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Tightening torque
Tube diameter
ø6.35 (1/4")
{140 – 180 kgf · cm}
ø9.52 (3/8")
{340 – 420 kgf · cm}
ø12.7 (1/2")
{490 – 610 kgf · cm}
ø15.88 (5/8")
{680 – 820 kgf · cm}
100 – 120 N · m
ø19.05 (6/8")*
{1,000 – 1,200 kgf · cm}
* When connecting the tube size ø19.05 with the system using refrigerant R32, be sure to connect by brazing.
● When tightening the flare nut on the liquid tube, use an adjustable wrench with a nominal
handle length of 200 mm.
5-3. Insulating the Refrigerant Tubing
Tubing Insulation
Must ensure that pipe-work shall be protected from physical damage.
● Thermal insulation must be applied to all units tubing,
including distribution joint (field supply).
* 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.
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.
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.
Additional Precautions For R32 Models
Ensure to do the re-flaring of pipes before connecting to units to avoid leaking.
To prevent the ingress of moisture into the joint which could have the potential to freeze and
then cause leakage, the joint must be sealed with suitable silicone and insulation material.
The joint should be sealed on both liquid and gas side.
Insulation material and silicone sealant.
Please ensure there are no gaps where moisture can enter the joint.
Silicone Sealant must be neutral cure and ammonia free. Use of silicone containing ammonia
can lead to stress corrosion on the joint and cause leakage.
Taping the flare nuts
Wind the insulating tape around the flare nuts at the gas / liquid tube connections.
Then cover up the tubing connections with the flare insulator (supplied). Wrap with the flare
insulator facing its seam upward.
Tube thickness
(approximate)
14 – 18 N · m
34 – 42 N · m
49 – 61 N · m
68 – 82 N · m
0.8 mm
0.8 mm
0.8 mm
1.0 mm
1.0 mm
44
Two tubes arranged together
Liquid tube
Insulation
Gas tube
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