BoilerFaultCodesYour boiler has detected an issue with the electrical power supply coming from your mains, which is preventing it from running safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Mains voltage
What causes this fault?
This fault occurs when the boiler's internal control board detects that the incoming electricity supply is outside of the safe operating range. It is usually triggered by a significant drop in voltage or an unstable flow of power from your home's mains supply. In some cases, it can also be caused by a failing circuit board that can no longer accurately read the incoming electrical signal.
This fault can be more common during periods of extreme weather or high local grid demand, which can lead to temporary fluctuations or 'brownouts' in the local power supply.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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