Low
d.23 on Vaillant ecoFIT Pure 435

This is a normal status code indicating whether your central heating is currently requested to be on or off.

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 heating demand (off=Heating off, on=Heating on)

DIY fix possible

Check if your room thermostat or programmer is set to a temperature higher than the current room temperatureEnsure the heating function is enabled on the boiler control panelNo action is required if the heating is working as intended, as this is an information code rather than a fault

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