F12

Whirlpool Ambient Temperature Sensor Failure

F12 error, hybrid water heater indicates ambient temperature sensor fault, may lock out heat pump mode

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.

Possible Causes

Open or shorted ambient thermistor, damaged sensor wiring, sensor dislodged from mounting location, control board input fault

How to Fix / Troubleshooting

Safety first: Turn OFF power at the breaker.

Sensor checks:

Locate the ambient temperature sensor near the air intake or on the control panel area.
Disconnect the sensor from the harness and measure resistance with a multimeter. Compare to Whirlpool's temperature/resistance chart.
Inspect the sensor body and wiring for damage, pinching, or corrosion at the connector.

Corrective actions:

Replace the ambient sensor if resistance is out of specification or intermittent.
Ensure the new sensor is mounted in free air, not touching hot surfaces.
If a known-good sensor still triggers F12, the main control board may have a defective sensor input and should be replaced.

Repair Difficulty

Medium 3/5

Required Part

Ambient Temperature Sensor

Check Price on Amazon

We may earn a commission from links on this page.