Power-vent gas water heater: blower won't start, runs without firing, or locks out
Power-vent tanks add a 120 V blower, an air pressure switch and often a vent temperature limit. Most no-heat calls are electrical supply, a kinked or water-filled pressure switch tube, condensate in the blower, or a restricted vent. The tech checks power and the low-voltage safety chain and inspects visually; gas valve, burner, igniter/flame sensor and vent repairs are referred to a licensed gas technician.
Cross-checked ~45 min moderateBrands: Rheem, A.O. Smith, State, Bradford White, All power-vent gas tanks
Before you start
- GAS: gas odor means leave and call the utility; no switches
- 120 V live tests are caution: use insulated probes, keep hands clear of the blower wheel
- Never jumper or bypass the pressure switch or vent limit switch
- Gas valve, burner, igniter/flame sensor, gas pressure and vent pipe repair/re-routing are blocked: refer to a licensed plumber/gas technician
- A blocked or disconnected vent can spill carbon monoxide: confirm CO alarms work
Diagnostic steps
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