Yes that is indeed the major disadvantage of my heating system. Did already discuss about that many times on Discourse over the last years, but never got time to work out an affordable solution.
I have a thermostatic valve at each radiator, which opens when its target temperature is not reached yet. So we have this kind of situations:
- My son increases the temperature on the thermostatic valve at the radiator in his study room.
- Then he needs to increase the temperature on the central wall-mount thermostat, to tell the pump it needs to start circulating hot water to all radiators. If he forgets to do that, his room will be cold when he wants to start studying.
- When he has finished studying, he should turn off the thermostatic valve in his study room. But sometimes he forgets to do that, and he doesn't notice it because someone else already lowered the temperature on the central wall-mount thermostat (which means the radiator in his study room will get cold anyway).
- Then someone wants to go to bath and raises the temperature of the thermostatic valve on the radiator in the bathroom, and he also raises the temperature again on the central wall-mount thermostat. The pump starts pumping and the bathroom gets warm. So far so good...
- However the study room will also start to get warmed up again, since my son has forgotten to turn down the thermostatic valve on that radiator. As a result we spoil energy and yet another discussion with the kids start ...
Which means that we use the central wall-mount thermostat only as a switch:
- We turn the pump off by adjusting it to 0°C
- We turn the pump off by adjusting it to the maximum temperature.
So very far from convenient...
After I drawed the above diagram this week, it became very clear to me that I should buy a box of Shelly TRV's, so that every radiator can ask Node-RED to turn my pump on/off. My heating system contains no logic and can be controlled simply buy a few optocouplers. So I think that is the only way to go. But the TRV's are quite expensive, and I need a lot of those. And I am still negotiating with my wife about a series of extra camera's, so won't be for tomorrow...
BTW I know that there are cheaper TRV's e.g. based on Zigbee, but (as explained in the past) I don't want to have multiple wireless networks in my house. Case closed 
Nice catch!! That I didn't think about that myself... Thanks!!
Thanks for thinking out loud!!!!
Main problem is that I can't control my TRV's at the moment. Changing the temperature of my central wall-mount thermostat via Node-RED has not much sense, because the rooms (where I want to control the temperature) are too far away from the thermostat.
