Gree GMV-PD100W/NAB-K, Service Manual

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DC Inverter Multi
VRF Service Manual
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.
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necessary.
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Nitrogen charging method:
Pressure is 0.5±0.1kgf/cm2. Nitrogen flow of 4~6L/min (gas flow can be sensed by hand) shall be
guaranteed to charge in work pieces.
After assembling, nitrogen begins to charge until welding is finished and will continue over 10s during
cooling after welding.
Main points of nitrogen charge(See the drawing below)
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Make sure nitrogen reaches all welding connectors in order to effectively discharge air
A vent port must be available when nitrogen charge is continuously performed, or otherwise gas would
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Nitrogen charge pipe
Copper pipe
Places requiring
protection during welding
Copper pipe
Vent port
Nitrogen( )
N
2
d. Welding heating
Notes:
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normally used. Copper pipe connectors shall be heated uniformly. Take care to distribute heat in terms of
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along length of connector to make it heated uniformly until braze welding temperature is approached; then
copper pipe is heated circularly to reach braze welding temperature (copper pipe becomes light red) and at the
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and cables.
e. Post-welding treatment(cooling)
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copper pipe changes color (200-300 ), i.e. annealing treatment.
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f. Quality and inspection of braze welding