BoilerFaultCodesYour boiler is unable to light the small ignition flame needed to start the main heating process.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Pilot fails to light. Electrode or lead damaged.
What causes this fault?
This fault occurs when the boiler tries to start up but cannot establish the small pilot flame required to ignite the main burner. The most common reasons are a build-up of carbon on the ignition probe, a worn-out spark lead, or a fault within the gas valve preventing fuel from reaching the pilot assembly.
This issue often surfaces after the summer months when the boiler is switched back on for the first time, as debris or spiders can block the small pilot injector during long periods of inactivity.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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A boiler cover plan would cover faults like A.(5) — no call-out fees, no surprises.
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