Low
d.16 on Vaillant ecoTEC plus System

Your boiler is currently receiving a signal from your thermostat telling it to stay off, so it is simply waiting for a command to start heating.

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 your room thermostat or smart controller settingsIncrease the target temperature on your thermostat to see if the boiler respondsCheck if your thermostat batteries need replacing

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Related fault codes

d.15View →d.17View →

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