Heating, something is wrong here. Hallway always 22°..

Hallway, except for the front door, presumably completely interior. What do the respective flows at the heating control valve look like? And what exactly are the temperatures? Entering the hallway with a jacket is different than the bathroom in underwear.

Yes, that's how it is, the hallway is the center of our house. And it spans two floors.
I have regulated all the flows so that in both bathrooms and the living area full flow (3 liters) runs, hallways and bedrooms 0.5 liters.
To have all temperatures exactly, I still have to put a thermometer in every room. But for example, in the hallway (a total of 19 sqm), it is really consistently 21.9-22°C, our large bathroom, 15 sqm, as I said, is only 20.5°C, where the towel radiator switches on in the morning. In the small bathroom, 6 sqm, it is 21°C.
The living area is currently at 22.5°C (50 sqm).

That should be the case in every house, but I somehow have the feeling that this is only the case with us. No matter whose house I enter, the hallway is never as stuffy warm as it is with us :-(
When you come in from outside, you really run into a wall. I then ventilate the hallways, which lets out good generated heat. That heat should be better in other rooms. To me, that simply doesn’t make any sense at all.

Troubleshooting from the outside is naturally quite difficult. All previous speakers bring up aspects that could be possible. I have the problem here of rating 22 degrees as "heat." For us, it is often 24/25 degrees and not remotely hot or warm. Could it be that the sensor in the hallway is badly positioned? Because if the floor in the hallway is not noticeably warm now, then it can’t be the underfloor heating. What is the position of the hallway? Panorama windows on the south side? Just upload the ground plan of the ground floor… or does the hallway still get warm daylight from above? Try the advice from

The hallway on the ground floor, our front door is facing north. In the basement, the large terrace door is on the south side, the sun shines there during the day. Still, it is 22° overnight and in the early morning when we get up, so it cannot be bad if the sun shines a little sometimes. Is the sensor built into the controller? See photo

The hallway on the ground floor, our front door faces north. In the basement, the large terrace door is on the south side, the sun shines on it during the day. Still, it is also 22° overnight and early in the morning when we get up, so it can't be a problem if the sun shines a little bit sometimes. The sensor, is it built into the controller? See photo

Unfortunately, I only understand parts of the post ;) Basically, the sensors in the controllers are just rough gauges. One on the outside wall, one on the inside wall. Therefore, first tip, buy a thermometer and measure everything yourself. And at the same height and not on outside walls. I didn’t understand the thing about the hallways. Is there now one hallway in the north and another in the south? If you don’t shade the south terrace window, then that is a very large heat input. Since new houses are well insulated, it lasts for a long time. The sun warms the floor, etc. You don’t have ventilation, do you? As first steps, I would, as already mentioned, check whether the connections actually fit. That does happen. And really measure what temperatures are actually there.

Unfortunately.

But yes, we also have a ventilation system. However, the hallway is not connected to it.

I think I might have expressed myself a bit unclearly just now. We have a house built into a slope, with a ground floor and a basement.
The hallway on the ground floor has only one window, frosted glass, on the north side, where the front door is also located.
The hallway downstairs has the terrace door, which faces south. The sun always shines strongly against it in the afternoon, that’s true. But can that be responsible for the warmth in the hallway in October? Even at night?

Yes, probably nothing else will help but to measure everything exactly.

The hallway on the ground floor, our front door faces north. In the basement, the large terrace door is on the south side, so the sun shines on it during the day. Nevertheless, it is still 22° overnight and in the early morning when we get up, so it can't hurt if the sun shines a little sometimes. The sensor, is it installed in the controller? See photo

In your controller, a bimetal switch is installed. As a test, turn this time to max and observe over 2 days whether it gets warmer in the hallway or in the bathroom.