What does the Glow-worm Betacom F89 fault code mean?
The F89 fault code on a Glow-worm Betacom boiler indicates a problem with the domestic hot water (DHW) inlet temperature sensor. This sensor is responsible for monitoring the temperature of the incoming water, and a fault can disrupt the boiler’s ability to provide hot water effectively.
Common Causes
- Faulty Temperature Sensor: The sensor may be malfunctioning or damaged, leading to incorrect temperature readings.
- Wiring Issues: Damaged or loose wiring connections to the sensor can cause communication failures, resulting in the fault code being triggered.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer to diagnose and repair this issue, as it involves electrical components and safety risks associated with gas appliances. Attempting to fix it yourself may void warranties or lead to further complications.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for the F89 fault code is around £150 to £200, which includes the replacement of the temperature sensor and any necessary wiring repairs. This cost reflects the typical price for parts and labour in the UK.