F02 error displayed, water heater not heating or shutting down shortly after start

Safety first: Turn OFF power at the breaker. For gas units, turn gas control to OFF and close gas shutoff valve.

Steps to check:

• Locate the tank temperature sensor (thermistor) on the tank well or attached to the tank surface under insulation, depending on model.
• Disconnect the sensor from the wiring harness.
• Using a multimeter set to resistance (ohms), measure the sensor resistance at room temperature. Compare to Whirlpool's thermistor chart (commonly ~10kΩ at 77°F/25°C, but verify for your model).
• If the reading is open (OL), near 0Ω, or far outside spec, the sensor is faulty.
• Inspect the harness from sensor to control board for cuts, pinched sections, or corrosion at connectors.

Replacement guidance:

• Order the correct Whirlpool tank temperature sensor/thermistor for your model.
• Remove insulation as needed, replace the sensor, and ensure it is firmly seated in the well or against the tank.
• Reinstall insulation and access covers, restore power, and clear the error by cycling power.

Note: If a new sensor does not clear F02, suspect a control board input fault.