American Water Heaters Short Cycling / Inadequate Run Time

Gas water heater burner lights but shuts off prematurely; water not reaching set temperature.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Faulty thermostat in gas control valve, Partially restricted vent causing poor draft, Dirty burner orifice, Flue baffle mispositioned

How to Fix / Troubleshooting

Safety: Turn off gas and allow the heater to cool before servicing.

  • 1. Check thermostat setting: Verify the temperature dial is set appropriately (around 120°F).
  • 2. Inspect venting: Ensure the vent is properly sized and unobstructed. Correct any sagging or disconnected sections.
  • 3. Clean burner and orifice: Remove the burner assembly and clean ports and orifice with compressed air.
  • 4. Inspect flue baffle: Confirm the baffle is correctly installed per the manual.
  • 5. Replace gas control: If short cycling persists, the gas control valve thermostat may be faulty and require replacement.
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Repair Difficulty

Medium 3/5

Required Part

Gas Control Valve / Thermostat
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