DC Inverter U-match Series Cassette Type Unit 
27 
Notice:
 Only for the GUD100W/NhA-T, GUD125W/NhA-T, 
GUD140W/NhA-T, GUD100W/NhA-X, GUD125W/NhA-X, GUD140W/NhA-X, 
GUD160W/NhA-X units. 
3.2.4 Connection Pipe Vacuum Pumping and Leak Detection 
3.2.4.1 Vacuum Pumping 
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. 
GUD71W/NhA-T, GUD85W/NhA-T, 
GUD100W/NhA-T, GUD100W/NhA-X 
GUD125W/NhA-T, GUD140W/NhA-T, 
GUD125W/NhA-X, GUD140W/NhA-X, 
GUD160W/NhA-X 
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 10min to see if the system pressure can remain unchanged. During this 
time, the reading of the pressure gauge at the low pressure side can not be 
larger than 0.005Mp (0.38cmHg).