Low
d.04 on Vaillant ecoFIT Pure 418

Your boiler is displaying the current temperature of the water inside your hot water storage cylinder.

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

Water temperature in the cylinder

DIY fix possible

This fault may be fixable without an engineer. Check your manual first.

Find a Gas Safe engineer
Search the official register →

Related fault codes

d.00View →d.40View →

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 →