What does the Glow-worm Ultimate F85 fault code mean?
The F85 fault code on the Glow-worm Ultimate indicates a problem with the Domestic Hot Water (DHW) PCB (Printed Circuit Board). This issue can prevent the boiler from properly heating water for taps and showers.
Common Causes
- PCB Failure: The PCB may have developed a fault due to age, wear, or electrical issues, leading to a malfunction in the DHW system.
- Wiring Issues: Damaged or loose wiring connections to the PCB can disrupt communication and functionality, causing the F85 error.
Can I fix it myself? (DIY)
It is highly recommended to call a Gas Safe Engineer for this issue, as it involves electrical components and safety risks. Attempting to fix it yourself could lead to further damage or safety hazards.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F85 fault is around £250 to £350, primarily due to the need for a replacement PCB and professional installation by a qualified engineer.