Carrier 38YCC Series Instructions and recipes

38YCC—50 Hz
Split System
Heat Pump
Installation and Start-Up Instructions
NOTE: Read the entire instruction manual before starting the
installation.
This symbol →indicates a change since the last issue.
SAFETY CONSIDERATIONS
Improper installation, adjustment, alteration, service, maintenance,
or use can cause explosion, fire, electrical shock, or other
conditions which may cause personal injury 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. Refer to the individual instructions pack-
aged with the kits or accessories when installing.
Follow all safety codes. Wear safety glasses and work gloves. Use
quenching cloth for brazing operations. Have fire extinguisher
available. Read these instructions thoroughly and follow all
warnings or cautions attached to the unit. Consult local building
codes and the national electric codes for special installation
requirements.
Recognize safety information. This is the safety-alert symbol .
When you see this symbol on the unit or in instructions and
manuals, be alert to the potential for personal injury.
Understand the signal words DANGER, WARNING, and CAU-
TION. These words are used with the safety-alert symbol. DAN-
GER 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.
Before installing, modifying, or servicing system, main elec-
trical disconnect switch must be in the OFF position. There
may be more than 1 disconnect switch. Lock out and tag
switch with a suitable warning label. Electrical shock can
cause personal injury or death.
INSTALLATION RECOMMENDATIONS
Refer to Fig. 2 for unit dimensional drawing.
NOTE: In some cases noise in the living area has been traced to
gas pulsations from improper installation of equipment.
1. Locate unit away from windows, patio decks, or any location
where sound may disturb customer.
2. Ensure that vapor and liquid tube diameters are appropriate to
capacity of unit.
3. Run refrigerant tubes as directly as possible by avoiding
unnecessary turns and bends.
4. Leave some slack between structure and unit to absorb
vibration.
5. When passing refrigerant tubes through the wall, seal opening
with RTV or other pliable silicon-based caulk. (See Fig. 3.)
6. Avoid direct tubing contact with water pipes, duct work, floor
joists, wall studs, floors, and walls.
7. Do not suspend refrigerant tubing from joists and studs with a
rigid wire or strap which comes in direct contact with tubing.
(See Fig. 3.)
8. Ensure that tubing insulation is pliable and completely sur-
rounds vapor tube.
9. When necessary, use hanger straps which are 1 in. (25.4mm)
wide and conform to shape of tubing insulation. (See Fig. 3.)
10. Isolate hanger straps from insulation by using metal sleeves
bent to conform to shape of insulation.
When outdoor unit is connected to factory-approved indoor unit,
outdoor unit contains system refrigerant charge for operation with
indoor unit of the same size when connected by 15 ft (4.57m) of
field-supplied or factory accessory tubing. For proper unit opera-
tion, check refrigerant charge using charging information located
on control box cover.
IMPORTANT: Maximum liquid line set is 3/8-in. O.D. for all
residential applications including long line.
IMPORTANT: Always install a liquid line filter drier. Refer to
Product Data Digest for appropriate part number.
INSTALLATION
Step 1—Check Equipment and Job Site
UNPACK UNIT — Move to final location. Remove carton taking
care not to damage unit.
INSPECT EQUIPMENT — File claim with shipping company
prior to installation if shipment is damaged or incomplete. Locate
unit rating plate on unit corner panel. It contains information
needed to properly install unit. Check rating plate to be sure unit
matches job specifications.
Fig. 1—Model 38YCC A97005
Visit www.carrier.com
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
Tab 5a 5a PC 101 Catalog No. 003-879 Printed in U.S.A. Form 38YCC-C3SI Pg 1 2-02 Replaces: 38YCC-C2SI

Fig. 2—Dimensional Drawing
Dimensions (In.)
UNIT
SIZE SERIES A B C D E F G H J K L M N P
024 70 22-1/2 33-15/16 3-3/16 5/8 3-11/16 18-1/8 19-3/4 21-5/8 14-3/8 18-7/8 22-1/16 12-1/2 12 14
036 70, 90 30 39-15/16 3-1/4 3/4 6-1/2 23-1/2 27-1/4 29-1/8 20 26-3/8 29-9/16 15 15-3/4 15-1/2
048 70, 90 30 33-15/16 3-1/4 7/8 6-1/2 23-1/2 27-1/4 29-1/8 20 26-3/8 29-9/16 15 15-3/4 15-1/2
048 92 30 33-15/16 3-1/4 7/8 6-1/2 23-1/2 27-1/4 29-1/8 20 26-3/8 29-9/16 15-1/4 15-5/8 15-1/2
060 90 30 33-15/16 3-1/4 7/8 6-1/2 23-1/2 27-1/4 29-1/8 20 26-3/8 29-9/16 15-3/4 15-5/8 15
060 92 30 33-15/16 3-1/4 7/8 6-1/2 23-1/2 27-1/4 29-1/8 20 26-3/8 29-9/16 15-5/8 15-3/4 15-1/8
Dimensions (mm)
UNIT
SIZE SERIES A B C D E F G H J K L M N P
024 70 571.5 862.0 81.0 15.9 93.6 460.4 501.7 549.3 365.1 479.4 560.4 317.5 304.8 355.6
036 70, 90 762.0 1014.4 82.6 19.1 165.1 596.9 692.2 739.8 508.0 669.9 750.9 381.0 400.1 393.7
048 70, 90 762.0 862.0 82.6 22.2 165.1 596.9 692.2 739.8 508.0 669.9 750.9 381.0 400.1 393.7
048 92 762.0 862.0 82.6 22.2 165.1 596.9 692.2 739.8 508.0 669.9 750.9 387.4 396.9 393.7
060 90 762.0 862.0 82.6 22.2 165.1 596.9 692.2 739.8 508.0 669.9 750.9 400.1 396.9 381.0
060 92 762.0 862.0 82.6 22.2 165.1 596.9 692.2 739.8 508.0 669.9 750.9 396.9 400.1 384.2
AIR DISCHARGE
AIR IN
ASQ
B
P
C
3/8 IN.
(9.5mm) DIA
TIEDOWN
KNOCKOUTS
(2) PLACES
27/8″
(73.0mm)
11/4″
(31.8mm)
H
G
F
E
FIELD CONTROL SUPPLY
CONN 7/8 IN. (22.2mm) DIA
HOLE
FIELD POWER SUPPLY CONN
7/8 IN. (22.2mm) DIA HOLE WITH
1 1/8 IN. (28.6mm) DIA KNOCKOUT
AND 1 3/8 IN. (34.9mm) DIA
KNOCKOUT
3/8 IN. (9.5mm) DIA LIQUID
LINE CONN
D DIA VAPOR LINE CONN
L
K
J
AIR IN
M
N
AIR DISCHARGE
AIR IN AIR IN
AIR DISCHARGE
NOTES:
1. Allow 30 in. (762.0 mm) clearance to service side of unit,
48 in. (1219.2 mm) above unit, 6 in. (152.4 mm) on one side,
12 in. (304.8 mm) on remaining side, and
24 in. (609.6 mm) between units for proper airflow.
2. Minimum outdoor operating ambient in cooling mode is 55°F (13°C)
(unless low ambient control is used) max. 125°F (52°C).
3. Maximum outdoor operating ambient in heating mode
is 66°F (19°C).
4. Series designation is the 13th position of the unit model number.
5. Center of gravity .
A97282
2

Step 2—Install on a Solid, Level Mounting Pad
If conditions or local codes require the unit be attached to pad, tie
down bolts should be used and fastened through knockouts
provided in unit base pan. Refer to unit mounting pattern in Fig. 4
to determine base pan size and knockout hole location.
On rooftop applications, mount on level platform or frame. Place
unit above a load-bearing wall and isolate unit and tubing set from
structure. Arrange supporting members to adequately support unit
and minimize transmission of vibration to building. Consult local
codes governing rooftop applications.
Roof mounted units exposed to winds above 5 mph may require
wind baffles to achieve adequate defrost. Consult Low-Ambient
Guideline for wind baffle construction.
NOTE: Unit must be level to within ±2˚ per compressor
manufacturer specifications.
Step 3—Clearance Requirements
When installing, allow sufficient space for airflow clearance,
wiring, refrigerant piping, and service. Allow 30-in. (762mm)
clearance to service end of unit and 48 in. (1219mm) above unit.
For proper airflow, a 6-in. (152mm) clearance on 1 side of unit and
12 in. (305mm) on all remaining sides must be maintained.
Maintain a distance of 24 in. (610mm) between units. Position so
water, snow, or ice from roof or eaves cannot fall directly on unit.
On rooftop applications, locate unit at least 6 in. (152mm) above
roof surface.
Step 4—Operating Ambients
The minimum outdoor operating ambient in cooling mode is 55˚F
(13˚C), and the maximum outdoor operating ambient in cooling
mode is 125˚F (52˚C). The maximum outdoor operating ambient in
heating mode is 66˚F (19˚C).
Step 5—Elevate Unit
Accumulation of water and ice in base pan may cause
equipment damage.
In areas where prolonged freezing temperatures are encountered,
elevate unit per local climate and code requirements to provide
clearance above estimated snowfall level and ensure adequate
drainage of unit. (See Fig. 5.)
Step 6—Check Indoor and Outdoor AccuRater®Piston
Check indoor coil piston to see if it matches the required piston
shown on outdoor unit rating plate. If it does not match, replace
indoor coil piston with piston shipped with outdoor unit. The
piston shipped with outdoor unit is correct for any approved indoor
coil combination.
Check outdoor unit piston. Remove retainer on liquid service valve
and check piston size with matching number listed on unit rating
plate.
Fig. 3—Connecting Tubing Installation A94028
INSULATION
VAPOR TUBE
LIQUID TUBE
OUTDOOR WALL INDOOR WALL
LIQUID TUBE
VAPOR TUBE
INSULATION
CAULK
Avoid contact between tubing and structureNOTE:
THROUGH THE WALL
HANGER STRAP
(AROUND VAPOR
TUBE ONLY)
JOIST
1″MIN.
SUSPENSION
Fig. 4—Mounting Unit to Pad
Dimensions (In.)
UNIT
SIZE
MINIMUM
MOUNTING PAD
DIMENSIONS
TIEDOWN KNOCKOUT LOCATIONS
ABC
024 22-1/2 X 22-1/2 3-11/16 18-1/8 14-3/8
036–060 30 X 30 6-1/2 23-1/2 20
Dimensions (mm)
UNIT
SIZE
MINIMUM
MOUNTING PAD
DIMENSIONS
TIEDOWN KNOCKOUT LOCATIONS
ABC
024 571.5 X 571.5 93.6 460.4 365.1
036–060 762.0 X 762.0 165.1 596.9 508.0
A94199
C
B
A
3⁄8″D. (9.53) TIEDOWN
KNOCKOUTS (2) PLACES
3

Remove indoor coil piston if unit is to be installed on system
with a TXV metering device.
Step 7—Make Piping Connections
Relieve pressure and recover all refrigerant before system
repair or final unit disposal to avoid personal injury or death.
Use all service ports and open all flow-control devices,
including solenoid valves.
To prevent compressor damage DO NOT bury more than 36
in. of refrigerant tubing. If ANY tubing is buried, provide 6
in. vertical rise at service valve.
To prevent damage to unit or service valves observe the
following:
•Use a brazing shield.
•Wrap service valves with wet cloth or use a heat sink
material.
Outdoor units may be connected to indoor section using accessory
tubing package or field-supplied refrigerant grade tubing of correct
size and condition. For tubing requirements beyond 50 ft (15.24m),
substantial capacity and performance losses can occur. Following
the recommendations in the Residential Split System Long-Line
Application Guideline will reduce these losses. Refer to Table 2
for accessory requirements.
For buried line applications greater than 36 in. (0.914m), refer to
Table 2 and Residential Split System Buried Line Application
Guideline. Buried line applications may not exceed 100 ft (30.5m).
If refrigerant tubes or indoor coil is exposed to atmosphere, it must
be evacuated to 500 microns to eliminate contamination and
moisture in the system.
OUTDOOR UNIT CONNECTED TO FACTORY-APPROVED
INDOOR UNIT —Outdoor unit contains correct system refriger-
ant charge for operation with indoor unit of same size when
connected by 15 ft (4.57m) of field-supplied or factory-accessory
tubing. Check refrigerant charge for maximum efficiency.
REFRIGERANT TUBING —Connect tubing to fittings on out-
door unit vapor and liquid service valves. (See Fig. 2 and 6.)
SWEAT CONNECTION —Use refrigerant grade tubing. Service
valves are closed from factory and ready for brazing. After
wrapping service valve with a wet cloth, tubing set can be brazed
to service valve using either silver bearing or non-silver bearing
brazing material. Consult local code requirements. Refrigerant
tubing and indoor coil are now ready for leak testing. This check
should include all field and factory joints.
IMPORTANT: Check factory tubing on both indoor and outdoor
unit to ensure tubes are not rubbing against each other or any sheet
metal. Pay close attention to feeder tubes, making sure wire ties on
feeder tubes are secure and tight.
IMPORTANT: Always install a liquid line filter drier. Refer to
Product Data Digest for appropriate part number.
Step 8—Make Electrical Connections
To avoid personal injury or death, do not supply power to unit
with compressor terminal box cover removed.
Be sure field wiring complies with local and national fire, safety,
and electrical codes, and voltage to system is within limits shown
on unit rating plate. Contact local power company for correction of
improper voltage. See unit rating plate for recommended circuit
protection device.
NOTE: Operation of unit on improper line voltage constitutes
abuse and could affect unit reliability. See unit rating plate. Do not
install unit in system where voltage may fluctuate above or below
permissible limits.
NOTE: Use copper wire only between disconnect switch and
unit.
NOTE: Install branch circuit disconnect per local codes to handle
unit starting current. Locate disconnect within sight from and
readily accessible from unit per local codes.
Fig. 5—Accessory Heat Pump Feet A97006
SERVICE
ACCESS
Fig. 6—Service Valve with Sweat Adapter Tube
A94029
PISTON BODY
PISTON
PISTON RETAINER
SWEAT/FLARE ADAPTER
4

ROUTE GROUND AND POWER WIRES —Remove access
panel and control box cover to gain access to unit wiring. Extend
wires from disconnect through power wiring hole provided and
into unit control box. (See Fig. 2.) Size wires per local codes but
not smaller than minimum wire size shown on unit rating plate.
CONNECT GROUND AND POWER WIRES —Connect ground
wire to ground connection in control box for safety. Connect
power wiring to contactor as shown in Fig. 7.
The unit cabinet must have an uninterrupted or unbroken
ground to minimize personal injury if an electrical fault
should occur. The ground may consist of electrical wire or
metal conduit when installed in accordance with existing
electrical codes. Failure to follow this warning can result in an
electric shock, fire, or death.
NOTE: Use No. 18 AWG (American Wire Gage) color-coded,
insulated (35°C minimum) wires. If thermostat is located more
than 100 ft (30.5m) from unit (as measured along the control
voltage wires), use No. 16 AWG color-coded wires to avoid
excessive voltage drop.
CONNECT CONTROL WIRING —Route 24-v control wires
through control wiring grommet and connect leads to control
wiring pigtails from terminal board. (See Fig. 8.)
Use furnace transformer, fan coil transformer, or accessory trans-
former for control power, 24-v/40-va minimum.
NOTE: Use of available 24-v accessories may exceed the mini-
mum 40-va power requirement. Determine total transformer load-
ing and increase the transformer capacity or split the load with an
accessory transformer as required.
NOTE: The defrost timer is factory set for 90-minute cycles. The
timer can be field set for 30- and 50-minute cycles depending on
defrost conditions in your geographic location.
IMPORTANT: Check factory wires and wire connections to
ensure terminations are secured properly. Check wire routing to
ensure wires are not in contact with tubing, sheet metal, etc.
Table 1—Refrigerant Connections and Recommended Liquid and Vapor Tube Diameters
LIQUID VAPOR VAPOR (LONG LINE)
UNIT SIZE Connection Diameter Tube Diameter Connection Diameter Tube Diameter Connection Diameter Tube Diameter
In. mm In. mm In. mm In. mm In. mm In. mm
024 3/8 9.53 3/8 9.53 5/8 15.88 5/8 15.88 5/8 15.88 3/4 19.05
036 3/8 9.53 3/8 9.53 3/4 19.05 3/4 19.05 3/4 19.05 7/8 22.23
048 3/8 9.53 3/8 9.53 7/8 22.23 7/8 22.23 7/8 22.23 1-1/8 28.58
060 3/8 9.53 3/8 9.53 7/8 22.23 1-1/8 28.58 7/8 22.23 1-1/8 28.58
NOTES:
1. Tube diameters are for lengths up to 50 ft (15.24m). For tubing lengths greater than 50 ft (15.24m), consult Residential Long-Line Application Guideline.
2. Do not apply capillary tube indoor coils to these units.
Table 2—Accessory Usage
ACCESSORY
REQUIRED FOR
LOW-AMBIENT
APPLICATIONS
(BELOW 55°F/12.8˚C)
REQUIRED FOR
LONG-LINE
APPLICATIONS*
(OVER 50 FT/15.24M)
REQUIRED FOR
BURIED LINE
APPLICATIONS†
(OVER 3 FT/0.914M)
Crankcase Heater Yes Yes Yes
Evaporator Freeze Thermostat Yes No No
Winter Start Control Yes‡No No
Accumulator No No Yes
Compressor Start Assist
Capacitor and Relay Yes Yes Yes
MotorMaster® Control Yes No No
Wind Baffle See Low-Ambient Instructions No No
Coastal Filter No No No
Support Feet Recommended No No
Liquid-Line Solenoid Valve
or
Hard Shutoff TXV No See Long-Line
Application
Guideline Yes
* For tubing line sets between 50 and 175 ft (15.24 and 53.34m), refer to Residential Split System Long-Line Application Guideline.
†For buried line applications, refer to Residential Split System Buried Line Application Guideline.
‡Only when low-pressure switch is used.
Fig. 7—Line Power Connections A94025
DISCONNECT
PER N.E.C. AND/OR
LOCAL CODES CONTACTOR
GROUND
LUG
FIELD GROUND
WIRING
FIELD POWER
WIRING
BLUE
3 PHASE ONLY
5

Fig. 8—24-v Control Circuit Connections A94332
FACTORY WIRING
FIELD WIRING
OUTDOOR THERMOSTAT
C
W2
L
G
Y
E
O
R
THERMOSTAT
SUBBASE INDOOR
SPLICE
CONNECTION
OUTDOOR
SPLICE
CONNECTION
DEFROST
BOARD
C
W2
L
G
Y
E
O
R
ODT
THERMOSTAT
SUBBASE INDOOR
SPLICE
CONNECTION
OUTDOOR
SPLICE
CONNECTION
DEFROST
BOARD
SHR
SHR
EHR
ODT
ODT
EMERGENCY HEAT RELAY
FIELD SPLICE
EHR
ODT
REMOVE WIRES FROM CRIMP NUT IN INDOOR FAN COIL WHEN INSTALLING OUTDOOR THERMOSTATS.
SYSTEMS WITH ONE OUTDOOR THERMOSTAT SYSTEMS WITH TWO OUTDOOR THERMOSTATS
G
R
W3
C
W2E
O
R
G
R
W3
C
E
IMPORTANT: WHEN USING OUTDOOR THERMOSTATS, W2MUST BE ENERGIZED WHEN REQUESTING
SUPPLEMENTAL HEAT.
C
W2
Y
W2
O
R
C
W2
Y
W2
C
L
G
Y
E
O
R
THERMOSTAT
SUBBASE
INDOOR
SPLICE
CONNECTION
OUTDOOR
SPLICE
CONNECTION DEFROST BOARD
FOR USE WITH FB4 FAN COILS
SYSTEMS WITHOUT OUTDOOR THERMOSTATS
C
G
R
W2
C
Y
O
R
W2
6

Step 9—Compressor Crankcase Heater
When equipped with a crankcase heater, energize heater a mini-
mum of 24 hr before starting unit. To energize heater only, set
thermostat to OFF and close electrical disconnect to outdoor unit.
A crankcase heater is required if the refrigerant tubing is longer
than 50 ft.
Step 10—Install Electrical Accessories
Refer to the individual instructions packaged with the kits or
accessories when installing.
Step 11—Start-Up and Check Charge
Do not operate unit in the vicinity of toxic or flammable
material. Failure to follow this warning can result in personal
injury, fire, or death.
To prevent compressor damage or personal injury, observe
the following:
•Do not overcharge system with refrigerant.
•Do not operate unit in a vacuum or at negative pressure.
•Do not disable low-pressure switch In scroll compressor
applications:
•Dome temperatures may be hot.
To prevent personal injury wear safety glasses, protective
clothing, and gloves when handling refrigerant and observe
the following:
•Back seating service valves are not equipped with Schrader
valves. Fully back seat (counter clockwise) valve stem before
removing gage port cap.
•Front seating service valves are equipped with Schrader
valves.
Do not vent refrigerant to atmosphere. Recover during system
repair or final unit disposal.
1. If equipped with a crankcase heater, energize a minimum of
24 hr before starting unit. To energize heater only, set
thermostat OFF and close electrical disconnect to outdoor
unit.
2. Fully open liquid and vapor service valves.
3. Unit is shipped with valve stem(s) front seated and caps
installed. Replace stem caps after system is opened to refrig-
erant flow. Replace caps finger tight and tighten additional
1/12 turn using a backup wrench on valve body flats to prevent
distortion of sheet metal.
4. Close electrical disconnects to energize system.
5. Set room thermostat at desired temperature.
6. Set room thermostat to HEAT or COOL and fan to ON or
AUTO mode, as desired. Operate unit for 15 minutes. Check
system refrigerant charge.
7. Factory charge is shown on unit rating plate. Adjust charge in
cooling mode by following procedure shown in charging
table. Check charge in heating mode by following procedure
shown on heating check chart. Both are located on unit.
•3-phase scroll compressors are rotation sensitive.
•A flashing LED on phase monitor indicates reverse rotation.
(See Fig. 9 and Table 3.)
•This will not allow contactor to be energized.
•Disconnect power to unit and interchange 2 field wiring
leads on unit contactor.
SEQUENCE OF OPERATION —With power supplied to indoor
and outdoor units, transformer is energized. Defrost control board
is equipped with 5-minute lockout timer which may be initiated
upon any interruption of power.
Cooling
On a call for cooling, the thermostat makes circuits R-O, R-Y, and
R-G. Circuit R-O energizes reversing valve, switching it to cooling
position. On three phase models with scroll compressors, the units
are equipped with a phase monitor to detect if the incoming power
is correctly phased for compressor operation. (See Fig. 9 and Table
3.) If phasing is correct, circuit R-Y energizes contactor, starting
outdoor fan motor and compressor circuit. R-G energizes indoor
unit blower relay, starting indoor blower motor on high speed.
NOTE: If the phasing is incorrect, the contactor will not be
energized. To correct the phasing, interchange any two of the three
power connections on the field side.
When thermostat is satisfied, its contacts open, de-energizing
contactor and blower relay. Compressor and motors stop.
NOTE: If indoor unit is equipped with a time-delay relay circuit,
the blower runs an additional 90 sec to increase system efficiency.
Heating
On a call for heating, the thermostat makes circuits R-Y and R-G.
If phasing is correct, circuit R-Y energizes contactor, starting
outdoor fan motor and compressor. Circuit R-G energizes indoor
blower relay, starting blower motor on high speed.
Should the temperature continue to fall, R-W2 is made through the
second-stage room thermostat bulb. Circuit R-W2 energizes a
sequencer, bringing on the first bank supplemental electric heat
and providing electrical potential to the second heater sequencer (if
used). If outdoor temperature falls below the setting of the outdoor
thermostat (field-installed option), contacts close to complete the
circuit and bring on the second bank of supplemental electric heat.
Table 3—Phase Monitor LED Indicators
LED STATUS
OFF No call for compressor
operation
FLASHING Reversed phase
ON Normal
Fig. 9—Phase Monitor Control A00010
7

When the thermostat is satisfied, its contacts open, de-energizing
contactor and sequencer. All heaters and motors should stop.
Quiet Shift
Quiet Shift is a field-selectable defrost mode, which will eliminate
occasional noise that could be heard at the start of the defrost cycle
and restarting of heating cycle. It is selected by placing DIP switch
3 (on defrost board) in ON position.
When Quiet Shift switch is placed in ON position, and a defrost is
initiated, the following sequence of operation will occur. Revers-
ing valve will energize, compressor will turn off for 30 sec, then
turn back on to complete defrost. At the start of heating cycle after
conclusion of defrost mode, reversing valve will de-energize, the
compressor will turn off for another 30 sec, and the fan will turn
off for 40 sec, before starting in the heating mode.
Defrost
The defrost control is a time/temperature control which includes a
field-selectable time period (DIP switch 1 and 2 on the board)
between defrost cycles of 30, 60, 90, or 120 minutes (factory set at
90 minutes).
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 flat head screwdriver in between for 5 sec and
releasing, to observe a complete defrost cycle. When the Quiet
Shift switch is selected, compressor will be turned off for two 30
sec intervals during this complete defrost cycle as explained
previously. 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 flat head screwdriver) for 5 sec 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 sec
compressor off period followed by 30 sec of defrost with com-
pressor operation). On return to heating operation, compressor will
again turn off for an additional 30 sec and the fan for 40 sec. When
the Quiet Shift is in OFF position, only a brief 30 sec cycle will be
observed.
If it is desirable to observe a complete defrost in warmer weather,
the thermostat must be closed as follows:
1. Turn off power to outdoor unit.
2. Disconnect outdoor fan motor lead from OF2 on control board
(See Fig. 10.) Tape to prevent grounding.
3. Restart unit in heating mode, allowing frost to accumulate on
outdoor coil.
4. After a few minutes in heating mode, liquid line temperature
should drop below closing point of defrost thermostat (ap-
proximately 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.
5. Turn off power to outdoor and reconnect fan motor lead to
OF2 on control board after above forced defrost cycle.
Step 12—Final Checks
IMPORTANT: Before leaving job, be sure to do the following:
1. Securely fasten all panels and covers.
2. Tighten service valve stem caps to 1/12-turn past finger tight.
3. Leave User’s Manual with owner. Explain system operation
and periodic maintenance requirements outlined in manual.
CARE AND MAINTENANCE
For continuing high performance and to minimize possible equip-
ment failure, periodic maintenance must be performed on this
equipment.
Frequency of maintenance may vary depending upon geographic
areas, such as coastal applications.
OF2
CESO130076–00
OF1
ON
QUIET SHIFT
120
30 60
60 30
90
INTERVAL TIMER OFF
P3
DFT
O R W2Y C
T2 C C O
DFT
T1 Y P1 J1
SPEEDUP
Speedup
Pins Defrost interval DIP switches
Quiet
Shift A99442
Figure 10—Defrost Control
Copyright 2002 CARRIER Corp. •7310 W. Morris St. •Indianapolis, IN 46231 38yccc3s
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
Tab 5a 5a PC 101 Catalog No. 003-879 Printed in U.S.A. Form 38YCC-C3SI Pg 8 2-02 Replaces: 38YCC-C2SI
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