Gree GMV-VQ280WM/C-X Owner's Manual page 42

(2) Operation procedures of vacuum drying
1) Before vacuuming, confirm that the stop valves of low pressure gas pipe, high pressure
gas pipe and liquid pipe are at closed status.
2) Connect the regulating valve and vacuum pump to the inspection joint of the gas pipe
valve and liquid pipe valve valves with a filling tube.
3) Vacuumize it for 4 hours, and check if the vacuum degree reaches -0.1 MPa 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 -0.1 MPa, 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 low pressure gas pipe, the high pressure gas pipe and the
liquid at the same time.
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.
GMV Heat Recovery DC Inverter VRF
Fig.3.6.2
38