What does the Baxi Duo-tec F51 fault code mean?
The F51 fault code on a Baxi Duo-tec boiler indicates that the domestic hot water (DHW) temperature is excessively high. This can lead to safety concerns and requires immediate attention to prevent potential damage or hazards.
Common Causes
- Faulty DHW Temperature Sensor: If the temperature sensor is malfunctioning, it may incorrectly read the water temperature, causing the boiler to overheat.
- Blocked Heat Exchanger: A blockage in the heat exchanger can restrict water flow, leading to overheating of the water being produced.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer to diagnose and repair 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 F51 fault code is around £150 to £250, primarily depending on whether the temperature sensor needs replacing or if the heat exchanger requires cleaning or replacement.