What does the Worcester Bosch Greenstar i F91 fault code mean?
The F91 fault code indicates that the boiler has detected a faulty system reminder, which may relate to maintenance or service reminders that need attention. This code does not indicate a critical failure but suggests that the system requires servicing or checks to ensure optimal performance.
Common Causes
- Service Reminder: The boiler may be due for a routine service, which is typically recommended annually.
- Faulty Sensors: Sensors that monitor system performance may be malfunctioning, leading to incorrect reminders being displayed.
Can I fix it myself? (DIY)
While you can check the boiler’s manual for service reminders, it is advisable to contact a Gas Safe Engineer for any issues related to gas or electrical components. Attempting to reset or bypass reminders without proper knowledge can lead to safety risks.
Estimated Repair Cost (2026 UK Prices)
The estimated cost for addressing the F91 fault code, including a service visit and any necessary parts, is around £150 to £250. This estimate reflects the typical cost of a professional service and potential sensor replacements if required.