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CAUTION: Remove indoor coil piston if unit is to be
installed on system with a TXV metering device.
Check outdoor unit piston. Remove retainer on liquid service valve
and check piston size with matching number listed on outdoor unit
rating plate.
VII. CHECK DEFROST THERMOSTAT
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 1 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 1 stub tube used with liquid header,
and on most units it is the bottom circuit.
VIII. MAKE PIPING CONNECTIONS
WARNING: 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.
CAUTION: 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.
CAUTION: 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 in length
or 20 ft vertical differential, substantial capacity and performance
losses can occur. Following the recommendations in the Residen-
tial Split System Long-Line Application Guideline will reduce
these losses. Refer to Table 1 for field tubing equivalent line
length.
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.
A. Outdoor Unit Connected to Factory-Approved In-
door Unit
Outdoor unit contains correct system refrigerant charge for opera-
tion with indoor unit of same size when connected by 15 ft of
field-supplied or factory-accessory tubing. Check refrigerant
charge for maximum efficiency.
B. Refrigerant Tubing
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.
C. Sweat Connection
CAUTION: To avoid valve damage while brazing, ser-
vice valves must be wrapped in a heat-sinking material
such as a wet cloth.
Remove plastic retainer holding outdoor piston in liquid service
valve and 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. Consult local code require-
ments. Refrigerant tubing and indoor coil are now ready for leak
testing. This check should include all field and factory joints.
D. Final Tubing Check
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.
TABLE 1—REFRIGERANT CONNECTIONS AND RECOMMENDED LIQUID AND VAPOR TUBE DIAMETERS (IN.)
UNIT
SIZE
LIQUID VAPOR VAPOR (LONG LINE)
Connection Diameter Tube Diameter Connection Diameter Tube Diameter Connection Diameter Tube Diameter
018, 024 3/8 3/8 5/8 5/8 5/8 3/4
060, 036 3/8 3/8 3/4 3/4 3/4 7/8
042, 048 3/8 3/8 7/8 7/8 7/8 1-1/8
060 3/8 3/8 7/8 1-1/8 7/8 1-1/8
NOTES:
1. Tube Diameters are for lengths up to 50 ft or 20 ft vertical differential. For tubing lengths greater than 50 ft, consult the Application Guideline and Service Manual for Air
Conditioners and Heat Pumps Using R-22 Refrigerant.
Fig. 5—Defrost Thermostat Location
A97517
FEEDER TUBE
DEFROST
THERMOSTAT
STUB TUBE
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