McQuay MDS030AR Applications Manual page 92

Design & installation Guide For McQuay MDS Multi System
-92-
2
kg/cm
0
-200
-400
-600
-700
-760
Vacuum drying
Special vacuum drying
This vacuum drying way is used when there are some moisture in the copper pipe.
Operating sequence:
Vacuum drying: pumping the system for 2 hours;
Nitrogen charging: Charge the nitrogen to the pressure of 0.5kg/cm
As Nitrogen is a dried gas, so it can dry the system; but if the moisture is too much, maybe it can
not dry the system thoroughly. So when install the refrigerant piping, please be careful enough
to prevent the water coming into the pipe or the condensated water.
Vacuum drying one more time: pumping the system for 1 hours;if the pressure is less than
-75 mmHg, then it is OK; if it can not reach -75 mmHg, then it should go back to item 2, then
item 3;
Stop vacuum pumping and wait for 1 hour;
Additional refrigerant charging;
Open the vale to charge.
Please note that the gas must be nitrogen, if oxygen is used by mistake, it can result in explosion
2
kg/cm
+0.5
0
-200
-400
-600
-700
-760
Ordinary vacuum drying
-755mmHg
Vacuum pump
Total for 3 hours
Special vacuum drying
Refrigerant charging
2
;