Chiller/Heater Troubleshooting
64 ARTC-SVX005A-EN
1. Symptom: Compressor will not start
Possible Causes Potential Solutions
Circuit breakers are in the OFF position Moves circuit breakers to the ON position in the power distribution panel
Temperature control not in demand Set point has been reached or still within band
Differential pressure switch open due condenser flow switch open Condenser side loss of flow; clean strainer
Refrigerant low pressure switch open
Low refrigerant level or low pressure event has occurred four times and
locked out the circuit
High pressure switch open Low flow rate; check for dirty or clogged strainer. Requires a manual reset
Flow switch defective Replace FS-1 and FS-2 switch
Compressor overload opened
Allow motor to cool and reset; high amp load/floodback; loose
connection, or low refrigerant charge
No high voltage power to contactor
Check breakers; energize from power distribution panel and module
electrical panel; check ON/OFF button in touchscreen interface
Phase monitor open or tripped Over or under 4% to 8%; loss of leg
2. Symptom: Compressor fails to continue running
Possible Causes Potential Solutions
Compressor not powered Assure all circuit breakers are in the ON position
Circuit breakers open Check circuits and motor winding for shorts or grounds
Tripped circuit breaker Reset breakers after fault is corrected
Investigate for possible overloading
Overloads are auto-reset. Monitor to assure the overload does not re-
occur
Electrical overamp breaker tripped Repair or replace
Defective contactor or coil Determine type and cause. Correct fault before replacing parts.
System shut down by safety devices
Repair, replace, or correct safety issue (for example, no flow, low
pressure)
Liquid line solenoid will not open
Check coil for open circuit, short circuit, or burnout. Replace coil or entire
valve, if needed
Motor electrical trouble Replace tandem compressors
3. Symptom: Compressor has excessive noise or vibration
Possible Causes Potential Solutions
Flooding of refrigerant into crankcase
Low fluid flow across heat exchanger; clogged strainer. Check setting of
expansion valve
Improper discharge piping support Repair as necessary. Relocate, add, or remove supports
Improper or worn compressor supports Replace supports
Worn compressor Replace tandem compressors
4. Symptom: Compressor cycles too short
Possible Causes Potential Solutions
Temperature differential set too low (4 °F (22 °C) minimum)
Ramp/set temperature set point. Default 5 °F raise up accordingly with
low loads.
Erratic water thermostat device Replace thermostat assembly.
Insufficient evaporator water flow Adjust flow rate or clean strainer.
5. Symptom: Compressor oil level in sight glass low
Possible Causes Potential Solutions
Low refrigerant charge Check for leaks and repair. Add refrigerant to proper charge
Leak in refrigerant line Repair leak; add refrigerant
6. Symptom: Low refrigeration suction pressure
Possible Causes Potential Solutions
Lack of refrigerant Check for leaks. Repair and add charge
Evaporator fouled Clean chemically
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