High Lockout
F.32 on Vaillant ecoTEC Pro 24

Your boiler has detected an issue with the fan that helps clear exhaust gases, 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

Fault: Fan - Fan defective or not connected

What causes this fault?

This fault occurs when the boiler's control board cannot correctly communicate with or control the speed of the internal fan. The most common reason is a mechanical failure within the fan motor or a localized electrical fault on the main circuit board that prevents it from sending power to the fan. Without a spinning fan to safely clear waste gases, the boiler is forced to shut down immediately.

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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