many thanks @SarahH !
so i think that my setup is very close to this one:
the only difference is that from the buffer we have only 1 hot water out pipe which firstly goes into the radiator/basement circuit (high temp, WL2) and then into the splitter valve where (if high temp circuit is ON) it will bring the floor water to the WL1 set temp.
in the picture from the samsung manual, the 2 circuits get hot water from the buffer at 2 different level.
in my setting bathrooms radiators can work both with high temp or low temp, as the radiator valves call for water pump F. While basement only works with high temp (that circuit is controlled by 2 way valve “H” from basement thermostat.
so not sure if that difference from the buffer is significant.
but mixed valve location seems in line with the samsung schema.
i just can’t get how it is controlled, because to me it doesn’t make sense…