Hitachi R410A Manuel D'installation page 9

6.2.1. Selecting the pipe material
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
0.004 oz/100ft.
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.)]
6.35 (1/4)
9.52 (3/8)
12.70 (1/2)
15.88 (5/8)
19.05 (3/4)
6.2.1. 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 248 °F.
(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
(19/32 in.) or thicker and if the expected humidity exceeds
80%, use heat insulation that is 20 mm (25/32 in.) 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 68 °F).
9374318438-05_IM_EN.indd 9
CAUTION
Thickness [mm (in.)]
0.80 (0.032)
0.80 (0.032)
0.80 (0.032)
1.00 (0.039)
1.20 (0.047)
CAUTION
CAUTION
CAUTION
Do not use mineral oil on À ared part. Prevent mineral
oil from getting into the system as this would reduce
the lifetime of the units.
While brazing the pipes, be sure to purge with
nitrogen gas.
6.2.3. Flaring
• Use special pipe cutter and À are 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 À are nut (always use the À are nut attached to the
indoor and outdoor units respectively) onto the pipe and
perform the À are processing with a À are tool. Use the special
R410A À are tool, or the conventional À are tool. Leakage of
refrigerant may result if other À are nuts are used.
(4) Protect the pipes by pinching them or with tape to prevent
dust, dirt, or water from entering the pipes.
B
Die
A
Pipe
Dimension A
Pipe outside
[mm (in.)]
diameter
Flare tool for R410A,
[mm (in.)]
clutch type
6.35 (1/4)
9.52 (3/8)
0 to 0.5
12.70 (1/2)
(0 to 0.020)
15.88 (5/8)
19.05 (3/4)
When using conventional À are tools to À are R410A pipes, the
dimension A should be approximately 0.5 mm (0.020 in.) more
than indicated in the table (for À aring with R410A À are tools)
to achieve the specified flaring. Use a thickness gauge to
measure the dimension A.
Width across
Pipe outside
À ats
diameter [mm (in.)]
6.35 (1/4 in.)
9.52 (3/8 in.)
12.70 (1/2 in.)
15.88 (5/8 in.)
19.05 (3/4 in.)
Check if [L] is À ared uniformly
and is not cracked or scratched.
L
Dimension B
0
-0.4
[mm (in.)]
9.1 (11/32)
13.2 (17/32)
16.6 (21/32)
19.7 (25/32)
24.0 (15/16)
Width across À ats
of Flare nut [mm (in.)]
17 (21/32)
22 (7/8)
26 (1-1/32)
29 (1-5/32)
36 (1-13/32)
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9/17/2010 1:47:42 PM