DC Inverter U-match Series Duct Type Unit 
 
3.2.4 Connection Pipe Vacuum Pumping and Leak Detection 
3.2.4.1 Vacuum Pumping 
NOTE! 
Make sure the outlet of vacuum pump is away from fire source and is 
well-ventilated. 
(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. 
Model  Time(min) 
GUD35PS/A-T 
GUD50P/A-T 
20 
GUD71PS/A-T 
GUD71PH/A-T 
GUD71PHS/A-T 
GUD85P/A-T 
GUD85PS/A-T 
GUD85PH/A-T 
GUD85PHS/A-T 
GUD100PH/A-T 
30 
GUD125PHS/A-T 
GUD140PH/A-T 
GUD140PHS/A-T 
GUD160PH/A-T 
45 
And verify if the pressure gauge at the low pressure side of the manifold valve 
assembly reads -0.1MPa (-750mmHg), if not, it indicates there is leak somewhere.