BoilerFaultCodesYour boiler's internal communication system has lost power, meaning the main control board cannot talk to the external controls or thermostats.
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
What causes this fault?
This fault occurs when the low-voltage communication line between your thermostat and the boiler's internal computer is overloaded or short-circuited. It is often triggered by a wiring fault, a malfunctioning external controller, or moisture getting into the electrical connections. Because this communication line has lost power, the boiler cannot receive the signal to turn on and heat your home.
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 F.49 — 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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