What does the Baxi Duo-tec F79 fault code mean?
The F79 fault code on a Baxi Duo-tec boiler indicates a fault with the domestic hot water (DHW) user interface. This typically means there is an issue with the communication between the control board and the DHW components.
Common Causes
- Faulty DHW Sensor: A malfunctioning sensor can disrupt the temperature readings, leading to communication errors.
- Wiring Issues: Damaged or loose wiring connections between the user interface and the control board can cause the fault code to appear.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for this issue, as it involves electrical components and safety risks. Attempting to fix it yourself may void warranties or lead to further complications.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F79 fault could be around £150 to £250, depending on whether the DHW sensor needs replacement or if wiring repairs are required. This cost reflects the typical labour and parts involved in such repairs.