GMV DC Inverter VRF
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3) Vacuumize it for 4 hours, and check if the vacuum degree reaches -0.1MPa or above. If
not, there may be a leak. It needs to conduct the leakage test once again. If there is no
leak, vacuumize it for another 2 hours.
4) If the vacuum degree cannot be maintained by two times of vacuums, you can confirm
that there is water inside the pipeline under the condition that there is no leakage. At
this time, the water should be removed by vacuum destruction. The specific method is:
fill the pipeline with 0.05MPa nitrogen gas, vacuumize it for 2 hours, and keep vacuum
for 1 hour. If it still can't reach the vacuum degree of -0.1MPa, repeat this operation until
the water is drained.
5) After vacuuming, close the valve of the regulating valve and stop vacuuming for 1 hour.
Confirm that the pressure of the regulating valve has not risen.
(3) Notices for vacuum drying
1) Vacuumize it from both the gas pipe and liquid at the same time.
Fig. 3.6.2
2) When the vacuum pump is turned off to stop vacuuming, the valve should be closed at
first and then cut off the power for the vacuum pump.
3) Keep the vacuum for 2 hours and confirm that the pressure of the vacuum gauge has
not risen.
3.7 Additional refrigerant charging
3.7.1 Calculation Method of Adding Refrigerant
Total refrigerant charging amount R= Pipeline charging amount A + Σ charging amount B of every
module.
(1) Pipeline charging amount:
Pipeline charging amount A= Σ Liquid pipe length × refrigerant charging amount of every 1m
liquid pipe
