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(2) Flare connecting procedures and precautions
a) Make sure that the flare and union portions do
not have any scar or dust, etc.
b) Correctly align the processed flare surface with
the union axis.
c) Tighten the flare with designated torque by
means of a torque wrench. The tightening
torque for R410A is the same as that for
conventional R22. Incidentally, when the torque
is weak, the gas leakage may occur.
Fig. 6-2-2 Relations between flare nut and flare seal surface
When it is strong, the flare nut may crack and
may be made non-removable. When choosing
the tightening torque, comply with values
designated by manufacturers. Table 6-2-7
shows reference values.
Note:
When applying oil to the flare surface, be sure to use
oil designated by the manufacturer. If any other oil is
used, the lubricating oils may deteriorate and cause
the compressor to burn out.
Tightening torque of torque
Nominal Outer diameter Tightening torque
wrenches available on the market
diameter (mm) N·m (kgf·cm)
N·m (kgf·m)
1/4 6.35 14 to 18 (140 to 180) 16 (160), 18 (180)
3/8 9.52 33 to 42 (330 to 420) 42 (420)
1/2 12.70 50 to 62 (500 to 620) 55 (550)
5/8 15.88 63 to 77 (630 to 770) 65 (650)
Table 6-2-7 Tightening torque of flare for R410A [Reference values]
45
° to 46
°
43° to 45°