High
F09 L09 on Ideal Logic Max System

Your boiler's main control board has lost its programmed settings and no longer knows how to operate the specific model it is installed in.

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

Unconfigured PCB

From this model's manual
Verified against the Ideal Logic Max System 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 central brain, the printed circuit board, suffers a memory failure or loses its identity settings. The most common reason is a sudden power surge or a component failure on the board that wipes the specific software instructions required to run your boiler safely.

This fault is often seen following summer storms, as power surges from lightning strikes can scramble the sensitive electronic memory of the boiler's control board.

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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Related fault codes

L09View →F01View →F02View →

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