Step 6—Thermostatic Expansion Valve
For proper unit operation and reliability, units must be
installed with field-supplied hard shutoff TXV. Do not install
with evaporator coils having capillary tube metering devices
or pistons.
Due to system design, this unit must be installed with a
factory-listed indoor section. Non-approved coils could cause
performance and reliability problems. Refer to pre-sale litera-
ture for approved indoor sections.
The outdoor section is factory equipped with a hard shut-off TXV
for metering refrigerant during heating mode. See Fig. 5 and 6 for
location of TXV and sensing bulb. This heat pump must be
matched with an approved indoor fan coil equipped with a hard
shut-off TXV. See Product Data literature for approved indoor
units.
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. 7.) 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.
Fig. 5—Positioning of Sensing Bulb
A81032
2 O'CLOCK
10 O'CLOCK
SENSING BULB
STRAP
SUCTION TUBE
8 O'CLOCK
4 O'CLOCK
7
⁄
8
IN. OD & SMALLER
LARGER THAN
7
⁄
8
IN. OD
Fig. 6—TXV Location on Outdoor Section
A96433
TXVTXV
STRAINER
SENSING BULB
DISCHARGE
MUFFLER
Fig. 7—Defrost Thermostat Location
A97517
FEEDER TUBE
DEFROST
THERMOSTAT
STUB TUBE
3
