Carrier R-22 Application Manual And Service Manual
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Air Conditioners and
Heat Pumps Using
R-22 Refrigerant
Application Guide
and Service Manual
NOTE: Read the entire instruction manual before starting the
installation.
This symbol → indicates a change since the last issue.
TABLE OF CONTENTS
SAFETY CONSIDERATIONS.....................................................2
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............................................................5
Liquid-Line Solenoid And Tubing Configuration...................5
Charging Information................................................................6
2–Speed Applications ...............................................................7
UNIT IDENTIFICATION .............................................................9
Product Number Stamped on Unit-Rating Plate......................9
Serial Number Identification..................................................10
CABINET.....................................................................................10
Remove Top Cover-WeatherMaker™ ...................................10
Remove Fan-Motor Assembly-WeatherMaker™ ..................10
Information Plate—WeatherMaker™.....................................11
Control-Box Cover—Cube Products......................................11
Remove Top Cover—Cube Products.....................................11
Remove Fan-Motor Assembly—Cube Products....................11
ELECTRICAL..............................................................................12
Aluminum Wire......................................................................12
Contactors................................................................................13
Capacitors................................................................................14
Cycle Protector........................................................................16
Crankcase Heater....................................................................16
Time-Delay Relay...................................................................17
Pressure Switches....................................................................18
Defrost Thermostats................................................................18
Defrost-Control Board............................................................18
Fan Motors..............................................................................22
Service Alarm Control Board.................................................23
Outdoor Thermostat(s)............................................................24
Compressor Plug.....................................................................24
Low-Voltage Terminals..........................................................24
RECIPROCATING COMPRESSOR ..........................................25
Mechanical Failures................................................................25
Electrical Failures ...................................................................26
System Cleanup After Burnout..............................................27
Compressor Removal And Replacement ...............................28
COPELAND SCROLL COMPRESSOR ....................................28
Features ...................................................................................28
Troubleshooting ......................................................................28
Discharge Thermostat.............................................................28
Discharge Solenoid Valve......................................................29
MILLENNIUM SCROLL COMPRESSOR................................29
Features ...................................................................................29
Compressor Protection............................................................29
Troubleshooting ......................................................................29
Scroll-Compressor, 3–Phase Monitor.....................................29
OLYMPIA SERIES HORIZONTAL UNITS.............................29
General....................................................................................29
Remove Fan Motor.................................................................31
Cleaning Coil..........................................................................31
TWO-SPEED SYSTEM ..............................................................31
Cautions and Warnings...........................................................31
System Functions....................................................................31
Factory Defaults......................................................................34
Major Components..................................................................34
LED Function/Malfunction Lights.........................................36
Troubleshooting ......................................................................36
REFRIGERATION SYSTEM .....................................................38
Refrigeration Cycle.................................................................38
Leak Detection........................................................................38
Brazing....................................................................................39
Service Valves ........................................................................39
AccuRater™ (Bypass-Type) Heat Pumps Only ....................40
Reversing Valve......................................................................41
Thermostatic-Expansion Valves (TXV).................................42
Thermostatic-Expansion Valve (Bi-Flow TXV)....................43
Coil Removal..........................................................................43
Liquid-Line Strainer (Heat Pumps Only) ..............................43
Accumulator............................................................................43
Contaminant Removal ............................................................45
System Charging.....................................................................45
Checking Charge.....................................................................45
CARE AND MAINTENANCE...................................................46
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1144
Tab 3a 5a 2a 5a
PC 101 Catalog No. 563-732 Printed in U.S.A. Form 38-10SM Pg 1 11-00 Replaces: 38-1SM, 38-16XA
SAFETY CONSIDERATIONS
Service and repair of these units should be attempted only by
trained service technicians familiar with Carrier 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.
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.
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 factoryauthorized kits or accessories when modifying this product.
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
Step 1—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 Digest
(PDD). DO NOT DEVIATE FROM PDD. Consult unit Installation Instructions for detailed information.
Step 2—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 suctionline filter drier as soon as possible, with a maximum of 72 hr.
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 Digest.
4. Replace outdoor unit.
5. Install liquid-line filter drier.
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.)
Step 3—Seacoast (For Air Conditioners Only)
Installation of these units in seacoast locations requires the use of
a coastal filter. (See section on care and maintenance.)
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.
Step 1—Compressor Crankcase Heater
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.
Step 2—Evaporator Freeze Thermostat
An SPST temperature-activated switch stops unit operation when
evaporator reaches freeze-up conditions.
Step 3—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.
Step 4—Compressor Start Assist—PTC
Solid-state electrical device which gives a ″soft″ boost to the
compressor at each start.
Step 5—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 hardshutoff TXV for all equipment.
Step 6—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.
Step 7—MotorMaster™ Control
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.
Step 8—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
Table 1—Required Field-Installed Accessories for Air Conditioners and Heat Pumps
REQUIRED FOR
ACCESSORY
Crankcase Heater Yes Yes No
Evaporator Freeze Thermostat Yes No No
Winter Start Control Yes† No No
Accumulator No No No
Compressor Start Assist
Capacitor and Relay
Low Ambient Controller,
MotorMaster™ Control,
Low-Ambient Pressure Switch
Liquid-Line Solenoid Valve
Ball-Bearing Fan Motor Yes‡ 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.
or
Wind Baffle See Low-Ambient Instructions No No
Coastal Filter No No Yes
Support Feet Recommended No Recommended
or
Hard-Shutoff TXV
Isolation Relay Yes** No No
LOW-AMBIENT
APPLICATIONS
(BELOW 55°F)
Yes Yes No
Yes No No
No
REQUIRED FOR
LONG-LINE
APPLICATIONS*
(OVER 50 FT)
See Long-Line
Application
Guideline
REQUIRED FOR
SEA COAST
APPLICATIONS
(WITHIN 2 MILES)
No
Step 9—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.
Step 10—Coastal Filter
A mesh screen inserted under top cover and inside base pan to
protect condenser coil from salt damage without restricting airflow.
Step 11—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.
Step 12—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.
Step 13—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
TXVs.
Step 14—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.
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, 3,
or 4 for wind baffle construction details.
LONG-LINE GUIDELINE
This Long-Line Application Guideline applies to all Carrier
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 Step 6 first.
NOTE: The presale literature for outdoor unit must be referred to
in conjunction with this guideline.
Step 1—Approved Systems
Any residential indoor/outdoor unit combination listed in the
outdoor unit presale literature is an approved system, EXCEPT the
following:
• Indoor coils with capillary-metering devices
• All equipment less than nominal 18,000 Btuh
• All 1/4-in. and 3/16–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
Step 2—Interconnecting Tubing Sizing
Table 5 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
6 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 5 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.
3
7
/32″ x 3/8″ (5.56 x 9.53) SLOT
4 REQ'D
6
1/16″
(154.0)
J
9
/64″ (3.45) DIA HOLE
2 REQ'D
H
3
(9.6)
TYP
/8″
1
(12.7)
TYP
1
/2″
(12.7)
TYP
7
C
A
/2″
/16″
(11.6)
TYP
9
/64″ (3.45) DIA HOLE
K
1 REQ'D
B
7
/32″ (5.56) DIA HOLE
3 REQ'D
1
M
(6.3)
TYP
/4″
L
BAFFLE
SCREW
10 REQ'D
MAT'L: 20 GA STEEL
F
G
SUPPORT
MAT'L: 18 GA STEEL
E
J
D
7
/32″ x 2″
(5.56 x 50.8) SLOT
7
/16″
(11.6)
TYP
1
/4″
(6.3)
TYP
SUPPORT
4 REQ'D
BAFFLE
2 REQ'D
BAFFLE ASSEMBLY
Fig. 1—WeatherMaker™ Units
Calculate the linear length of vapor tube required, adding any
losses for the total number of elbows for application. (See Table
6.) Using this equivalent length, select desired vapor-line size from
Table 5. 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 5.
NOTE: When specifying vapor-line insulation, be aware of the
following standard practice:
All standard accessory-tubing kits are supplied with 3/8-in. insulation on vapor line.
OUTDOOR
UNIT
4
AA
A95444
For minimal capacity loss in long-line application, 1/2-in. insulation should be specified.
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° Fto200°F (-17.8° Cto93° 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.
Table 2—Wind Baffle Dimensions for WeatherMaker™ Units with Star-Burst Top (In.)
UNIT SIZE AA UNIT HEIGHT A B C D E F G H J K L M
21-7/8 17 25-1/4 10-3/8 19-3/4 20-1/2 34 19-11/16 20-7/16 19-5/8 0 0 6-1/8
Small 27-1/2
Medium 34-15/16
Large 45
25-7/8 17 25-1/4 10-3/8 23-3/4 24-1/2 34 23-11/16 24-7/16 23-5/8 0 11-7/8 6-1/8
31-7/8 17 25-1/4 10-3/8 29-3/4 30-1/2 34 29-11/16 30-7/16 29-5/8 0 14-7/8 6-1/8
25-7/8 21 32 11-3/16 23-3/4 24-1/2 42 23-11/16 24-7/16 23-5/8 19-11/16 11-7/8 6-11/16
31-7/8 21 32 11-3/16 29-3/4 30-1/2 42 29-11/16 30-7/16 29-5/8 19-11/16 14-7/8 6-11/16
37-7/8 21 32 11-3/16 35-3/4 36-1/2 42 35-11/16 36-7/16 35-5/8 19-11/16 17-7/8 6-11/16
31-7/8 25-3/16 42 12-15/16 29-3/4 30-1/2 50-7/16 29-11/16 30-7/16 29-5/8 22-11/16 14-7/8 7-1/16
37-7/8 25-3/16 42 15-15/16 35-3/4 36-1/2 50-7/16 35-11/16 36-7/16 35-5/8 22-11/16 17-7/8 7-1/16
Table 3—Wind Baffle Dimensions for WeatherMaker™ Units with Silencer System™ Top (In.)
UNIT SIZE AA UNIT HEIGHT A B C D E F G. H. J K L M
23-13/16 17 25-1/4 10-3/8 19-3/4 20-1/2 34 19-11/16 20-7/16 19-5/8 0 0 6-1/8
Small 27-1/2
Medium 34-15/16
Large 45
Step 3—Metering Device Sizing
The metering device for a long-line application must be flexible
enough to compensate for frictional losses due to long refrigerant
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 7 and 8 provide necessary changes for a given application.
Use Tables 7 and 8 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 7 and 8 as they
relate to system design (outdoor unit above or below indoor unit)
per equivalent length of tubing.
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 7 and 8.
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 9. If piston size is increased, round new piston
number up to nearest common piston number found in Table 9.
27-13/16 17 25-1/4 10-3/8 23-3/4 24-1/2 34 23-11/16 24-7/16 23-5/8 0 11-7/8 6-1/8
33-13/16 17 25-1/4 10-3/8 29-3/4 30-1/2 34 29-11/16 30-7/16 29-5/8 0 14-7/8 6-1/8
27-13/16 21 32 11-3/16 23-3/4 24-1/2 42 23-11/16 24-7/16 23-5/8 19-11/16 11-7/8 6-11/16
33-13/16 21 32 11-3/16 29-3/4 30-1/2 42 29-11/16 30-7/16 29-5/8 19-11/16 14-7/8 6-11/16
39-13/16 21 32 11-3/16 35-3/4 36-1/2 42 35-11/16 36-7/16 35-5/8 19-11/16 17-7/8 6-11/16
33-13/16 25-3/16 42 12-15/16 29-3/4 30-1/2 50-7/16 29-11/16 30-7/16 29-5/8 22-11/16 14-7/8 7-1/16
39-13/16 25-3/16 42 15-15/16 35-3/4 36-1/2 50-7/16 35-11/16 36-7/16 35-5/8 22-11/16 17-7/8 7-1/16
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 7. 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 9 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 8. 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 9, 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.
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.
Step 4—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 10 for
liquid-line solenoid kit part numbers.
NOTE: When installing a liquid-line solenoid, the system may
require a minimum 60-va low-voltage transformer.
5
7
7
/8″
(200.0)
3
/16″
(4.6)
E
1
/8″ (3.45) DIA
2 REQ'D
3
5
/64″
(128.0)
F
5
8
/64″ (205.3)
TYP
7
7
/8″
(199.9)
C
1
/4″
(6.4)
B
1
/4″ (5.56) DIA
2 REQ'D
1
/4″ x 3/8″ (5.56 x 9.53) SLOT
6 REQ'D
9
4
/64″ (105.2)
45°
TYP
1
/4″
(6.4)
1
(12.7)
3
5
/64″
(128.0)
25
D
A
21
1
5
2
/64″
(52.6)
57
4
⁄
64
(124.2) TYP
1
/2″ (12.7)
TYP
23
/64″ (9.2)
/2″
/64″ (10.0)
1
2
/2″
(63.5)
/32″ (42.1)
23
/64″
(9.2)
″
BAFFLE - LEFT
MAT'L: 20 GA STEEL
J
SUPPORT
MAT'L: 18 GA STEEL
1
2
/2″
(63.5)
21
1
A
D
25
⁄64″ (10.0)
1
/4″ (5.56) DIA
2 REQ'D
13
(5.4)
TYP
/32″ (42.1)
G
LEFT
SIDE
/64″
C
E
1
/2″
(12.7)
29
7
TYP
BAFFLE - RIGHT
MAT'L: 20 GA STEEL
1
/4″ x 3/8″ (5.56 x 9.53) SLOT
6 REQ'D
1
/4″ (5.56) DIA
4 REQ'D
AA
C
OUTDOOR
UNIT
/32″ (200.8)
RIGHT
SIDE
SCREW
14 REQ'D
SUPPORT
3 REQ'D
1
/8″ (3.45) DIA.
J
H
4 REQ'D
Fig. 2—Cube Units
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.
Step 5—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
BAFFLE ASSEMBLY
A95446
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.
EXAMPLE:
To calculate additional charge required for a 25–ft line set:
25 ft – 15 ft = 10 ft X 0.6 oz/ft=6ozofadditional charge
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.
6
Table 4—Wind Baffle Dimensions for Cube Units (In.)
UNIT SIZE AA UNIT HEIGHT A B C D E F G. H. J
21-15/16 19-7/8 13-3/4 28-1/8 10-11/16 20-1/4 11-11/16 3-13/16 19-13/16 17-13/16
23-15/16 21-7/8 13-3/4 28-1/8 10-11/16 20-1/4 11-11/16 3-13/16 21-13/16 19-13/16
25-15/16 23-7/8 13-3/4 28-1/8 10-11/16 20-1/4 11-11/16 3-13/16 23-13/16 21-13/16
Small 18
Medium 22-1/2
Large 30
27-15/16 25-7/8 13-3/4 28-1/8 10-11/16 20-1/4 11-11/16 3-13/16 25-13/16 23-13/16
29-15/16 27-7/8 13-3/4 28-1/8 10-11/16 20-1/4 11-11/16 3-13/16 27-13/16 25-13/16
31-15/16 29-7/8 13-3/4 28-1/8 10-11/16 20-1/4 11-11/16 3-13/16 29-13/16 27-13/16
33-15/16 31-7/8 13-3/4 28-1/8 10-11/16 20-1/4 11-11/16 3-13/16 31-13/16 29-13/16
21-15/16 19-7/8 18-5/16 32-5/8 10-11/16 24-3/4 16-3/16 8-1/4 19-13/16 17-13/16
23-15/16 21-7/8 18-5/16 32-5/8 10-11/16 24-3/4 16-3/16 8-1/4 21-13/16 19-13/16
25-15/16 23-7/8 18-5/16 32-5/8 10-11/16 24-3/4 16-3/16 8-1/4 23-13/16 21-13/16
27-15/16 25-7/8 18-5/16 32-5/8 10-11/16 24-3/4 16-3/16 8-1/4 25-13/16 23-13/16
29-15/16 27-7/8 18-5/16 32-5/8 10-11/16 24-3/4 16-3/16 8-1/4 27-13/16 25-13/16
31-15/16 29-7/8 18-5/16 32-5/8 10-11/16 24-3/4 16-3/16 8-1/4 29-13/16 27-13/16
33-15/16 31-7/8 18-5/16 32-5/8 10-11/16 24-3/4 16-3/16 8-1/4 31-13/16 29-13/16
35-15/16 33-7/8 18-5/16 32-5/8 10-11/16 24-3/4 16-3/16 8-1/4 33-13/16 31-13/16
37-15/16 35-7/8 18-5/16 32-5/8 10-11/16 24-3/4 16-3/16 8-1/4 35-13/16 33-13/16
25-15/16 23-7/8 25-3/4 40-1/8 10-11/16 32-1/4 23-11/16 15-13/16 23-13/16 21-13/16
27-15/16 25-7/8 25-3/4 40-1/8 10-11/16 32-1/4 23-11/16 15-13/16 25-13/16 23-13/16
29-15/16 27-7/8 25-3/4 40-1/8 10-11/16 32-1/4 23-11/16 15-13/16 27-13/16 25-13/16
31-15/16 29-7/8 25-3/4 40-1/8 10-11/16 32-1/4 23-11/16 15-13/16 29-13/16 27-13/16
33-15/16 31-7/8 25-3/4 40-1/8 10-11/16 32-1/4 23-11/16 15-13/16 31-13/16 29-13/16
35-15/16 33-7/8 25-3/4 40-1/8 10-11/16 32-1/4 23-11/16 15-13/16 33-13/16 31-13/16
37-15/16 35-7/8 25-3/4 40-1/8 10-11/16 32-1/4 23-11/16 15-13/16 35-13/16 33-13/16
39-15/16 37-7/8 25-3/4 40-1/8 10-11/16 32-1/4 23-11/16 15-13/16 37-13/16 35-13/16
Table 5—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
*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.
LONG-LINE
VAPOR-LINE
DIAMETER
(IN.)†
5/8 57 9 121214
3/4 134557
5/8 6913161922
3/4 011234
5/8 6810131517
3/4 234567
3/4 710141721NR
7/8 2 4 6 8 10 11
3/4 71013172023
7/8 3 4 6 7 8 10
1-1/8 0 0 1122
3/4 10 14 18 22 NR NR
7/8 4 6 7 9 11 13
1-1/8 0 0 1122
7/8 7911141619
1-1/8 1 2 2334
50 75 100 125 150 175
EQUIVALENT LINE LENGTH (FT)
Step 6—2–Speed Applications
Outdoor units may be connected to indoor section using accessory
tubing package or field-supplied refrigerant grade tubing or 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
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.
7
90° STD
Table 7—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
Table 8—Calculation of Outdoor Piston No.
OUTDOOR UNIT ABOVE INDOOR
A
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
B
90° LONG RAD
C
45° STD
Table 6—Fitting Losses in Equivalent Ft
TUBE SIZE OD
(IN.)
5/8 1.6 1.0 0.8
3/4 1.8 1.2 0.9
7/8 2.0 1.4 1.0
1-1/8 2.6 1.7 1.3
REFERENCE DIAGRAM IN FIG. 1
ABC
Fig. 3—Tube Bend Losses
A92498
Table 9—Common Piston Sizes
ACCURATER™ CHATLEFF ACCURATER™ CHATLEFF
— 32 65 65
— 33 67 67
35 35 — 68
— 36 70 70
— 37 — 71
38 38 73 73
— 39 — 74
40 40 76 76
— 41 78 78
42 42 80 80
— 43 — 81
— 45 82 82
46 — 84 84
— 47 86 86
49 49 88 88
51 51 — 89
52 52 90 90
— 53 — 92
55 55 93 93
57 57 96 96
59 59 98 98
61 61 101 101
— 62 104 104
63 63 109 —
Table 10—Liquid-Line Solenoid Kit Part Numbers
TYPE OF VALVE PART NO.
Single Flow KAALS0101LLS
Bi-Flow KHALS0101LLS
8
175' MAX.
GROUND LEVEL
BASEMENT
Fig. 4—Application with Air Conditioner Installed in a Horizontal Configuration
A90074
Fig. 5—Application with Heat Pump Installed in a Horizontal Configuration
UNIT IDENTIFICATION
Step 1—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, and 2—Model Number
Example:
A 38 indicates the unit is either an air conditioner or a heat pump.
Positions 3, 4, and 5—Model Letters
Identifies a specific product model.
175' MAX.
GROUND LEVEL
BASEMENT
A90075
Positions 6, 7, and 8—Nominal Cooling Capacity (in thousands
Btuh)
Example: 036 = 36,000 Btuh or 3–ton capacity.
Position 9—Not Used
Ths position will contain a dash (—).
Position 10—Description
C—Canada
L—Limited Edition
Position 11—Not Used
Ths position will contain a dash (—).
Position 12—Electrical Characteristics
9
TRAP
50' MAX.
HEAT PUMP ONLY
GROUND LEVEL
Fig. 6—Application with Air Conditioner or Heat Pump Installed with Indoor Unit Above Outdoor Unit
Example:
3—230 or 208–230 or 208/230, 1 Phase, 60 Hertz
5—230 or 208–230 or 208/230, 3 Phase, 60 Hertz
6—460, 3 Phase, 60 Hertz
7—220/240, 1 Phase, 50 Hertz
8—220, 3 Phase, 50 Hertz
9—380/415, 3 Phase, 50 Hertz
Position 13—Series
New units have a 0. As major component variations occur,
including compressor changes, fan motors, coil circuitry size, etc.,
the change is identified by increasing this digit in increments of 1.
Position 14—Packaging
On split-system products, this digit will be 0.
Positions 15 and 16—Not Used
These positions will contain dashes (———).
Step 2—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
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
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.
Step 1—Remove Top Cover-WeatherMaker™
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.
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.
Step 2—Remove Fan-Motor Assembly-WeatherMaker™
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
A90076
150' MAX.
HEAT PUMP ONLY
Fig. 7—Application with Air Conditioner or Heat Pump Installed Above Indoor Unit
Step 3—Information Plate—WeatherMaker™
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.
Step 4—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.
Step 5—Remove Top Cover—Cube Products
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.
A90077
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.
6. Lift top cover from unit.
7. Reverse sequence for reassembly.
Step 6—Remove Fan-Motor Assembly—Cube Products
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
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ PAASFLDLKREW
SEFL JOSDJ
SEFL JOSDJ ATC
SEFL JOSDJ
SEFL JOSDJ UTUHD
SEFL JOSDJ
SEFL JOSDJC MD
SEFL JOSDJ
SEFL JOSDJHR ITYALK
SEFL JOSDJ
SEFL JOSDJ
Fig. 9—Information Plate
Fig. 8—Basic Cabinet Designs
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.
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 locating the cause of a
problem and correcting system malfunctions.
Step 1—Aluminum Wire
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
A88411
unit on Carrier 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
12
A00009
ELECTRICAL
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ PAASFLDLKREW
SEFL JOSDJ ATC
SEFL JOSDJ UTUHD
SEFL JOSDJC MD
SEFL JOSDJHR ITYALK
SEFL JOSDJ
A88412
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ
SEFL JOSDJ PAASFLDLKREW
SEFL JOSDJ ATC
SEFL JOSDJ UTUHD
SEFL JOSDJC MD
SEFL JOSDJHR ITYALK
SEFL JOSDJ
Fig. 10—Information Plate Removed/Installed Below Control Box
A88350
Fig. 11—Contactor
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.
Step 2—Contactors
NOTE: The section applies to single-speed models only.
A88413
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.
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.
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.
13
Step 3—Capacitors
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.)
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.
A91455
Fig. 12—Capacitors
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.
Capacitors are used as a phase-shifting device to aid in starting
certain single-phase motors. Check capacitors as follows.
1. After power is off, discharge capacitors as outlined above.
Disconnect capacitor from circuit. Put ohmmeter onRX10k
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.
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.
Exercise extreme caution when taking readings while power
is on. Electrical shock can cause personal injury or death.
Use the following formula to calculate capacitance:
Capacitance (mfd) = (2650 X amps) divided by (volts)
20-36
OHMS
BLUE
20 OHM
(BLUE COLOR)
12.5-22.5
12.5 OHM
(BEIGE COLOR)
OHMS
25-45
25 OHM
(BLUE COLOR)
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.
1. Shut off all power to system.
2. Check thermistor with ohmmeter as described below.
3. Shut off all power to unit.
4. Remove PTC from unit. Wait at least 10 minutes for PTC to
cool to ambient temperature.
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.
4. Reconnect start thermistor.
14
OHMS
A88414
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
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.
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.
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 Section on proper compressor-winding check.)
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.
3. Obtain a start capacitor in the range of 150–180µF 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, needlenose pliers and shorting a 15,000–ohm, 2–watt resistor across
terminals.
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.
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:
1. Turn off all power to unit.
2. Discharge start and run capacitors as outlined earlier.
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
L2
FIELD POWER
SUPPLY
L1
C
Start capacitor
(SC)
SC
temporarily
connected
Capacitance boosting
Fig. 14—Capacitance Boosting
15
R
C
COMP
RC
S
C
A00195
T2
T1
T3 T1 T2
HN67ZA002
A91438
T2
T1
T3
HN67ZA003
A91439
Fig. 15—Cycle-Protector Device
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.
Step 4—Cycle Protector
Solid-state cycle-protector device protects unit compressor by
preventing short cycling. After a system shutdown, cycle protector
provides fora5±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.)
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. After5±2minutes, voltmeter should read 24v,
indicating control is functioning normally. If no time delay is
encountered or device never times out, change control.
HN67ZA008
T1 YEL T2 VIO
HN67PA025
Step 5—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
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
16
T3
A94005
T3 BLK
T3 BLK
A91440
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