Carrier Air Conditioner 25HCR User Manual

25HCR  
COMFORTt SERIES R---22 HEAT PUMPS  
SIZES 18 TO 60  
1---1/2 TO 5 NOMINAL TONS  
Installation Instructions  
TABLE OF CONTENTS  
PAGE  
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . 2  
INSTALLATION RECOMMENDATIONS . . . . . . . . . . . . . 2  
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 -- 10  
Step 1 -- Check Equipment & Jobsite . . . . . . . . . . . . . . . 3  
Step 2 -- Install on Solid Pad . . . . . . . . . . . . . . . . . . . . . . 3  
Step 3 -- Clearance Requirements . . . . . . . . . . . . . . . . . . 3  
Step 4 -- Operating Ambient . . . . . . . . . . . . . . . . . . . . . . 3  
Step 5 -- Install TXV . . . . . . . . . . . . . . . . . . . . . . . . . 3 -- 4  
Step 6 -- Check Defrost Thermostat . . . . . . . . . . . . . . . . . 4  
Step 7 -- Make Piping Connections . . . . . . . . . . . . . . 4 -- 6  
Step 8 -- Make Electrical Connections . . . . . . . . . . . . 6 -- 7  
Step 9 -- Compressor Crankcase Heater . . . . . . . . . . . . . 7  
Step 10 -- Install Electrical Accessories . . . . . . . . . . . . . . 7  
Step 11 -- Start--Up . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 -- 9  
Step 12 -- Check Charge . . . . . . . . . . . . . . . . . . . . . . . . . 10  
Step 13 -- Final Checks . . . . . . . . . . . . . . . . . . . . . . . . . . 10  
CARE AND MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . 10  
A05341  
Fig. 1 --- 25HCR  
NOTE: Read the entire instruction manual before starting the  
installation.  
 
INSTALLATION  
STEP 1 Check Equipment and Job Site  
Unpack Unit  
On rooftop applications, locate unit at least 6 in. above roof  
surface.  
STEP 4 Operating Ambient  
The minimum outdoor operating ambient in cooling mode is  
55°F, and the maximum outdoor operating ambient in cooling  
mode is 125°F. The maximum outdoor operating ambient in  
heating mode is 66 °F.  
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.  
STEP 5 Install TXV  
NOTE: Applies to non--TXV indoor units only. If installing a  
rated and approved indoor coil without a factory installed R--22  
TXV, remove and replace the fixed orifice or PuronR TXV  
expansion device with an R--22 TXV.  
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.  
3 to determine base pan size and knockout hole location.  
!
CAUTION  
UNIT OPERATION HAZARD  
For hurricane tie downs, contact distributor for details and PE  
Certification (Professional Engineer), if required.  
Failure to follow this caution may result in equipment damage  
or improper operation.  
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.  
All indoor coil units must be installed with a hard shut off  
R--22 TXV metering device.  
IMPORTANT: If not factory installed, the TXV should be  
mounted as close to the indoor coil as possible and in a vertical,  
upright position. Avoid mounting the inlet tube vertically down.  
Valve is more susceptible to malfunction due to debris if inlet  
tube is facing down. A factory--approved filter drier must be  
installed in the liquid line.  
Roof mounted units exposed to winds above 5 mph may require  
wind baffles. Consult the Service Manual -- Residential Split  
System Air Conditioners and Heat Pumps for wind baffle  
construction.  
NOTE: Unit must be level to within ±2° (±3/8 in./ft.) per  
compressor manufacturer specifications.  
Installing TXV in Place of Piston  
STEP 3 Clearance Requirements  
1. Pump system down to 2 psig and recover refrigerant.  
When installing, allow sufficient space for airflow clearance,  
wiring, refrigerant piping, and service. Allow 30--in. clearance to  
service end of unit and 48 in. above unit. For proper airflow, a  
6--in. clearance on 1 side of unit and 12 in. on all remaining sides  
must be maintained. Maintain a distance of 24 in. between units.  
Position so water, snow, or ice from roof or eaves cannot fall  
directly on unit.  
2. Remove hex nut from piston body. Use backup wrench on  
fan coils.  
3. Remove and discard factory--installed piston. Be sure  
Teflon seal is in place.  
4. Reinstall hex nut. Finger tighten nut plus 1/2 turn.  
NOTE: If the piston is not removed from the body, TXV will  
not function properly.  
3/8---in. Dia. Tiedown  
Knockouts in Basepan  
(2) Places  
!
CAUTION  
EQUIPMENT DAMAGE HAZARD  
Failure to follow this caution may result in equipment  
damage or improper operation.  
Use a brazing shield and wrap TXV with wet cloth or  
use heat sink material.  
5. Install TXV on indoor coil liquid line. Sweat swivel  
adapter to inlet of indoor coil and attach to TXV outlet.  
Use backup wrench to avoid damage to tubing or valve.  
Sweat inlet of TXV, marked “IN” to liquid line. Avoid  
excessive heat which could damage valve.  
View From Top  
6. Install vapor elbow with equalizer adapter to suction tube  
of line set and suction connection to indoor coil. Adapter  
has a 1/4--in. male connector for attaching equalizer tube.  
TIEDOWN KNOCKOUT LOCATIONS  
UNIT BASE PAN  
DIMENSIONS  
A
B
C
26 X 26  
31–1/2 X 31–1/2  
35 X 35  
9–1/8  
9–1/8  
9–1/8  
4–7/16  
6–9/16  
6–9/16  
21–1/4  
24–11/16  
28–7/16  
7. Connect equalizer tube of TXV to 1/4--in. equalizer fitting  
on vapor line adapter.  
8. Attach TXV bulb to horizontal section of suction line  
using clamps provided. Insulate bulb with field--supplied  
insulation tape. See Fig. 4 for correct positioning of  
sensing bulb.  
A05177  
Fig. 3 --- Clearance Requirements  
9. Proceed with remainder of unit installation.  
3
 
STEP 6 Check Defrost Thermostat  
10 O'CLOCK  
2 O'CLOCK  
Check defrost thermostat to ensure it is properly located and  
securely attached. There is a liquid header with a brass distributor  
and feeder tube going into outdoor coil. At the end of the one of  
the feeder tubes, there is a 3/8 in. O.D. stub tube approximately 2  
in. long. (See Fig. 5.) The defrost thermostat should be located on  
stub tube. Note that there is only one stub tube used with liquid  
header, and on most units it is the bottom circuit.  
SENSING BULB  
STRAP  
SUCTION TUBE  
8 O'CLOCK  
FEEDER TUBE  
STUB TUBE  
4 O'CLOCK  
7
7
LARGER THAN  
8 IN. OD  
8 IN. OD & SMALLER  
A81032  
Fig. 4 --- Position of Sensing Bulb  
Replacing TXV on Puron Indoor Coil  
1. Pump system down to 2 psig and recover refrigerant.  
2. Remove coil access panel and fitting panel from front of  
cabinet.  
3. Remove TXV support clamp using a 5/16--in. nut driver.  
Save the clamp.  
DEFROST  
THERMOSTAT  
4. Remove Puron TXV using a backup wrench on flare  
connections to prevent damage to tubing.  
A97517  
5. Using wire cutters, cut equalizer tube off flush with vapor  
tube inside cabinet.  
Fig. 5 --- Defrost Thermostat Location  
6. Remove bulb from vapor tube inside cabinet.  
STEP 7 Make Piping Connections  
7. Braze equalizer stub--tube closed. Use protective barrier as  
necessary to prevent damage to drain pan.  
!
WARNING  
IMPORTANT: Route the equalizer tube of R--22 TXV through  
suction line connection opening in fitting panel prior to replacing  
fitting panel around tubing.  
PERSONAL INJURY AND ENVIRONMENTAL  
HAZARD  
Failure to follow this warning could result in personal  
injury or death.  
8. Install TXV with 3/8--in. copper tubing through small hole  
in service panel. Use wrench and backup wrench, to avoid  
damage to tubing or valve, to attach TXV to distributor.  
Relieve pressure and recover all refrigerant before  
system repair or final unit disposal. Use all service  
ports and open all flow--control devices, including  
solenoid valves.  
9. Reinstall TXV support clamp (removed in item 3).  
10. Attach TXV bulb to vapor tube inside cabinet, in same  
location as original was when removed, using supplied  
bulb clamps (nylon or copper). See Fig. 4 for correct  
positioning of sensing bulb.  
11. Route equalizer tube through suction connection opening  
(large hole) in fitting panel and install fitting panel in  
place.  
12. Sweat inlet of TXV, marked IN to liquid line. Avoid  
excessive heat which could damage valve.  
13. Install vapor elbow with equalizer adapter to vapor line of  
line set and vapor connection to indoor coil. Adapter has  
a 1/4--in. male connector for attaching equalizer tube.  
!
CAUTION  
UNIT DAMAGE HAZARD  
Failure to follow this caution may result in equipment  
damage or improper operation.  
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. Do not  
bury lines longer than 36 in.  
14. Connect equalizer tube of TXV to 1/4--in. equalizer fitting  
on vapor line adapter. Use backup wrench to prevent  
damage to equalizer fitting.  
!
CAUTION  
15. Proceed with remainder of unit installation.  
UNIT DAMAGE HAZARD  
Failure to follow this caution may result in equipment  
damage or improper operation.  
To prevent damage to unit or service valves, observe the  
following:  
S Use a brazing shield  
S Wrap service valves with wet cloth or use a heat sink  
material.  
4
 
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 80 ft., substantial capacity and performance losses can  
occur. Following the recommendations in the Application  
Guideline and Service Manual--Residential Split--System Air  
Conditioners and Heat Pumps will reduce these losses. Refer to  
Table 1 for accessory requirements. Refer to Table 2 for field  
tubing diameters.  
Remove plastic retainer holding outdoor piston in liquid service  
valve, leaving the piston and piston retainer inside the valve.  
Connect sweat/flare adapter provided, to valve. (See Fig. 6.)  
Connect refrigerant tubing to fittings on outdoor unit vapor and  
liquid service valves. 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. Do not use soft  
solder (materials which melt below 800°F). Consult local code  
requirements. Refrigerant tubing and indoor coil are now ready  
for leak testing. This check should include all field and factory  
joints.  
There are no buried--line applications greater than 36 in.  
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.  
Outdoor Unit Connected to Factory--Approved Indoor Unit  
PISTON BODY  
Outdoor unit contains correct system refrigerant charge for  
operation with approved ARI rated indoor unit when connected  
by 15 ft. of field--supplied or factory--accessory tubing, and  
factory supplied filter drier. Check refrigerant charge for  
maximum efficiency.  
Refrigerant Tubing and Sweat Connections  
Connect vapor tube to fitting on outdoor unit vapor service  
valves (see Table 2). Connect liquid tubing to adapter tube on  
liquid service valve. Use refrigerant grade tubing.  
PISTON  
PISTON  
RETAINER  
!
CAUTION  
SWEAT/FLARE ADAPTER  
UNIT DAMAGE HAZARD  
Failure to follow this caution may result in equipment  
damage or improper operation.  
A05226  
Fig. 6 --- Liquid Service Valve  
Service valves must be wrapped in a heat--sinking  
material such as a wet cloth while brazing.  
Table 1—Accessory Usage  
REQUIRED FOR LOW---AMBIENT AP-  
PLICATIONS  
REQUIRED FOR LONG LINE APPLICA-  
TIONS* (Over 80 ft.)  
Accessory  
(Below 55 °F)  
Crankcase Heater  
Evaporator Freeze Thermostat  
Winter Start Control  
Yes  
Yes  
Yes  
No  
No  
Yes  
Accumulator  
No  
No  
Compressor Start Assist Capacitor and Relay  
Support Feet  
Yes  
Recommended  
No  
Yes  
No  
Liquid Line Solenoid Valve  
See Long---Line Application Guideline  
* For Tubing Set lengths between 80 and 200 ft. horizontal or 20 ft. vertical differential (250 ft. Total Equivalent Length), refer to the Long Line Guidelines for Air  
Conditioners and Heat Pumps using R---22.  
Table 2—Refrigerant Connections and Recommended Liquid and Vapor Tube Diameters (in.)  
LIQUID  
VAPOR (up to 80 ft.*)  
UNIT SIZE  
Tube  
Connection Diameter  
Connection Diameter  
Rated Tube Diameter  
Diameter  
018, 024  
030, 036  
042, 048  
060  
3/8  
3/8  
3/8  
3/8  
3/8  
3/8  
3/8  
3/8  
5/8  
3/4  
7/8  
7/8  
5/8  
3/4  
7/8  
1 -1/8  
Notes:  
1. Tube diameters are for total equivalent lengths up to 80 ft..  
2. Do not apply capillary tube or fixed orifice indoor coils to these units.  
*
For Tubing Set lengths between 80 and 200 ft. horizontal or 20 ft. vertical differential (250 ft.Total Equivalent Length), refer to the Longline Guidel in e --- Air  
Conditioners and Heat Pumps using R---22  
5
 
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, makings sure wire ties on feeder  
tubes are secure and tight.  
STEP 8 Make Electrical Connections  
!
WARNING  
ELECTRICAL SHOCK HAZARD  
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.  
Failure to follow this warning could result in personal  
injury or death.  
Do not supply power to unit with compressor terminal  
box cover removed.  
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 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.  
!
CAUTION  
UNIT DAMAGE HAZARD  
Route Ground and Power Wires  
Failure to follow this caution may result in equipment  
damage or improper operation.  
Remove access panel to gain access to unit wiring. Extend wires  
from disconnect through power wiring hole provided and into  
unit control box.  
Installation of filter drier in liquid line is required.  
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. 8.  
Install Liquid Line Filter Drier Indoor  
Refer to Fig. 7 and install filter drier as follows:  
1. Braze 5 in. liquid tube to the indoor coil.  
2. Wrap filter drier with damp cloth.  
!
WARNING  
3. Braze filter drier to 5 in. long liquid tube from step 1.  
4. Connect and braze liquid refrigerant tube to the filter drier.  
ELECTRICAL SHOCK HAZARD  
Failure to follow this warning could result in personal  
injury or death.  
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.  
Connect ground wire to ground connection in control box for  
safety. Connect power wiring to contactor as shown in Fig. 8.  
DISCONNECT  
PER N. E. C. AND/OR  
LOCAL CODES  
CONTACTOR  
FIELD POWER  
WIRING  
FIELD GROUND  
A05227  
Fig. 7 --- Liquid Line Filter Drier  
WIRING  
GROUND  
LUG  
A94025  
Fig. 8 --- Line Connections  
6
 
Connect Control Wiring  
STEP 11 Start--Up  
Route 24v control wires through control wiring grommet and  
connect leads to control wiring. See Thermostat Installation  
Instructions for wiring specific unit combinations. (See Fig. 9.)  
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.  
!
CAUTION  
PERSONAL INJURY HAZARD  
Failure to follow this caution may result in personal  
injury.  
Wear safety glasses, protective clothing, and gloves when  
handling refrigerant and observe the following:  
S Front seating service valves are equipped with Schrader  
All wiring must be NEC Class 1 and must be separated from  
incoming power leads.  
Use furnace transformer, fan coil transformer, or accessory  
transformer for control power, 24v/40va minimum.  
valves.  
NOTE: Use of available 24v accessories may exceed the  
minimum 40va power requirement. Determine total transformer  
loading and increase the transformer capacity or split the load  
with an accessory transformer as required.  
!
CAUTION  
ENVIRONMENTAL HAZARD  
Final Wiring Check  
Failure to follow this caution may result in environmental  
damage.  
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, etc.  
Federal regulations require that you do not vent refrigerant to  
the atmosphere. Recover during system repair or final unit  
disposal.  
STEP 9 Compressor Crankcase Heater  
When equipped with a crankcase heater, furnish power to heater a  
minimum of 24 hr before starting unit. To furnish power to heater  
only, set thermostat to OFF and close electrical disconnect to  
outdoor unit.  
A crankcase heater is required if refrigerant tubing is longer than  
80 ft. Refer to the Long Line Guideline--Residential Split--System  
Air Conditioners and Heat Pumps.  
STEP 10 Install Electrical Accessories  
Refer to the individual instructions packaged with kits or  
accessories when installing.  
!
CAUTION  
UNIT OPERATION AND SAFETY HAZARD  
Failure to follow this caution may result in minor personal  
injury, equipment damage or improper operation.  
To prevent compressor damage or personal injury,  
observe the following:  
S Do not overcharge system with refrigerant.  
S Do not operate unit in a vacuum or at negative pressure.  
S Do not disable low pressure switch in scroll compressor  
applications.  
S Dome temperatures may be hot.  
Follow these steps to properly start up system:  
1. After system is evacuated, fully open liquid and vapor  
service valves.  
2. Unit is shipped with valve stem(s) front seated (closed)  
and caps installed. Replace stem caps after system is  
opened to refrigerant flow (back seated). Replace caps  
finger--tight and tighten with wrench an additional 1/12  
turn.  
3. Close electrical disconnects to energize system.  
4. Set room thermostat at desired temperature. Be sure set  
point is below indoor ambient temperature.  
5. Set room thermostat to HEAT or COOL and fan control to  
ON or AUTO mode, as desired. Operate unit for 15  
minutes. Check system refrigerant charge.  
7
 
HEAT  
PUMP  
TYPICAL  
FAN COIL  
HP THERMOSTAT  
R
C
R
R
C
24 VAC HOT  
24 VAC COM  
HEAT STAGE 2  
C
*
W2  
W2  
W2  
*
*
E
W3  
G
COOL/HEAT  
STAGE 1  
Y
Y
G
INDOOR FAN  
O
E
RVS COOLING  
O
EMERGENCY  
HEAT  
IF AVAILABLE  
*
LEGEND  
24-V FACTORY WIRING  
24-V FIELD WIRING  
FIELD SPLICE CONNECTION  
OUTDOOR THERMOSTAT  
EMERGENCY HEAT RELAY  
SUPPLEMENTAL HEAT RELAY  
ODT  
EHR  
SHR  
A02325 / A97413  
Fig. 9 --- Generic Wiring Diagrams  
(See Thermostat Installation Instructions for specific unit combinations)  
HK32EA003  
Speedup  
Pins  
Quiet  
Shift  
Defrost interval  
DIP switches  
A05378  
Fig. 10 --- Defrost Control  
8
 
Sequence of Operation  
Quiet Shift  
Quiet shift is a field selectable defrost mode (factory set to OFF),  
which will eliminate occasional noise that could be heard at the  
start of defrost cycle and restarting of heating cycle. It is selected  
by placing DIP switch 3 on defrost board (see Fig. 12) in the ON  
position.  
NOTE: Defrost control board is equipped with 5 minute lockout  
timer that is initiated upon any interruption of power.  
Turn on power to indoor and outdoor units. Transformer is  
energized.  
Cooling  
When Quiet Shift switch is placed in ON position, and a defrost is  
initiated, the following sequence of operation will occur.  
Reversing valve will energize, compressor will turn off for 30  
seconds, and then turn back on to complete defrost. At the start of  
heating after conclusion of defrost, reversing valve will  
de--energize, compressor will turn off for another 30 seconds, and  
the fan will turn off for 40 seconds, before starting in the heating  
mode.  
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. Circuit R--Y sends low voltage through the  
safeties and energizes the T1 terminal on the circuit board. If the  
compressor  
has been off for 5 minutes, or power has not been cycled for 5  
minutes, the OF2 relay and T2 terminal will energize. This will  
close the contactor, and start the outdoor fan motor and  
compressor.  
Defrost  
The defrost control is a time/temperature control which has field  
selectable settings of 30, 60, 90, or 120 minutes, factory set to  
90 minutes. These settings represent the amount of time that must  
pass after closure of the defrost thermostat before the defrost  
sequence begins.  
When the cycle is complete, R--Y is turned off, stopping the  
compressor and outdoor fan. The 5 minute time guard begins  
counting. Compressor will not come on again until this delay  
expires. In the event of a power interruption, the time guard will  
not allow another cycle for 5 minutes.  
The defrost thermostat senses coil temperature throughout the  
heating cycle. When the coil temperature reaches the defrost  
thermostat setting of approximately 32 degrees F, it will close,  
which energizes the DFT terminal and begins the defrost timing  
sequence. When the DFT has been energized for the selected  
time, the defrost cycle begins.  
NOTE: If the indoor blower off delay is enabled, it will run up  
to an additional 90 seconds to increase system efficiency.  
Heating  
On a call for heating, thermostat makes circuits R--Y and R--G.  
Circuit R--Y sends low voltage through the safeties and energizes  
the T1 terminal on the circuit board. T1 energizes the defrost  
logic circuit. If the compressor has been off for 5 minutes, or  
power  
Defrost cycle is terminated when defrost thermostat opens, or  
automatically after 10 minutes.  
Defrost Speedup  
has not been cycled for 5 minutes, the OF2 relay and T2 terminal  
will energize. This will close the contactor, start the outdoor fan  
motor and compressor.  
To initiate a forced defrost, speedup pins (J1) must be shorted  
with a flat head screwdriver for 5 seconds and RELEASED. If  
the defrost thermostat is open, a short defrost cycle will be  
observed (actual length depends on Quiet Shift switch position).  
When Quiet Shift is off, only a short 30 second defrost cycle is  
observed. With Quiet Shift ON, the speedup sequence is one  
minute; 30 second compressor off period followed by 30 seconds  
of defrost with compressor operation. When returning to heating  
mode, the compressor will turn off for an additional 30 seconds  
and the fan for 40 seconds.  
When the cycle is complete, R--Y is turned off , stopping the  
compressor and outdoor fan. The 5 minute time guard begins  
counting. Compressor will not come on again until this time  
delay expires. In the event of a power interruption, the time guard  
will  
not allow another cycle for 5 minutes.  
If the defrost thermostat is closed, a complete defrost cycle is  
initiated. If the Quiet Shift switch is turned on, the compressor  
will be turned off for two 30 second intervals as explained  
previously.  
9
 
STEP 12 Check Charge  
Table 3—Required Liquid--Line Temperature  
Liquid  
Factory charge and charging method are shown on unit rating  
plate. To check charge in cooling mode, refer to Cooling Only  
Procedure. To check charge in heating mode, refer to Heating  
Check Chart Procedure.  
Pressure  
at Service  
Valve  
Required Subcooling Temperature (°F)  
Cooling Only Procedure  
(PSIG)  
134  
141  
148  
156  
163  
171  
179  
187  
196  
205  
214  
223  
233  
243  
253  
264  
274  
285  
297  
309  
321  
331  
346  
359  
5
10  
66  
15  
61  
20  
56  
71  
NOTE: If 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. Favorable conditions fall within the ranges given on  
the charging chart on the outdoor unit plate.  
74  
69  
64  
59  
77  
72  
67  
62  
80  
75  
70  
65  
83  
78  
73  
68  
This system requires charging by the subcooling method.  
86  
81  
76  
71  
1. Operate unit a minimum of 10 minutes before checking  
charge.  
2. Measure liquid service valve pressure by attaching an  
accurate gage to service port.  
3. Measure liquid line temperature by attaching an accurate  
thermistor type or electronic thermometer to liquid line  
near outdoor coil.  
89  
84  
79  
74  
92  
87  
82  
77  
95  
90  
85  
80  
98  
93  
88  
83  
101  
104  
107  
110  
113  
116  
119  
122  
125  
128  
131  
134  
137  
140  
96  
91  
86  
99  
94  
89  
4. Refer to unit rating plate for required subcooling  
temperature.  
5. Refer to Table 3. Find the point where required subcooling  
temperature intersects measured liquid service valve  
pressure.  
102  
105  
108  
111  
114  
117  
120  
123  
126  
129  
132  
135  
97  
92  
100  
103  
106  
109  
112  
115  
118  
121  
124  
127  
130  
95  
98  
101  
104  
107  
110  
113  
116  
119  
122  
125  
6. To obtain required subcooling temperature at a specific  
liquid line pressure, add refrigerant if liquid line  
temperature is higher than indicated or reclaim refrigerant  
if temperature is lower. Allow a tolerance of ± 3°F.  
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.  
CARE AND MAINTENANCE  
For continuing high performance and to minimize possible  
equipment failure, periodic maintenance must be performed on  
this equipment.  
STEP 13 Final Checks  
IMPORTANT: Before leaving job, be sure to do the following:  
Frequency of maintenance may vary depending upon geographic  
areas, such as coastal applications. See Users Manual for  
information.  
1. Ensure that all wiring is routed away from tubing and  
sheet metal edges to prevent rub-- through or wire  
pinching.  
2. Ensure that all wiring and tubing is secure in unit before  
adding panels and covers. Securely fasten all panels and  
covers.  
3. Tighten service valve stem caps to 1/12--turn past finger  
tight.  
4. Leave Users Manual with owner. Explain system  
operation and periodic maintenance requirements outlined  
in manual.  
5. Fill out Dealer Installation Checklist and place in  
customer file.  
Printed in U.S.A.  
Edition Date: 02/06  
Copyright 2006 Carrier Corp. S 7310 W. Morris St. S Indianapolis, IN 46231  
Catalog No: 25HCR-2SI  
Replaces: 25HCR--1SI  
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.  
10  
 

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