BoilerFaultCodesTechnical description
Flame Failure or Blocked Condensate Drain
What causes this fault?
This fault occurs when the boiler tries to light but cannot detect a stable flame, prompting the system to shut down for safety. The most common reasons are a lack of gas supply, a dirty sensing probe that can't 'see' the flame, or a blockage in the waste water pipe that causes water to back up into the heat exchanger. In many cases, it is simply a sign that the components responsible for the spark or flame monitoring have worn out.
This fault is significantly more common during freezing winter temperatures, as the external condensate pipe can freeze, causing water to back up and prevent the boiler from lighting.
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.