Underfloor heating on the upper floor - one room always remains too cold

In the meantime, I am waiting for the electrician's inspection regarding the wiring of the heating system and for the heating engineer concerning the rest of the system.

The topic [EER raus] is a philosophical question. Ask 10 installers, and you get 10 opinions nowadays. Besides the hydraulic balancing, many other factors come into play, such as the heating curve, parallel shift, system setup (buffer tank yes/no), etc. That is why I consider this general statement "EER raus" too vague. It may be useful in many cases but is by no means the "non-plus-ultra" in all configurations.

yellow = office (10sqm) TARGET = 20, ACTUAL = 22.2 green = bedroom (17sqm) = TARGET = 21.5, ACTUAL = 21.5 red = child 1 (17sqm) = TARGET = 21.5, ACTUAL = 19.9! purple = child 2 (12sqm) = TARGET = 21.5, ACTUAL = 21.5 blue = bathroom (12sqm) = TARGET = 22, ACTUAL = 21.9 Thermal balancing done 2 weeks ago, I had a friendly heating engineer here. Since no result, reset to factory settings again. I also don’t understand why heating circuit 2 in the bedroom is mostly off and only heating circuit 1 runs. *Edit Heating pump runs at full power (40W).

This all suggests that the thermostats do not match the rooms and something was wired incorrectly. We had the same in our new build. It took weeks until I figured it out. You tend to trust the labeling. At some point, I got fed up and manually turned on only one heating circuit per day, all others off. Then I checked where it was warm and noted it down. Did that once with all of them. It takes 1–2 weeks, but you have to be patient because the underfloor heating is really sluggish. Alternatively, turn all heating circuits on (all actuators down, label them beforehand!) and see if the green child’s room gets warm. But this might not work because you may need more valve lift to heat everything at full power. That means you won’t see any real effect.

Meanwhile, I am waiting for the electrician to check the wiring of the heating system and for the heating engineer regarding the rest of the system.

The issue of EER out is a question of philosophy. Asked 10 installers, 10 opinions nowadays. Besides the hydraulic balancing, much more comes into play such as the heating curve, parallel shift, system setup (buffer tank yes/no), etc. That’s why I consider the general statement “EER out” too vague. It may be sensible in many cases but is by no means the “non-plus-ultra” in all constellations.

Your statement shows that you have not understood the principle of what these components are for.

A buffer tank never plays a decisive role in the rooms. The buffer regulates the temperature of the return flow delayed back to the heat pump. The best buffer is your screed; no buffer tank can achieve this mass.

The parallel shift is temperature-dependent on the outside temperature during the transition period.

The heating curve is the only point that influences the room temperature of all rooms. To determine the correct curve without any actuators interfering, the errors must go away.

And again, if you ask 10 installers, 9 out of 10 say we have always done it this way. And that is exactly wrong.

Learn and understand for yourself.