BoilerFaultCodesYour boiler's internal computer system has lost communication with its external controls or smart thermostat, meaning it cannot receive instructions to turn on.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: No communication via EMS BUS connection
What causes this fault?
This fault occurs when the link between your boiler's main brain and your thermostat is physically broken or scrambled. The most common reason is a loose or damaged wire between the boiler and the control base, or a localized power surge that has caused the communication port on the internal circuit board to freeze.
DIY fix possible
Check that your smart thermostat gateway or hub is plugged in and powered onEnsure your Wi-Fi router is working correctlyTurn the boiler power off and back on at the fused spur switch to reboot the system
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like 1010 — 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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