Filter
Top Products
77
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 match-
ing 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 for-
mation 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 connect-
ing 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 thick-
ness as shown in the table at right.
Apply refrigerant
lubricant
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 asphyxia-
tion 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.