Hydraulic balancing air-water heat pump + efficiency circulation pump

The pump is set to 900 mbar, which according to Vaillant corresponds to a maximum performance of 100%.

The problem will be that all heating engineers, including Vaillant as the manufacturer, will refer to the energy saving ordinance and the obligation to use ERR and then argue that the system only works with ERR.

That we want to control via the self-regulating effect without actuators does not matter to them.

However, I have already written to Vaillant about this.

What spread do you have with it at the moment?

I'm at work now, I can only say tonight... Usually something between 3-4.4 K, but there have also been 2 K.
However, I have to differentiate here: I can read the spread once according to the regulation, i.e., basically what comes out of the heat pump, and then also measure manually at the heating circuit distributor at the flow and return pipes.

Have you set the system pressure as shown in your linked image in the technical area? It says something about from 240 to 750 mbar

No, the system pressure is set to 900mbar as set by the customer during commissioning.

Also, I don’t actually know the system pressure; I only know about 95 mbar for the unfavorable heating circuit of the underfloor heating.

I once set the pump to lower, I think 350 or 400 mbar, but apart from the message that the residual head limitation was active, it had no effect, but that was a long time ago..

If I take the 95 mbar from the most unfavorable FB circuit plus 6 m of 28 mm pipe with a few bends and shut-offs, I don't think I even reach the 200 mbar that I can set at least. The distributor is practically right next to the heat pump, so hardly any pipe network with pressure loss adds up.