BoilerFaultCodesYour boiler's internal computer is having trouble communicating with an external plug-in control or a hot water cylinder component.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: System configuration: incompatible BUS device. IPM for cylinder must be set to identification 3 or higher.
What causes this fault?
This fault occurs when the boiler's main control board fails to communicate correctly with an external component, such as a hot water cylinder sensor or a plug-in timer. The most common reason is a configuration error where the electronic 'address' of a connected device is set incorrectly, causing the system to stop as a safety precaution. It can also be triggered by loose wiring or a failing control module that can no longer send clear signals to the central computer.
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 Fault 14 / 119 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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