BoilerFaultCodesYour boiler's burner has detected light when it should be dark inside, causing it to shut down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Eliminate the extraneous light
What causes this fault?
This fault occurs when the boiler's internal light sensor detects a flame or light source before the ignition process has even started. The most common reasons are a faulty sensor sending a false signal, a leaking fuel valve allowing a stray flame to persist, or light leaking into the burner housing through damaged seals.
DIY fix possible
Check that the burner cover and all casing panels are securely fitted and not letting in external light.Inspect the clear plastic viewing window for damage or missing seals.Press the reset button on the burner control box once all covers are tightened.
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A boiler cover plan would cover faults like Off — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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