What does the Worcester Bosch Greenstar Si F66 fault code mean?
The F66 fault code indicates a faulty configuration within the boiler’s settings, which may prevent it from operating correctly. This issue often arises from incorrect installation or changes made to the system that are not compatible with the boiler’s requirements.
Common Causes
- Incorrect Installation: If the boiler was not installed according to the manufacturer’s specifications, it may lead to configuration errors.
- Software Issues: Outdated or corrupted software can cause the boiler to misinterpret its settings, resulting in the F66 fault code.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer to address this issue, as it involves the boiler’s internal configuration and may require specialist knowledge and tools.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F66 fault code is around £150 to £250. This cost reflects the need for a professional assessment and potential reconfiguration of the boiler settings.