Furnace shows E18, fan may run continuously, no heating.
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.
Possible Causes
How to Fix / Troubleshooting
Safety: Turn off power and allow the furnace to cool. Do not bypass safety devices.
Steps:
- Locate safety devices: Identify the high limit thermostat, flue safety thermostat, and any manual reset cutouts on the furnace casing or flue.
- Reset manual devices: If a manual reset button is present on a safety thermostat, press it once until it clicks. Do not repeatedly reset a device that keeps tripping.
- Inspect wiring: Check the continuity of the safety chain wiring and ensure all connectors are firmly attached.
Professional help: A technician must determine why a safety device opened (overheat, flue blockage, etc.) and correct the underlying cause before replacing any faulty safety components.
Repair Difficulty
Required Part
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