Applicable Systems
Copeland Scroll Compressor (CoreSense/Comfort Alert)
Symptoms
The compressor reports a phase sequence protection trip. The controller has detected incorrect phase rotation and locked out the compressor start.
Possible Causes
- Power supply phase sequence changed by utility work
- Wiring modification during maintenance altered the phase order
- Phase loss causing single-phase operation
Troubleshooting Steps
- Step 1: Verify phase sequence at the compressor disconnect with a rotation tester
Correct L1-L2-L3 sequence is confirmed - Step 2: Check for any open fuses or broken conductors in the supply
All three phases have equal voltage - Step 3: Correct the wiring if the phase sequence is wrong
Phase rotation tester shows correct sequence
How to Reset
To reset: Correct the phase sequence and verify all three phases, then cycle the compressor power.
Source: Copeland Scroll Compressor Service Manual, Emerson Climate Technologies
Category: Refrigeration