High Lockout
F9 on Ideal Logic Combi ESP1

Your boiler's main control board hasn't been set up correctly to tell it which model it is, so it doesn't know how to operate yet.

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

Display shows F9 on power on (Unprogrammed PCB)

What causes this fault?

This fault occurs when the boiler's internal computer brain is blank and hasn't been told which specific model it is installed in. This usually happens because a new part was recently fitted but not configured, or because a sudden electrical glitch has caused the memory to wipe itself.

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

L9View →F7View →L2View →

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