COM-SVN003B-EN
17
Start-Up
Follow the instructions in the unit Installation, Operation,
and Maintenance manual. If there are no instructions
available, use these guidelines:
•
Never start the compressor without refrigerant in the
system.
•
Never bypass the low pressure switch to start the unit.
•
Monitor oil level for 60 minutes to ensure that oil
returns from the system.
•
Check system pressures and temperatures to ensure
they are in line with unit design pressures. Refer to the
unit Installation, Operation, and Maintenance manual
for this information.
•
To top off the unit, charge liquid refrigerant may added
by slowly throttling it into the suction line. This must be
done only when the compressor is operating.
•
Do not overcharge the unit.
•
Recommended system full load superheats—unless
specified differently in the unit Installation, Operation,
and Maintenance manual—is 16°F–20°F.
•
Measure the oil sump superheat. Oil sump superheat
should be greater than 20°F. Oil sump superheat is
calculated as follows:
Oil Sump Superheat = Oil Sump Temperature –
Saturated Suction Temperature
•
Measure the oil sump temperature by placing a
thermocouple on the bottom of the compressor,
preferably in the center, and insulate it. Calculate sump
superheat. If less than 20°F, recheck the expansion
valve superheat and increase it. Low sump superheat
is indicated by foaming compressor oil.
•
After fully charging the unit, recheck all pressure,
temperatures, and electrical readings.
NOTICE
Equipment Damage!
Failure to follow guidelines below could result in
equipment damage.
