What does the Viessmann Vitodens 111-W F81 fault code mean?
The F81 fault code indicates a problem with the heating circuit feedback, suggesting that the boiler is not receiving the correct information about the temperature or flow from the heating system. This can lead to inefficient heating or the boiler shutting down to prevent damage.
Common Causes
- Faulty Temperature Sensor: The temperature sensor may be malfunctioning, providing incorrect readings to the boiler.
- Wiring Issues: Damaged or loose wiring connections in the heating circuit can disrupt feedback signals to the boiler.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for any repairs related to gas or electrical components. Attempting to fix these issues without proper training can be dangerous.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for addressing the F81 fault could range from £150 to £300, depending on whether the temperature sensor needs replacement or if wiring repairs are necessary. This estimate includes parts and labour.