What does the Baxi Duo-tec F59 fault code mean?
The F59 fault code on a Baxi Duo-tec boiler indicates a fault within the domestic hot water (DHW) system. This typically suggests issues with the flow sensor or the DHW heat exchanger, affecting the boiler’s ability to provide hot water.
Common Causes
- Flow Sensor Failure: A malfunctioning flow sensor may not detect water flow correctly, leading to the F59 error.
- DHW Heat Exchanger Blockage: A blockage in the heat exchanger can prevent efficient heat transfer, causing the boiler to fail to heat water.
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 DIY repairs can be dangerous and may void your warranty.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F59 fault could range from £150 to £300, depending on whether the flow sensor or heat exchanger needs replacement. This estimate includes parts and labour, reflecting the complexity of the repair.