How to tell if underfloor heating is running - ERR still without thermostat cover

It should be observed whether there is a continuous flow. Do you have an IR thermometer?

Has the hydraulic balancing already been carried out by the heating engineer?

I don't have an Infotot thermometer. The circuit was open both downstairs and upstairs in the bathroom. After adjusting the ERR, it was resolved. I don't know why it was running at all. What would need to be checked/adjusted for that? The hydraulic balancing was done about 4 weeks ago. I don't have a plan or proof for it yet. Should I check again tomorrow morning (after the cool night) to see if anything is running again?

1. I would lower the heating limit. 2. For later, when the house is finished and handed over, deactivate/set ERR to max. The heat pump needs a continuous volume flow to release the heat. ERR prevent this and cause the heat pump to cycle. This is neither efficient, cost-saving, nor gentle on the equipment.

Hello everyone.
I spoke with a technician from ELCO.

1. I as a user cannot see the floor heating flow and return. There are no indicators installed in the pipes and the setting can only be adjusted in the "professional area" of the heating system itself.
The heating system apparently regulates the flow temperature itself according to the corresponding outside temperatures. He said that currently (about 15 degrees outside temperature) it is around 22 degrees. If the return temperature is then colder, the heating system regulates up.
At the statistical 0 degrees, the flow temperature is probably around 32-33 degrees.
What do you think about that? Can it all stay like this? The maximum temperature possible here is apparently 45 degrees. I also know 32-33 degrees as the optimal flow temperature. But I don't know if that is the value for 0 degrees.
At -10 degrees (which is rare here in Lower Saxony) I do not want a flow temperature of 40 degrees if it is not necessary in our new building.

2. The outside temperature at which the heating starts is currently 20 degrees. I can adjust this myself and will later set it down to 16 degrees. Or what do your experiences say?

Additionally, I have the option to switch the heating to summer operation in summer. Then water is only heated once daily. I also see this as sensible, right?

So I am also just a "layman" with self-acquired knowledge... but what you have there is already a total disaster. The electricity meter ticks in winter like the fuel gauge at the gas station when you fill a V8 with SuperPlus.

According to your statements, you have a house with Kfw 40 insulation standard (although that in itself doesn't say much) and your heating runs from 20 degrees outside temperature? That sounds totally ridiculous already. The heating limit should be around 12 degrees. And the flow temperature (assuming the underfloor heating was properly designed) should be at the standard outside temperature (so with you around -10 degrees or something similar that applies to your location) at 33 degrees. With a good insulation standard, actually significantly less should be possible. If I were you, I would start completely from the beginning. That means reading into your heating system, getting instruction. And if the heating engineer can't manage that/is not willing to set it properly, then start from scratch yourself. Maybe someone here will help you with that, even better you would probably be well placed in the magenta-colored forum.