BoilerFaultCodesYour boiler has detected a general internal fault and has locked itself out to prevent damage.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Fault diagnostic (identified by flashing lights on facia). Cleared by removing fault and/or main switch off/on.
What causes this fault?
This fault occurs when the boiler's internal computer identifies a communication failure between vital components, most often involving the fan or the air pressure switch. It acts as a safety shutdown because the system cannot confirm that harmful exhaust gases are being safely vented outside. Over time, electrical wear on the main control board or a buildup of debris in the fan can trigger this sudden stop.
This issue often surfaces during the first cold snap of autumn when the fan and electronic components are forced to work harder after sitting idle throughout the summer.
DIY fix possible
Turn the main power switch to the boiler offWait for 30 secondsTurn the power back on to see if the fault clears
Find a Gas Safe engineer
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A boiler cover plan would cover faults like Fast flash — no call-out fees, no surprises.
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Worcester Bosch 24CDi BF 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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