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
