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Caution Before Connecting Tubes Tightly
(1) Apply a sealing cap or water-proof tape to prevent dust
or water from entering the tubes before they are used.
(2) Be sure to apply refrigerant lubricant to the matching
surfaces of the flare and union before connecting them
together. This is effective for reducing gas leaks.
(Fig. 6-4)
(3) For proper connection, align the union tube and flare
tube straight with each other, then screw in the flare nut
lightly at first to obtain a smooth match. (Fig. 6-5)
● Adjust the shape of the liquid tube using a tube bender
at the installation site and connect it to the liquid tubing
side valve using a flare.
Cautions During Brazing
● Replace air inside the tube with nitrogen gas to
prevent copper oxide film from forming during the
brazing process. (Oxygen, carbon dioxide and Freon
are not acceptable.)
● Do not allow the tubing to get too hot during
brazing. The nitrogen gas inside the tubing may
overheat, causing refrigerant system valves to
become damaged. Therefore allow the tubing to
cool when brazing.
● Use a reducing valve for the nitrogen cylinder.
● Do not use agents intended to prevent the formation
of oxide film. These agents adversely affect the
refrigerant and refrigerant oil, and may cause
damage or malfunctions.
6-2. Connecting Tubing Between Indoor and
Outdoor Units
(1) Tightly connect the indoor-side refrigerant tubing
extended from the wall with the outdoor-side tubing.
(2) To fasten the flare nuts, apply specified torque as at
right:
● When removing the flare nuts from the tubing
connections, or when tightening them after connecting
the tubing, be sure to use 2 monkey wrenches or
spanners as shown. (Fig. 6-6)
If the flare nuts are over-tightened, the flare may be
damaged, which could result refrigerant leakage and
cause in injury or asphyxiation to room occupants.
● For the flare nuts at tubing connections, be sure to use
the flare nuts that were supplied with the unit, or else
flare nuts for R410A (type 2). The refrigerant tubing that
is used must be of the correct wall thickness as shown in
the table at right.
Apply refrigerant
lubricant here and here
Fig. 6-4
Flare nut
Union
Fig. 6-5
Fig. 6-6
Indoor unit
Outdoor unit
Spanner
Torque wrench
1/32"
(0.8 mm)
1/32"
(0.8 mm)
1/32"
(0.8 mm)
5/128"
(1.0 mm)
over 5/128"
(1.0 mm)
Tube diameter
ø1/4" (ø6.35 mm)
ø3/8" (ø9.52 mm)
ø1/2" (ø12.7 mm)
ø5/8" (ø15.88 mm)
ø3/4" (ø19.05 mm)
Tightening torque,
approximate
120 – 160 lbs
·
inch
(140 – 180 kgf
·
cm)
300 – 360 lbs
·
inch
(340 – 420 kgf
·
cm)
430 – 530 lbs
·
inch
(490 – 610 kgf
·
cm)
590 – 710 lbs
·
inch
(680 – 820 kgf
·
cm)
870 – 1040 lbs
·
inch
(1000 – 1200 kgf
·
cm)
Tube thickness
Because the pressure is approximately 1.6 times higher
than conventional refrigerant pressure, the use of ordinary
flare nuts (type 1) or thin-walled tubes may result in tube
rupture, injury, or asphyxiation caused by refrigerant
leakage.
● In order to prevent damage to the flare caused by over-
tightening of the flare nuts, use the table above as a guide
when tightening.
● When tightening the flare nut on the liquid tube, use a
monkey wrench with a nominal handle length of 7-7/8 in.
07-007 W-2WAY_II_NA 1/23/07 6:09 PM Page 64