Low
S.31 on Vaillant Turbomax Plus 828 E

Your boiler is perfectly fine; it is simply set to 'summer mode' which means it will provide hot water when you turn on a tap, but will not heat your radiators.

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 radiator temperature dial on the front of the boiler control panel.Turn the dial clockwise to your desired temperature setting.The boiler will automatically switch from 'summer mode' to normal operation.

Find a Gas Safe engineer
Search the official register →

Related fault codes

S.30View →

Related guides you might find useful

No hot water but heating works

Almost always a stuck diverter valve on combis.

Read →

Radiators cold at the bottom

Sludge build-up — needs flushing, not bleeding.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →