Low Information
D.40 on Vaillant ecoTEC plus Regular

Your boiler is displaying its current target temperature and is working normally, as this is an information status code rather than a fault.

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

Flow temperature target value

What causes this fault?

This status appears because the boiler is communicating with its internal controls to determine exactly how hot the water needs to be at that moment. It occurs during normal operation as the system calculates the ideal temperature for your radiators based on your thermostat settings. There is no physical failure; your boiler is simply showing you the 'goal' temperature it is currently working toward.

DIY fix possible

No action is required as this is an informative status code.Check that your external thermostat or programmer is set to the desired temperature.Bly observe the display; it should change once the target temperature is reached or adjusted.

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