What happens
An internal winding path is broken, preventing intended motor operation.
Typical symptoms
No start or hum despite appropriate supply and start components.
Checks that distinguish this cause
After safe isolation, identify the actual terminal scheme and separate the harness. Compare winding tests with model data, accounting for an internal protector that may be open while hot.
What can look similar
A hot overload or broken external lead can look like an open winding.
Repair direction
Replace a confirmed failed hermetic compressor using the approved refrigeration procedure and investigate the original stress.
Verify the repair
Verify supply, starting, current and refrigeration performance after repair.
Equipment-specific limits
Single-phase C/R/S checks do not apply to every inverter or three-phase compressor. Use model data, isolate electronics as directed and never run or perform insulation tests under vacuum.
Practice this diagnosis
These simulated calls exercise this component or repair family. The article describes a broader diagnostic process; a call may represent a different cause within that family.
References and applicability
Original HVACSim explanations with manufacturer and instrument-maker references for further reading. These resources support the subject; their model-specific examples are not specifications for every system.
- Copeland: CoreSense diagnostics for scroll air-conditioning compressors (AE8-1379)Model-specific diagnostic examples; flash codes are not universal.
- Copeland: Refrigeration basics: troubleshooting fundamentalsCompressor and refrigerant troubleshooting concepts, not a charging specification.
- Copeland: Compressor terminal venting safetyStop conditions and hazards around compressor electrical terminals.
- Fluke: Insulation resistance and electrical testing for HVAC compressor motorsInsulation-testing precautions, including avoiding tests under vacuum; use compressor-specific instructions.
Editorial review: 2026-09-29. Verify the current manual for the installed model.