BoilerFaultCodesYour boiler's internal computer has encountered an electronic error and can no longer control the heating and hot water Safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: There is an internal fault in the Automatic Control Module.
What causes this fault?
This fault occurs when the main control board's internal circuitry fails, meaning it can no longer process data or send signals to parts like the pump or fan. The most common reason is electronic component fatigue over time, or sometimes a power surge that damages the sensitive microchips on the board.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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A boiler cover plan would cover faults like 03 — no call-out fees, no surprises.
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