F05 error code, water heater will not start heating cycle, fan may run briefly then stop (power vent or hybrid models)

Safety first: Turn OFF power at the breaker and shut off gas if applicable.

Vent and air path checks:

• Inspect the exhaust vent termination outside for bird nests, debris, or ice. Clear any obstructions.
• Check intake air piping (if separate) for blockages or kinks.
• Verify vent piping slope and joints are intact and not sagging with condensate.

Pressure switch checks:

• Locate the pressure switch near the inducer fan. Inspect the rubber tubing for cracks, water, or disconnection. Replace tubing if brittle.
• With power OFF, disconnect the tubing and gently blow through it to ensure it is clear.
• Use a multimeter to test continuity across the pressure switch terminals while the inducer is running (requires careful live testing; only if qualified). The switch should close when proper draft is established.

Corrective actions:

• Replace a defective pressure switch with the Whirlpool-specified part.
• If the inducer fan does not run or is noisy, test for power at the fan and replace the inducer motor assembly if failed.

Warning: Improper venting can cause carbon monoxide hazards. If you are unsure about vent design or measurements, contact a licensed technician.