What does the Glow-worm Ultimate F69 fault code mean?
The F69 fault code indicates a problem with the domestic hot water (DHW) thermistor, which is responsible for measuring the temperature of the water. This error suggests that the thermistor may be faulty or there is an issue with its connection.
Common Causes
- Faulty Thermistor: The thermistor itself may be defective, leading to incorrect temperature readings.
- Wiring Issues: Damaged or loose wiring connections to the thermistor can cause communication failures with the boiler’s control board.
Can I fix it myself? (DIY)
It is 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 replacing the DHW thermistor is around £120-£150, including parts and labour. This cost reflects the price of the thermistor and the expertise required for safe installation.