E17
Napoleon
Emergency Heat / Fault Mode – Limit or Board Failure
Furnace displays E17; blower runs at high speed continuously, no heat
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Safety Warning
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.
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Possible Causes
Repeated limit trips, Control board entering fault fan mode, Shorted fan relay, Failed temperature sensor on board
How to Fix / Troubleshooting
Safety first: Turn off power before inspecting internal components.
- Check for stored codes: Many Napoleon boards will flash additional diagnostic LEDs. Note any patterns and refer to the service manual.
- Inspect filters and airflow: Replace dirty filters and open all vents to prevent overheating that can trigger fault fan mode.
- Power cycle: Turn off power for 5 minutes, then restore. If the blower immediately runs on high and E17 returns, suspect a stuck fan relay or board fault.
- Check fan terminals: With power off, inspect the control board for burned or welded fan relay contacts. Any visible damage indicates the need for board replacement.
- When to replace: If airflow is normal and no limits are open but the blower remains locked in high speed with E17, replace the integrated control board.
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Repair Difficulty
Hard
4/5
Required Part
Integrated Furnace Control Board
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