c. Operate the refrigeration compressor so that the
refrigerant is pumped from the suction side of the
compressor into the receiver until the suction pressure
drops to 0 psi.
d. Allow the unit to stand for a few minutes; then if
the pressure gage shows a rise above zero, restart the
compressor to get rid of the refrigerant which has come
out of the oil.
e. If removing or opening the condenser, shut off
the receiver inlet valve at the front end of the inlet line
(4). A small amount of refrigerant will probably be lost
unavoidably, whenever the system is opened. This is
not serious as long as the foregoing steps to prevent
major loss of refrigerant are observed.
Refrigerant sight glass
Oil level sight glass
Receiver tank inlet line
Freon charging port
Suction valve shut-off
Oil filler plug
Figure 4-85. Refrigeration compressor, installed view.