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2. Procedure and precautions for flare connection
Table 11 R410A flaring dimensions
Nominal
diameter
Outside
diameter
(mm)
Wall thickness
(mm)
A (mm)
R410A flaring
tool, clutch type
Conventional flaring tool
Clutch type Wing-nut type
1/4 6.35 0.8 0 - 0.5 1.0 - 1.5 1.5 - 2.0
3/8 9.52 0.8 0 - 0.5 1.0 - 1.5 1.5 - 2.0
1/2 12.70 0.8 0 - 0.5 1.0 - 1.5 2.0 - 2.5
Table 12 R410A flaring dimensions
Nominal
diameter
Outside
diameter
(mm)
Wall thickness
(mm)
A (mm)
R410A flaring
tool, clutch type
Conventional flaring tool
Clutch type Wing-nut type
1/4 6.35 0.8 0 - 0.5 0.5 - 1.0 1.0 - 1.5
3/8 9.52 0.8 0 - 0.5 0.5 - 1.0 1.0 - 1.5
1/2 12.70 0.8 0 - 0.5 0.5 - 1.0 1.5 - 2.0
Table 13 R410A flaring and flare nut dimensions Unit: mm
Nominal
diameter
Outside
diameter (mm)
Wall thickness
(mm)
A +0, -0.4 B
dimension
C
dimension
D
dimension
Flare nut
width
1/4 6.35 0.8 9.1 9.2 6.5 13 17
3/8 9.52 0.8 13.2 13.5 9.7 20 22
1/2 12.70 0.8 16.6 16.0 12.9 23 26
Table 14 R410A flaring and flare nut dimensions Unit: mm
Nominal
diameter
Outside
diameter (mm)
Wall thickness
(mm)
A +0, -0.4 B
dimension
C
dimension
D
dimension
Flare nut
width
1/4 6.35 0.8 9.0 9.2 6.5 13 17
3/8 9.52 0.8 13.0 13.5 9.7 20 22
1/2 12.70 0.8 16.2 16.0 12.9 20 24
a. Check to make sure there are no scratches, dust, etc., on the flare and union.
b. Align the flared surface with the axial center of the union.
c. Use a torque wrench, and tighten to the specified torque. The tightening torque for R410A is the same as the conventional
torque value for R22. Be careful, because if the torque is too weak, it may lead to a gas leak. If it is too strong, it may split
the flare nut or make it impossible to remove the flare nut.
Table 15 R410A tightening torque
Nominal
diameter
Outside
diameter (mm)
Tightening torque
N.m (kgf.cm)
Torque wrench tightening torque
N.m (kgf.cm)
1/4 6.35 14 - 18 (140 - 180) 18 (180)
3/8 9.52 33 - 42 (330 -420) 42 (420)
1/2 12.70 55 (550) 55 (550)
10.3.3. Storing and managing Piping Materials
1. Types of piping and their storage
The following is a general classification of the refrigerant pipe materials used for ACs.
Because the gas pressure of R410A is approximately 1.6 times as high as that of R22, copper pipes with the thickness shown
in Table 10, and with minimal impurities must be used. Care must also be taken during storage to ensure that pipes are not
crushed, deformed, or scratched, and that no dust, moisture or other substance enters the pipe interior. When storing sheathed
copper pipes or plain copper pipes, seal the openings by pinching or taping them securely.
2. Makings and management
a. Sheathed copper pipes and copper-element pipes
When using these pipes, check to make sure that they are the stipulated thickness. For flare nuts, be sure to used the same
nut that is used on the AC unit.
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