LED_1_FLASH
American Water Heaters Thermopile Low Voltage / Pilot Not Sustained

Gas control status light flashes 1 time repeatedly; water heater will not heat.

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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

Weak thermopile, Dirty pilot orifice, Misaligned pilot flame, Loose thermopile connections at gas control

How to Fix / Troubleshooting

Safety: Turn gas control knob to OFF and wait several minutes before working near the burner.

  • 1. Inspect pilot flame: Remove the burner access cover and observe the pilot flame. It should be steady and engulf the thermopile tip.
  • 2. Clean pilot orifice: If the flame is small or unstable, shut off gas, remove the pilot tube from the burner, and clean the orifice with compressed air. Do not enlarge the opening.
  • 3. Check thermopile connections: Tighten the thermopile leads at the gas control valve. Clean any corrosion from terminals.
  • 4. Test thermopile output: With the pilot lit, measure millivolts across the thermopile leads. Compare to the manual (often 350 mV or higher). Replace the thermopile if output is low.
  • 5. Relight pilot: Follow the lighting instructions on the heater label to relight the pilot and verify normal operation.
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Repair Difficulty

Medium 3/5

Required Part

Thermopile / Pilot Assembly
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