BoilerFaultCodesYour boiler is not receiving the steady electrical voltage it needs to safely fire up and run.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Lockout Burner Mains - Permanent live and switched live need to be a minimum of 190V to function
What causes this fault?
This fault occurs when the boiler's internal computer detects that the incoming electricity is too weak or unstable to power the safety components. The most common reasons are a loose connection in the wall socket wiring, a failing printed circuit board, or a wider issue with the power grid entering your home.
This fault is more common during winter or periods of extreme weather when the national grid is under heavy load, which can lead to slight drops in local voltage.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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 Electrical Supply Fault — no call-out fees, no surprises.
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Potterton Performa SL HE 9 2 is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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