Thermal balancing - Initial values taken for adjustment

The actuators would have pressed the pins down, the ones that stick out at the top, I assume, right? I still have protective caps. If I screw them on, the pins will eventually go down. I just pressed 3 individual pins once. The respective float then briefly goes to 0.

That's right. With that, you can permanently close the heating circuits.

The actuators can only be fully open or closed - not "slightly open" or "almost closed." That is why you basically have the stop in the valve, which can be adjusted via the square made of copper.

The puzzle was solved. You have to adjust the red parts including the sight glass. So I first brought everything back to the starting position at the top and then turned the glasses. It works in both directions and the floats reacted immediately. The tip came from a forum about [Haustechnik] ;) Nevertheless, thanks to you too!