Low
d.20 on Vaillant ecoFIT Pure 425

Your boiler is notifying you of the maximum temperature your hot water is allowed to reach, usually based on your current settings.

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

Check the hot water temperature dial or digital setting on the boiler control panelAdjust the temperature setting up or down to your preferenceMonitor the display to see if the status code clears once the setting is saved

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 →