Air and moisture in the refrigerant system have undesirable effects as indicated below:
Pressure in the system rises.
Operating current rises.
Cooling or heating efficiency drops.
Moisture in the refrigerant circuit may freeze and block capillary tubing.
Water may lead to corrosion of parts in the refrigeration system.
Therefore, the indoor unit and tubing between the indoor and outdoor unit must be
leak tested and evacuated to remove any noncondensables and moisture from the
system.
Air purging with vacuum pump
Preparation
Check that each tube(both liquid and gas side tubes) between the indoor and
outdoor units have been properly connected and all wiring for the test run has
been completed. Remove the service valve caps from both the gas and the liquid
side on the outdoor unit. Note that both the liquid and the gas side service valves
on the outdoor unit are kept closed at this stage.
Pipe length and refrigerant amount:
Connecting
pipe length
Less than 5m
More than 5m
Air purging
method
Use vacuum
pump.
Use vacuum
pump.
Additional amount of refrigerant to be charged
Air purging
9K - 18K Models: (Pipe length-5) x 15g/m
21K - 28K Models: (Pipe length-5) x 40g/m
AIR PURGING
20
:
C