BoilerFaultCodesTechnical description
Refer to fault finding section on Page 30 (displayed when control fails to detect flame after ignition attempts).
What causes this fault?
This fault occurs when the boiler tries to light the gas three times but fails to detect a steady flame, causing the system to shut down for safety. The most common reasons are a worn-out ignition spark, a dirty sensor that can't 'see' the flame, or a blockage in the gas supply preventing fuel from reaching the burner.
This issue is more frequent during the first cold snap of autumn, as components like the gas valve or electrodes can seize or fail after being dormant over the summer.
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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