BoilerFaultCodesYour boiler's internal computer has encountered an error and is unable to communicate properly with the rest of the system.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Control box fault
What causes this fault?
This fault occurs when the boiler's main control board experiences an internal electronic failure or a loss of data. It is often caused by a component failure on the circuit board itself or a loose connection in the internal wiring preventing the computer from sending instructions to the burner. In some cases, an external power surge or moisture ingress can also damage the sensitive electronics inside.
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 74 — no call-out fees, no surprises.
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Worcester Bosch Greenstar Utility 18/25 is discontinued — time for a new one?
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