Low
S.31 on Vaillant ecoTEC plus Aquaplus

Your boiler is perfectly healthy and is currently set to only provide hot water while the central heating is switched off for the summer.

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

Summer mode (heating control knob in off position)

DIY fix possible

Locate the heating control knob on the front panel of your boilerTurn the knob clockwise to your desired temperature settingObserve the display as the S.31 screen message disappears

Find a Gas Safe engineer
Search the official register →

Related guides you might find useful

No hot water but heating works

Almost always a stuck diverter valve on combis.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →