Ice formation brine pipe heat pump

That was hot water preparation (visible by the faucet symbol)

How does it look this morning, was the night different from the previous one?

So I turned off the cooling yesterday at around 12 o'clock. Until 8 pm, the compressor was only on twice to produce hot water. This morning at 8 o'clock, the compressor start count had risen from 1127 to 1171!? The pipes were also iced up again but not that thick, see pictures, and now at 10 o'clock they are already ice-free again. However, we had -7° on the supply and -10° on the return when the system was running this morning, that seems a bit low, doesn't it?

On October 12th, the head of the building technology company wants to take a look at it together with his colleague, well, I'm curious...

If you only use one third of the brine line, then it is also clear why it freezes: this could be easily fixed by finally using the other 2/3. The heating engineer is needed here.

If the brine is frozen because too much was taken out there, then it will get tight for the winter because the brine no longer regenerates. Then you need a few weeks without heating and warmth/water. This could become tight in this heating period. Do you have a second heat source (stove, heating rod)? How this looks commercially – here the heating engineer (or the general contractor) is even more needed.

Good luck, and it would be nice if you keep us updated

44 bars in one night. There must be something wrong with the return flow, as the switch-on value is reached so often. I have a crazy idea: is the return line exposed somewhere next to a frost protection or the brine lines and pulling the temperature of the return line down?

Maybe the heat pump keeps stopping because of the too low supply temperature of the heat source. As soon as it is one degree warmer again, the compressor starts up again, and so on. But all of this is just theory. In my opinion, it is still most likely that something is wrong with the heat source, the rest are consequential errors. That your problem becomes a matter for the boss is a good sign. In the end, the drilling is ruined, that would be the worst-case scenario.