High Lockout
F3 on Ideal Logic Max System

Your boiler has detected an issue with the fan that pushes exhaust gases out of your home, causing the system to shut down for safety.

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

Fan Fault

What causes this fault?

This fault occurs when the boiler's internal computer can no longer control or receive speed signals from the fan that removes combustion gases. The most common reason is that the fan motor has physically burnt out or suffered a mechanical failure, though it can also be caused by loose electrical connections or a fault on the main control board. For safety, the boiler will stop firing immediately if it cannot confirm the fan is spinning at the correct speed.

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

F1View →L2View →F2View →

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