What does the Worcester Bosch Greenstar Si F99 fault code mean?
The F99 fault code on the Worcester Bosch Greenstar Si indicates an issue with the boiler’s system updates, which may affect its operational efficiency. This typically suggests that the boiler’s software or firmware has not been updated correctly or is experiencing a malfunction.
Common Causes
- Software Glitch: A temporary error in the boiler’s software that prevents it from updating properly.
- Communication Failure: An issue with the connection between the boiler and the update server, which can hinder the download of necessary updates.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for this issue, as it involves software and system updates that require professional handling. Attempting DIY fixes could lead to further complications or safety risks.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F99 fault code is around £150 to £250. This includes the cost of a technician’s visit and any necessary software updates or repairs to the control board.