What does the Viessmann Vitodens 111-W F85 fault code mean?
The F85 fault code on the Viessmann Vitodens 111-W indicates a problem with the heating circuit status, which may involve issues such as a malfunctioning sensor or a fault in the heating system’s control. This can prevent the boiler from operating efficiently or at all.
Common Causes
- Faulty Temperature Sensor: A malfunctioning sensor can provide incorrect readings, leading the boiler to shut down to prevent damage.
- Wiring Issues: Damaged or loose wiring connections in the heating circuit can disrupt communication between components, triggering the fault code.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for any repairs related to gas or electrical issues. Attempting to fix these problems without proper training can be dangerous.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for addressing the F85 fault code could range from £150 to £300, depending on whether a sensor replacement or wiring repair is needed. This estimate includes parts and labour costs typical for a qualified engineer.