High
L (Flashing) on Potterton Envoy 30

Your boiler has detected that the electrical supply is incorrectly connected and is refusing to start as a safety precaution.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Wiring fault Live on neutral connection Correct fault

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.

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