Your boiler has failed to ignite or stay lit after several attempts and requires a manual reset and investigation by a professional.

Final fault code (Refer to section 7.11)

What causes this fault?

This fault occurs when the boiler's control system attempts to start the burner multiple times but cannot confirm that a stable flame has been established. The most common reasons include a lack of gas supply to the unit, a worn-out ignition spark, or a sensor that can no longer detect the heat of the flame. It essentially acts as a safety shutdown to prevent unburnt gas from building up inside the appliance.