HVACopediaAll brands · Electrical troubleshooting
Single phasing (one fuse/breaker open)
What is going on
Motor runs hot, may burn out; phase-loss monitor trips.
Check in this order
- Voltage on each of the three legs at motor terminals
- Wrong/missing leg → power supply/fuse. All three correct → ohm each winding set
- Unequal = shorted or open winding → service/replace
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Source: General HVAC service practice — verify per model. Written in our own words; check the manual for your exact model.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.