Sterlco S Series Central Chilling Stations - Manual (Page 78)

Page 78 of 86 SSC Series Central Chilling Stations
Problem Possible Cause Solution
Allow time to cool and reset.
Check for high/low voltage.
Voltage must be within plus
or minus ten percent (±10%)
of nameplate rating.
Check for poor compressor
electrical connections.
Compressor internal overload
open.
Check compressor rotation
on scroll compressors.
Compressor contactor
holding coil open.
Repair or replace.
Defective fan motor. Repair or replace.
Fan motor out on overload. Reset and test.
Defective freezestat. Replace.
Refrigerant low. Check the refrigerant charge.
Defective fan cycling control. Replace.
Low refrigerant pressure
switch contact open.
Sight glass should be clear
while comperssor runs. Call
for service if bubbling or
foaming.
Defective pump motor
interlock to compressor
control circuit.
Repair or replace.
Pump runs,
compressor does not
(cont’d).
Broken wire in the
compressor control circuit.
Locate and repair.
Freezestat control setting is
too high.
Lower set point to 10°F (6ºC)
below the leaving water
temperature you want with at
least 15 degrees differential.
Pump runs, compressor
cycles at short intervals.
Refrigerant is too low.
Check refrigeration charge;
check refrigerant sight glass
for bubbles or a level in the
glass.
Improper water/glycol
mixture.
Be sure the antifreeze
mixture protection is right for
the process.
Defective freezestat control. Replace.
Leaving water temperature is
not at set point.
Refrigerant charge is low.
Call service to find and repair
the leak. Add refrigerant.
Pump pressure is too high. Restricted water flow.
Check for partially closed
valves etc. Be sure all lines
are properly sized.