Compressor broken after 6 years (Ecoforest ground heat pump / well construction Heth)

If the problem already existed back then. The numbers you mentioned do not indicate how the starts are distributed over the operating hours. You assume a linear distribution, but it is also possible that something broke down at a later point in time. That’s exactly why maintenance is performed. And even if the problem had already existed initially and the first technician didn’t notice it, you still have a good chance that the next technician will notice it.

Not signing a maintenance contract because it’s “too expensive,” and then complaining when a defect occurs after 6.5 years even though the numbers clearly indicate that something has been off for a while, is certainly a bit simplistic thinking.

Well, let's not exaggerate. In winter at below zero temperatures, you certainly don't have a flow temperature of 23 but rather between 27 and 32 degrees. And you can definitely feel that the tile is warm. But that is very pleasant and not comparable to the past in houses from the 90s with underfloor heating.

At -15 degrees, the flow temperature on our heating curve is exactly 27 degrees, and to me that doesn't feel "warm," but I'd be happy to include you when I hear again in winter that the floor feels cold and to ask if the heating is even running ;)

At -15 degrees, the supply temperature on our heating curve is exactly 27 degrees, and to me that doesn't feel "warm" but I'm happy to involve you if I hear again in winter that the floor feels cold, is the heating even working ;)

Yes, fine. Just stick to the standard that 95% have here. You probably have a passive house or 20 degrees room temperature. There are also cavemen who don't have any heating at all. And anyone who now thinks that maintenance would make it better, seriously? Normally the heating engineer who installed it does the maintenance. And as often, they have no clue and the systems short cycle to death. There really is nothing unusual here. Anyone who takes out a maintenance contract for a heat pump either has zero clue or too much money or both.

Even though I am usually on the side of the craftsmen... to suggest to a layperson here that they are too stupid and have mishandled their heat pump because they don’t pull and analyze the diagram monthly...

I see it very similarly. A professional should have noticed that during the first maintenance.

I’ll compare it to a modern start-stop automatic engine. If something is wrong with the sensors, it will stall at every traffic light in winter. The professional immediately thinks, "Oh no, and at -5°C, that must be a fault...".
The layperson, on the other hand, is happy about the modern technology that apparently has no problem shutting off the engine after 500m of driving even at -5°C. How should the absolute layperson know that even a modern engine can’t handle that?
School doesn’t teach that engine oil ideally needs to be at 55°C before gently applying partial load to the unit.

Not everyone has studied engineering sciences or learned something technical or has a hobby interest in it.
You simply can’t expect a layperson to know the optimal start behavior of their heat pump.

Especially not if even the professional is unable to recognize it during maintenance.

By the way, one reason why some people have serious reservations about buying a heat pump is that the operator often has no clue and completely misinterprets it. The technician sets it up incorrectly. And in the end it goes: What?? You haven’t read the manual, studied 2 semesters of thermodynamics, and optimized the heat pump over a period of 2-3 months? Well, then it’s your own fault if it breaks down after 3 years. It’s all written right here, on pages 20-658 and. Yes, exactly according to the optimization table in appendix 3B. Excuse me? No, you have to solve the differential equation correctly yourself, we obviously can’t do that for everyone. Yes, the initial values are important too... Tell me, did you sleep through Mathematics IV?

Yes, ideally it would of course be required that such large appliances have a 10 or preferably 20-year warranty.

Or the appliances monitor themselves better.
With cars, you used to have to check the oil level yourself, then they eventually had sensors for it, and now they don’t need oil at all. ;-)