F06 error, hybrid or heat pump water heater not heating properly, unit may revert to electric resistance mode

Safety first: Turn OFF power at the breaker. Do not attempt to open sealed refrigeration components unless EPA-certified.

Basic owner checks (hybrid models):

• Ensure the unit has adequate clearance around it for airflow (typically at least 6–12 inches on all sides and above).
• Clean the air filter and evaporator coil area. Remove dust and lint using a soft brush and vacuum.
• Verify the unit is not installed in a space below the minimum ambient temperature specified by Whirlpool.
• Check that the mode is set to Heat Pump or Hybrid and not to Electric Only.

Technical checks (for technicians):

• Measure sensor resistances (evaporator, discharge, ambient) and compare to Whirlpool charts.
• Check compressor current draw and continuity.
• Inspect for oil stains or frost patterns indicating refrigerant leaks.

Corrective actions:

• Replace faulty sensors or control relays as needed.
• Refrigerant diagnosis, leak repair, and recharging must be performed by a qualified HVAC technician.
• Until repaired, the unit can typically operate in Electric mode to provide hot water.