20
General Troubleshooting
Problem
Possible Cause
Remedy
Compressor will not
start
Compressor overload
Check supply voltage, amperage of each leg,
contactor and wiring, and overload set point
Compressor contactor
Replace if faulty
Compressor failure
Contact Customer Service for assistance
Pump will not start
Pump overload
Check supply voltage, amperage of each leg,
contactor and wiring, and overload set point
Pump contactor
Replace if faulty
Pump failure
Replace if faulty
Low refrigerant
pressure
Low refrigerant charge
Contact refrigeration service technician
Refrigerant leak
Contact refrigeration service technician
Low refrigeration pressure sensor
Check for proper range, replace if faulty
High refrigerant
pressure
Dirty air filters (air-cooled units only)
Clean filters
Air flow obstruction (air-cooled units only)
Make sure chiller is installed in accordance with
recommendations in this manual
High ambient air temperature (air-cooled units only)
Ambient temperature must be reduced below 110°F
Condenser fan motor (air-cooled units only)
Replace if faulty
Condenser fan cycling control (air-cooled units only)
Confirm proper operation, replace if faulty
Plugged condenser (water-cooled units only)
Clean out tubes
Insufficient condenser water flow (water-cooled units only) Make sure chiller is installed in accordance with the
recommendations of this manual
High condenser water temperature (water-cooled units
only)
Condenser water temperature must be reduced
below 100°F
Condenser water regulating valve
Check setting, replace if faulty
Refrigerant circuit overcharged
Contact refrigeration service technician
High refrigerant pressure sensor
Replace if faulty
Freezestat
Low flow through evaporator
Adjust flow to proper level
Freezestat control module
Check for proper setting (Protected Setting)
Freezestat sensor
Replace if faulty
Low pump discharge
pressure
Pump running backwards
Switch 2 legs of the incoming power
Pump pressure gauge
Replace if faulty
Pump failure
Replace if faulty
Excessive flow
Reduce flow
High pump discharge
pressure
Closed valves in process piping
Open valves
Obstruction in piping or process
Remove obstruction
Clogged Y-strainer
Clean strainer
Pressure gauge
Replace if faulty
Erratic temperature
control
Low coolant flow through evaporator
Adjust flow to proper level
Intermittent overloading of chiller capacity
Check to make sure chiller is properly sized for
process load
Hot gas bypass valve
Contact refrigeration service technician
Temperature sensor
Replace if faulty
Insufficient cooling
(temperature continues
to rise above set point)
Process load too high
Check to make sure chiller is properly sized for
process load
Coolant flow through evaporator too high or low
Adjust flow to proper level
Insufficient condenser cooling
See “High Refrigerant Pressure”
Hot gas bypass valve stuck open
Contact refrigeration service technician
Refrigeration circuit problem
Contact refrigeration service technician
Temperature sensor
Replace if faulty
Drawings
We have prepared a custom set of drawings for your
unit and placed them inside the control panel prior
to shipment. Please refer to these drawings when
troubleshooting, servicing, and installing the unit. If
you cannot find these drawings or wish to have
additional copies, please contact our Customer
Service Department and reference the serial number
of your unit.
