BoilerFaultCodesYour boiler is failing to light the gas burner, which means you currently have no heating or hot water.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Boiler fails to light
What causes this fault?
This fault occurs when the boiler's control system attempts to start the burner but cannot detect a flame after several attempts. The most common reasons are a lack of gas reaching the unit, worn-out spark electrodes that fail to ignite the gas, or a faulty sensor that cannot confirm the flame is lit.
This fault is frequently seen during extreme cold snaps, as the external condensate drainage pipe can freeze and back up, preventing the boiler from lighting.
DIY fix possible
Check if your gas meter has credit and that the gas supply valve is open.Inspect the condensate pipe (outside white plastic pipe) for ice blockages if it is freezing weather.Press and hold the reset button for five seconds.
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 BLUE power indicator (B) and reset button (E) flashing alternately — no call-out fees, no surprises.
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Worcester Bosch Greenstar 24i Junior is discontinued — time for a new one?
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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