DC Inverter U-match Series Duct Type Unit
18
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 24k/30k/36k units, 45 minutes
for the 42k/48k units. And verify if the pressure gauge at the low pressure
side of the manifold valve assembly reads -1.0MPa (145psig), 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 18k/24k units, 10 minutes for the 30k/36k/42k/48k units.
During this time, the reading of the pressure gauge at the low pressure side
can not be larger than 0.005MPa (0.72psig).
(7)
Slightly open the liquid valve and let some refrigerant go to the
refrigerant
pipe to balance the pressure inside and outside of the
refrigerant
pipe, so
that air will not come into the
refrigerant
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.
Hose with the valve pin
gauge manifold
Pressure gauge (Low-pressure)
Pressure gauge (Hi-pressure)
Switch (Low-pressure)
Switch (Hi-pressure)
Connection pipe (to indoor unit)
Liquid valve
Gas valve
Service port
Cap
Hose
Vacuum pump
Cap
Service pipe
Cap
Refrigerant
pipe
Fig. 4.19
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.
