There is an arrow cast into the side of the pump housing, you can check again.
I checked again (see pictures in the attachment, unfortunately they didn’t turn out very well...), the arrow points upwards, that should be correct for the return flow, right?
Somehow there is something wrong with my heating system overall and/or I don’t understand the operation or not fully...
We do not live here yet (we are still in the middle of the renovation phase), but to ensure frost protection we installed some of the old radiators on the ground floor last autumn.
Unfortunately, our heating unit has no setting option for heating operation without heating the domestic hot water. Therefore, I lowered the target temperature for the hot water to 16°C (this was recommended to me by the Viessmann service line to save gas accordingly), but nevertheless the domestic hot water temperature is maintained at >50°C...
I thought it might be due to an anti-legionella function, but this is not activated.
The Viessmann service only says: “Without knowing the hydraulics and the setup of the system on site, we unfortunately cannot make a statement about this.” OK, I understand that! But the heat certainly does not come from the solar thermal system in January and February, so why is the hot water kept so high when 16°C is set?
And then last week the stratified storage tank on top was wet... Apparently water leaked or was drained from the manometer mounted on top of the tank, but why...?!
I know, without an expert I probably won’t be able to find out anything...
Thanks for your help!