indoor coil piston with piston shipped with outdoor unit. The
piston shipped with outdoor unit is correct for any approved indoor
coil combination.
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.
Step 7—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 3 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.
Step 8—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.
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.
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, substan-
tial 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 equivalent line length. Refer to Table 2 for
accessory requirements.
For buried-line applications greater than 36 in., consult your local
distributor.
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
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.
REFRIGERANT TUBING
Connect tubing to fittings on outdoor unit vapor and liquid service
valves. (See Table 1.) Use refrigerant grade tubing.
SWEAT CONNECTION
To avoid valve damage while brazing, service 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.
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
030, 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. For tubing lengths greater than 50 ft, consult Residential Split System Long-Line Application Guideline.
2. Do not apply capillary tube indoor coils to these units.
Fig. 5—Defrost Thermostat Location
A97517
FEEDER TUBE
DEFROST
THERMOSTAT
STUB TUBE
3
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