116
12.1.5.2 Connecting Tubing Between Indoor and Outdoor Units
(1) Tightly connect the indoor-side refrigerant tubing extended from the wall with the outdoor-side tubing.
Indoor Unit Tubing Connection
Unit : mm
Indoor unit type
S-71WF3E
Gas tube
Ø12.7
Liquid tube
Ø6.35
(2) To fasten the flare nuts, apply specified torque.
When removing the flare nuts from the tubing connections, or when tightening them after connecting the tubing,
be sure to use two spanners.
When tightening the flare nuts, use a torque wrench.
If the flare nuts are over-tightened, the flare may be damaged, which could result in refrigerant leakage and
cause injury or asphyxiation to room occupants.
For the flare nuts at tubing connections, be sure to use the flare nuts that were supplied with the unit, or else flare
nuts for R410A, R32 (type 2). The refrigerant tubing that is used must be of the correct wall thickness as shown
in the table at right.
Because the pressure is approximately 1.6 times higher than conventional refrigerant R22 pressure, the use of
ordinary flare nuts (type 1) or thin-walled tubes may result in tube rupture, injury, or asphyxiation caused by
refrigerant leakage.
In order to prevent damage to the flare caused by over-tightening of the flare nuts, use the table on the right as a
guide when tightening.
When tightening the flare nut on the liquid tube, use an adjustable wrench with a nominal handle length of
200 mm.
Tube diameter
Tightening torque
(approximate)
Tube thickness
ø6.35 (1/4”)
14 – 18 N ꞏ m
{140 – 180 k
g
f ꞏ cm}
0.8 mm
ø9.52 (3/8”)
34 – 42 N ꞏ m
{340 – 420 k
g
f ꞏ cm}
0.8 mm
ø12.7 (1/2”)
49 – 55 N ꞏ m
{490 – 550 k
g
f ꞏ cm}
0.8 mm
ø15.88 (5/8”)
68 – 82 N ꞏ m
{680 – 820 k
g
f ꞏ cm}
1.0 mm
