What does the Vaillant ecoTEC plus F39 fault code mean?
The F39 fault code on the Vaillant ecoTEC plus indicates a malfunction with the flue gas temperature sensor. This sensor is crucial for monitoring the temperature of the exhaust gases, and its failure can lead to inefficient operation or safety concerns.
Common Causes
- Faulty Sensor: The temperature sensor may be defective or damaged, leading to incorrect readings.
- Wiring Issues: Damaged or loose wiring connections to the sensor can disrupt its functionality.
Can I fix it myself? (DIY)
It is strongly recommended to call a Gas Safe Engineer for this issue, as it involves gas and electrical components that require professional expertise to ensure safety and compliance with regulations.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for replacing the flue gas temperature sensor is around £150 to £200. This includes the cost of the part and labour, reflecting the complexity of the repair and the need for a qualified technician.