BoilerFaultCodesTechnical description
Flame Failure or Blocked Condensate Drain
What causes this fault?
This fault occurs when the boiler tries to light but fails to detect a steady flame, or when the internal drain for waste water becomes blocked. The most common reason is a buildup of debris in the condensate trap or a worn-out ignition spark causing a failed startup. If the waste pipe is blocked, the boiler shuts down as a safety precaution to prevent water from backing up into the combustion chamber.
This fault is significantly more common during freezing winter spells, as the external condensate pipe can freeze, causing water to back up and trigger the sensor.
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.
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