What does the Baxi Duo-tec F31 fault code mean?
The F31 fault code on a Baxi Duo-tec boiler indicates a high limit thermostat fault, which means the boiler has detected that the temperature has exceeded safe operating limits. This safety feature is designed to prevent overheating and potential damage to the system.
Common Causes
- Blocked Flue: A blockage in the flue can restrict airflow, causing the boiler to overheat.
- Faulty High Limit Thermostat: The thermostat itself may be malfunctioning, leading to incorrect temperature readings.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for this issue, as it involves gas and electrical components that can be dangerous if handled improperly. Attempting to fix it yourself may void warranties or lead to further complications.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for addressing an F31 fault could be around £150 to £250, depending on whether the high limit thermostat needs replacing or if additional issues are found during inspection.