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.

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.