System Troubleshooting Guide

[Athanatos]

Compressor

Compressor will not run. Does not try to start.
1. Main power switch open.
2. Fuse blown or tripped circuit breaker.
3. Thermal overloads tripped.
4. Defective contactor or coil.
5. System shut down by safety devices.
6. Open thermostat or control. No cooling required.
7. Liquid line solenoid will not open.
8. Loose wiring.
Compressor hums, but will not start.
1. Improperly wired.
2. Low line voltage.
3. Loose wiring.
4. Defective start or run capacitor.
5. Defective start relay.
6. Motor windings damaged.
7. Internal compressor mechanical damage.
Compressor starts, but trips on overload protector.
1. Improperly wired.
2. Low line voltage.
3. Loose wiring.
4. Defective start or run capacitor.
5. Defective start relay.
6. Excessive suction or discharge pressure.
7. Tight bearings or mechanical damage in compressor.
8. Defective overload protector.
9. Motor windings damaged.
10. Overcharged system.
11. Shortage of refrigerant.
12. Suction or discharge pressure too high.
13. Inadequate ventilation.
14. Operating system beyond design conditions.
Compressor short cycles.
1. Low pressure control differential set too low.
2. Shortage of refrigerant.
3. Low airflow at evaporator(s).
4. Discharge pressure too high.
5. Compressor internal discharge valves leaking.
6. Incorrect unit selection (oversized).
Contact welded stuck on start relay
1. Short cycling.
2. No bleed resistor on start capacitor
Start capacitor burns out
1. Improperly wired.
2. Short cycling.
3. Low line voltage.
4. Relay contacts sticking.
5. Incorrect capacitor.
6. Start winding remaining in circuit for prolonged period.
Compressor noisy or vibrating.
1. Flood back of refrigerant.
2. Improper piping support on the suction or discharge lines.
3. Broken or worn internal compressor parts.
4. Incorrect oil level.
5. Scroll compressor rotating in reverse (three phase).
6. Improper mounting on unit base.
Discharge pressure too high.
1. Non-condensables in the system.
2. System overcharged with refrigerant.
3. Discharge service valve partially closed.
4. Condenser fan not running.
5. Dirty condenser coil.(air-cooled condensers)
6. Dirty tubes. (water-cooled condensers)
7. Defective or improperly set water regulating valve. (water-cooled condensers)
8. Defective or improperly set flooded head pressure control.
Discharge pressure too low.
1. Low suction pressure.
2. Cold ambient air.
3. Suction service valve partially closed.
4. Shortage of refrigerant.
5. Defective or improperly set water regulating valve. (water-cooled condensers)
6. Defective or improperly set flooded head pressure control.

[Athanatos]

Condensing Unit

Suction pressure too high.
1. Excessive load.
2. Compressor internal valves broken.
3. Incorrect unit selection (undersized).
4. Improper TXV bulb charge.
Suction pressure too low.
1. Shortage of refrigerant.
2. Evaporator dirty or iced up.
3. Clogged liquid line filter drier.
4. Clogged suction line filter or compressor suction strainers.
5. Expansion valve malfunctioning.
6. Condensing temperature too low.
7. Improper TX valve selection.
8. Evaporator distributor feed problems.
Low or no oil pressure.
1. Low oil level.(trapped oil in evaporator or suction line)
2. Clogged suction oil strainer.
3. Excessive liquid refrigerant in the crankcase.
4. Worn oil pump.
5. Oil pump reversing gear sticking in the wrong position.
6. Worn bearings.
7. Loose fitting on oil line.
8. Pump housing gasket leaking.
Compressor loses oil.
1. Refrigerant leak.
2. Short cycling.
3. Excessive compressor ring blowby.
4. Refrigerant flood back.
5. Improper piping or traps.
6. Trapped oil in evaporator.
Compressor runs continuously
1. Excessive load.
2. Too low of a system thermostat setting or defective thermostat.
3. Shortage of refrigerant.
4. Leaking compressor internal valves.
5. Malfunctioning liquid line solenoid.
6. Incorrect unit selection (undersized).