Big̲PAC̲eng.indb 15
4. Out Bottom
Flare Process
●
The ø25.4 gas main will not pass easily into the opening for
coolant pipes in the pipe cover, so make sure you connect the
ø25.4 pipe with the ø 19.05 pipe outside of the outdoor unit.
(2) Tightly connect the indoor-side refrigerant tubing extended
from the wall with the outdoor-side tubing.
(3) 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 2 monkey wrenches or spanners. (Fig. 7-6)
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.
Torque wrench
Spanner
Indoor unit
Outdoor unit
●
When removing or tightening the gas tube flare nut, use 2
adjustable wrenches together: one at the gas tube flare nut,
and the other at part A. (Fig. 7-7)
A
●
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 – 55 N · m
ø12.7 (1/2")
0.8 mm
(490 – 550 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")
1.2 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.
● Do not use a spanner to tighten the valve stem caps. Doing
so may damage the valves.
● Depending on the installation conditions, applying excessive
torque may cause the nuts to crack.
Precautions for Packed Valve Operation
● If the packed valve is left for a long time with the valve stem
cap removed, refrigerant will leak from the valve. Therefore,
do not leave the valve stem cap removed. (Fig. 7-8)
● Use a torque wrench to securely tighten the valve stem cap.
Packed valve
Charging port
Valve stem
Main valve
Valve stem cap
● Valve stem cap tightening torque:
Charging port
8 – 10 N • m (80 – 100 kgf • cm)
ø9.52
19 – 21 N • m (190 – 210 kgf • cm)
Valve stem cap
ø12.7
25 – 30 N • m (250 – 300 kgf • cm)
ø19.05
13 – 14 N • m (130 – 140 kgf • cm)
7-3. Insulating the Refrigerant Tubing
Tubing Insulation
● Thermal insulation must be applied to all units tubing,
including distribution joint (purchased separately).
Fig. 7-6
* 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 tube
Inter-unit control
Fig. 7-7
wiring
Liquid tube
Armoring tape
Insulation
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.
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Big̲PAC̲eng.indb 16
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. 7-10)
Sealer (supplied)
Insulation tape (white) (supplied)
Unit side
insulator
Flare nut
Vinyl clamps (supplied)
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.
Fig. 7-8
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.
Fig. 7-9
7-4. 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.
Flare insulator (supplied)
(3) Clamp the tubing bundle to the wall, using 1 clamp approx.
each meter. (Fig. 7-11)
Tube insulator
(not supplied)
Heat resistant
120°C or above
Inter-unit
control wiring
Fig. 7-10
NOTE
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.
7-5. Finishing the Installation
After finishing insulating and taping over the tubing, use sealing
putty to seal off the hole in the wall to prevent rain and draft
from entering. (Fig. 7-12)
Apply putty here
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Gas tube
Liquid tube
Armoring tape
Insulation
Fig.7-11
Tubing
Fig.7-12