What does the Viessmann Vitodens 100-W F24 fault code mean?
The F24 fault code on the Viessmann Vitodens 100-W indicates an overheating issue within the boiler. This typically occurs when the temperature of the water in the system exceeds safe operating limits, potentially leading to damage if not addressed promptly.
Common Causes
- Blocked Heat Exchanger: A buildup of debris or limescale can restrict water flow, causing the boiler to overheat.
- Faulty Temperature Sensor: If the temperature sensor is malfunctioning, it may incorrectly read the water temperature, leading to overheating.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for this issue, as it involves potentially dangerous gas and electrical components. Attempting to fix it yourself could lead to further complications or safety hazards.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for addressing the F24 fault code could range from £150 to £300, depending on whether the heat exchanger needs cleaning or the temperature sensor requires replacement. This cost reflects the labour and parts involved in resolving the overheating issue.