Hitachi Set Free mini-HNRQ1 Series Installation & Maintenance Manual page 25

(B) Joint Selection
The minimum thickness of joint and flare nut dimension are selected from the
table below:
Minimum Thickness of Joint
Unit: mm
Diameter(Φd)
6.35
9.52
12.7
15.88
19.05
NOTE:
Do not use a thin joint other than the ones shown in the table above.
(C) Verify that there are no scratches, metal particles, gaps, or deformations at the flared end before
making connections to the system.
(D) Apply refrigerant oil (field-supplied) slightly on the flare surface of the pipe and flare nut before
performing flaring work. Tighten the flare nut with the specified torque settings using two wrenches.
Perform flaring work to the liquid piping side before treating the gas piping side. Verify that no gas
leakage has occurred after completing flaring work.
(E) Be sure to use two wrenches as shown.
Use two wrenches as shown
Flare Nut Dimension B
R410A Diameter(Φd)
0.5
0.6
0.7
0.8
0.8
Apply Refrigerant Oil
21
Unit: mm
R410A
6.35 17
9.52 22
12.7 26
15.88 29
19.05 36
Do not apply
refrigerant oil
to exterior flared
surfaces.
Stop Valve
Do not apply the two wrenches work here.
Refrigerant leakage shall occur
Tightening Work for Stop Valve
B
Flare Nut
Flare Nut