U-Match Series Service Manual
61
(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, 20 minutes for the 18k units,
30 minutes for the 24/30/36k units, 45 minutes for the 42/48/60k 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
18K~24k units, 10 minutes for the units more than 36K~60k. 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 3-2-4
Note: For the large-sized unit, it has the service port for both the gas valve and the liquid valve.
During evacuation, it is available to connect two hoses of the manifold valve assembly to two service
ports to quicken the evacuating speed.
3.1.7.2 Additional Charge
Refrigerant suitable for a piping length of 5m is charged in the 18~42k outdoor unit at the factory,
and for 48~60k outdoor unit refrigerant is charged for a piping length of 7.5m.
When the piping of 18~42k unit is longer than 7.0m or the piping of 48~60k unit is longer than 9.5m,
additional charging is necessary.
For the additional amount, see Table 3-2-3.
Table 3-2-3
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