GREE U-Match 5 SERIES UNIT SERVICE MANUAL
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（
6
）
Wait for 10min to see if the system pressure can remain unchanged. During this time, the reading of the pressure gauge at the
low pressure side can not be larger than 0.005Mp (0.38cmHg).
（
7
）
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.
（
8
）
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.
Step 2: After vacuum drying, close the high and low pressure gauge valves. Then remove the middle gauge
line from the connector of vacuum pump. Then connect to the refrigerant tank.
Step 3: Loosen the middle gauge line from the connector of pressure gauge to a proper extent and slightly
open the valve of refrigerant tank. Evacuate the middle gauge line. Then tighten up the connector again and
completely open the valve of refrigerant tank at the same time.
Step 4: Keep the refrigerant tank erect and put it on an electronic scale. Record the current weight as m1.
