●
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.
Tightening torque
Tube diameter
Tube thickness
(approximate)
14 – 18 N · m
ø6.35 (1/4")
0.8 mm
(140 – 180 kgf · cm)
34 – 42 N · m
ø9.52 (3/8")
0.8 mm
(340 – 420 kgf · cm)
49 – 61 N · m
ø12.7 (1/2")
0.8 mm
(490 – 610 kgf · cm)
68 – 82 N · m
ø15.88 (5/8")
1.0 mm
(680 – 820 kgf · cm)
100 – 120 N · m
ø19.05 (3/4")
1.0 mm
(1000 – 1200 kgf · cm)
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.
5-3. Insulating the Refrigerant Tubing
Tubing Insulation
● Thermal insulation must be applied to all units tubing,
including distribution joint (local 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.
Two tubes arranged together
Gas tubing
Liquid tubing
Insulation
Fig. 5-7
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 fl are 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. 5-8)