What does the Baxi Duo-tec F93 fault code mean?
The F93 fault code on a Baxi Duo-tec boiler indicates a domestic hot water (DHW) safety fault. This typically means there is an issue with the temperature control or a malfunction in the DHW system that prevents safe operation.
Common Causes
- Faulty DHW Sensor: A malfunctioning sensor can incorrectly read the water temperature, triggering the safety fault.
- Blocked Heat Exchanger: A blockage can prevent proper heat transfer, leading to overheating and safety shutdowns.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer to diagnose and repair the 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 F93 fault could be around £150 to £250, depending on whether the DHW sensor needs replacing or if the heat exchanger requires cleaning or replacement.