Low
d.20 on Vaillant ecoFIT Pure 835

Your boiler is limited to a specific maximum temperature for your hot water, which is a setting adjustment rather than a mechanical breakdown.

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

Maximum hot water set target temperature

DIY fix possible

Navigate to the 'd.20' setting in the installer level menu (refer to manual)Adjust the value to your preferred maximum hot water temperaturePress the tick or 'OK' button to save the new setting

Find a Gas Safe engineer
Search the official register →

Related fault codes

d.00View →d.01View →

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 →