BoilerFaultCodesYour boiler's internal computer parts are having trouble communicating with each other or have been replaced with mismatched versions.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: User interface / Main PCB incompatibility
What causes this fault?
This fault occurs when the boiler's main control board and the display panel are unable to talk to each other correctly. It most commonly happens after a repair where a new part has been installed that isn't compatible with the existing software or model version. In some cases, it can also be caused by a loose connection or a sudden electrical surge that disrupts the internal communication between these two components.
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 F20 — no call-out fees, no surprises.
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