BoilerFaultCodesYour boiler’s internal control system has suffered an electrical component failure and can no longer manage the heating process.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Green diode damaged (Control board replacement).
What causes this fault?
This fault occurs when an electrical component on the boiler's internal computer, specifically a diode, burns out or degrades over time. Without this component functioning, the control board can no longer safely manage the signals required to fire the boiler, leading to a total system failure. It is typically caused by general wear and tear of the circuitry or a minor power surge that the board could no longer handle.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like FAIL POINT C — 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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