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5
Refrigerant piping
WARNING
•
If the refrigerant gas leaks during installation work, ventilate the room immediately.
If the leaked refrigerant gas comes into contact with a source of fire, noxious gas maybe generated.
•
After installation work is complete, check refrigerant gas does not leak.
If the refrigerant leaks into the room and comes into contact with a naked flame, noxious gas maybe generated.
Pipe forming / End positioning
◆
Flaring
1. Cut the pipe with a pipe cutter.
2. Insert a flare nut into the pipe, and flare the pipe.
As the flaring sizes of R410A differ from those of
refrigerant R22, the flare tools newly manufactured
for R410A are recommended.
However, the conventional tools can be used by
adjusting projection margin of the copper pipe.
• Flaring size : A (Unit : mm)
* In case of flaring for R410A with the conventional
flare tool, pull it out approx. 0.5 mm more than that of
R22 to adjust to the specified flare size.
The copper pipe gauge is useful for adjusting
projection margin size.
• Projection margin in flaring :
B (Unit : mm)
Rigid (Clutch type)
Imperial (Wing nut type)
NO GOOD
OK
Obliquity
Roughness
Warp
90°
Outer dia. of copper pipe
A
R410A
R22
9.5
13.2
13.0
15.9
19.7
19.4
Outer dia.
of copper
pipe
R410A tool used
Conventional tool used
R410A
R22
R410A
R22
9.5
0 to 0.5 (Same as left) 1.0 to 1.5
0.5 to 1.0
15.9
0 to 0.5 (Same as left) 1.0 to 1.5
0.5 to 1.0
Outer dia. of copper pipe
R410A
R22
9.5
1.5 to 2.0
1.0 to 1.5
15.9
2.0 to 2.5
1.5 to 2.0
A
+0
-0.4
B
Tightening of connecting part
(Unit: N•m)
• Align the centers of the connecting pipes and tighten
the flare nut strong as far as possible with your
fingers.
Then fix the nut with a spanner and tighten it with
torque wrench as shown in the figure.
• As shown in the figure, be sure to use a double
spanner to loosen or tighten the flare nut of the valve
at gas side. If using a single spanner, the nut cannot
be tightened with necessary tightening torque.
On the contrary, use a single spanner to loosen or
tighten the flare nut of the valve at liquid side.
REQUIREMENT
1. Do not put the spanner on the cap. The valve may
be broken.
2. If applying excessive torque, the nut may be broken
according to some installation conditions.
• After the installation work, be sure to check gas leak
of connecting part of the pipes with nitrogen.
• Pressure of R410A is higher than that of R22
(Approx. 1.6 times). Therefore, using a torque
wrench, tighten the flare pipe connecting sections
which connect the indoor / outdoor units at the
specified tightening torque. Incomplete connections
may cause not only a gas leak, but also a trouble of
the refrigeration cycle.
Do not apply refrigerating machine oil to the
flared surface.
Outer dia. of copper pipe
Tightening torque
9.5 mm (diam.)
33 to 42 (3.3 to 4.2 kgf•m)
15.9 mm (diam.)
63 to 77 (6.3 to 7.7 kgf•m)
Externally
threaded side
Internally
threaded side
Half union or packed valve
Tighten with torque wrench.
Fix with spanner.
Flare nut
Cover
Flare nut
Cap
Tightened
Piping valve
Loosened
Valve at gas side
Cover
NO GOOD
13-EN
14-EN
