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9-6. Refrigerant Piping
9-6-1. Refrigerant Piping
1. If the outdoor units are to be mounted on a wall,
make sure that the platform supporting is suffi-
ciently strong. The platform should be designed
and manufactured to maintain its strength over a
long period of time, and sufficient consideration
should be given to ensuring that the outdoor unit
will not fall.
2. Use copper pipe with 0.8 mm or more thick-
ness.
3. Flare nut and flare works are also different from
those of the conventional refrigerant.
Take out the flare nut attached to the main unit of
the air conditioner, and use it.
CAUTION
IMPORTANT 4 POINTS FOR PIPING WORK
1. Take away dust and moisture from the inside of
the connecting pipes.
2. Tight connection (between pipes and unit)
3. Evacuate the air in the connecting pipes using
VACUUM PUMP.
4. Check the gas leakage. (connected points)
[Flaring]
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.
Fig. 9-6-1
• Projection margin in flaring : B (Unit : mm)
Rigid (Clutch type)
Outer diam. of copper pipe
6.35
9.52
12.7
R410A
R22
1.5 to 2.0
1.0 to 1.5
1.5 to 2.0
1.0 to 1.5
2.0 to 2.5
1.5 to 2.0
Outer diam. of
copper pipe
6.35
9.52
12.7
R410A tool used
R410A
R22
0 to 0.5 (Same as left)
0 to 0.5 (Same as left)
0 to 0.5 (Same as left)
Conventional tool used
R410A
R22
1.0 to 1.5
0.5 to 1.0
1.0 to 1.5
0.5 to 1.0
1.0 to 1.5
0.5 to 1.0
Imperial (Wing nut type)
• Flaring size : A (Unit : mm)
Outer diam. of
copper pipe
6.35
9.52
12.7
A
R410A
R22
9.1
9.0
13.2
13.0
16.6
16.2
+0
- 0.4
* In the case of flaring for R410A with
the conventional flare tool, pull out it
approx. 0.5 mm more than that for R22
to adjust to the specified flare size.
The copper pipe gauge is useful for
adjusting projection margin size.
Fig. 9-6-2
[Tightening connection]
Align the centers of the connecting pipes and tighten
the flare nut as far as possible with your fingers.
Then tighten the nut with a spanner and torque wrench
as shown in the figure.
CAUTION
• Do not apply excess torque. Otherwise, the nut
may crack depending on the conditions.
(Unit : N•m)
Outer diam. of copper pipe
6.35 mm (diam.)
9.52 mm (diam.)
12.7 mm (diam.)
Tightening torque
14 to 18 (1.4 to 1.8 kgf•m)
33 to 42 (3.3 to 4.2 kgf•m)
50 to 62 (5.0 to 6.2 kgf•m)
• Tightening torque of flare pipe connections
Pressure of R410A becomes higher than that of
R22.
(Approx. 1.6 times) Therefore, using a torque
wrench, tighten firmly the flare
pipe connecting sections which
connect the indoor and outdoor
units up to the specified
tightening torque.
Incorrect connections may
cause not only a gas
leakage, but also a trouble
of the refrigeration cycle.
Fig. 9-6-3
B
A
Flare at
indoor
unit side
Flare at
outdoor
unit side
Half union
Flare nut
Externally
threaded side
Internally
threaded side
Use a wrench to secure.
Use a torque wrench to tighten.
Fig. 9-6-4
