What is the appropriate spacing for floor cooling installation?

Why 10 Euro part?
It's not about the additional valve but about the HKV.
If it only has space for 8 valves, we need a bigger HKV.
But good hint - maybe I can get the bigger HKV myself.

No, we are not getting [Solarthermie].

What else nice will be installed then?
A mixer module does not bode well.

To what extent? Can you please explain that? As far as I know, the Arotherm Plus 55/6, unistor WW storage 300 liters, hydraulic station and the 45-liter buffer. In the living area, the sensocomfort 720

A mixer is not needed if the heat pump goes directly into the heating circuit. With a combined storage tank, hygienic storage tank, or separation buffer, a mixer is required. Now the question is, what exactly the mixer module is.

As far as I know, we don't have any of that... What is a separation buffer? We have a hydraulic separator - so a buffer in series according to my understanding.

A buffer in series is not a hydraulic separator.