Underfloor heating + radiator -> two thermostats in one room

Hi. What supply temperature does the heating system run at? Are the underfloor heating and radiators connected to one circulation pump or are they controlled separately? What does the hydraulics look like? Mixing buffer? If you notice a difference between with and without radiators, you probably have a (too) high supply temperature. This then leads to the underfloor heating circuits being shut off via the ERR with cycling of the heat pump, which would be extremely inefficient and stressful on the equipment. Please provide more information about the entire system as well as the heat load calculation. Regards

As far as I can tell, there is no separate pump for the two radiators. I just read a flow temperature of 28.7 degrees. I even have the heat load calculation in softcopy, but as a layperson I obviously can't make sense of it. Regarding the hydraulics: during installation, the company apparently made a pre-calculated setting for the hydraulic balancing. With the result that the ground floor stayed cold because the flow regulators were only 25% open. I then had the heating company's customer service come by, and they noticed this. They said hydraulic balancing is a nice idea in theory, but in practice often leads to the opposite. They then fully opened all the regulators and since then it has worked. When I say I notice when the radiators help, they are still only lukewarm. But as an example: last night I turned the radiator to 0 and left the setting on the room controller as it was before, which had shown over 23 degrees in the morning. Without the radiator, it was 22 degrees this morning and the room controller still showed a deviation from the setpoint. I explain it this way: apparently the surface area of the radiator is already enough to compensate for the fact that the bathroom is relatively small. It is 10 sqm – bathtub and shower. So maybe 8 sqm that can serve as heating surface. The radiator is 0.72 sqm, times three (front, back and the space in between). Well, I will now leave the radiator at 5 and leave the regulation to the room controller. At some point the heating maintenance will be due, then I will interview the technician. Thank you all.

Unfortunately, you remain somewhat vague about which parts have been installed and how they are connected.
Which heat pump do you have?
How long is the duration of a heating cycle?

I am not vague, I am a layperson and simply do not know more about it.
I have a Rotex HPSU Compact 308.

There's no need to make a big deal out of it now. Without the radiator, it's too cold, so set it to 5 and always keep it running along with the underfloor heating. Of course, a radiator that is warmer than the air also heats the room. Essentially, such a part simply increases the surface area of the underfloor heating.