Your boiler has detected that its electrical power wires have been connected in the wrong order, preventing it from starting up safely.

Live and Neutral reversed

What causes this fault?

This fault occurs when the electrical supply to the boiler has been wired incorrectly, meaning the 'live' and 'neutral' power connections are swapped. This often happens after recent electrical work in the home or if a new plug or fused spur was installed without checking the correct polarities. To ensure your safety, the boiler's internal computer detects this error and prevents the system from firing up.