What does the Glow-worm Ultimate F55 fault code mean?
The F55 fault code on the Glow-worm Ultimate indicates a failure in the domestic hot water (DHW) temperature regulation. This typically means that the boiler is unable to achieve or maintain the desired water temperature for hot water supply.
Common Causes
- Faulty DHW Sensor: The temperature sensor may be malfunctioning, leading to incorrect readings and failure to regulate the water temperature.
- Blocked Heat Exchanger: A blockage in the heat exchanger can prevent proper heat transfer, resulting in inadequate hot water temperature.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for any repairs related to gas or electrical components. Attempting to fix these issues without proper training can be dangerous.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F55 fault could range from £150 to £300, depending on whether the DHW sensor needs replacement or if the heat exchanger requires cleaning or replacement.