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7
6. Tighten to 20 to 30 ft lbs. Use backup wrench on all wrench
flats.
NOTE: Overtightening may crush the Teflon
®
seal and cause
a leak.
7. Connect the external equalizer line to the equalizer port on
the suction line.
8. Tighten to 8 ft lbs.
9. Attach the superheat sensing bulb to the suction header with
the strap provided with the thermal expansion valve.
NOTE: If installing a thermal expansion valve on an indoor coil
that previously used a fixed orifice, be sure to remove the existing
fixed orifice. Failure to remove a fixed orifice when installing a
thermal expansion valve to the indoor coil may result in improper
operation and damage to the system.
Connect Liquid and Suction Lines
1. Route the suction and liquid lines from the fittings on the
indoor coil to the fittings on the heat pump. Run the lines in
as direct a path as possible, avoiding unnecessary turns and
bends.
2. For product efficiency, be sure that the suction line is
insulated over the entire exposed length and that both
suction and liquid lines are not in direct contact with floors,
walls, ductwork, floor joists, or other piping.
3. Remove valve cores.
4. Wrap the service valves with a wet rag.
5. Connect the suction and liquid lines, using a brazing
compound. Braze with an alloy of silver or copper and
phosphorus with a melting point above 1,100°F.
NOTE: Do not use soft solder.
6. Make sure indoor coil has been put in place according to the
Installation Instructions and is connected to the refrigerant
lines.
7. Replace valve cores.
8. Pressurize the lines and indoor coil with a pressure not to
exceed 20 psig.
9. Leak test the lines with a pressure not to exceed 20 psig.
10. Evacuate the indoor coil and lines to a minimum of
500 microns to remove contamination and moisture, then
disconnect the vacuum pump.
11. Open the suction and liquid service valves fully.
12. Insulate the suction line with refrigerant line insulation
material of ¹⁄₄" or more wall thickness.
13. Pack insulating material around refrigerant lines where they
penetrate the structure to protect the lines and to minimize
vibration transmission.
Refrigerant Charge
Refrigerant lines must be connected by a licensed, EPA certified
refrigerant technician in accordance with established procedures.
IMPORTANT:
■ Refrigerant charge adjustment will be required for line set
lengths greater than 15 ft and for evaporator coils not
matched to the systems.
■ The heat pump is factory charged with the proper refrigerant
charge amount for a matching evaporator and 15 ft of
refrigerant line. Refer to the heat pump rating plate for the
exact amount of this factory charge.
■ Adjustment of the refrigerant charge will be necessary based
on the system combination and line length. To adjust the
refrigerant size for increased line lengths, add the following
amount of refrigerant.
For line set lengths greater than 15 ft, add refrigerant by
weighing in 0.60 oz per ft of ³⁄₈" O.D. liquid line.
■ If necessary, adjust the refrigerant charge for compatibility
with the evaporator coil.
■ In heat pump systems, horizontal suction lines should be
slightly sloped toward the heat pump. Piping must avoid dips
or low spots, which can collect oil.
Check Charge Using Normal Operating Pressures
Use Normal Operating Pressures chart to perform maintenance
checks.
NOTES:
■ The Normal Operating Pressures chart is not a procedure for
charging the system.
■ Minor variations in these pressures may be due to differences
in installations.
■ Significant deviations could mean that the system is not
properly charged or that a problem exists with some
component in the system.
A. Equalizer port
B.Superheat sensing bulb
C. Thermal expansion valve
D.Liquid line
E.Suction line
F. Equalizer line
E
F
A
B
C
D