Low
d.16 on Vaillant ecoFIT Pure 425

This is a normal status message showing whether your external thermostat is currently telling the boiler to turn the heating on or off, rather than a genuine fault.

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

Status of the 24V room thermostat (off=Heating off, on=Heating on)

DIY fix possible

Check if your room thermostat is set to a temperature higher than the current room temperatureEnsure the thermostat batteries are not depletedVerify the thermostat is properly connected to its receiver or wifi bridge

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