What does the Worcester Bosch Greenstar i F78 fault code mean?
The F78 fault code indicates that the boiler has detected a failure in its system safety checks, which are essential for safe operation. This could be due to various issues, including sensor malfunctions or electrical faults.
Common Causes
- Faulty Sensors: Malfunctioning temperature or pressure sensors can lead to incorrect readings, triggering the F78 fault code.
- Electrical Issues: Problems with wiring or connections within the boiler can disrupt safety checks, causing the fault to appear.
Can I fix it myself? (DIY)
It is strongly advised to call a Gas Safe Engineer to diagnose and repair this fault, as it involves safety-critical components that require professional expertise.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving an F78 fault could be around £150 to £250, primarily depending on whether sensor replacement or electrical repairs are needed.