Hitachi FSG1 Series Technical Catalogue page 299

Allen key Size (mm)
Model Liquid Valve
RAS-5FSG
RAS-5FS3
RAS-8FSG
RAS-8FS3
RAS-10FSG
RAS-10FS3
RAS-16FSG
RAS-16FS3
RAS-20FSG
RAS-20FS3
(As for wrenches of 5 mm and 10 mm, use field-
supplied wrenches.)
&
CAUTION:
Do not apply force to the spindle valve at the end of
opening (5 Nm or smaller). The back seat construction
is not provided.
Do not loosen the stop ring. When the stop ring is
loosened, the spindle will hop out.
During the test run, fully open the spindle. If it is not
fully opened, the devices will be damaged.
13.3.5. BRAZING WORK
1. The most important work in the refrigerant piping work
is brazing work. If leakage due to careless mistakes
hydration generation accidentally occurs, it will cause
clogged capillary pipes or serious compressor failure.
2. Pipe Dimensions after Expanding.
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, the following
dimensions should be secured.
Cooper
Tube Ø d1 Gap a
Size
+0.08 +0.1 0.33
Ø6.35 Ø6.5 6
-0.08 0 0.07
+0.08 +0.1 0.35
Ø9.53 Ø9.7 8
-0.08 0 0.09
+0.08 +0.1 0.38
Ø12.7 Ø12.9 8
-0.08 0 0.19
+0.09 +0.1 0.41
Ø15.88 Ø16.1 8
-0.09 0 0.13
+0.09 +0.1 0.44
Ø19.05 Ø19.3 10
-0.09 0 0.16
REFRIGERANT PIPING AND REFRIGERANT CHARGE
Gas Valve
4 10
5 10
8 10
8 10
8 10
a
Cooper
Tube Ø d1 Gap a
Size
+0.09 +0.1 0.39
Ø22.22 Ø22.42 10
-0.09 0 0.11
+0.12 +0.1 0.42
Ø25.4 Ø25.6 12
-0.12 0 0.08
+0.12 +0.1 0.42
Ø28.58 Ø28.78 12
-0.12 0 0.08
+0.12 +0.1 0.47
Ø31.75 Ø32.0 12
-0.12 0 0.13
+0.12 +0.1 0.52
Ø38.1 Ø38.3 14
-0.12 0 0.18
A basic brazing method is shown below.
2. Heat the outer tube
evenly, resulting in good
flow of filler metal
High Pr. Hose
Nitrogen Gas Flow
0.05 m³/h or smaller
Reducer Valve:
Open this valve only
when supplying
$
ATTENTION:
-
Use nitrogen gas for blowing during pipe brazing. If
oxygen, acetylene or fluorocarbon gas is used, it will
cause an explosion or poisonous gas.
-
A lot of oxidation film will occur inside of tubes if no
nitrogen gas blowing is performed during brazing
work. This film will be flecked off after operation and
will circulate in the cycle, resulting in clogged
expansion valves, etc. This will cause bad influence to
the compressor.
-
Use a reducer valve when nitrogen gas blowing is
performed during brazing. The gas pressure should be
maintained within 0.03 to 0.05 MPa. If a excessively
high pressure is applied to a pipe, it will cause an
explosion.
13
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1. Heat inner side tube evenly.
Rubber Plug
Packless Valve
0.03 to 0.05 MPa
(0.3 to 0.5 Kg·cm² G)