Gree U-MATCH Series Service Manual page 75

U-Match Series DC Inverter Service Manual
3.1.6 Heat Insulation on the Pipe Joints (Indoor Side Only)
Stick coupler heat insulation (large and small) to the place where connecting pipes.
3.1.7 Vacuum and Gas Leakage Inspection
Do not purge the air with refrigerants but use a vacuum pump to vacuum the installation! There is no
extra refrigerant in the outdoor unit for air purging!
3.1.7.1 Vacuum
(1) Remove the caps of the liquid valve, gas valve and also the service port.
(2) Connect the hose at the low pressure side of the manifold valve assembly to the service port of
the unit‟s gas valve, and meanwhile the gas and liquid valves should be kept closed in case of refrigerant
leak.
(3) Connect the hose used for evacuation to the vacuum pump.
(4) Open the switch at the lower pressure side of the manifold valve assembly and start the vacuum
pump. Meanwhile, the switch at the high pressure side of the manifold valve assembly should be kept
closed, otherwise evacuation would fail.
(5) The evacuation duration depends on the unit‟s capacity, generally, 30 minutes for the 24/36k
units, 45 minutes for the 42/48/60 units. And verify if the pressure gauge at the low pressure side of the
manifold valve assembly reads -1.0Mp (-75cmHg), if not, it indicates there is leak somewhere. Then,
close the switch fully and then stop the vacuum pump.
(6) Wait for some time to see if the system pressure can remain unchanged, 5 minutes for the
24/36k units, 10 minutes for the units more than 42k. 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. Note 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.
Figure 3-2-7
CAUTION!
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