What does the Worcester Bosch Greenstar Si F25 fault code mean?
The F25 fault code indicates that there is no water flow detected within the heating system of the Worcester Bosch Greenstar Si boiler. This can lead to overheating and potential damage if not addressed promptly.
Common Causes
- Blocked Filter: A blockage in the system filter can restrict water flow, triggering the F25 fault code.
- Low Water Pressure: Insufficient water pressure in the system can prevent proper circulation, leading to the fault being displayed.
Can I fix it myself? (DIY)
If you are comfortable, check the pressure gauge on your boiler; it should typically be between 1-1.5 bar. If it’s low, you can top up the system using the filling loop. However, for any gas or electrical issues, it is crucial to call a Gas Safe Engineer.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for addressing the F25 fault could be around £150 to £250, depending on whether a filter cleaning or replacement is needed, or if a pressure issue requires more extensive work.