Bending Copper Pipes; Brazing Copper Refrigeration Pipes - Hitachi RCI-1.0FSN3 Service Manual

3 Piping work and
refrigerant charge

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 flow 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 flow 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 fitting 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
Ø6.35 /
+0.08
Ø9.52 /
+0.08
Ø12.7 /
+0.08
Ø15.88
+0.09
Ø19.05
+0.09
Ø22.22
+0.09
Ø25.4 /
+0.12
Ø28.58
+0.12
Ø31.75
+0.12
Ø38.1 /
+0.12
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
•
filter or compressor blockages.
• NEVER USE oxygen, acetylene or fluorocarbonated gas to replace nitrogen gas: this will cause an explosion
or will generate toxic gas.
99
SMGB0077 rev.0 - 01/2013
-0.08
-0.08
-0.08
/
-0.09
/
-0.09
/
-0.09
-0.12
/
-0.12
/
-0.12
-0.12
Ød1
Ø6.5 /
+0.1
0
Ø9.7 /
+0.1
0
Ø12.9 /
+0.1
0
Ø16.1 /
+0.1
0
Ø19.3 /
+0.1
0
Ø22.42 /
+0.1
0
Ø25.6 /
+0.1
0
Ø28.78 /
+0.1
0
Ø32.0 /
+0.1
0
Ø38.3 /
+0.1
0
Tolerance a
/ 6
+0.33
0.07
/ 8
+0.35
0.09
/ 8
+0.38
0.19
/ 8
+0.41
0.13
/ 10
+0.44
0.16
/ 10
+0.39
0.11
/ 12
+0.42
0.08
/ 12
+0.42
0.08
/ 12
+0.47
0.13
/ 14
+0.52
0.18
3