What does the Worcester Bosch Greenstar Ri F77 fault code mean?
The F77 fault code indicates a problem with the system performance, often related to the heating system’s ability to maintain the desired temperature or pressure. This can be caused by various issues, including low water pressure or a malfunctioning component.
Common Causes
- Low Water Pressure: Insufficient water pressure in the system can prevent the boiler from functioning correctly, leading to the F77 error.
- Faulty Sensors: Malfunctioning temperature or pressure sensors can provide incorrect readings, causing the boiler to shut down or operate inefficiently.
Can I fix it myself? (DIY)
If the issue is related to low water pressure, you can check and refill the system pressure using the filling loop. However, for sensor issues or any gas/electrical problems, it is crucial to call a Gas Safe Engineer for safety reasons.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F77 fault could range from £150 to £300, depending on whether it involves simply refilling the system or replacing faulty sensors, which can be more expensive due to parts and labour.