Refrigerant Charging - Gree U-Match 6 Series Service Manual

GREE
And verify if the pressure gauge at the low pressure side of the manifold valve assembly reads
-0.1MPa (-750mmHg), if not, it indicates there is leak somewhere. Then, close the switch fully and then
stop the vacuum pump.
(1) Wait for 10min to see if the system pressure can remain unchanged. If the pressure increase, there
may be leakage.
(2) Slightly open the liquid valve and let some refrigerant go to the connection pipe to balance the
pressure inside and outside of the connection pipe, so that air will not come into the connection pipe
when removing the hose. Notice that the gas and liquid valve can be opened fully only after the
manifold valve assembly is removed.
(3) Place back the caps of the liquid valve, gas valve and also the service port.
NOTICE:
For large-size units, there are maintenance ports for liquid valve and gas valve. During evacuation,
you may connect the two hoses of the branch valve assembly to the maintenance ports to speed up the
evacuation.
Refrigerant should be reclaimed into the appropriate storage tank. System should use oxygen-free
nitrogen purging to ensure safety. This process may need to repeat several times. Do not use
compressed air or oxygen in this process.

4.3 Refrigerant Charging

Pre-charging
Step 1: Connect the high pressure gauge line to the valve of liquid pipe and connect the low pressure
gauge line to the valve of gas pipe. Connect the middle gauge line to the vacuum pump. Power on the
vacuum pump and perform vacuum drying.
U-Match 6 SERIES UNIT SERVICE MANUAL
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