BoilerFaultCodesTechnical description
Flame Failure or Blocked Condensate Drain
What causes this fault?
This fault happens when the boiler attempts to light but fails to detect a stable flame, often because the electrodes are worn or the gas supply is restricted. It can also be triggered if the internal waste water pipe becomes backed up with debris or liquid, which prevents the combustion process from starting safely. In both cases, the boiler shuts down as a safety precaution to prevent unburnt gas from building up.
This fault is particularly common during freezing winter temperatures, as the external portion of the condensate drainage pipe can freeze solid, causing water to back up into the boiler.
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.