What does the Glow-worm Ultimate F23 fault code mean?
The F23 fault code on the Glow-worm Ultimate indicates a flame failure, meaning the boiler is unable to detect a flame during operation. This can lead to the boiler shutting down to prevent unsafe conditions.
Common Causes
- Insufficient Gas Supply: A blockage or issue in the gas supply line can prevent the boiler from receiving the necessary gas to ignite.
- Faulty Flame Sensor: A malfunctioning flame sensor may fail to detect the flame, causing the boiler to shut down as a safety precaution.
Can I fix it myself? (DIY)
It is advisable to call a Gas Safe Engineer for any gas or electrical issues, as working on gas appliances can be dangerous. However, you can check the gas supply and ensure that the boiler pressure is within the recommended range.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving an F23 fault could be around £150 to £250, primarily depending on whether the flame sensor needs replacement or if there are issues with the gas supply that require professional intervention.