Is the heating dimensioning sufficient?

Have you had the system from Vaillant inspected?

According to HB yes... unfortunately I was not there. I also don't know if it happened in person or over the phone. The times I dealt with Vaillant customer service were not highlights either... keyword "well" instead of "ground probe" and the heat load calculation (wrong Ht value as a basis).

Then you should now have a sticker and a service booklet from Vaillant - the inspection is a condition for the 5-year warranty.

You didn’t take advantage of the Vaillant subsidy, did you?

Regarding the system diagram: There are of course many types, but there was always a buffer - either the hated large one in the supply line or this safety buffer in the return line. However, this should have no impact on efficiency - just costs a few euros (just under 400 euros) and unfortunately I had to agree to it because of the warranty conditions.

I'll follow up on that... thanks for the tip.

The acceptance must take place within 4 weeks after installation - at least that's what I think.

I’ll just step on my HB’s toes there...