Low
d.90 on Vaillant ecoFIT Pure 830

Your boiler is having a minor communication issue with your thermostat, which means it may not be receiving correct instructions on when to turn the heating on or off.

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.

What the manual says

Manufacturer manual

Status of the eBUS room thermostat

From this model's manual
Verified against the Vaillant Ecofit Pure 830 installation & service manual, page 32.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Check that your room thermostat has fresh batteries and the screen is activeEnsure the thermostat is not showing a 'no connection' or 'signal lost' iconTurn the boiler off at the mains switch for 60 seconds and turn it back on to reset the connection

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Related fault codes

d.91View →d.93View →

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