En-8
5. 4. Pipe connection
CAUTION
Do not use mineral oil on a fl ared part. Prevent mineral oil from getting into the system
as this would reduce the lifetime of the units.
While brazing the pipes, be sure to blow dry nitrogen gas through them.
5. 4. 1. Flaring
• Use special pipe cutter and fl are tool exclusive for R410A.
(1) Cut the connection pipe to the necessary length with a pipe cutter.
(2) Hold the pipe downward so that the cuttings will not enter the pipe and remove any
burrs.
(3) Insert the fl are nut (always use the fl are nut attached to the indoor and outdoor
units respectively) onto the pipe and perform the fl are processing with a fl are tool.
Leakage of refrigerant may result if other fl are nuts are used.
(4) Protect the pipes by pinching them or with tape to prevent dust, dirt, or water from
entering the pipes.
L
Check if [L] is fl ared uniformly
and is not cracked or scratched.
Pipe
A
B
Die
Pipe outside
diameter [mm (in.)]
Dimension A (mm)
Dimension B
0
- 0.4
[mm]
Flare tool for R410A,
clutch type
6.35 (1/4)
0 to 0.5
9.1
9.52 (3/8) 13.2
12.70 (1/2) 16.6
15.88 (5/8) 19.7
19.05 (3/4) 24.0
• When using conventional fl are tools to fl are R410A pipes, the dimension A should
be approximately 0.5mm more than indicated in the table (for fl aring with R410A
fl are tools) to achieve the specifi ed fl aring. Use a thickness gauge to measure the
dimension A.
Pipe outside
diameter
[mm (in.)]
Width across fl ats
of Flare nut
[mm]
6.35 (1/4) 17
9.52 (3/8) 22
12.70 (1/2) 26
15.88 (5/8) 29
19.05 (3/4) 36
Width across fl ats
5. 4. 2. Bending pipes
CAUTION
To prevent breaking of the pipe, avoid sharp bends. Bend the pipe with a radius of
curvature of 100mm or more.
If the pipe is bent repeatedly at the same place, it will break.
• If pipes are shaped by hand, be careful not to collapse them.
• Do not bend the pipes at an angle of more than 90°.
• When pipes are repeatedly bent or stretched, the material will harden, making it dif-
fi cult to bend or stretch them any more.
• Do not bend or stretch the pipes more than 3 times.
5. 4. 3. Pipe connection
CAUTION
Be sure to install the pipe against the port on the indoor unit and the outdoor unit cor-
rectly. If the centering is improper, the fl are nut cannot be tightened smoothly.
If the fl are nut is forced to turn, the threads will be damaged.
Do not remove the fl are nut from the outdoor unit pipe until immediately before connect-
ing 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 fl are nut by hand.
(3) Tighten the fl are nut of the connection pipe at the outdoor unit valve connector.
(4) After tightening the fl are nut by hand, use a torque wrench to fully tighten it.
3-way valve (Liquid)
3-way valve
(Gas)
Connection pipe
(Liquid)
Flare nut
Connection
pipe (Gas)
Flare nut
CAUTION
Hold the torque wrench at its grip, keeping it in a right angle with the pipe, in order to
tighten the fl are nut correctly.
• Outer panel may be distorted if fastened only with a wrench. Be sure to fi x the el-
ementary part with a holding wrench (spanner) and fasten with a torque wrench (refer
to below diagram). Do not apply force to the blank cap of the valve or hang a wrench,
etc., on the cap. If blank cap is broken, it may cause leakage of refrig
erant.
Blank cap
Flare nut
90°
Torque wrench
Holding
wrench
Torque wrench
Flare nut
[mm (in.)]
Tightening torque
[N·m (kgf·cm)]
6.35 (1/4) dia. 16 to 18 (160 to 180)
9.52 (3/8) dia. 32 to 42 (320 to 420)
12.70 (1/2) dia. 49 to 61 (490 to 610)
15.88 (5/8) dia. 63 to 75 (630 to 750)
19.05 (3/4) dia. 90 to 110 (900 to 1100)
5. 4. 4. Handling precautions for the valves
• Mounted part of Blank cap is sealed for protection.
• Fasten blank cap tightly after opening valves.
Operating the valves
• Use a hexagon wrench (size 4mm).
• Opening (1) Insert the hexagon wrench into the valve shaft, and turn it
counterclockwise.
(2) Stop turning when the valve shaft can no longer be turned.
(Open position)
• Closing (1) Insert the hexagon wrench into the valve shaft, and turn it
clockwise.
(2) Stop turning when the valve shaft can no longer be turned.
(Closed position)
Opening direction
Hexagon wrench
Seal (blank cap
installation portion)
Liquid pipe
Gas pipe
Opening direction
9380545149-02_IM_EN.indd 89380545149-02_IM_EN.indd 8 9/7/2021 1:38:53 PM9/7/2021 1:38:53 PM
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