What does the Glow-worm Ultimate F98 fault code mean?
The F98 fault code on the Glow-worm Ultimate indicates a warning related to the domestic hot water (DHW) valve. This typically suggests that there is an issue with the valve’s operation, which may affect the boiler’s ability to provide hot water.
Common Causes
- Faulty DHW Valve: The valve may be stuck or malfunctioning, preventing it from opening or closing properly.
- Electrical Issue: There could be a problem with the wiring or connections to the valve, leading to improper signals being sent.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for this issue, as it involves gas and electrical components that require professional handling for safety reasons.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for addressing the F98 fault could be around £200 to £300, primarily due to the potential need for a new DHW valve and labour costs associated with a qualified engineer’s visit.