What does the Viessmann Vitodens 100-W F29 fault code mean?
The F29 fault code indicates that the flue gas temperature is too high, which can lead to overheating and potential damage to the boiler. This issue typically arises from problems with the flue system or combustion process.
Common Causes
- Blocked Flue: A blockage in the flue can restrict the flow of exhaust gases, causing a rise in temperature.
- Faulty Temperature Sensor: If the temperature sensor is malfunctioning, it may incorrectly report high temperatures, triggering the fault code.
Can I fix it myself? (DIY)
It is strongly advised to call a Gas Safe Engineer for this issue, as it involves gas and electrical components that can be dangerous if handled improperly.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F29 fault could be around £150 to £300, depending on whether the issue is a simple flue cleaning or a more complex sensor replacement.