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4. PIPE INSTALLATION
]
CAUTION
• Be more careful that foreign matter (oil, water, etc.) does
not enter the piping than with refrigerant R410A models.
Also, when storing the piping, securely seal the openings
by pinching, taping, etc.
• While welding the pipes, be sure to blow dry nitrogen gas
through them.
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4.1. Selecting the pipe material
CAUTION
• Do not use existing pipes.
• Use pipes that have clean external and internal sides
without any contamination which may cause trouble
during use, such as sulfur, oxide, dust, cutting waste, oil,
or water.
• It is necessary to use seamless copper pipes.
Material : Phosphor deoxidized seamless copper pipes
It is desirable that the amount of residual oil is less than
40 mg/10 m.
• Do not use copper pipes that have a collapsed,
deformed, or discolored portion (especially on the interior
surface). Otherwise, the expansion valve or capillary tube
may become blocked with contaminants.
• Improper pipe selection will degrade performance. As an
air conditioner using R410A incurs pressure higher than
when using conventional refrigerant, it is necessary to
choose adequate materials.
• Thicknesses of copper pipes used with R410A are as shown
in the table.
• Never use copper pipes thinner than those indicated in the
table even if they are available on the market.
Thicknesses of Annealed Copper Pipes (R410A)
Pipe outside diameter [mm (in.)]
Thickness [mm]
6.35 (1/4)
0.80
9.52 (3/8)
0.80
12.70 (1/2)
0.80
15.88 (5/8)
1.00
19.05 (3/4)
1.20
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4.2. Pipe requirement
CAUTION
• 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.
•
CAUTION
•
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).
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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.
Check if [L] is flared uniformly
and is not cracked or scratched.
Die
Pipe
A
B
L
Pipe outside
diameter
[mm (in.)]
Dimension A [mm]
Dimension B
-
0
0.4
[mm]
Flare tool for R410A,
clutch type
6.35 (1/4)
0 to 0.5
9.1
9.52 (3/8)
13.2
12.70 (1/2)
16.6
15.88 (5/8)
19.7
19.05 (3/4)
24.0
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.
Pipe outside
diameter [mm (in.)]
Width across flats
of Flare nut [mm]
6.35 (1/4)
17
9.52 (3/8)
22
12.70 (1/2)
26
15.88 (5/8)
29
19.05 (3/4)
36
Width across
flats
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