18
Maintenance
General
This section provides instructions on preventive maintenance, refrigerant
charging, liquid pumpdown and compressor oil charging procedures.
1. General Maintenance
Once a day during the normal operating cycle, with the COMPRESSOR
RUNNING, the refrigerant level in the surge drum sight glass should be
checked. A liquid level consistently above the 3/4-point of the sight glass
indicates a refrigerant overcharge. Excess refrigerant should be pumped
out and reclaimed. A liquid level consistently below the center of the
surge drum sight glass indicates a refrigerant undercharge condition and
possible a refrigerant leak.
Door panel hinges should be adjusted to reduce any door sag by
tightening the hinge mounting screws. Door panel gaskets should be
check regularly. Hinges and the door latch should be adjusted if
necessary to affect a proper seal. If the tendency for a gasket is to freeze,
apply Dow Corning Slipicone or other suitable gasket dressing to the
gasket surface.
2. Crankcase Oil Level
At least once a week, the crankcase oil level in the crankcase sight glass
should be checked WITH THE COMPRESSOR RUNNING. An oil level
below the center of the crankcase sight glass indicates that the
compressor is low on oil.
3. Oil Pressure Safety Control
In the event the oil pressure safety control shuts the compressor down,
the compressor switch on the operator control panel should be placed in
the “OFF” position. The oil return solenoid valve (SV2) should be closed
when the compressor is not running and should be open whenever the
compressor is running. If no defective component is found, charge the
proper amount of oil to the crankcase. DO NOT reset the safety control
before adding oil.
4. Liquid Pumpdown Procedure
If a freezer is to be shut off for a period of more than two days, or if the
unit is to be replaced, the following pumpdown procedure should be
followed:
