Underfloor heating: actual flow temperature does not change

Hello,

in the course of the screed heating program, the set supply temperature of the underfloor heating was 35 degrees on 4.5., 40 degrees on 6.5., 43 degrees on 7.5., and 45 degrees on 8.5., which is supposed to remain the highest setting. However, the actual supply temperature has only increased from 36 degrees to 38 degrees since 4.5. Is that normal?
Thank you very much.

tomorrow, a few more details would be helpful because this is not normal. what type of heating is installed?? how much area is being heated?? we once had this problem in a multi-family house. the builder tried to use a heat pump for the screed drying. however, the heating element had not yet been installed, so the heat pump simply couldn't manage the flow temperature. the solution was an additional electric heater.

Be glad. I would keep it at that temperature if it is a new build.

For functional heating, the current recommendation is to only go up to the maximum design temperature of the underfloor heating because that is better for the screed. In new buildings, the maximum flow temperature is 35 degrees or better yet lower. I have also often read about blanket recommendations/heating protocols to heat up to 55 degrees – but that is outdated.

By the way, screed drying is formally something different, but even there the temperature is not set higher.

I went only up to 28 degrees myself, because that was calculated as the maximum flow temperature.

Why your heating cannot manage more can only be speculated due to lack of information. It sounds like a heat pump at first. And in that case, it would also be completely fine.