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1
4.2. Pipe requirement
• Refer to the Installation Manual of the outdoor unit
for description of the length of connecting pipe or for
difference of its elevation.
•
Use pipe with water-resistant heat insulation.
• Install heat insulation around both the gas and liquid
pipes. Failure to do so may cause water leaks.
Use heat insulation with heat resistance above 120 °C.
(Reverse cycle model only)
In addition, if the humidity level at the installation location
of the refrigerant piping is expected to exceed 70 %,
install heat insulation around the refrigerant piping.
If the expected humidity level is 70-80 %, use heat
insulation that is 15 mm or thicker and if the expected
humidity exceeds 80 %, use heat insulation that is 20
mm or thicker. If heat insulation is used that is not as
thick as specified, condensation may form on the surface
of the insulation.
In addition, use heat insulation with heat conductivity of
0.045 W/(m·K) or less (at 20 °C).
1
4.3. Flare connection (pipe connection)
4.3.1. Flaring
• Use special pipe cutter and flare tool exclusive for R410A.
(1) Cut the connection pipe to the necessary length with a
pipe cutter.
(2) Hold the pipe downward so that cuttings will not enter the
pipe and remove any burrs.
(3) Insert the flare nut (always use the flare nut attached to
the indoor and outdoor units respectively) onto the pipe
and perform the flare processing with a flare tool. Use the
special R410A flare tool, or the conventional flare tool.
Leakage of refrigerant may result if other flare nuts are
used.
(4) Protect the pipes by pinching them or with tape to prevent
dust, dirt, or water from entering the pipes.
Die
A
Pipe
Dimension A [mm]
Pipe outside
diameter
Flare tool for R410A,
[mm (in.)]
6.35 (1/4)
9.52 (3/8)
12.70 (1/2)
15.88 (5/8)
19.05 (3/4)
When using conventional flare tools to flare R410A pipes,
the dimension A should be approximately 0.5 mm more
than indicated in the table (for flaring with R410A flare tools)
to achieve the specified flaring. Use a thickness gauge to
measure the dimension A.
En-6
CAUTION
CAUTION
Check if [L] is flared uniformly
B
and is not cracked or scratched.
L
Dimension B
[mm]
clutch type
9.1
13.2
0 to 0.5
16.6
19.7
24.0
Width across
flats
4.3.2. Bending pipes
•
The pipes are shaped by your hands or pipe bender. Be
careful not to collapse them.
•
Do not bend the pipes in an angle more than 90°.
•
When pipes are repeatedly bend or stretched, the material
will harden, making it difficult to bend or stretch them any
more. Do not bend or stretch the pipes more than three
times.
• To prevent breaking of the pipe, avoid sharp bends.
• If the pipe is bent repeatedly at the same place, it will
break.
4.3.3. Pipe connection
When the flare nut is tightened properly by your hand,
hold the body side coupling with a separate spanner, then
tighten with a torque wrench.
• Hold the torque wrench at its grip, keeping it in the right
angle with the pipe, in order to tighten the flare nut
correctly.
• Tighten the flare nuts with a torque wrench using the
specified tightening method. Otherwise, the flare nuts
could break after a prolonged period, causing refrigerant
to leak and generate a hazardous gas if the refrigerant
comes into contact with a flame.
Torque wrench
Indoor unit pipe
(Body side)
• Be sure to apply the pipe against the port on the indoor
unit and the outdoor unit correctly. If the centering is
0
-
0.4
improper, the flare nut cannot be tightened smoothly.
If the flare nut is forced to turn, the threads will be
damaged.
• Do not remove the flare nut from the indoor unit pipe until
immediately before connecting the connection pipe.
• Do not use mineral oil on flared part. Prevent mineral
oil from getting into the system as this would reduce the
lifetime of the units.
Pipe outside
Width across flats
diameter [mm (in.)]
of Flare nut [mm]
6.35 (1/4)
9.52 (3/8)
12.70 (1/2)
15.88 (5/8)
19.05 (3/4)
CAUTION
CAUTION
Tighten with two wrenches.
Holding wrench
Flare nut
Connection pipe
CAUTION
17
22
26
29
36
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