BoilerFaultCodesYour boiler is currently attempting to light the flame but is failing to do so, meaning you won't have heating or hot water until it succeeds.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: ignition
What causes this fault?
This fault occurs when the boiler tries to light the burner but cannot detect a stable flame after several attempts. The most common reasons are a lack of gas reaching the unit, worn-out spark electrodes that can no longer create a light, or a buildup of debris blocking the ignition process.
This fault is more common during the first cold snap of winter, when increased demand can highlight failing components or issues with gas supply pressure.
DIY fix possible
Check if other gas appliances, like a cooker, are working to ensure gas supply is activeCheck if your gas meter has credit (if using a pre-payment meter)Reset the boiler by pressing the reset button to see if it clears a temporary glitch
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like S.03 — no call-out fees, no surprises.
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Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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