Technical description
The burner fails to ignite after five attempts, the device does not start up and switches to “Fault”.
What causes this fault?
This fault occurs when the boiler is running normally but the flame suddenly disappears and the system fails to relight it. The most common reasons include a temporary interruption in the gas supply, a blocked flue vent, or a buildup of carbon on the ignition electrodes that prevents them from detecting the flame.
This fault is more frequent during extreme cold spells, as frozen external condensate pipes can cause the boiler to back up and extinguish the flame.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.