High Lockout
9U on Ideal Maximiser SE

Your boiler's main control computer is unable to communicate with its internal memory chip, meaning it cannot access the settings needed to run safely.

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

Control panel not able to read BIM.

What causes this fault?

This fault occurs when the boiler's main brain loses its connection to the plug-in memory chip that identifies the specific model and its safety limits. The most common reason is an internal electronic communication failure between the memory module and the main circuit board, often caused by age or a minor electrical surge. Because the boiler no longer knows its own identity or settings, it shuts down immediately as a safety precaution.

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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