Underfloor heating and heat pump. I thought I understood it

And where is the big rest? "2x the half" is still missing.

(I'm not the OP) What information do you want? (You said "only the relevant"). What is, for you, the big rest of the information that is missing? (Or is there a list somewhere here that one can work through?) As I said, I'm not the thread creator and my head always hurts whenever I look into heating topics because from page 2 onwards it's mostly gibberish to me. (I still read them in the hope that by the time it becomes relevant to me, the mess in my head is a bit more organized.) My feeling is just that I don't know what you want to know (I might have a few ideas, but maybe you would then say "irrelevant"), but maybe the OP feels differently. The point is, I would probably find it difficult to give a satisfactory response to a paraphrased "now just give out some info" :s (that might work when experts discuss on equal footing, but among laypeople it’s almost always difficult).

I still haven't understood everything about underfloor heating and heat pumps even after 4 years :-D It should get warm, but you should keep the heating curve low, you shouldn't throttle the rooms, but if you don't throttle them enough, it gets too warm. If you lower the heating curve, it's okay there, but too cold in the other room, etc. :-D vicious circle

Vicious circle

No, slow approach to the optimum with ever smaller steps and subsequent bliss ;)

(I'm not the OP) what information do you need?

Well, the title is "I thought I understood it." If that were the case, he would also know which data is needed to carry out an "evaluation" of the system/floor heating. Design temperature/number of heating circuits (rooms)/length/flows/heating curve/target room temperature/cycling/spread/...