How to fix Vaillant ecoFIT pure fault code F36

What does the Vaillant ecoFIT pure F36 fault code mean?

The F36 fault code on the Vaillant ecoFIT pure indicates a problem with the flame sensor, which is responsible for detecting whether the burner is lit. If the sensor fails or is malfunctioning, the boiler will not operate safely, leading to a shutdown.

Common Causes

  • Dirty Flame Sensor: A buildup of soot or debris can prevent the sensor from accurately detecting the flame.
  • Faulty Flame Sensor: The sensor itself may be defective or damaged, requiring replacement.

Can I fix it myself? (DIY)

While cleaning the flame sensor can be a DIY task, it is crucial to call a Gas Safe Engineer for any repairs or replacements, as working with gas appliances poses safety risks.

Estimated Repair Cost (2026 UK Prices)

The estimated repair cost for replacing a faulty flame sensor on a Vaillant ecoFIT pure is around £120 to £180. This includes the cost of the part and labour, reflecting the typical charges for a qualified engineer in the UK.