What does the Viessmann Vitodens 100-W F25 fault code mean?
The F25 fault code on the Viessmann Vitodens 100-W indicates a malfunction with the temperature sensor, which is crucial for monitoring the system’s heating performance. This issue can lead to improper temperature regulation, potentially affecting the boiler’s efficiency and safety.
Common Causes
- Faulty Temperature Sensor: The sensor may be damaged or malfunctioning, leading to inaccurate readings.
- Wiring Issues: Damaged or loose wiring connections to the temperature sensor can disrupt its functionality.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer to diagnose and repair the issue, as working with gas appliances can be dangerous. Attempting to fix electrical components without proper training can also pose safety risks.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for replacing a faulty temperature sensor on a Viessmann Vitodens 100-W is approximately £150 to £250. This includes the cost of the part and labour, reflecting the complexity of the repair and the need for a qualified technician.