A basic brazing method is shown below.
Pre-heat the outer tube for better flowing of the filler metal
Heat inner side tube evenly
Rubber plug
Packless valve
High pressure hose
0.03 to 0.05 MPa (0.3 to 0.5 kg/cm
2
G)
Reducer valve: open this valve only when the gas is needed
Nitrogen gas flow 0.05 m
3
/h or smaller
!
C A U T I O N
•
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.
3.2 Piping connection for RASC unit
The stop valves are located on the right side of unit cover. Before connecting refrigerant piping, the stop valve protection
cover shall be removed.
Gas valve
Liquid
valve
1
Mount the piping cover in order to avoid water entering into the unit. Seal the holes where pipes and wires are
inserted, by using a insulation (field-supplied).
2
If the field-supplied piping is connected with stop valves directly, it is recommended use a tube bender.
3
Check to ensure that the stop valves are completely closed before connecting pipes.
4
Connect the field supplied refrigerant pipes to the indoor unit and RASC unit. Apply the oil thinly at the seat flare nut
and pipe before tightening.
The required tightening torque is as follows:
Pipe Size
Tightening Torque (Nm)
Ø 6.35 mm (1/4”)
20
Ø 9.52 mm (3/8”)
40
Ø 12.70 mm (1/2”)
60
Ø 15.88 mm (5/8”)
80
Ø 19.05 mm (3/4”)
100
3 Piping work and refrigerant charge
Piping connection for RASC unit
SMGB0091 rev.2 - 11/2015
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