Chiller Troubleshooting
ARTC-SVX002A-EN 65
11. Symptom: Low chilled water temperature
Possible Causes Potential Solutions
Temperature controllers set too low Reset temperature controllers to correct design specifications
Water velocity through evaporator too low Clean strainer; check pump, VFD, and differential pressure settings
Temperature controllers malfunctioning Replace temperature sensor
12. Symptom: High chilled water temperature
Possible Causes Potential Solutions
Load higher than capacity of chiller Refer to chiller design specifications
Loss of refrigeration charge Pressure test refrigeration system
Fouled evaporator Reverse flush evaporator; check strainer for debris
Obstructed flow through evaporator
Reverse flush evaporator; check strainer for debris; check VFD, pump,
valves
13. Symptom: Compressor thermal protector switch open
Possible Causes Potential Solutions
Operating beyond design conditions Check fan switch or fan pressure settings as appropriate
Discharge valve partially shut Open valve
Faulty compressor overload Replace overload if external type provided
14. Symptom: No low voltage (24 Vac)
Possible Causes Potential Solutions
Control circuit fuse open Check fuse prong contact points; replace fuse
Phase monitor opened or tripped Check for correct voltages
Transformer T1 defective Replace transformer T1, T2, T3
No primary voltage on T1 Check breakers, fuses; check power supply specifications
15. Symptom: Thermal Expansion valve superheat too high
Possible Causes Potential Solutions
Water/glycol temperature too warm Low refrigerant level; recharge chiller
Obstructed filter dryer Replace dryer core
Low refrigerant charge Recharge refrigerant as per data plate
Improperly adjusted superheat valve setting Reset valve settings to factory specifications
16. Symptom: Thermal expansion valve superheat too low
Possible Causes Potential Solutions
Sensing bulb not properly located
Check if secured to pipe or insulated; check sensor position on pipe at 4-
8-10-2 clock positions
Defective thermostatic element Replace power head
Valve adjusted too far open Re-adjust to 10° to 12°(scroll) or 13° to 16°(digital scroll)
17. Symptom: Contactor/relay inoperative
Possible Causes Potential Solutions
Coil shorted or open Replace coil
Mechanical parts broken or jammed Replace assembly
Contacts pitted or burned Replace contactors
No 24 Vac to coil Replace secondary fuse to T2 transformer
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