BoilerFaultCodesYour boiler's internal communication system has failed, meaning the different electronic parts are no longer talking to each other correctly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Control mode - Communications fault-LON communication module
What causes this fault?
This fault occurs when the main control board loses its connection with the internal plug-in communication module. The most common reason is an electronic component failure within the module itself or a loose physical connection caused by vibrations over time. Without this link, the boiler's brain cannot send or receive the data it needs to operate safely, causing it to stop running.
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 CF — no call-out fees, no surprises.
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