Carrier Heat Pump 38YCW User Manual

38YCW  
10 SEER 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 death, 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  
packaged with the kits or accessories when installing.  
Follow all safety codes. Wear safety glasses, protective clothing,  
and work gloves. Use quenching cloth for brazing operations.  
Have fire extinguisher available. Read these instructions thor-  
oughly and follow all warnings or cautions included in literature  
and attached to the unit. Consult local building codes and National  
Electrical Code (NEC) for special requirements.  
A98525  
Fig. 1—Model 38YCW  
Recognize safety information. This is the safety-alert symbol  
When you see this symbol on the unit and in instructions or  
manuals, be alert to the potential for personal injury.  
.
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. 2.)  
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.  
6. Avoid direct refrigerant 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 that comes in direct contact with tubing.  
(See Fig. 2.)  
8. Ensure that refrigerant tubing insulation is pliable and com-  
pletely surrounds vapor tube.  
9. When necessary, use hanger straps which are 1 in. wide and  
conform to shape of tubing insulation. (See Fig. 2.)  
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(es) with a suitable warning label. Electrical shock can  
cause personal injury or death.  
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 of  
field-supplied or factory-accessory tubing. For proper unit opera-  
tion, check refrigerant charge using charging information located  
on control-box cover and/or in the Check Charge section of this  
Instruction.  
INTRODUCTION AND RECOMMENDATIONS  
NOTE: In some cases noise has been traced to improper instal-  
lation of equipment.  
1. Locate unit away from windows, patios, decks, and so forth  
where unit operation sounds may disturb customer.  
IMPORTANT: Maximum liquid-line size is 5/8-in. O.D. for all  
residential applications including long line applications.  
2. Ensure that vapor- and liquid-tube diameters are appropriate to  
capacity of unit.  
IMPORTANT: Always install a liquid-line filter drier. Refer to  
Product Data Digest for appropriate part number. Obtain filter  
drier from your distributor or branch.  
3. Run refrigerant tubes as directly as possible by avoiding  
unnecessary turns and bends.  
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.  
Book  
Tab 5a 5a  
1
4
PC 101  
Catalog No. 533-80020  
Printed in U.S.A.  
Form 38YCW-3SI  
Pg 1  
2-02  
Replaces: 38YCC-4SI  
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Table 1Refrigerant Connections and Recommended Liquid- and Vapor-Tube Diameters (In.)  
LIQUID  
Connection Diameter  
VAPOR  
Connection Diameter  
VAPOR (LONG LINE)  
Connection Diameter Tube Diameter  
UNIT  
SIZE  
Tube Diameter  
Tube Diameter  
018, 024  
030, 036  
042, 048  
060  
3/8  
3/8  
3/8  
3/8  
3/8  
3/8  
3/8  
3/8  
3/4  
3/4  
7/8  
7/8  
3/4  
3/4  
3/4  
3/4  
7/8  
7/8  
3/4  
7/8  
7/8  
1-1/8  
1-1/8  
1-1/8  
NOTES:  
1. Tube diameters are for lengths up to 50 ft. For tubing lengths greater than 50 ft, consult Long Line section of the Application Guideline.  
2. Do not apply capillary-tube indoor coils to these units.  
Step 8Make Piping Connections  
non-silver-bearing brazing material. Consult local code re-  
quirements.  
Refrigerant tubing and indoor coil are now ready for leak testing.  
This check should include all field and factory joints.  
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.  
PISTON BODY  
If ANY refrigerant tubing is buried, provide a 6 in. vertical  
rise at service valve. Refrigerant tubing lengths up to 36 in.  
may be buried without further special consideration. For  
lengths above 36 in., consult your local distributor.  
PISTON  
PISTON  
RETAINER  
To prevent damage to unit or service valves observe the  
following:  
Use a brazing shield.  
STRAINER  
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 cor-  
rect size and condition. For tubing requirements beyond 50 ft  
length or 20 ft vertical differential, 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 1 for field-tubing diam-  
eters.  
SWEAT/FLARE ADAPTER  
A97512  
Fig. 4Liquid-Service Valve with Sweat-Adapter  
Tube  
FINAL TUBING CHECK  
REFRIGERANT TUBING  
IMPORTANT: Check to be certain factory tubing on both indoor  
and outdoor unit has not shifted during shipment. 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.  
Connect tubing to fittings on outdoor unit vapor- and liquid-  
service valves. (See Table 1.) Use refrigerant-grade tubing. Refer  
to appropriate section below for type of service valves installed on  
unit.  
Step 9Make Electrical Connections  
SWEAT CONNECTION  
To avoid personal injury or death, do not supply power to unit  
with compressor terminal-box cover removed.  
To avoid valve damage while brazing, service valves must be  
wrapped in a heat-sinking material such as a wet cloth.  
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.  
1. Remove plastic retainer holding outdoor piston in liquid-  
service valve.  
2. Locate adapter tube shipped with unit.  
3. Install strainer in adapter tube and connect tube to service  
valve. (See Fig. 4.)  
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 or phase imbalance (3 phase)  
may fluctuate above or below permissible limits.  
4. Connect refrigerant tubing to fittings on outdoor-unit vapor-  
and liquid-service valves.  
5. 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  
NOTE: Use copper wire only between disconnect switch and  
unit.  
3
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NOTE: Install branch-circuit disconnect of adequate size per  
NEC to handle unit-starting current. Locate disconnect within sight  
from and readily accessible from unit, per Section 440-14 of NEC.  
only, set thermostat to OFF and close electrical disconnect to  
outdoor unit. A crankcase heater is required if refrigerant tubing is  
longer than 50 ft.  
ROUTE GROUND AND POWER WIRES  
Step 11Install Electrical Accessories  
Remove access panel and control box to gain access to unit wiring.  
Extend wires from disconnect through power-wiring hole provided  
and into unit-control box.  
Refer to the individual instructions packaged with kits or acces-  
sories when installing.  
Step 12Start-Up  
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.  
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.  
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. 5.  
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 (counterclockwise) valve stem before  
removing gage-port cap.  
DISCONNECT  
PER N.E.C. AND/OR  
LOCAL CODES  
CONTACTOR  
Front-seating service valves are equipped with Schrader  
valves.  
FIELD POWER  
WIRING  
BLUE  
3 PHASE ONLY  
FIELD GROUND  
WIRING  
Do not vent refrigerant to atmosphere. Recover during system  
repair or final unit disposal.  
GROUND  
LUG  
If refrigerant tubes or indoor coil are exposed to atmosphere, they  
must be evacuated to 500 microns to eliminate contamination and  
moisture in the system.  
A94025  
Fig. 5Line Power Connections  
CONNECT CONTROL WIRING  
Follow these steps to properly start up the system:  
1. Fully back seat (open) liquid- and vapor-tube service valves.  
Route 24v control wires through control-wiring grommet and  
connect leads to control wiring. Refer also to Installation Instruc-  
tions packaged with thermostat.  
2. Unit is shipped with valve stem(s) front seated (closed) and  
caps installed. Replace stem caps after system is opened to  
refrigerant flow. Replace caps finger-tight and tighten with  
wrench an additional 1/12 turn.  
Use No. 18 AWG color-coded, insulated (35°C minimum) wire. If  
thermostat is located more than 100 ft from unit, as measured  
along the control-voltage wires, use No. 16 AWG color-coded  
wire to avoid excessive voltage drop.  
3. Close electrical disconnects to energize system.  
4. Set room thermostat to desired temperature. Be sure set point  
is below indoor ambient temperature.  
All wiring must be NEC Class 1 and must be separated from  
incoming power leads.  
5. Set room thermostat to HEAT or COOL and fan control to ON  
or AUTO, as desired. Operate unit for a minimum of 15  
minutes. Check system refrigerant charge.  
Use furnace transformer, fan-coil transformer, or accessory trans-  
former for control power, 24v/40va minimum.  
NOTE: Use of available 24v accessories may exceed the mini-  
mum 40va power requirement. Determine total transformer load-  
ing and increase the transformer capacity or split the load with an  
accessory transformer as required.  
3-phase scroll compressors are rotation sensitive.  
A flashing LED on phase monitor indicates reverse rotation.  
(See Fig. 7 and Table 2.)  
This will not allow contactor to be energized.  
Disconnect power to unit and interchange 2 field-wiring  
leads on unit contactor.  
FINAL WIRING CHECK  
IMPORTANT: Check factory wiring and field-wire connections  
to ensure terminations are secured properly. Check wire routing to  
ensure wires are not in contact with tubing, sheet metal, and so  
forth.  
Step 13Check Charge  
Step 10Compressor Crankcase Heater  
Factory charge is shown on unit-rating plate. To check charge in  
cooling mode, refer to Cooling-Only Procedure on unit wiring and  
charging label.  
When equipped with a crankcase heater, furnish power to heater a  
minimum of 24 hr before starting unit. To furnish power to heater  
4
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COOLING-ONLY PROCEDURE  
NOTE: If superheat- or subcooling-charging conditions are not  
favorable, charge must be weighed in accordance with unit-rating  
plate ±0.6 oz/ft of 3/8-in. liquid line above or below 15 ft  
respectively.  
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  
HEATING CHECK-CHART PROCEDURE  
To check system operation during heating cycle, refer to the  
Heating Check Chart on outdoor unit. This chart indicates whether  
a correct relationship exists between system operating pressure and  
air temperature entering indoor and outdoor units. If pressure and  
temperature do not match on chart, system-refrigerant charge may  
not be correct. Do not use chart to adjust refrigerant charge.  
NOTE: When charging is necessary during heating season,  
charge must be weighed in accordance with unit rating plate ±0.6  
oz/ft of 3/8-in. liquid line above or below 15 ft respectively.  
A00010  
Table 2Phase-Monitor LED Indicators  
LED  
OFF  
STATUS  
Step 14Final Checks  
No call for compressor  
operation  
IMPORTANT: Before leaving job, be sure to do the following:  
1. Securely fasten all panels and covers.  
FLASHING  
ON  
Reversed phase  
Normal  
2. Tighten service valve-stem caps to 1/12-turn past finger-tight.  
Fig. 7Phase-Monitor Control  
3. Leave Users Manual with owner. Explain system operation  
and periodic maintenance requirements outlined in manual.  
4. Fill out Dealer Installation Checklist and place in customer  
file.  
5
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FA, FB, FC,  
FD, FF, FH  
FAN COIL  
ONE  
OUTDOOR  
THERMOSTAT  
OTHER  
NON-PROGRAMMABLE  
HP THERMOSTAT  
FA, FB, FC,  
FD, FF  
FAN COIL  
OTHER  
HP THERMOSTAT  
HEAT  
PUMP  
HEAT  
PUMP  
ODT  
R
C
W3  
R
R
R
C
24 VAC HOT  
24 VAC COM  
HEAT STAGE 2  
R
C
24 VAC HOT  
24 VAC COM  
HEAT STAGE 2  
R
C
C
C
W2  
W2  
W
Y
W2  
Y
W2  
W2  
COOL/HEAT  
STAGE 1  
COOL/HEAT  
STAGE 1  
Y
E
G
G
INDOOR FAN  
G
Y
INDOOR FAN  
G
O
O
E
RVS COOLING  
RVS COOLING  
O
O
EMERGENCY  
HEAT  
EMERGENCY  
HEAT  
E
NOTE: Remove wires from crimp nut in indoor fan coil  
when installing outdoor thermostat.  
IMPORTANT: When using outdoor thermostat, W must be  
2
energized when requesting supplemental heat.  
CARRIER  
CARRIER  
PROGRAMMABLE  
THERMOSTAT  
MODEL HP  
PROGRAMMABLE  
THERMOSTAT  
MODEL HP  
40FKA  
FK4C  
FAN COIL  
FA, FB, FC,  
FD, FF, FH  
FAN COIL  
HEAT  
PUMP  
HEAT  
PUMP  
DH  
R
J1 JUMPER  
R
R
G
R
24 VAC HOT  
INDOOR FAN  
HEAT STAGE 2  
R
24 VAC HOT  
INDOOR FAN  
HEAT STAGE 2  
R
G
G
G
*
W2  
W2  
W/W1  
Y/Y2  
W/W1  
Y/Y2  
W1  
W2  
*
*
E
COOL/HEAT  
STAGE 1  
COOL/HEAT  
STAGE 1  
J2 JUMPER  
W3  
W2  
Y
RVS COOLING O/W2  
RVS COOLING O/W2  
Y
Y/Y2  
O
NOT USED  
Y1/W2  
O
NOT USED  
Y1/W2  
O
C
C
C
B
L
24 VAC COM  
NOT USED  
TROUBLE  
C
B
L
C
24 VAC COM  
NOT USED  
TROUBLE  
C
Y1  
IF AVAILABLE  
*
S1  
S2  
OPTIONAL  
OUTDOOR  
SENSOR  
S1  
S2  
OPTIONAL  
OUTDOOR  
SENSOR  
CONNECTION  
CONNECTION  
CARRIER  
PROGRAMMABLE  
THERMOSTAT  
MODEL HP  
CARRIER  
ONE  
OUTDOOR  
THERMOSTAT  
FA, FB, FC,  
FD, FF, FH  
FAN COIL  
TWO  
OUTDOOR  
PROGRAMMABLE  
THERMOSTAT  
MODEL HP  
FA, FB, FC, FD, FF, FH  
FAN COIL  
HEAT  
PUMP  
HEAT  
PUMP THERMOSTATS  
ODT  
W3  
R
W3  
R
R
G
24 VAC HOT  
INDOOR FAN  
HEAT STAGE 2  
R
G
24 VAC HOT  
INDOOR FAN  
HEAT STAGE 2  
EHR  
R
R
G
G
W/W1  
Y/Y2  
W/W1  
Y/Y2  
ODT  
W2  
W2  
W2  
Y
W2  
COOL/HEAT  
STAGE 1  
COOL/HEAT  
STAGE 1  
E
RVS COOLING O/W2  
EHR  
Y1/W2  
RVS COOLING O/W2  
Y
O
NOT USED  
NOT USED  
Y1/W2  
ODT  
O
E
C
C
B
L
24 VAC COM  
NOT USED  
TROUBLE  
C
B
L
24 VAC COM  
NOT USED  
TROUBLE  
EHR  
C
C
C
S1  
S2  
S1  
S2  
OPTIONAL  
OUTDOOR  
SENSOR  
OPTIONAL  
OUTDOOR  
SENSOR  
CONNECTION  
CONNECTION  
NOTE: Remove wires from crimp nut in indoor fan coil  
when installing outdoor thermostats.  
NOTE: Remove wires from crimp nut in indoor fan coil  
when installing outdoor thermostat.  
IMPORTANT: When using outdoor thermostats, W must be  
2
energized when requesting supplemental heat.  
IMPORTANT: When using outdoor thermostat, W must be  
2
energized when requesting supplemental heat.  
A01384  
Fig. 6Typical 24v Circuit Connections  
6
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WIRING DIAGRAM NOTES:  
When thermostat is satisfied, its contacts open, de-energizing  
contactor and sequencer. All heaters and motors should stop.  
1. CARRIER THERMOSTAT-WIRING DIAGRAMS ARE  
ONLY ACCURATE FOR MODEL NUMBERS BEGINNING  
WITH TSTAT_ _ _ _ _ _ _.  
When the thermostat is satisfied, its contacts open, de-energizing  
contactor and sequencer. All heaters and motors should stop.  
2. WIRING MUST CONFORM TO NEC OR LOCAL CODES.  
3. SOME UNITS ARE EQUIPPED WITH PRESSURE  
SWITCH(ES), TEMPERATURE SWITCH, OR 5MINUTE  
COMPRESSOR-CYCLE PROTECTION. CONNECT 24V  
FIELD WIRING TO FACTORY-PROVIDED STRIPPED  
LEADS.  
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.  
4. THERMOSTATS ARE FACTORY CONFIGURED WITH  
5-MINUTE COMPRESSOR-CYCLE PROTECTION AND  
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.  
4-CYCLES-PER-HR  
LIMIT.  
SEE  
THERMOSTAT-  
INSTALLATION INSTRUCTIONS FOR DETAILS.  
5. TO STAGE ELECTRIC-RESISTANCE HEAT, CONSULT  
OUTDOOR THERMOSTAT-INSTALLATION INSTRUC-  
TIONS.  
6. UNDERLINED LETTER ON DUAL TERMINAL INDI-  
CATES ITS USAGE.  
FOR EXAMPLE: O/W2 MEANS O; O/W2MEANS W2  
7. OUTDOOR-TEMPERATURE SENSOR MUST BE AT-  
TACHED IN ALL DUAL-FUEL INSTALLATIONS. JUMPER  
WIRE BETWEEN O/W2 AND L THERMOSTAT TERMINALS  
MUST BE PRESENT.  
8. Y1 AND O CONNECTIONS TO 2STAGE FURNACES  
MAY NOT EXIST OR MAY ONLY BE A WIRE RATHER  
THAN A SCREW TERMINAL.  
SEQUENCE OF OPERATION  
NOTE: Defrost-control board is equipped with 5-minute lockout  
timer that may be initiated upon any interruption of power.  
With power supplied to indoor and outdoor units, transformer is  
energized.  
CESO13007600  
Speedup  
Pins  
Quiet  
Shift  
Defrost interval  
DIP switches  
Cooling  
A91444  
On a call for cooling, thermostat makes circuits R-O, R-Y, and  
R-G. Circuit R-O energizes reversing valve, switching it to cooling  
position. On 3-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. If phasing is correct,  
circuit R-Y energizes contactor, starting outdoor-fan motor and  
compressor circuit. R-G energizes indoor unit-blower relay, start-  
ing indoor-blower motor on high speed.  
Fig. 8Defrost Control  
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).  
NOTE: If the phasing is incorrect, the contactor will not be  
energized. To correct the phasing, interchange any 2 of the 3  
power connections on the field side.  
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.  
When thermostat is satisfied, its contacts open, de-energizing the  
contactor and blower relay. Compressor and motors should 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, 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.  
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.  
Should temperature continue to fall, R-W2 is made through  
second-stage room-thermostat bulb. Circuit R-W2 energizes a  
sequencer, bringing on first bank of supplemental electric heat and  
providing electrical potential to second heater sequencer (if used).  
If outdoor temperature falls below setting of outdoor thermostat  
(field-installed option), contacts close to complete circuit and bring  
on second bank of supplemental electric heat.  
7
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If it is desirable to observe a complete defrost in warmer weather,  
the thermostat must be closed as follows:  
Step 1Final Checks  
IMPORTANT: Before leaving job, be sure to do the following:  
1. Securely fasten all panels and covers.  
1. Turn off power to outdoor unit.  
2. Disconnect outdoor fan motor lead from OF2 on control  
board. (See Fig. 8.) Tape to prevent grounding.  
2. Tighten service valve stem caps to 1/12-turn past finger tight.  
3. Leave Users Manual with owner. Explain system operation  
3. Restart unit in heating mode, allowing frost to accumulate on  
outdoor coil.  
and periodic maintenance requirements outlined in manual.  
4. After a few minutes in heating mode, liquid line temperature  
should drop below closing point of defrost thermostat (ap-  
proximately 30°F).  
CARE AND MAINTENANCE  
For continuing high performance and to minimize possible equip-  
ment failure, periodic maintenance must be performed on this  
equipment.  
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.  
Frequency of maintenance may vary depending upon geographic  
areas, such as coastal applications.  
5. Turn off power to outdoor and reconnect fan motor lead to  
OF2 on control board after above forced defrost cycle.  
Copyright 2002 CARRIER Corp. 7310 W. Morris St. Indianapolis, IN 46231  
38ycw3si  
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.  
Book  
Tab 5a 5a  
1
4
PC 101  
Catalog No. 533-80020  
Printed in U.S.A.  
Form 38YCW-3SI  
Pg 8  
2-02  
Replaces: 38YCC-4SI  
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