Willis WST12MC16S Service Manual page 52

Evacuation
(All amount of refrigerant leaked)
Vacuum pump
• Procedure
(1) Connect the vacuum pump to the center hose
of charge set center hose
(2) Evacuation for approximately one hour.
– Confirm that the gauge needle has moved
toward -76 cmHg (vacuum of 4 mmHg or less).
68
Liquid side
Indoor unit
Gas side
Lo
OPEN
CLOSE
3-Way
valve
Open
3-Way
valve
Open
(3) Close the valve (Lo side) on the charge set,
turn off the vacuum pump, and confirm that
the gauge needle does not move (approxima-
tely 5 minutes after turning off the vacuum
pump).
(4) Disconnect the charge hose from the vacuum
pump.
– Vacuum pump oil.
If the vacuum pump oil becomes dirty or
depleted, replenish as needed.
Troubleshooting
Outdoor unit