Suspension Of Refrigerant Piping; Brazing Work - Hitachi RASC-4HNPE Service Manual

3 Piping work and refrigerant charge
Piping work connection considerations

3.1.5 Suspension of refrigerant piping

Suspend the refrigerant piping at certain points and prevent the refrigerant piping from touching the weak part of the
building such as wall, ceiling, etc...
(If touched, abnormal sound may occur due to the vibration of the piping. Pay special attention in case of short piping
length).
Do not fix the refrigerant piping directly with the metal fittings (The refrigerant piping may expand and contract).
Some examples for suspension method are shown below.

3.1.6 Brazing work

The most important work in the refrigerant piping installation work is the brazing of the pipes. If it accidentally occurs a
leakage due to a careless brazing process, it will cause clogged capillary pipes or serious compressor failure.
It is important to control the clearance of the pipe fitting portion as shown below. In the case that a cooper tube expansion
jig is used, following dimensions should be secured.
In order to guarantee a proper brazing neck between different pipes surfaces, accurate pipe dimensions after the
expansion process (see the following table):
Copper pipe size Ød1
+0.08
Ø6.35 Ø6.5
-0.08
+0.08
Ø9.52 Ø9.7
-0.08
+0.08
Ø12.7 Ø12.9
-0.08
+0.09
Ø15.88 Ø16.1
-0.09
+0.09
Ø19.05 Ø19.3
-0.09
33 SMGB0091 rev.2 - 11/2015
1~15m
Indoor unit
For Suspending
For piping
Heavies along the wall
Gap a
+0.1 0.33
6
0 0.07
+0.1 0.35
8
0 0.09
+0.1 0.38
8
0 0.19
+0.1 0.41
8
0 0.13
+0.1 0.44
10
0 0.16
Fire-proof section
treatment
For instant
installation work
Copper pipe size Ød1
+0.09
Ø22.22 Ø22.42
-0.09
+0.12
Ø25.4 Ø25.6
-0.12
+0.12
Ø28.58 Ø28.78
-0.12
+0.12
Ø31.75 Ø32.0
-0.12
+0.12
Ø38.1 Ø38.3
-0.12
Gap a
+0.1 0.39
10
0 0.11
+0.1 0.42
12
0 0.08
+0.1 0.42
12
0 0.08
+0.1 0.47
12
0 0.13
+0.1 0.52
14
0 0.18
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