What does the Vaillant ecoTEC pro F42 fault code mean?
The F42 fault code indicates a malfunction with the flue gas temperature sensor in the Vaillant ecoTEC pro boiler. This sensor is crucial for monitoring the temperature of the flue gases to ensure safe and efficient operation.
Common Causes
- Faulty Temperature Sensor: The sensor may be defective or damaged, leading to inaccurate readings.
- Wiring Issues: Damaged or loose wiring connections to the sensor can disrupt its functionality.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer to address this issue, as it involves gas and electrical components that require professional handling for safety reasons.
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 work involved.