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
(approximate)
14 – 18 N · m
ø6.35 (1/4")
{140 – 180 kgf · cm}
34 – 42 N · m
ø9.52 (3/8")
{340 – 420 kgf · cm}
49 – 61 N · m
ø12.7 (1/2")
{490 – 610 kgf · cm}
68 – 82 N · m
ø15.88 (5/8")
{680 – 820 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 (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.
Insulation of the flare nuts
Attach the flare insulator (supplied) just like wrapping around
the flare nut (supplied). Match the both slits of flare insulators
for gas and liquid tubes facing upward. Tightly attach the end of
the flare insulators to the tube cradle without any space. Then
clamp the flare insulator with the clampers about 20 mm away
from both ends.
Facing upward
Liquid tubing
Gas tubing
Insulator (not supplied)
Clamper
Outdoor unit
side
About 20 mm
NOT E
Tighten the clampers to prevent any condensation that may
occur as the copper tubing is exposed.
Tube thickness
0.8 mm
0.8 mm
0.8 mm
1.0 mm
Flare insulator (for gas tube)
Flare insulator
(for liquid tube)
Tube cradle
Without any space
Flare nut
Clamper
Tube cradle
(supplied)
Indoor unit
side
About 20 mm
Insulation material
The material used for insulation must have good insulation
characteristics, be easy to use, be age resistant, and must not
easily absorb moisture.
CAUTION
After a tube has been insulated, never try to bend it into
a narrow curve because it can cause the tube to break or
crack.
Never grasp the drain or refrigerant connecting outlets
when moving the unit.
5-4. Taping the Tubes
(1) At this time, the refrigerant tubes (and electrical wiring
if local codes permit) should be taped together with
armoring tape in 1 bundle. To prevent condensation from
overflowing the drain pan, keep the drain hose separate
from the refrigerant tubing.
(2) Wrap the armoring tape from the bottom of the outdoor
unit to the top of the tubing where it enters the wall. As you
wrap the tubing, overlap half of each previous tape turn.
(3) Clamp the tubing bundle to the wall, using 1 clamp approx.
each meter. (Fig. 5-9)
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.
N OT E
Do not wind the armoring tape too tightly since this will
decrease the heat insulation effect. Also ensure that the
condensation drain hose splits away from the bundle and drips
clear of the unit and the tubing.
Fig. 5-7
16
Two tubes arranged together
Liquid tubing
Gas tubing
Insulation
Insulated tubes
Fig. 5-8
Clamp
Drain hose
Fig. 5-9