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Electric furnace or air handler with heat strips: fall pre-season check

Electric resistance heat has no burner or flue, so the fall check is about airflow, connections and proving every heat stage turns on. Measure supply voltage and the current of each element stage against the rating plate, look for heat-damaged wiring at the element terminals and sequencers or relays, and confirm the limits and blower work. Values come from the unit's rating plate and wiring diagram, not from this guide.

Cross-checked ~45 min advancedBrands: All

Before you start

  • Electric furnaces and strip kits run on 240 V with large breakers and often have more than one supply circuit; turn off every breaker that feeds the unit and verify dead before touching terminals
  • Live current readings mean working near energized high-current terminals; use proper PPE and keep one hand out of the cabinet
  • Never jumper or remove a limit or fusible link to make the heat work

Diagnostic steps

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Electric furnace or air handler with heat strips: fall pre-season check · OnCall Tech