What does the Baxi Duo-tec F42 fault code mean?
The F42 fault code on a Baxi Duo-tec boiler indicates a problem with the central heating flow switch. This fault typically suggests that the flow switch is either stuck or malfunctioning, preventing the boiler from properly regulating the heating system.
Common Causes
- Faulty Flow Switch: The flow switch may be defective or worn out, leading to incorrect readings and triggering the fault code.
- Blocked System: A blockage in the heating system can prevent water flow, causing the flow switch to fail to operate correctly.
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 require professional handling. Attempting to fix it yourself could pose safety risks.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for fixing the F42 fault code is around £150 to £250, primarily due to the need for a replacement flow switch and potential system flushing if blockages are present.