Display shows E13; furnace may shut down during operation, especially at high load.
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 the furnace and do not operate it until the cause of flue overheating is identified. Risk of flue gas spillage.
- Check flue terminal: Outside, ensure the Kospel flue terminal is clear of obstructions and meets clearance requirements.
- Inspect combustion fan and air intake: Verify the fan runs smoothly and the air intake is not blocked.
- Clean heat exchanger: Have a qualified technician remove and clean the primary heat exchanger and flue passages to restore proper heat transfer.
Because flue gas overheating is a safety issue, further diagnosis (including combustion analysis) must be performed by an authorized Kospel technician.
Repair Difficulty
Required Part
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