BoilerFaultCodesYour boiler's small starter flame is lit, but the main burner is failing to ignite because it isn't receiving the gas flow it needs 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: PILOT LIT BUT NO MAINS GAS
What causes this fault?
This fault occurs when the boiler successfully lights its small pilot flame but fails to transfer that flame to the main burner. The most common reason is a mechanical failure within the gas valve or a faulty electronic command from the control board, preventing the main flow of gas from being released. It essentially means the ignition process has started, but the 'full' heat cannot be triggered.
This issue is more frequent during the first cold snap of autumn, as gas valve internal components can seize up after being inactive throughout the summer months.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like 53 — no call-out fees, no surprises.
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