How to Fix / Troubleshooting

Safety: Turn OFF power at the breaker.

Locate ambient sensor: On hybrid models, the ambient thermistor is usually mounted near the air intake grille at the top of the unit.
Clean intake: Remove dust and lint from the intake grille and surrounding area to ensure proper airflow and accurate temperature sensing.
Inspect sensor and wiring: Ensure the sensor is not covered by insulation and that its wiring is intact and firmly connected to the control board.
Test thermistor: Disconnect and measure resistance; compare to the expected value for room temperature. Replace if out of spec.
Replace sensor: Install a new ambient air temperature sensor / thermistor if needed.
Reassemble and test: Restore power and verify that E22 clears and the unit operates in heat pump mode.

Kenmore hybrid water heater displays E22 and may shut down heat pump operation

Possible Causes