Signs of Compressor Failure: Early Detection & Diagnosis Guide

Early Warning Signs of Compressor Problems

Unusual Sounds

• Clicking at startup: Electrical issues or hard starting
• Grinding/growling: Bearing failure
• Squealing: High pressure or refrigerant issues
• Chattering: Loose internal components
• Banging: Liquid slugging or broken internal parts

Performance Issues

• Longer run times without reaching temperature
• Warm air from supply vents
• System short cycling
• Higher than normal energy bills

Electrical Symptoms

High Amp Draw

Compressor drawing higher than rated amps indicates:

• Mechanical wear increasing resistance
• High head pressure from dirty condenser
• Low voltage supply
• Internal shorts beginning to develop

Tripping Breaker

Repeated breaker trips suggest:

• Compressor grounding (winding-to-ground short)
• Locked rotor condition
• Severe electrical failure

Mechanical Symptoms

Vibration

Excessive vibration indicates internal damage or mounting issues. Check:

• Mounting grommets and bolts
• Refrigerant lines for rubbing
• Internal component looseness

Oil Issues

• Oil spots around compressor suggest seal failure
• Dark or acidic oil indicates internal damage
• Low oil level from chronic leaks

Testing Procedures

Winding Resistance Test

1. Disconnect all wires from compressor terminals
2. Measure resistance C-R, C-S, and R-S
3. C-R + C-S should equal R-S
4. All readings should be within manufacturer specs

Megohm Test

Test for grounded windings:

1. Use megohmmeter set to 500V minimum
2. Test each winding terminal to ground
3. Should read infinity (no continuity)
4. Any reading indicates grounded compressor