BoilerFaultCodesYour boiler's electronic brain has developed a software or hardware 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 boiler's main control board suffers an internal hardware failure or a memory error in its programming. It most commonly happens due to electrical wear over time, but can also be triggered by a sudden power surge or dampness affecting the circuitry.
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 26 — no call-out fees, no surprises.
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