BoilerFaultCodesYour boiler has detected that the electricity supply coming into your home is at a lower voltage than it needs to operate safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: LOW MAINS VOLTAGE - CONTACT ELECTRICITY PROVIDER
What causes this fault?
This fault occurs when the power supply entering the boiler drops below the minimum level required for the internal components to function. It is usually caused by a temporary fluctuation in the local power grid or an issue with your home's main electrical incoming supply rather than a component failure inside the boiler itself.
This fault can be more common during periods of extreme cold or high demand on the national grid, when local power networks can experience voltage drops.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like F7 — 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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