Display shows E109; unit may not fire or may shut down intermittently.

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

Weak or failing fan motor, Blocked intake/exhaust, Faulty fan speed feedback sensor, Loose fan connector

Safety: Turn OFF power before opening the unit.

Steps:

1. Check intake and exhaust: Inspect for obstructions and clear any debris or ice.
2. Inspect fan wiring: Ensure the fan motor connector is fully seated and the cable is not pinched or damaged.
3. Listen to fan: Restore power and call for hot water. If the fan is noisy, slow to start, or stops abruptly, it may be failing.

Persistent E109 typically requires fan motor replacement and possibly combustion tuning by a Navien technician.

Hard 4/5

Combustion Fan Motor

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