Low Information
S.6 on Vaillant ecoTEC Plus 840

Your boiler's fan is continuing to run for longer than expected after the heating or hot water has finished.

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

Fan over run

What causes this fault?

This status occurs when the boiler's fan continues to spin after the demand for heating or hot water has ended to clear any remaining combustion gases from the system. While it is usually part of the boiler's normal cooling-down process, it can indicate a minor delay in the communication between the control board and the fan. In rare cases, it may signal that the fan is beginning to wear out or that there is a slight fault with the electrical signals from the main circuit board.

DIY fix possible

Wait for the fan to stop naturally as this is often a normal cooling cycleMonitor the boiler for several minutes to see if it moves to a different statusCheck for any active thermostats or 'comfort' pre-heat settings that may be requesting heat

Find a Gas Safe engineer
Search the official register →

Related fault codes

S. 7View →S. 0View →F. 32View →

Related guides you might find useful

No hot water but heating works

Almost always a stuck diverter valve on combis.

Read →

Banging / kettling / whistling noise

Each noise points to a different fault.

Read →

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →