30.9 degrees at 3 degrees outside temperature is far too high. The return temperature is only 0.2K below the flow temperature, i.e. the heating energy remains in the water. Probably all ERR closed?! I would file a complaint about the system. Nothing is right.
What do you mean by all ERR closed? We are currently heating all rooms via the thermostats.
chewbacca, didn’t someone write here that he spent a few hours intensively dealing with the user manual so that he can optimally adjust his heating? I think you won’t be able to avoid that either.
Also noticeable is also 49 degrees for hot water, which is quite high and correspondingly energy-intensive. 45 should be sufficient, depending on storage size and usage behavior even less.
How is this actually compatible with legionella prevention? I know (from the gas heating context) the guideline of 60 degrees in the storage tank, which is also currently easy to find on the internet. Are there other ways to prevent the proliferation of legionella here?