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

We had the problem in the kitchen. The chocolate melted in the base cabinets. It turned out that our switches were installed upside down.

By walking into a wall I mean when you come in from outside, from the street. Yes, our hallway is connected by a staircase, ground floor with basement. Next week our sanitation guy is coming by, he wants to take a look at the situation since he has to service equipment here anyway. I can't explain the backflow in the heat at night, yes during the day, but at night? I am curious, I will just measure everywhere now and then we will see. I thank you all for your contributions

try something simple first:

check at the heating circuit distributor whether the controller in the hallway really closes the associated valve at the heating circuit distributor (HKV).
You have sight glasses with a flow indicator at the HKV.
If the controller is on MIN or OFF, the flow indicator at the heating circuit hallway should show "0".

Turn your HKP down one level. 3L in the bathroom and living area are way too much! You certainly have a very low temperature spread here and the heat cannot be optimally released into the room. Where the "cold" return flow from the living area should actually come back, "warm" return flow is rushing through the hallway!

Hi, before simply reducing the flow, the temperature of the return flow at the HK manifold should first be measured. You bought an IR thermometer back then. Just measure at the return flow bar during the heating cycle. And always keep an eye on the total flow when turning down. You have a large heat pump that requires the corresponding flow rate. If you turn down too much, the heat pump will not be able to get rid of the heat and will go into fault mode. When the heating technician was here, check if he reopened the override valve. I'm curious whether the labeling in the HKV was mixed up. Greetings from Hamburg

Lower your HKP by one level.
3L in the bathroom and living area is way too much!
You certainly have a very small spread here and the heat cannot be optimally transferred into the room.
Where the "cold" return flow from the living area should actually come back, "warm" return flow is rushing through the hallway!

Hi Alessandro
I've thought about this for a while.
But it's not just about the spread, it's also about the volume of water circulated, which results in the amount of heat provided. What's decisive for the heat output from the underfloor heating to the room is rather the temperature difference between the floor covering surface and the room temperature. How the floor covering surface temperature is achieved is ultimately irrelevant. Or am I mistaken?
Could you otherwise provide sources for this statement to read up on? I'm really interested now.
Regards