Chiller Troubleshooting
64 ARTC-SVX002A-EN
Low water temperature Raise set point; check design specification
Compressor will not unload Replace solenoid or controller
Low discharge pressure Refrigerant charge; replace compressor
Expansion valve malfunctioning Reset for proper superheat (10-12 º SH)
Mis-adjusted or defective TXV Adjust or replace valve
Receiver service valve closed
Turn counterclockwise completely. Do not fully backseat if pressure
switch is installed on service port
Compressor service valves closed Dangerous! Turn counterclockwise completely
Clogged liquid line filter-drier Replace cartridges
Excessive glycol concentration Drain, refill (deionized water), retest
Liquid line solenoid restricted or faulty Replace solenoid valve, coil, or internals as necessary
Insufficient chilled water Adjust flow rate across evaporator
Restricted water/glycol line Clean strainers; check manual and electronic valves
Water/glycol mixture contaminated
Intensive cleanup effort needed to identify source of contamination;
external filter may be required
Evaporator tubing clogged or fouled Reverse flush with appropriate chemical solutions
7. Symptom: Low refrigeration suction pressure (continued)
Possible Causes Potential Solutions
8. Symptom: High refrigeration suction pressure
Possible Causes Potential Solutions
Expansion valve opened too far Re-adjust to 10° to 12°
Excessive refrigerant charge
Creates high pressure alarms; reclaim excess refrigerant and verify
proper sub-cooling and superheat.
High water temperature Low refrigerant charge; failing compressor; check design specifications
9. Symptom: Low refrigerant discharge pressure
Possible Causes Potential Solutions
Suction shut off valve partially closed Open valve
Insufficient refrigerant in chiller Check for leaks. Repair and add refrigerant as needed
Compressor operating unloaded See failure of compressor to unload or load up below
Low ambient conditions Check condenser rating tables
Low suction pressure See low pressure below
Condenser pressure regulating valve not properly adjusted
Refer to OEM manufacturer manual for default settings; check equipment
room ambient temperature
Fan cycling controls not properly set Reset cut-in, cut-out settings to conform to design specifications
10. Symptom: High refrigerant discharge pressure
Possible Causes Potential Solutions
System overcharged with refrigerant Remove excess refrigerant
Dirty tube and fin surface Clean with compressed air or water spray, use fin comb if fins are bent
Non-condensables in chiller Purge non-condensables.
Fan cycling controls not properly set Reset fan cycle setting; replace motor controller fuse
Condensing fans not operating Reset fan cycle setting; replace motor controller fuse
Restricted bypass line Check valves obstructed; flush line; blow out line with dry nitrogen gas
Discharge shut off valve partially closed Open valve
Condenser is undersized Check condenser rating tables with operating parameters
High ambient conditions exist Check condenser rating tables with operating parameters
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