Sanyo C4272R S/C - Manual (Page 98)

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Fig. 9-7
● 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. 9-6)
If the flare nuts are over-tightened, the flare may
be damaged, which could result in refrigerant
leakage and cause injury or asphyxiation to
room occupants.
● When removing or tightening the gas tube flare
nut, use 2 monkey wrenches together: one at
the gas tube flare nut, and one at part A.
(Fig. 9-7)
● 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. 9-4
Flare nut Union
Fig. 9-5
Fig. 9-6
Indoor unit
Outdoor unit
Spanner
Torque wrench
Tube diameter
ø1/4" (6.35 mm)
ø3/8" (9.52 mm)
ø1/2" (12.7 mm)
ø5/8" (15.88 mm)
Tightening torque
(approximate)
14 – 18 N · m
(140 – 180 kgf · cm)
34 – 42 N · m
(340 – 420 kgf · cm)
49 – 61 N · m
(490 – 610 kgf · cm)
68 – 82 N · m
(680 – 820 kgf · cm)
1/32 in.
1/32 in.
1/32 in.
1/32 in.
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.
A
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. 9-4)
(3) For proper connection, align the union tube and flare tube straight with
each other, then screw on the flare nut lightly at first to obtain a smooth
match. (Fig. 9-5)
● Adjust the shape of the liquid tube using a tube bender at the installa-
tion 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.
9-2. 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.
07-115 SSHP_II 5/7/07 4:00 PM Page 98