18
31
5-2.
Connecting Tubing Between Indoor and Outdoor
Units
(1)
Preparing the Joint Tube (10 HP only).
●
The tubing of the gas main has a diameter of ø22.22, but
the connection to the service valve of the outdoor unit has a
diameter of ø19.05, so a flare has to be used.
Consequently, be sure to use the enclosed joint tube B and
joint tube A in making connections (braze).
●
Align the joint tube in the direction the tubing comes out and
see the following references “Examples of Making Tube
Connections” 1 to 4 in cutting it to the required length and
then braze it.
●
For the connection to the service valve on the outdoor unit,
use the supplied joint tube B.
Thereby, perform flaring process in a ø19.05 on the joint
tube end B (connecting side to the service valve).
●
Cut out the supplied joint tube A according to the required
length by referring to the following connection tubing
samples 1 to 4.
●
Perform brazing the supplied joint tube A with the supplied
joint tube B in the appropriate direction.
●
To protect the wiring and parts inside the unit, perform
the brazing outside the unit. (Also, take note that each of
the joint tubes in 1 to 3 have to be installed in a specific
direction, so make sure they are as depicted in the figure
when you braze them.)
●
Make a flare connection of the supplied joint tubes A and B
to the gas side service valve on the outdoor unit.
Examples of Making Tube Connections
1. Out Front
2. Out Right
3. Out Rear
4. Out Bottom
Flare process
Cutout
320 mm
Joint tube B
F
ront view
Right side view
Joint tube A
Flare process
Cutout
320 mm
Joint tube B
Right side view
Joint tube A
Flare process
Cutout
60 mm
Right side view
Joint tube A
Joint tube B
Cutout
320 mm
190 mm
Right side view
Joint tube A
Joint tube B
Flare process
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32
●
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 ø22.22 pipe with the ø19.05 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 a torque wrench and a spanner.
Torque wrench
Spanner
Indoor unit
Outdoor unit
If the flare nuts are over-tightened, the flare may be
damaged, which could result refrigerant leakage and cause
in injury or asphyxiation to room occupants.
●
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.
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 following table.
Tube diameter
Tightening torque,
approximate
Tube thickness
ø6.35 (1/4")
14 – 18 N · m
{140 – 180
kg
f · cm}
0.8 mm
ø9.52 (3/8")
34 – 42 N · m
{340 – 420
kg
f · cm}
0.8 mm
ø12.7 (1/2")
49 – 61 N · m
{490 – 610
kg
f · cm}
0.8 mm
ø15.88 (5/8")
68 – 82 N · m
{680 – 820
kg
f · cm}
1.0 mm
ø19.05 (3/4")
100 – 120 N · m
{1000 – 1200
kg
f · cm}
1.2 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, see the table 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.
●
Use a torque wrench to securely tighten the valve stem cap.
●
Valve stem cap tightening torque:
Service port
ø9.52 (liquid)
8 – 10 N · m
{80 – 100
kg
f · cm}
ø19.05 (gas)
6.9 – 11.8 N · m
{69 – 118
kg
f · cm}
Valve stem cap
ø9.52 (liquid)
19 – 21 N · m
{190 – 210
kg
f · cm}
ø19.05 (gas)
13 – 14 N · m
{130 – 140
kg
f · cm}
Flare nut
ø9.52 (liquid)
34 – 42 N · m
{340 – 420
kg
f · cm}
ø19.05 (gas)
100 – 120 N · m
{1000 – 1200
kg
f · cm}
Packed valve
Valve stem cap
Service port
Valve stem cap
Service port
Hexagon screw
Torque wrench
Spanner (Fixed)
Gas side
Do not apply spanner at this position.
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