BoilerFaultCodesTechnical description
Flame failure during operation
What causes this fault?
This fault occurs when your boiler successfully starts but then loses its flame while it is running. The most common reasons are a build-up of carbon on the sensing probe or a blockage in the drainage system that causes water to back up into the burner. In some cases, the gas valve may be failing to maintain a steady flow of fuel to keep the flame lit.
This fault is more common in freezing winter conditions, as a frozen external condensate pipe can cause water 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.
Find a Gas Safe engineer
Search the official register →