Low Information
S.11 on Vaillant ecoTEC exclusive

Your boiler is currently preparing to fire up by starting its internal fan, which is a normal part of the ignition process.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description

DHW mode: Fan start-up

What causes this fault?

This is a normal status message rather than a mechanical failure, occurring every time the boiler prepares to heat your water or radiators. It indicates that the control board has sent a signal to the internal fan to begin spinning, which clears out the combustion chamber before the burner ignites. If the boiler stays on this code for a long time without firing, it may suggest the fan is struggling to reach the required speed.

DIY fix possible

This fault may be fixable without an engineer. Check your manual first.

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Related fault codes

S.01View →S.02View →S.03View →

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