Excellent!!

Thank you very much, that iindeed just the start entrance I need to go and understand how to set it up.

On the internet I found a sensor with a +5v / ground/ flow dependent V output (at least I assume the yellow cable gives 0-5V dependent on the l/min flow that passes true the sensor. DF777615-7703-41C2-88AB-BD7D7CD88FE6.jpeg I have domoticz set up with a switch id 50, and all I need now is something ...