High Lockout
F8 on Ideal Logic Combi C24 C30 C35

Your boiler's computer brain has lost its settings or is experiencing an electrical fault, preventing the system from starting up.

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

PCB UNCONFIGURED/FAULTY OR GAS VALVE SHORT CIRCUIT. SEE SECTION 3.19 IF FAULT PERSISTS REPLACE PCB

What causes this fault?

This fault occurs when the boiler's main control board loses its identity or suffers an internal electrical failure, meaning it no longer knows how to safely manage the heating process. It can also be triggered by a faulty gas valve or damaged wiring creating a short circuit that prevents the system from starting. Essentially, the 'brain' of the boiler has become corrupted or disconnected from the components it needs to control.

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

F9View →L9View →F8View →L8View →

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