BoilerFaultCodesYour boiler's computer is confused because it has detected a change in its connected control components and needs to be told how to work with them again.
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: BUS device changed or replaced. Check system configuration for heating circuit!
What causes this fault?
This fault occurs when the boiler's main control board loses communication with a connected component, such as a smart thermostat or a plug-in wiring module. It most commonly happens after a power cut, a surge, or when a new control device has been installed but hasn't been properly synced with the system. Essentially, the boiler has detected a change in its electronic 'nervous system' and has shut down as a safety precaution until the configuration is confirmed.
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 13 / 159 — 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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