What does the Viessmann Vitodens 111-W F41 fault code mean?
The F41 fault code indicates a problem with the outdoor temperature sensor, which is responsible for measuring the external temperature to adjust the heating system accordingly. This can lead to inefficient heating and potential comfort issues within the property.
Common Causes
- Damaged Sensor: The outdoor temperature sensor may be physically damaged or malfunctioning, leading to inaccurate readings.
- Wiring Issues: There could be a fault in the wiring connecting the sensor to the boiler, such as frayed wires or poor connections.
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 cost for replacing the outdoor temperature sensor is around £150 to £200, including parts and labour. This is based on typical service charges and the cost of the sensor itself.