What does the Vaillant ecoTEC plus F23 fault code mean?
The F23 fault code indicates a flame failure in the Vaillant ecoTEC plus boiler, meaning the appliance is unable to detect a flame during operation. This can lead to the boiler shutting down to prevent unsafe conditions.
Common Causes
- Insufficient Gas Supply: A blockage or issue in the gas supply line can prevent the boiler from receiving the necessary gas to ignite.
- Faulty Flame Sensor: If the flame sensor is dirty or malfunctioning, it may not detect the flame, causing the boiler to shut down.
Can I fix it myself? (DIY)
Before attempting any repairs, ensure the boiler pressure is within the recommended range and reset the boiler. If the fault persists, it is crucial to call a Gas Safe Engineer to address potential gas or electrical issues safely.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F23 fault could range from £150 to £300, depending on whether the issue is a simple cleaning of the flame sensor or a more complex gas supply problem that requires parts replacement.