BoilerFaultCodesIdeal 9U Fault Code
The Ideal 9U fault code means: 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.. It appears on 1 Ideal model in our database.
Technical description: Control panel not able to read BIM.
What causes the Ideal 9U 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 fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Ideal models that show the 9U fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal 9U fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026