Gree HOME GMV [188/367] Operation order basic procedures for welding

Gree HOME GMV [188/367] Operation order basic procedures for welding
Dc Inverter VRF plus Water Heater Solution Service Manual INSTALLATION
184
i. To avoid the position difficult to weld, you may add a prefabricated assembly below.
3Operation order
Basic procedures for welding:
a. Cleaning of portions for braze welding
Polishing……………………Removing metal materials at connection portion. (Removing
oxidation film using non-woven fabric, abrasive cloth or abrasive paper)
Ungrease……………………If any oil stain is existent, acetone or spirit solvent shall be used for
ungrease treatment.
At the same time, compressed air at 0.8MPa (gauge pressure) shall be used for cleaning. The
cleaning shall be repeated not less than 3 times, until there is no dirt discharged.
b. Check whether clearance between pipe and connector is proper.
Put the connector into the pipe and face downward. If the connector does not fall down
depending on friction force, the clearance is considered proper.
c. Nitrogen-filled protection
Since vigorous oxidation would occur on the surface of copper pipe at braze welding
temperature, to effectively restrain the generation of oxide coating in copper pipe,
nitrogen-filled protection for copper pipe is necessary.
After copper pipes are assembled, nitrogen shall be filled in copper pipe connectors.
Nitrogen charging method
Assemble copper
pipes
Cleaning
Check whether clearance
is proper.
Fill nitrogen N2
Nitrogen pressure 0.05-0.3Mpa 0.5±0.1kgf/cm
2
Welding flux
Acknowledge
welding flux
Add welding flux
Cooling, continue to fill nitrogen
for over 10s
Shut off nitrogen
Welding heating
Make visual inspection to
the weld quality
Difficult to weld at
this position
Drainage pipe

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