BoilerFaultCodesYour boiler has detected an issue with the electrical frequency coming from the mains power supply or a fault within its own internal control board.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Wrong power supply (Hz)
What causes this fault?
This fault occurs when the boiler's internal computer detects that the incoming electricity supply does not match the required 50Hz frequency standard used in the UK. The most common reason is a temporary fluctuation in the national grid or a malfunctioning internal circuit board that can no longer accurately read the incoming power. In some cases, it can also be triggered if the property is running on a backup generator that isn't providing a stable enough current.
This fault is more common during severe winter storms, as extreme weather can cause instability or 'brownouts' in the local electrical grid that disrupt the power frequency.
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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