What does the Viessmann Vitodens 050-W E390 fault code mean?
The E390 fault code indicates a problem with the outdoor sensor of the Viessmann Vitodens 050-W boiler. This sensor is crucial for measuring the outdoor temperature and adjusting the heating system accordingly.
Common Causes
- Faulty Outdoor Sensor: The sensor may be malfunctioning or damaged, leading to incorrect temperature readings.
- Wiring Issues: Damaged or loose wiring connections between the sensor and the boiler can disrupt communication, causing the fault code to appear.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for this issue, as it involves electrical components and potential safety risks. Attempting to fix it yourself may void warranties or lead to further complications.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for replacing the outdoor sensor is approximately £150 to £200. This includes the cost of the part and labour, as the sensor itself typically costs around £50 to £100.