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ARTC-SVX001B-EN
6. Symptom: Compressor loses oil
Possible Causes
Potential Solutions
Low refrigerant charge
Check for leaks and repair. Add refrigerant to proper charge.
Gas velocity in risers too low
Check riser sizes against compressor gas flow
Oil trapped in line
Check pitch of lines and refrigerant velocities
Excessive compression ring blow by
Replace or rebuild compressor
Liquid refrigerant
Check compressor superheat. Superheat at the compressor suction
should be approximately 15° F (8.3° C).
7. Symptom: Low refrigeration suction pressure
Possible Causes
Potential Solutions
Lack of refrigerant
Check for leaks. Repair and add charge.
Evaporator dirty
Clean chemically
Clogged suction line or suction gas strainers
Clean strainers
Condensing temperature too low
Check condensing temperature regulation system
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
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