High
L9 on Ideal Logic Max Combi

Your boiler's main internal computer has lost its settings or has developed an internal electrical fault, preventing it from starting.

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.

What the manual says

Manufacturer manual

PCB UNCONFIGURED OR FAULTY

From this model's manual
Verified against the Ideal Logic Max Combi installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler's main control board loses the essential software instructions needed to operate the system safely. The most common reason is a memory failure within the data chip or an electrical surge that has corrupted the board's internal settings, meaning the boiler no longer knows which model it is or how to fire correctly.

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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