Hitachi RPI-5.0FSN4E - Bending Copper Pipes; Brazing Copper Refrigeration Pipes

3 Piping work and
refrigerant charge
99
3
SMGB0077 rev.0 - 01/2013
3.4.5 Bending copper pipes
Where the refrigerant pipes are to be bent, always use a bending tool or a spring, both of a diameter that is adapted to the
pipe to be bent.
The bending radii must be as wide as possible so that the gas or liquid refrigerant ow is not altered and no circulation
noise is generated during operation.
N O T E
• Bendsinrefrigerantpipesreducesystemperformanceduetochangesintheowofgasandliquidrefrigerant
circulation.
• Do not use any other tool to bend pipes, as the pipe may be excessively bent or crushed and its inner diameter
reduced.
C A U T I O N
Never bend pipes with radii of less than 90°.
3.4.6 Brazing copper refrigeration pipes
Brazing is the most important job in the installation of refrigeration pipes. In the event of an accidental leak due to negligence
during the brazing process, the capillary tubes will be obstructed or the compressor seriously damaged.
To guarantee correct brazing between pipe surfaces, prepare them for widening according to the data in the following table.
C A U T I O N
• Itisimportanttocheckthepipettingmeasurementasindicatedinthefollowingtable.
• If a tool is used to widen the copper pipe, the dimensions indicated must be respected.
Copper pipe size Ød1 Tolerance a
Ø6.35
+0.08
/
-0.08
Ø6.5
+0.1
/
0
+0.33
/
0.07
6
Ø9.52
+0.08
/
-0.08
Ø9.7
+0.1
/
0
+0.35
/
0.09
8
Ø12.7
+0.08
/
-0.08
Ø12.9
+0.1
/
0
+0.38
/
0.19
8
Ø15.88
+0.09
/
-0.09
Ø16.1
+0.1
/
0
+0.41
/
0.13
8
Ø19.05
+0.09
/
-0.09
Ø19.3
+0.1
/
0
+0.44
/
0.16
10
Ø22.22
+0.09
/
-0.09
Ø22.42
+0.1
/
0
+0.39
/
0.11
10
Ø25.4
+0.12
/
-0.12
Ø25.6
+0.1
/
0
+0.42
/
0.08
12
Ø28.58
+0.12
/
-0.12
Ø28.78
+0.1
/
0
+0.42
/
0.08
12
Ø31.75
+0.12
/
-0.12
Ø32.0
+0.1
/
0
+0.47
/
0.13
12
Ø38.1
+0.12
/
-0.12
Ø38.3
+0.1
/
0
+0.52
/
0.18
14
The necessary brazing must be done by brazing, using a copper and silver alloy.
Before you start brazing, install a dry nitrogen gas injection system inside the pipes to prevent the copper from being
exposed to the air while it is subjected to high temperatures.
C A U T I O N
• Do not braze on refrigerant pipes without a dry nitrogen gas injection system.
• Otherwise, a layer of rust will form that may become detached when the refrigeration system is started, causing
lterorcompressorblockages.
• NEVERUSEoxygen,acetyleneoruorocarbonatedgastoreplacenitrogengas:thiswillcauseanexplosion
or will generate toxic gas.