Design and Technical Manual

6. SYSTEM DESIGN
PIPE CONNECTION

CAUTION
Be sure to install the pipe against the port on the indoor unit and the outdoor unit correctly. If the ●
centering is improper, the flare nut cannot be tightened smoothly. If the flare nut is forced to turn,
the threads will be damaged.
Do not remove the flare nut from the outdoor unit pipe until immediately before connecting the ●
connection pipe.
After installing the piping, make sure that the connection pipes do not touch the compressor or ●
outer panel. If the pipes touch the compressor or outer panel, they will vibrate and produce noise.
(1) Detach the caps and plugs from the pipes.
(2) Center the pipe against the port on the outdoor unit, and then turn the are nut by hand.
(3) Tighten the are nut of the connection pipe at the outdoor unit valve connector.
(4) After tightening the are nut by hand, use a torque wrench to fully tighten it.
3-way valve
(Liquid)
Connection pipe
(Liquid)
Connection pipe
(Gas)
3-way valve
(Gas)
Flare nut
Flare nut
CAUTION
Hold the torque wrench at its grip, keeping it in a right angle with the pipe, in order to tighten the ●
flare nut correctly.
Outer panel may be distorted if fastened only with a wrench. Be sure to fix the elementary ●
part with a spanner and fasten with a wrench (refer to below diagram).
Do not apply force to the blank cap of the valve or hang a wrench, etc., on the cap. It may ●
cause leakage of refrigerant.
90°
Holding
wrench
Blank cap
Flare nut
Torque wrench
Torque wrench
Flare nut
[in. (mm)]
Tightening torque
[lbf· ft (N·m)]
1/4 (6.35) 11.8 to 13.3 (16 to 18)
3/8 (9.52) 23.6 to 31.0 (32 to 42)
1/2 (12.70) 36.1 to 45.0 (49 to 61)
5/8 (15.88) 46.5 to 55.3 (63 to 75)
3/4 (19.05) 66.4 to 81.1 (90 to 110)
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SYSTEM DESIGN SYSTEM DESIGN