BoilerFaultCodesYour boiler has detected a safety-related issue and has locked itself out to prevent further damage, requiring a manual reset to restart.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Can only be cleared by using the facia reset button (press for at least one second).
What causes this fault?
This fault occurs when the boiler fails to detect a stable flame after several attempts to light. The most common reasons include a lack of gas supply, worn-out ignition parts that can no longer create a spark, or a sensor that is too dirty to 'see' the flame even when it is present.
This fault is more common in winter, as severe cold can cause external gas regulators to freeze or pipes to become blocked, disrupting the fuel flow required for ignition.
DIY fix possible
Locate the reset button on the front control panelPress and hold the reset button for at least one secondRelease the button and wait for the boiler to attempt to restartIf the boiler refires, monitor it closely; if the light returns, call an engineer
Find a Gas Safe engineer
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A boiler cover plan would cover faults like Slow flash — no call-out fees, no surprises.
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Worcester Bosch 25si and 28si 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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