Low
S.16 on Vaillant Home System

Your boiler is briefly cooling down its internal components after finishing a cycle of heating your hot water.

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 overrun

DIY fix possible

No action is required as this is a normal status message and not a breakdown code.Wait a few minutes for the status to change and the fan to stop automatically.If the code persists for hours, try resetting the boiler once.

Find a Gas Safe engineer
Search the official register →

Related fault codes

S.10View →S.14View →S.17View →

Related guides you might find useful

No hot water but heating works

Almost always a stuck diverter valve on combis.

Read →

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →