BoilerFaultCodesYour thermostat receiver has lost power, meaning it cannot communicate with your boiler to turn the heating on.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Check Smart Interface is securely plugged into the interface bracket. Check power to bracket.
What causes this fault?
This fault occurs when the communication hub, which acts as the 'brain' between your thermostat and the boiler, stops receiving electrical power. The most common reason is that the interface module has been accidentally knocked loose from its bracket or there is a loose connection in the internal wiring. Without this power, the device cannot tell the boiler to fire up, leaving you without heating or hot water control.
DIY fix possible
Ensure the Smart Interface is pushed firmly and securely into its wall bracket.Check your home's fuse box/consumer unit to see if a circuit breaker has tripped.Check if the fused spur switch for the heating system is turned on.
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 No illumination (Smart Interface Power LED) — 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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