Thank you for the answer and no problem for German text. I'm also able to read a bit of German but not to write it anymore, my lessons are too far
I disagree, most of the presscontrol have a spring to limit water hamer. A few examples :
I understood that presscontrol stop the pump when there are no more water flow (which equal indeed to max pressure of the pump). I'm not sure to understand this : sollte man einen mechanischen Zweipunktdruuckschalter mit Kessel verwenden