BoilerFaultCodesYour boiler is unable to start because the small pilot flame that ignites the main burner cannot be lit.
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. Piezo unit not working.
What causes this fault?
This fault occurs when the manual ignition system fails to create a spark or provide enough gas to establish the initial pilot flame. It is usually caused by a faulty spark generator, a cracked electrode, or a tiny blockage in the pilot jet that prevents gas from reaching the ignition point. Without this small flame being present and detected, the boiler cannot safely fire up the main burner.
This issue is frequently seen after a long summer break when the boiler has been turned off, as debris or spiders can block the small pilot injector during 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.(4) — no call-out fees, no surprises.
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