E4
Whirlpool Flammable Vapor Sensor Activation / Failure

E4 error on gas model, flammable vapor sensor (FVS) fault or lockout

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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

Flammable vapors detected near heater, contaminated FVS, failed FVS, wiring damage

How to Fix / Troubleshooting

Safety first: If flammable liquids or vapors are present (gasoline, solvents), remove the source and ventilate the area. Turn OFF gas and power.

Inspection:

  • Locate the flammable vapor sensor near the base of the heater.
  • Inspect for contamination (paint, oil, dirt) and clean the area around it gently.
  • Check wiring for damage or loose connections.

Corrective actions:

  • If the sensor has been exposed to flammable vapors or is out of spec (per Whirlpool resistance chart), replace it with the correct OEM sensor.
  • Some models require a specific reset procedure or control replacement after FVS activation; follow Whirlpool service instructions.

Warning: Never store flammable liquids near the water heater.

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Repair Difficulty

Hard 4/5

Required Part

Flammable Vapor Sensor
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