BoilerFaultCodesYour boiler is struggling to keep its small pilot flame lit, which prevents the main burner from firing up to heat your home.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Main burner fails to light and pilot is extinguished when pressure on the control knob is released. Pilot rate too low.
What causes this fault?
This fault occurs when the boiler's safety mechanism cannot detect a strong enough pilot flame to proceed with ignition. The most common reason is a build-up of soot or debris in the small pilot burner hole, or a worn-out thermocouple sensor that can no longer signal to the gas valve that it is safe to stay open.
This issue often surfaces after the boiler has been switched off over the summer, as dust and debris can settle in the pilot assembly 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 B.(3) — no call-out fees, no surprises.
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