Hydraulic balancing air-water heat pump + efficiency circulation pump

Let's see what Vaillant writes, according to the diagram there should be more flow at 100% pump.

That can take a few days Vaillant does always reply diligently but some time always passes until then

What still makes me suspicious is the statement that the system (according to the diagram) would run optimally at a nominal volume flow of 540 l/h and a 5k temperature difference. I think I'll test what happens if I throttle everything until 530 l/h is displayed in the control and whether the pump then regulates the volume flow to 5k...

540 x 1.16 x 5k = 3132 watts heating capacity

So at 900 mbar there was exactly a 2K spread according to the control.

At the inlet of the heating circuit distributor as well.
In the individual heating circuits it varied from 3K in the throttled circuits to 1.5K.

I have now set the pump from 900 mbar to 450 mbar.

I thought the pump was already at 900? What were the flow rates at 900?

It was also at 900 mbar the whole time, it was briefly at 200 mbar but then I suddenly had a fault in the system. Now I have set it to 450 mbar.

At 900 mbar I have 729 l/h when WC and domestic hot water are throttled... If all circuits are open it is around 748 l/h at 900 mbar.

Currently, the pump shows a flow of 729 l/h at 450 mbar.

So here’s the thing: when I close the 3 living room circuits, 2 kitchen circuits, 2 hallway circuits, and utility room including WC via ERR, the total flow decreases to 493 l/h, but the flow to the remaining open circuits (bathroom, 2 guest rooms, and 2 bedrooms) increases to about ~2 l/min. Without ERR, with all circuits fully open, I only get around 1 l/min (if at all) or just under 1.5 l/min everywhere else.

Which brings me back to my theory about ERR: the short heating circuits/small rooms heat up the fastest in principle, so the actuator closes them via ERR. This in turn supplies the next remaining short circuit with more water, and so on, until all rooms are heated and all actuators/heating circuits are closed. This causes the pressure in the system to rise until eventually the overflow valve opens, which then leads to the return temperature approaching the supply temperature and the system shutting down?

I’ll try that tomorrow; what’s the worst that could happen? The system starts short cycling...