumulator. Scratch matching marks on new accumulator. Unbraze stubs from old accumulator and braze into new
accumulator.
5. Thoroughly rinse any flux residue from joints and paint
with corrosion-resistant coating such as zinc-rich paint.
6. Reinstall accumulator into system with copper-slip couplings.
7. Evacuate and charge system.
8. Pour and measure oil quantity (if any) from old accumulator. If more than 20 percent of oil charge is trapped in
accumulator, add oil to compressor to make up for this loss.
XII. CONTAMINANT REMOVAL

CAUTION: Always wear safety glasses and gloves
when handling refrigerants.

If system has lost all charge, weigh in charge using dial-a-charge
or digital scale.
System charge should be fine-tuned by using the superheat or
subcooling method, whichever is appropriate. These methods are
covered in the Checking Charge section below.
NOTE: Heat-pump check charts are for checking charge and
performance and for adding a small amount of charge. During
heating mode, correct method of charging is the weight method. In
heating mode, check should be made approximately 15 minutes
after a defrost with unit running with a clean coil. In cooling cycle,
system should run at least 10 minutes for temperatures and
pressures to stabilize. All charts assume there are no system
abnormalities and indoor coil airflows are correct. If system
abnormalities exist, correct them before checking system charge.

Proper evacuation of a unit removes non-condensibles and assures
a tight, dry system before charging. The 2 methods used to
evacuate a system are the deep-vacuum method and the tripleevacuation method.
DEEP-VACUUM METHOD
The deep-vacuum method requires a vacuum pump capable of
pulling a vacuum of 1000 microns and a vacuum gage capable of
accurately measuring this vacuum depth. The deep-vacuum
method is the most positive way of assuring a system is free of air
and liquid water.
TRIPLE-EVACUATION METHOD
The triple-evacuation method can be used where the vacuum pump
is capable of pumping down to only 28 in. of mercury vacuum, and
the system does not contain any liquid water. The procedure is as
follows.

XIV.

CHECKING CHARGE

Superheat charging is the process of charging refrigerant into a
system until the temperature (superheat) of the suction gas entering
the compressor reaches a prescribed value. Small variations of
charge affect suction-gas superheat temperatures greatly. Therefore, this method of charging is very accurate. This method can be
used only on split-system condensing units and heat pumps
(operating in the cooling mode) with fixed-restrictor-type metering
devices such as Check-Flo-Rater™, cap tube, etc. For units using
—43—

TABLE 21—SUPERHEAT CHARGING TABLE
OUTDOOR TEMP (°F)
55
60
65
70
75
80
85
90
95
100
105
110
115

50
9
7
—
—
—
—
—
—
—
—
—
—
—

52
12
10
6
—
—
—
—
—
—
—
—
—
—

54
14
12
10
7
—
—
—
—
—
—
—
—
—

56
17
15
13
10
6
—
—
—
—
—
—
—
—

INDOOR COIL ENTERING AIR TEMP (°F WET BULB)
58
60
62
64
66
68
70
20
23
26
29
32
35
37
18
21
24
27
30
33
35
16
19
21
24
27
30
33
13
16
19
21
24
27
30
9
12
15
18
21
24
28
5
8
12
15
18
21
25
—
—
8
11
15
19
22
—
—
5
9
13
16
20
—
—
—
6
10
14
18
—
—
—
—
8
12
15
—
—
—
—
5
9
13
—
—
—
—
—
6
11
—
—
—
—
—
—
8

72
40
38
36
33
31
28
26
24
22
20
17
15
14

74
42
40
38
36
34
31
30
27
25
23
22
20
18

76
45
43
41
39
37
35
33
31
29
27
26
25
23

Where a dash appears, do not attempt to charge system under these conditions or refrigerant slugging may occur.

TABLE 22—REQUIRED VAPOR TEMPERATURE (°F)
SUPERHEAT TEMP
(°F)
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40

61.5
35
37
39
41
43
45
47
49
51
53
55
57
59
61
63
65
67
69
71
73
75

64.2
37
39
41
43
45
47
49
51
53
55
57
59
61
63
65
67
69
71
73
75
77

VAPOR PRESSURE AT SERVICE PORT (PSIG)
67.1
70.0
73.0
76.0
79.2
39
41
43
45
47
41
43
45
47
49
43
45
47
49
51
45
47
49
51
53
47
49
51
53
55
49
51
53
55
57
51
53
55
57
59
53
55
57
59
61
55
57
59
61
63
57
59
61
63
65
59
61
63
65
67
61
63
65
67
69
63
65
67
69
71
65
67
69
71
73
67
69
71
73
75
69
71
73
75
77
71
73
75
77
79
73
75
77
79
81
75
77
79
81
83
77
79
81
83
85
79
81
83
85
87

a TXV, the subcooling method must be used. Heat pumps must be
operating in the cooling mode. To charge by superheat, a service
technician needs an accurate superheat thermocouple or
thermistor-type thermometer, a sling psychrometer, and a gage
manifold. Do not use mercury or small-dial-type thermometers as
they are not adequate for this type of measurement. Then use 1 of
the following procedures:
SUPERHEAT CHARGING METHOD

82.4
49
51
53
55
57
59
61
63
65
67
69
71
73
75
77
79
81
83
85
87
89

85.7
51
53
55
57
59
61
63
65
67
69
71
73
75
77
79
81
83
85
87
89
91

5. Measure indoor-air (entering indoor coil), wet-bulb temperature with a sling psychrometer.
6. Locate outdoor temperature and evaporator entering air
wet-bulb temperature in Table 21. At this intersection note
the superheat.
7. Locate superheat temperature located in previous step and
vapor pressure in Table 22. At this intersection note
vapor-line temperature.
8. If unit has a higher vapor-line temperature than charted
temperature, add refrigerant until charted temperature is
reached.
9. If unit has a lower vapor-line temperature than charted
temperature, bleed refrigerant until charted temperature is
reached.
10. If outdoor-air temperature or pressure at vapor valve
changes, charge to new vapor-line temperature indicated on
chart.
SUBCOOLING CHARGING METHOD
1. Operate unit a minimum of 15 minutes before checking
charge.

1. Operate a unit a minimum of 10 minutes before checking
charge.
2. Measure vapor pressure by attaching a gage to vapor
valve-service port.
3. Measure vapor-line temperature by attaching a service
thermometer to unit vapor line near vapor valve. On a heat
pump, attach to the suction tube between the accumulator
and the compressor. Insulate thermometer for accurate
readings.
4. Measure outdoor-air, dry-bulb temperature with a second
thermometer.
—44—

TABLE 23—SUBCOOLING AT LIQUID-SERVICE VALVE FOR UNITS PRODUCED THROUGH DECEMBER, 1992
RELIANT AIR CONDITIONERS
Model

Series
014
018
024
030
036
038
042
048
060

590A

A
14
17
13
15
13
—
13
15
19

591A/592A

B
14
17
13
15
12
—
13
14
22

C
—
—
—
—
—
—
14
—
—

A
14
14
17
9
16
—
16
18
18

B
14
14
17
10
16
—
19
14
18

C
14
14
17
10
16
—
19
18
18

593A/594A

D
—
—
—
—
—
—
15
—
—

A
6
7
8
6
12
—
12
14
14

B
6
7
8
6
12
—
12
14
14

C
—
—
—
10
5
—
—
—
—

593B

D
—
—
—
13
—
—
—
—
—

A
—
11
13
11
9
16
11
18
11

B
—
—
—
—
—
—
—
—
—

593C

A
—
9
16
15
13
—
13
17
16

594C

B
—
9
21
15
12
—
—
—
—

A
—
—
12
14
16
—
21
14
19

B
—
—
—
—
—
—
—
—
—

595A

596A

597A

597B

598A
High

598A
Low

A
—
9
13
10
14
—
11
10
—

A
—
8
12
9
13
—
11
10
—

A
—
—
11
10
12
—
15
11
12

A
—
—
13
11
14
—
15
11
11

A
—
—
—
—
12
—
—
12
12

A
—
—
—
—
9
—
—
9
9

RELIANT HEAT PUMPS
Model
Series
014
018
024
030
036
042
048
060

MODEL
Series
014
018
024
030
036
042
048
060

690A
A
7
18
18
13
18
13
22
23

B
7
18
18
13
18
11
17
23

C
7
18
18
13
18
11
15
23

D
—
—
—
—
—
—
14
—

691A/692A

693A/694A

A
—
16
16
20
14
18
19
13

A
—
11
11
10
10
15
13
14

B
—
16
16
20
14
18
14
13

CUBE UNIT—AIR CONDITIONERS
561A/571A
A
B
—
—
15
16
14
11
12
12
18
16
18
17
—
17
—
21

B
—
11
11
10
10
15
13
14

693B

693C

694C

697A

697B

A
—
10
13
11
11
12
—
—

A
—
9
6
10
13
10
15
15

A
—
7
5
10
12
12
12
10

A
—
9
11
9
9
11
10
12

A
—
10
11
10
10
12
11
7

CUBE UNIT—HEAT PUMPS
661A/671A
A
B
—
—
11
14
14
8
9
10
11
7
7
—
12
—
10
—

2. Measure liquid service-valve pressure by attaching an
accurate gage to the service port.

698A
Cooling
Heating
High
Low
High
Low
A
A
A
A
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
12
7
18
15
—
—
—
—
14
9
25
18
14
9
22
21

HORIZONTAL
566D
C
10
12
—
—
—
—
—
—

AIR CONDITIONERS
566E
D
A
—
—
—
17
—
19
12
—
—
—
—
—
—
—
—

cally on this equipment. The frequency with which maintenance is
performed is dependent on such factors as hours of operation,
geographic location, and local environmental conditions.

3. Measure the liquid-line temperature by attaching an accurate thermistor-type or electronic thermometer to the liquid
line near the outdoor coil.

WARNING: Disconnect all electrical power to unit
before performing any maintenance or service on outdoor
unit. Remember to disconnect power supply to air handler
as this unit supplies low-voltage power to the outdoor
unit. Electric shock can cause personal injury or death.

4. Refer to unit-rating plate to find required subcooling
temperature for units produced during or after January
1993. For units produced through December 1992, refer to
Table 23. Find the point at which the required subcooling
temperature intersects the measured liquid service-valve
pressure on Table 24.

The minimum maintenance that should be performed on this
equipment is as follows.

5. To obtain the required subcooling temperature at a specific
liquid-line pressure, add refrigerant if liquid-line temperature is higher than indicated or remove refrigerant if
temperature is lower. Allow a tolerance of 3°F.

1. Check outdoor coil for cleanliness each month during the
heating (heat pump only) or cooling season and clean as
necessary, but clean at least once each heating (heat pump
only) and cooling season.

CARE AND MAINTENANCE
To assure high performance and minimize possible equipment
malfunction, it is essential that maintenance be performed periodi-

2. Check fan motor and blade for cleanliness each heating and
cooling season and clean as necessary.
—45—

TABLE 24—REQUIRED LIQUID-LINE TEMPERATURE
PRESSURE (PSIG)
AT SERVICE FITTING
134
141
148
156
163
171
179
187
196
205
214
223
233
243
253
264
274
285
297
309
321
331
346
359

0
76
79
82
85
88
91
94
97
100
103
106
109
112
115
118
121
124
127
130
133
136
139
142
145

5
71
74
77
80
83
86
89
92
95
98
101
104
107
110
113
116
119
122
125
128
131
134
137
140

REQUIRED SUBCOOLING TEMPERATURE (°F)
10
15
20
66
61
56
69
64
59
72
67
62
75
70
65
78
73
68
81
76
71
84
79
74
87
82
77
90
85
80
93
88
83
96
91
86
99
94
89
102
97
92
105
100
95
108
103
98
111
106
101
114
109
104
117
112
107
120
115
110
123
118
113
126
121
116
129
124
119
132
127
122
135
130
125

3. Check electrical connections for tightness and controls for
proper operation each heating (heat pump only) or cooling
season and service as necessary.

25
51
54
57
60
63
66
69
72
75
78
81
84
87
90
93
96
99
102
105
108
111
114
117
120

3. Check fan-blade setscrew for tightness.
4. Reinstall fan motor and blade to top cover and check for
alignment.

CAUTION: Because of possible damage to the equipment or personal injury, maintenance should be performed by qualified personnel only.

5. Reinstall top cover and position blade as per Fig. 24.
6. Reconnect electrical power and check for proper operation.
ELECTRICAL CONTROLS AND WIRING
1. Disconnect power to both the outdoor and indoor units.

COIL CLEANING
1. Remove top cover. See Remove Top Cover section.

2. Check all electrical connections for tightness. Tighten all
screws on electrical connections. If any connections appear
to be burned or smoky, disassemble the connection, clean
all parts and stripped wires, and reassemble. Use a new
connector if old one is burned or corroded and crimp
tightly.

CAUTION: Coil fin damage can result in higher operating costs or compressor damage. Do not use flame,
high-pressure water, steam, or volatile or corrosive cleaners on fins or tubing.

3. Reconnect electrical power to the indoor and outdoor units
and observe unit through 1 complete operating cycle.
2. Clean coil using vacuum cleaner and its crevice tool. Move
crevice tool vertically, close to area being cleaned, making
sure tool touches only the dirt on the fins and not the fins.
To prevent fin damage, do not scrub fins with tool or move
tool horizontally against fins.
3. If oil deposits are present, spray coil with ordinary household detergent. Wait 10 minutes, and proceed to next step.
4. Using garden hose, spray coil vertically downward with
constant stream of water at moderate pressure. Keep nozzle
at a 15° to 20° angle, about 3 in. from coil face and 18 in.
from tube. Spray so debris is washed out of coil and
basepan.
5. Restore power to unit.
CLEANING OUTDOOR FAN MOTOR AND BLADE
1. Remove fan motor and blade. Refer to Remove Fan-Motor
Assembly section of this manual. Be careful not to bend or
dent fan blade.
2. Clean motor and blade with soft brush or cloth. Be careful
not to disturb balance weights on fan blade.

4. If there are any discrepancies in the operating cycle,
troubleshoot to find the cause, and correct.
REFRIGERANT CIRCUIT
1. Check the refrigerant charge using the superheat or subcooling method, whichever is applicable. If low on charge,
check unit for leaks using an electronic leak detector.
2. If any leaks are found, recover or isolate charge (pumpdown) if applicable and make necessary repairs.
3. Evacuate, recharge, and operate unit through entire cycle.
FINAL CHECKOUT
After the unit has been operating, the following items should be
checked:
1. Check that unit operational noise is not excessive due to
vibration of components, tubing, panels, etc. If present,
isolate problem and correct.
2. Check to be sure caps are installed on service valves and
that they are tight.
—46—

3. Check to be sure tools, loose parts, and debris are removed
from the unit.

3. Addition of coastal filter (see pre-sale literature for accessory listing).

4. Check to be sure all panels and screws are in place and
tight.
Desert and Seacoast Locations
Special consideration must be given to the installation and maintenance of condensing units and heat pumps installed in seacoast
or desert locations. Salt and the alkali content of the sand adhere
to the aluminum fins of the coil and can cause premature coil
failure due to corrosion.
Preventive measures can be taken during installations, such as:

Special maintenance requirements are as follows:
1. Frequent inspection of coil and base pan, especially after
storms and/or high winds.
2. Cleaning coil by flushing out sand from between coil fins
and out of base pan as frequently as inspection determines
necessary.
3. Protecting the unit in ″off season″ with cover that allows air
to circulate through but prevents sand from sifting in (such
as canvas material). Do not use plastic as plastic will hold
moisture.

1. Locating the unit on side of structure opposite the prevailing
winds.
2. Elevating the unit to height where drifting sand cannot pile
up against coil. Four-in.-high mounting feet or an 18-in.high mounting rack are available as accessories and can be
used to elevate the unit.

—47—

AIR CONDITIONER
TROUBLESHOOTING CHART
NO COOLING OR
INSUFFICIENT
COOLING

COMPRESSOR
WILL NOT RUN

COMPRESSOR
RUNS BUT
CYCLES ON
INTERNAL
OVERLOAD

COMPRESSOR
RUNS BUT
INSUFFICIENT
COOLING

CONTACTOR
OPEN

CONTACTOR
CLOSED

OUTDOOR FAN
STOPPED OR
CYCLING ON
OVERLOAD

LOOSE LEAD
AT FAN MOTOR

LOW SUCTION
PRESSURE

HIGH SUCTION
LOW HEAD
PRESSURE

HIGH SUCTION
LOW
SUPERHEAT

POWER SUPPLY

COMPRESSOR
POWER SUPPLY
OPEN

OUTDOOR AIR
RESTRICTED OR
RECIRCULATING

MOTOR
DEFECTIVE

DIRTY AIR
FILTERS

DEFECTIVE
COMPRESSOR
VALVES

UNIT
OVERCHARGED

DEFECTIVE
LOW-VOLTAGE
TRANSFORMER

LOOSE LEADS AT
COMPRESSOR

RESTRICTED
DISCHARGE
TUBE

INCORRECT
OFM
CAPACITOR

DUCT
RESTRICTED

INTERNAL
PRESSURE
RELIEF OPEN

INCORRECT
SIZE
PISTON

OPEN
THERMOSTAT

FAULTY START
GEAR (1-PH)

OVERCHARGE
OR NONCONDENSABLES
IN SYSTEM

DAMPERS
PARTLY CLOSED

OPEN CONTROL
CIRCUIT

OPEN SHORTED
OR GROUNDED
COMPRESSOR
MOTOR
WINDINGS

LOW
REFRIGERANT
CHARGE

INDOOR COIL
FROSTED

LOSS OF
CHARGE

COMPRESSOR
STUCK

LINE VOLTAGE
TOO HIGH OR
LOW

SLIGHTLY
LOW ON
REFRIGERANT

CONTACTOR OR
COIL DEFECTIVE

COMPRESSOR
INTERNAL
PROTECTION
OPEN

DEFECTIVE RUN
CAPACITOR

LIQUID LINE
SLIGHTLY
RESTRICTED

LOOSE
ELECTRICAL
CONNECTION

DEFECTIVE RUN
CAPACITOR

COMPRESSOR
BEARINGS

PISTON
RESTRICTED

HIGH
SUPERHEAT

INCORRECT
SIZE
PISTON

INDOOR COIL
STRAINER
RESTRICTED

INDOOR
BLOWER MOTOR
DEFECTIVE OR
CYCLING ON OL

A90208

Fig. 52—Air-Conditioner Troubleshooting Chart

—48—

HEAT PUMP
TROUBLESHOOTING–COOLING CYCLE
NO COOLING OR
INSUFFICIENT
COOLING

COMPRESSOR
RUNS BUT
CYCLES ON
INTERNAL
OVERLOAD

COMPRESSOR
WILL NOT RUN

COMPRESSOR
RUNS BUT
INSUFFICIENT
COOLING

CONTACTOR
OPEN

CONTACTOR
CLOSED

OUTDOOR FAN
STOPPED OR
CYCLING ON
OVERLOAD

LOOSE LEAD
AT FAN MOTOR

LOW SUCTION
PRESSURE

HIGH SUCTION
LOW HEAD
PRESSURE

HIGH SUCTION
LOW
SUPERHEAT

POWER SUPPLY

COMPRESSOR
POWER SUPPLY
OPEN

OUTDOOR AIR
RESTRICTED OR
RECIRCULATING

DEFROST RELAY
N.C. CONTACTS
OPEN

DIRTY AIR
FILTERS

REVERSING
VALVE HUNG UP
OR INTERNAL
LEAK

UNIT
OVERCHARGED

DEFECTIVE
LOW-VOLTAGE
TRANSFORMER

LOOSE LEADS AT
COMPRESSOR

DAMAGED OR
STUCK
REVERSING
VALVE

MOTOR
DEFECTIVE

DUCT
RESTRICTED

DEFECTIVE
COMPRESSOR
VALVES

INCORRECT
SIZE
PISTON

OPEN
THERMOSTAT

FAULTY START
GEAR (1-PH)

RESTRICTED
DISCHARGE
TUBE

INCORRECT
OFM
CAPACITOR

DAMPERS
PARTLY CLOSED

INTERNAL
PRESSURE
RELIEF OPEN

OPEN CONTROL
CIRCUIT

OPEN SHORTED
OR GROUNDED
COMPRESSOR
MOTOR
WINDINGS

OVERCHARGE
OR NONCONDENSABLES
IN SYSTEM

DEFECTIVE
DEFROST
THERMOSTAT

INDOOR COIL
FROSTED

LOSS OF
CHARGE

COMPRESSOR
STUCK

LOW
REFRIGERANT
CHARGE

SLIGHTLY
LOW ON
REFRIGERANT

CONTACTOR OR
COIL DEFECTIVE

COMPRESSOR
INTERNAL
PROTECTION
OPEN

LINE VOLTAGE
TOO HIGH OR
LOW

LIQUID LINE
SLIGHTLY
RESTRICTED

LOOSE
ELECTRICAL
CONNECTION

DEFECTIVE RUN
CAPACITOR

PISTON
RESTRICTED

COMPRESSOR
BEARINGS

INCORRECT
SIZE
PISTON

HIGH
SUPERHEAT

INDOOR COIL
STRAINER
RESTRICTED

INDOOR
BLOWER MOTOR
DEFECTIVE OR
CYCLING ON OL

A90207

Fig. 53—Heat-Pump Troubleshooting Chart — Cooling Cycle

—49—

HEAT PUMP
TROUBLESHOOTING–HEATING CYCLE
NO HEATING OR
INSUFFICIENT
HEATING

COMPRESSOR
RUNS BUT
CYCLES ON
INTERNAL
OVERLOAD

COMPRESSOR
WILL NOT RUN

COMPRESSOR
RUNS
INSUFFICIENT
HEATING

CONTACT
OPEN

CONTACTOR
CLOSED

DIRTY FILTERS
OR INDOOR
COIL

DEFECTIVE LOWVOLTAGE
TRANSFORMER

COMPRESSOR
POWER SUPPLY

INDOOR FAN
STOPPED OR
CYCLING ON
OVERLOAD

DEFECTIVE FAN
MOTOR
CAPACITOR

OUTDOOR FAN
STOPPED

OUTDOOR FAN
RUNNING

OUTDOOR
THERMOSTAT
DEFECTIVE

REMOTE
CONTROL
CENTER
DEFECTIVE

LOOSE LEADS AT
COMPRESSOR

DAMAGED
REVERSING
VALVE

LOOSE LEADS
AT
FAN MOTOR

LOOSE LEADS
AT OUTDOOR
FAN MOTOR

REVERSING
VALVE STUCK

ODT SETTING
TOO LOW

CONTACTOR
COIL OPEN OR
SHORTED

FAULTY START
GEAR (1-PH)

RESTRICTION IN
DISCHARGE LINE

FAN MOTOR
BURNED
OUT

INTERNAL FAN
MOTOR KLIXON
OPEN

RESTRICTED
LIQUID LINE

CAP TUBE
PINCHED OR
BULB NOT
SENSING TRUE
ODT

OPEN INDOOR
THERMOSTAT

COMPRESSOR
STUCK

OVERCHARGE
OR NONCONDENSABLES
IN SYSTEM

FAN MOTOR
BURNED OUT

PISTON
RESTRICTED OR
IS CLOGGED

STRIP HEATER
RELAY OR
CONTACTOR
DEFECTIVE

LIQUID-LINE
PRESSURE
SWITCH OPEN

COMPRESSOR
INTERNAL
OVERLOAD
OPEN

LOW
REFRIGERANT
CHARGE

DEFROST RELAY
N.C. CONTACTS
OPEN ON
CIRCUIT BOARD

UNDERCHARGED

OPENING IN
POWER CIRCUIT
TO HEATER
ELEMENTS

LOSS OF
CHARGE

OPEN SHORTED
OR GROUNDED
COMPRESSOR
WINDINGS

LINE VOLTAGE
TOO HIGH OR
LOW

OUTDOOR COIL
DIRTY

BROKEN FUSE
LINK

OPEN CONTROL
CIRCUIT

DEFECTIVE RUN
CAPACITOR

DEFECTIVE RUN
CAPACITOR
(1-PH)

STRAINER
RESTRICTED

BROKEN
HEATER
ELEMENT

COMPRESSOR
BEARINGS

OUTDOOR COIL
HEAVILY
FROSTED

OPEN (KLIXON)
OVER
TEMPERATURE
THERMOSTAT
DEFECTIVE
ROOM
THERMOSTAT
(2ND STAGE)

STRIP HEATERS
NOT OPERATING

LOW SUCTION
LOW HEAD

HIGH-LOAD
CONDITION

FAN MOTOR
CONTACTS
WELDED CLOSED
IN DEFROST
RELAY

DEFECTIVE
DEFROST
THERMOSTAT

REVERSING
VALVE JAMMED
IN MIDPOSITION

REVERSING
VALVE DID NOT
SHIFT

DEFROST
THERMOSTAT IN
POOR PHYSICAL
CONTACT WITH
TUBE

HIGH
SUPERHEAT

UNIT NOT
PROPERLY
CHARGED

DEFECTIVE
CIRCUIT BOARD

BAD ELECTRICAL
CONNECTION
ANYWHERE IN
DEFROST
CIRCUIT

A90206

Fig. 54—Heat-Pump Troubleshooting Chart — Heating Cycle

—50—

—51—

—52—

Printed in U.S.A.

sm01,025

Catalog No. 5356-109

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