High Lockout
529 on Ideal Ideal Classic SE15P FF

Your boiler's fan is spinning but the control board cannot detect its speed, preventing the boiler from firing up 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

Air flow - Fan keeps turning / no tacho signal

What causes this fault?

This fault occurs when the boiler's control board expects a signal confirming how fast the fan is spinning but receives no data back. It is usually caused by a failure in the fan's internal electronics or a loose connection in the wiring harness that links the fan to the main computer. Even if you can hear the fan moving, the boiler will refuse to light the gas for safety reasons because it cannot verify the air flow is sufficient.

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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