How to fix Vaillant fault code F.29

What does the Vaillant F.29 fault code mean?

The Vaillant F.29 fault code indicates that the flame has extinguished during the operation of the boiler. This can lead to a loss of heating and hot water, requiring immediate attention to ensure safe and efficient operation.

Common Causes

  • Flue Blockage: A blockage in the flue can prevent proper ventilation, causing the flame to extinguish.
  • Gas Supply Issues: Insufficient gas supply or pressure can lead to the flame going out during operation.

Can I fix it myself? (DIY)

If you suspect a flue blockage, you can check for any visible obstructions outside the boiler. However, if the issue relates to gas supply or internal components, it is essential to contact a Gas Safe Engineer for a thorough inspection and repair.

Estimated Repair Cost (2026 UK Prices)

The estimated repair cost for addressing the F.29 fault can range from £150 to £400. This includes potential costs for clearing a flue blockage or replacing a faulty gas valve, with parts typically costing between £100 to £300 and labor around £50 to £100.