I just spoke again with my heating engineer. He also said that the heating curve is way too high. There was once an employee here who had less experience. At the time, I asked him about the warm utility room, and he apparently turned the curve up. The boss, who sets up the systems initially, would not have done it that way.
Well, let's see what 0.4 brings. But for now, I have also raised the desired temperature from 16°C to 22°C. I think that is correct. When adjusting, I also noticed regarding water (not heating) that the flow temperature is 55°C. Does that at least fit?
: Thanks for the hint. I will read into the topic so that I can manage the fine-tuning better. This should be best possible during the cold season.