Display shows E10 and unit does not start; fan may run briefly (gas models)

Safety first: Turn off power and gas. Working on combustion air and venting components should be done carefully to avoid CO hazards.

Steps to check:

• Inspect the exhaust vent and air intake for obstructions such as bird nests, debris, or ice. Clear any blockages.
• Remove the combustion blower cover and attempt to spin the combustion blower wheel by hand. It should rotate freely without grinding.
• Check the blower motor wiring harness and connector at the main control PCB.
• If the blower is stiff, noisy, or does not start when commanded, replace the combustion blower assembly.
• If the blower runs but E10 persists, the fan speed sensor or its circuit on the control board may be faulty, requiring blower or control board replacement.

Warning: After any venting or combustion work, a combustion safety test should be performed by a qualified technician.