BoilerFaultCodesYour boiler has lost communication with its external controls like your thermostat because there is an electrical problem with the wiring connecting them.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: eBUS low voltage fault (short circuit)
What causes this fault?
This fault occurs when the low-voltage communication line between your boiler and thermostat is interrupted, usually by a short circuit. The most common cause is a loose wire at a connection point or moisture getting into the external control box. In some cases, it can be triggered by a fault within the boiler's internal computer board failing to process the signal.
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 F49 — no call-out fees, no surprises.
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