Air-to-water heat pump sizing in new construction

(50l?)

I received 100l. We have quite a bit of water in the system with our three heated floors.

I’ll let the heating engineer handle it for now. This year I’m not doing anything with the heat pump anyway and will use the room thermostats. In winter 22/23 I will then try to understand the system better and perform the hydraulic balancing and deactivate the thermostats.

Your plumber is legally obligated to perform the hydraulic balancing during installation. It probably won't work as well as if you do it yourself, but as a basic setting it should be fine. Ah, he is supposed to do the balancing with the room valves fully open and you want to have the protocols!

As my heating technician explained to me, the buffer is about the heat pump running for at least 5 minutes when the room controllers are closed but a heating demand is signaled, before it switches off again, because the coolant simultaneously lubricates the compressor. That should actually be independent of the water volume in the heating circuit. But who knows what your heating technician was thinking when he chose a bigger one. It won't be much worse. Maybe he just had it leftover.... I'm glad that my heating technician's statement is correct and I don’t have another ton standing around somewhere in the utility room, which is already too small and hardly usable as such (more like UR).

Your heating engineer should have sized the modulating heat pump so that it doesn’t keep shutting off. Then he wouldn’t have needed the botched buffer.

Write Vaillant like this. And it probably doesn't work if all ERR are closed, the heat simply cannot be taken away, how low should it modulate there?

Until the stop or do you believe that 50 liters of water absorb that much energy?