Heat pump produces more heat at colder temperatures

Hello, I have noticed that our air-to-water heat pump makes the rooms (underfloor heating) warmer the colder it is outside. Although no changes have been made to the thermostat or the heating. It should always maintain the same value, right?

Is it controlled by the outside temperature? Maybe something is wrong with the curve, you can make adjustments there. But a professional did it for us, so I wouldn't tinker with it myself.

That is completely normal. Since more heating power is required, the heat pump raises the temperature (heating curve).

The steepness of the curve is probably not right, but if it is colder outside than inside, that is somehow normal.
Still, please check how many cycles your heat pump has.

But the professional did it for us, I wouldn’t fiddle with it myself.

Isn't that a misconception and exactly the problem why 95% of households have wrong settings or heat inefficiently? ;)

The heaters are controlled by the outdoor temperature. The colder the OT, the higher the temperatures in the heater. That is normal.

But if you mean the room temperature, then either the radiator temperature was previously so low, and the ERR was set so high that the valves never closed before, or it is due to the inertia, so that the screed simply heats up too much until the ERR shuts off. The fluctuation range around the desired temperature is then correspondingly large, so you perceive it as too warm. Have you set differences between day and night operation?

A few years ago, I had the same phenomenon at colder temperatures, too, after I deactivated the ERR in my place at the beginning of autumn/winter and adjusted the run times. It became too warm in the rooms during the deeper winter. That is due to the steepness of the heating curve. I then reduced it accordingly. That had the consequence that in spring, during the transition period, the temperature especially in the bathroom was no longer right. I was able to offset this somewhat through a parallel shift.