High
neon flashing on Baxi System

Your boiler has detected an internal error and has locked itself out for safety, requiring a professional inspection to identify the specific part that has failed.

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

Fault investigation is necessary. Go to sections 'J' & 'M'

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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