ᐅ Setting the underfloor heating – desired temperature preference

Mycraft schrieb:

that is already covered by the AT regulation.

The AT specifies a possible heat demand, which does not necessarily reflect the actual heat demand, since it is based solely on the outside temperature and does not take other factors into account, such as solar radiation or wind.

The return temperature can certainly be included as an additional parameter in the control system. However, this only applies if the flow rate is simultaneously measured or remains constant.

What flow rate is recommended for 5 heating circuits? For the living room / dining room / kitchen, is it better to have a high flow rate, around 3 liters (0.8 gallons), or just 1 liter (0.26 gallons)?

You will need to experiment with this. Rooms with higher heat demand and/or less heating surface should receive maximum flow. These are almost always the bathrooms. You adjust the supply temperature so that the desired temperature is easily reached there (the room thermostat turns off). For the other rooms, reduce the flow gradually until the desired room temperature is no longer achieved, then increase the flow slightly again. This process takes time because the system is very slow to respond, and you should wait at least 24 hours after each adjustment.

For some users, the heat demand on the upper floor is reportedly still higher than on the ground floor, so the flow rate on the ground floor is the lowest.

In the bathrooms, I have 4 liters per minute (l/min), and in all other rooms about 1 liter per minute (l/min).

The documentation from your heating installer should also include the designed flow rates. This can at least serve as a reference point.

Thank you very much for the detailed response.
I have now set the flow rate in the living room / dining area / kitchen to 1 liter per minute (l/min). The room thermostat (RT) is set to level 4. In the bathrooms on the ground floor and upper floor, I have set the flow to maximum. At 3 l/min in both rooms, the RT is set to 6, which means fully on.

Small update after 24 hours of fiddling with the flow control valve.
The apartment is still warm. Showering with 50°C (122°F) instead of 60°C (140°F) hot water works well too. Maybe the risk of Legionella is a bit overestimated? Or what temperature do you set your hot water to?