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, 15 minutes for the 09k/12k
units, 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, 3 minutes for the units
less than 18k, 5 minutes for the 18k~24k 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 3-2-4
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.
To Next Page
Loading...
Need help?
General
