GREE DC Inverter Multi VRF System II Service Manual
140
6 Common Maintenance
6.1 Vacuum drying for the system
6.1.1 Selection requirement for the vaccum pump
Do not use different vacuum pump for vaccum-pumping for different refrigerant system˗
The final vacuum for the vacuum pump should reach -0.1Mpa;
The air discharge volume for the vacuum pump should reach 4L/S above;
The precision of vacuum pup should reach 0.02mmHg above;
The system vacuum pump for R410A must be with check valve.
6.1.2 Operation procedure and notices for Vacuum drying
1
˅
Operation procedure
a
ˊ
Before vacuum-pumping, please confirm that the cut-off valve for gas pipe and liquid pipe is at off
status;
b
ˊ
Use charging conduct pipe to connect the governing value and vacuum heat pump to the detection
joint of gas valve and liquid valve;
c
ˊ
After vacuum-pumping for 4h, check whether the vacuum degree is reached to -0.1MPa or above; If
not, there may be gas leakage. Please perform the leakage inspection again. If there’s no gas
leakage, please vacuum pump for another 2h.
d. If the required vaccum degree can’t be satisfied after vacuum-pumping for two times, there are water
inside the pipeline. Please drain out the water by the method of vaccum damage. The detailed
method: charge 0.05MPa nitrogen into the pipeline, vacuum pump for 2h and then keep the cacuum
for 1h. If -0.1 MPa vaccum degree still can’t be reached, repeat this operation unitl the water is
drained out completely.
2
˅
After the vacuum pump is finished, turn off the valve of governing valve and stop vacuum pump and
keep it for 1h. Please confirm that the pressure of governing valve hasn’t been increased.
a
ˊ
Vacuum pump for the gas pipe and liquid valve at the same time;
b
ˊ
When turn off the vacuum pump to stop vacuum-pumping, please turn off the valve at first and then
de-energize the vacuum pump;
c
ˊ
Keep the vacuum pump for 2h and confirm that the pressure of vacuum meter hasn’t been increased.
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