What does the Glow-worm Ultimate F86 fault code mean?
The F86 fault code indicates a problem with the domestic hot water (DHW) sensor in the Glow-worm Ultimate boiler. This alert suggests that the sensor is either malfunctioning or providing incorrect temperature readings, which can affect the boiler’s ability to heat water effectively.
Common Causes
- DHW Sensor Failure: The sensor may be defective or damaged, leading to inaccurate temperature readings.
- Wiring Issues: Loose or damaged wiring connections to the DHW sensor can cause communication failures between the sensor and the boiler control unit.
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 concerns. Attempting to fix it yourself could lead to further complications or safety hazards.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for replacing the DHW sensor is around £150 to £200, which includes the cost of the part and labour. This price reflects the typical cost of sensor replacement and the expertise required for safe installation.