Nat9 wrote: I understand that you should set them to 6 and leave them alone? Do not screw or combine?
If you have thermostatic heads with position 6 as max, set 6 on the head in the room where you have the room regulator and let it stay that way.
For the test on other radiators, also unscrew to max 6 and see how your boiler will behave, i.e. when the temperature drops to 19.5 degrees and the room regulator will turn on the heating.
I mean how long (how many minutes) the burner will run before it turns off due to reaching the upper temperature set on the boiler.
How much time will elapse before the controller senses 20.5 degrees in the room and turns the heating off.
How many cycles on / off the burner in the boiler will be between switching the heating on by the controller at 19.5 and switching it off at 20.5 in the meantime.
Anyway, enter what temperature you have set on the boiler as the temperature of the heating water on the supply, because we do not know it.
Increasing the temperature in the boiler will extend the heating cycle a bit, but will also increase the temperature differences, so it has to be selected experimentally.
You can also change the temperature range on the controller, instead of 19.5-20.5 it is e.g. 20-21.
You have to think about it a bit and choose the optimal variant.
If so, in the boiler MENU you can set the maximum power for what, but it requires freedom when using electronics such as a smartphone, computer, etc., because if you have 2 left hands for such matters, there is no need to rummage yourself. According to the instructions, the P6 parameter corresponds to the power and there the power is set as a percentage. As for your needs, you can easily set the value of 50, in theory it will give 50% or 12kW.
If I understand the instructions correctly, the boiler fires at minimum power and then gradually increases power over the course of 10 minutes, until it reaches the maximum set under P6.
Nat9 wrote: So it is. The apartment has less than 50 m2.
For a building that is not insulated, it is possible to assume 100W / m2, which gives about 5kW for frost -20.
But at home, I noticed that the computationally accepted 85W / m2 is also OK and then for you, for 50m2, it would be 4.3kW for frost -20.
If you have an insulated building, if we take 60W / m2, it gives 3kW for frost -20.
If you divide in half what is for frost -20, the required power will be obtained for temperatures of 0 degrees, but for the variant, when we heat for 24 hours.
Due to the fact that your boiler has a minimum of 9.5 kW, it must heat impulse, which means that it should provide large portions of energy in a short time, so that it is sufficient on average for your needs.
As a result, there will be periods of hot, and then cooling down, which is such an average comfort.
Assuming that for -20 you need 4.3kW, then for about 0 it will be up to about 2.2kW.
2.2kW x 24h = 52.8kWh of energy.
If we assume that your boiler works on average with a power of 10kW, in order to produce 52.8kWh of energy, it must operate at least about 5.3h (52.8Kwh / 10kW) per day.
As mentioned before, the boiler must have an adequate water flow in the installation so that the radiators receive the heat generated by the boiler.
The lower the flow through the radiator, the slower it receives heat and the faster the temperature rise in the boiler. The faster the water flow, the faster the heat is collected by the radiator and the slower the temperature rise in the boiler. Although due to the large disproportion of the minimum power of the boiler and your needs, the differences in time may be small.
Generally, when you set all radiators to 6, see how the temperature will be distributed in individual rooms, if some rooms are too warm, you can start twisting the heads, but not up to 3 to 20 degrees, but as the lower extreme value, take, for example, the equivalent of 22 degrees, to avoid close the water flow through the radiator completely.
Switching the boiler on for a few seconds is a mistake, if you manage to set the installation so that the boiler burner works for at least a few minutes, it will be a big positive change, although the feeling of thermal comfort will change then, because more heat energy will be pumped into the radiator, and each has a different threshold for perceiving heat and heat.
You have to try and experiment, good luck