BoilerFaultCodesYour boiler has detected that the electrical wiring is connected the wrong way around, or there is a fault with the electronics that makes it think so.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: PHASE REVERSAL ERROR
What causes this fault?
This fault occurs when the boiler detects that the live and neutral electrical connections have been swapped, which is often caused by recent electrical work or a DIY mistake at the plug or fused spur. In some cases, it can also be triggered by a failing control board that is no longer able to correctly identify the incoming electrical polarity. Because it is a safety risk, the boiler will refuse to fire until the wiring is corrected or the faulty component is replaced.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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