Our radiator valves are not connected to a central thermostat or to a boiler. But still it controls the heating.
Here’s how it works; you should always keep the boiler open and adjust the central thermostat to a certain degree, probably 22 or 23 degrees.
When there is demand for the heat in the rooms, the radiators will be open to heat the rooms. When there is no demand, they will be closed.
But still you need to keep the boiler open, but don’t worry the boiler will use energy when there is no demand for heat. Because when the radiator valves are closed, the boiler will pump the hot water to the radiators and that hot water will return to the boiler at the same degree. So in the next stage the water does not need to be reheated, so even if the radiator valves are closed and there is no demand for heat, the boiler must remain open.
But this has no effect on the boiler’s energy consumption, because the hot water is returned directly to the boiler.