What does the Glow-worm Ultimate F64 fault code mean?
The F64 fault code indicates a malfunction in the domestic hot water (DHW) temperature sensor or system. This can lead to issues with the boiler’s ability to heat water to the desired temperature.
Common Causes
- Faulty DHW Temperature Sensor: The sensor may be malfunctioning or damaged, leading to incorrect temperature readings.
- Wiring Issues: Damaged or loose wiring connections to the temperature sensor can disrupt the signal and cause the fault code to appear.
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 a faulty DHW temperature sensor is around £150 to £200, which includes parts and labour. This cost reflects the complexity of diagnosing and replacing the sensor safely.