What does the Worcester Bosch Greenstar CDi F24 fault code mean?
The F24 fault code indicates that the boiler is experiencing overheating issues, which can lead to potential damage if not addressed promptly. This typically occurs when the temperature of the water exceeds safe operating limits.
Common Causes
- Blocked Heat Exchanger: A buildup of debris or limescale can restrict water flow, causing the boiler to overheat.
- Faulty Thermistor: If the thermistor, which monitors the temperature, is malfunctioning, it may incorrectly signal the boiler to overheat.
Can I fix it myself? (DIY)
It is advisable to call a Gas Safe Engineer for this issue, as it involves gas and electrical components that can be dangerous if handled improperly. Attempting DIY repairs could void your warranty and pose safety risks.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for addressing an F24 fault could range from £150 to £300, depending on whether the issue is a blocked heat exchanger or a faulty thermistor. This includes parts and labour, with the heat exchanger being a more costly component to replace.