Your boiler was working but the flame has gone out unexpectedly, often due to an interrupted gas supply or a blockage in the drainage pipe.

Flame extinguished re-ignition unsuccesful | Gas supply absent or insufficient

What causes this fault?

This fault occurs when the boiler successfully lights but the flame is lost unexpectedly during operation. The most common reasons are an interruption in the gas supply, a blocked condensate drainage pipe, or a build-up of carbon on the sensing electrodes which prevents the boiler from 'seeing' the flame.