BoilerFaultCodesTechnical description
Flame not detected.
What causes this fault?
This fault occurs when the boiler's internal computer tries to start the burner but cannot confirm that a flame is safely lit. The most common reasons are a lack of gas reaching the unit, worn-out sparking components that fail to ignite the fuel, or a dirty sensor that cannot see the flame even if it is present.
This fault is significantly more common during freezing winter temperatures, as the external condensate drainage pipe can freeze and back up, preventing 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.
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