BoilerFaultCodesWhat the manual says
Manufacturer manualLow mains voltage Contact electricity provider
What causes this fault?
This fault occurs when the electrical supply entering your home drops below the minimum level required for the boiler to function safely. The most common reason is an external issue with the local power grid, though it can also be caused by a faulty internal circuit board failing to process the incoming voltage correctly.
This fault can be more common during peak winter periods or extreme weather events when the national grid is under heavy load or power lines are damaged.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Avoid the next call-out bill
A cover plan would handle faults like F7: no call-out fees, no surprise bills.
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