The underfloor heating is not turning on in one room

Could be. They definitely did not take into account that the electrician still has to lay control cables in the HKV.

He should actually think of that by himself. Presumably there are also cables there, it can happen that one or even several circuits are mixed up.

Aha. But you won’t have to open up the floor anywhere again for that, will you? How many euros do you think this problem is worth, that is, how much does it cost to solve it? We are currently withholding the last installment to our construction company.

No, the floor will most likely not have to suffer. It is 99% a matter of wiring and settings.

That is already very relieving! That sounds like tinkering. You have already tried it once. Since then, at least the underfloor heating in the attic hallway works. Is it actually normal for underfloor heating to be weaker in some parts of a room than in other parts? One half of our living room is quite cool, the other noticeably warm.

If it is partly warm and partly cold, there is air in the heating circuit. The heating system would need to be vented.