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Chapter 6: Troubleshooting - HP A0554832 User Manual

2–40 hp portable chillers
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Chapter 6: Troubleshooting

Unit does not run.
Pump runs; compressor does not.
Pump runs, compressor cycles at
short intervals.
2-40 HP Portable Chillers
Possible cause
No power.
Wrong voltage supplied to unit.
Defective on/off switch.
Control circuit fuse blown.
Defective control transformer.
Piping flow switch circuit open.
Pump motor off on overload.
High/Low thermostat set higher
than temperature of liquid in
Defective High/Low thermostat.
Low refrigerant indicator on.
Refrigerant low pressure switch
contacts open.
Refrigerant high-pressure indicator
Fan motor out on overload.
Defective fan cycling control.
Defective fan motor.
Compressor internal overload or
fuses are open.
Compressor contactor holding coil
Defective pump motor to
compressor auxiliary contact.
Broken wire in the compressor
control circuit.
Incorrect High/Low Thermostat
Chapter 6: Troubleshooting
Check main disconnect, fuses, wiring,
and power lead to unit.
Voltage must be within plus or minus
10% of nameplate rating.
Replace control circuit fuse.
Check transformer.
Check for a short circuit.
Add water or water/glycol solution as
Reset and test.
Lower thermostat stage 1 set to 10°F
(6°C) below the leaving temperature
you want.
Check refrigerant charge.
Sight glass should be clear and the
moisture indicator should be green
while compressor is running. Bubbles or
foaming is normal when the hot-gas by-
pass solenoid is energized. Call for
service if bubbling is occurring and/or
moisture indicator is yellow.
Clean the air filters.
Check condenser fans for proper
Check for dirty condenser.
Reset and test.
Reset and test.
Repair or replace.
Allow time to cool and reset, then check
for high/low volt-age. It must be within
plus or minus 10% of the nameplate
Check for open fuses and loose
compressor electrical connections.
Repair or replace.
Repair or replace.
Locate and repair.
Lower set point to 10°F (6°C) below
desired leaving water temperature.
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