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Fuse blows / breaker trips repeatedly

What is going on

Possible causes and checks for: fuse blows / breaker trips repeatedly.

Likely causes

  • Wrong fuse rating/type for the motor (fast-acting on a compressor)
  • Short in the circuit
  • Motor overload

Check in this order

  1. Confirm rating against motor fuse table (A21) and UL nameplate
  2. Use time-delay fuses on compressors
  3. If rating is correct, hunt for a short. Breaker: examine capacity
  4. If adequate, there's a short or other trouble

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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.