What does the Viessmann Vitodens 050-W E339 fault code mean?
The E339 fault code indicates a problem with the system water quality sensor in the Viessmann Vitodens 050-W boiler. This sensor is crucial for monitoring the quality of the water in the heating system, and its failure can lead to operational issues.
Common Causes
- Sensor Malfunction: The water quality sensor may be defective or damaged, leading to inaccurate readings.
- Contaminated Water: High levels of impurities or contaminants in the system water can cause the sensor to trigger a fault.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer to diagnose and repair this issue, as it involves sensitive components and potential gas safety risks.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for replacing the water quality sensor is around £150 to £250, depending on the service charge and parts required. This cost reflects the complexity of the repair and the need for a qualified technician.