1
1-396
6-6. Connecting Tubing Between Indoor and Outdoor Units
(1) Tightly connect the indoor-side refrigerant tubing extended from the wall with the outdoor-side tubing.
6-7. Insulating the Refrigerant Tubing
Tubing Insulation
(2) To fasten the flare nuts, apply specified torque.
Indoor Unit Tubing Connection (
Indoor unit type
36
45
Gas tubing (mm)
ø12.7
Liquid tubing (mm)
ø6.35
50
1,
2... n-1)
When removing the flare nuts from the tubing connections,
or when tightening them after connecting the tubing, be sure
to use 2 adjustable wrenches or spanners. (Fig. 1-134)
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.
Outdoor unit
Torque wrench
Spanner
Indoor unit
Fig. 1-134
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 (type 2). The refrigerant tubing that is used must be of the correct wall thickness as shown in the table below.
Tube diameter
Tightening torque
(approximate)
Tube thickness
ø6.35 (1/4")
14 – 18 N · m
{140 – 180
kgf
· cm}
0.8 mm
ø9.52 (3/8")
34 – 42 N · m
{340 – 420
kgf
· cm}
0.8 mm
ø12.7 (1/2")
49 – 61 N · m
{490 – 610
kgf
· cm}
0.8 mm
ø15.88 (5/8")
68 – 82 N · m
{680 – 820
kgf
· cm}
1.0 mm
Because the pressure is approximately 1.6 times higher than conventional refrigerant 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 above 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.
Thermal insulation must be applied to all units tubing,
including distribution joint (local supply).
Insulation material thickness must be 10 mm or greater.
If the conditions inside the ceiling exceed DB 30°C and RH
70%, increase the thickness of the gas tubing insulation
material by 1 step.
* For gas tubing, the insulation material must be heat
resistant to 120°C or above. For other tubing, it must be
heat resistant to 80°C or above.
Two tubes arranged together
Liquid tubing
Gas tubing
Insulation
Fig. 1-135
CAUTION
If the exterior of the outdoor unit valves has been finished with a square duct covering, make sure you allow sufficient
space to access the valves and to allow the panels to be attached and removed.
Taping the flare nuts
Wind the white insulation tape around the flare nuts at the gas tube connections.
Then cover up the tubing connections with the flare insulator, and fill the gap at the union with the supplied black insulation tape.
Finally, fasten the insulator at both ends with the supplied vinyl clamps. (Fig. 1-136)
SM830231-02̲Single̲欧州.indb 396
SM830231-02̲Single̲欧州.indb 396
2014/09/19 13:22:05
2014/09/19 13:22:05