Central Heating again

[BertiWooster]

Following on from the question below, I know that turning the thermostatic radiator valves up and down controls how hot or cool / cold the radiator gets.

However what actually happens in the valves to make this happen - i.e how does the valves work .
Is it simply regulating the amount of water that goes into the radiator - i.e the more or less water it allows into the radiator , the more warmer or cooler the radiator gets ?

[AlBags]

It works like a thermostat on a car .. except an adjustable one. There is a wax filled capsule inside, or some use liquid. The capsule expands or contracts according to the ambient temperature surrounding the capsule or cylinder. The handwheel on a TRV applies a counterforce to the expanding capsule assembly. Together, they control the integral water valve according to the AIR temperature surrounding the valve, and modulate the water flow into the radiator accordingly. Simple!

[BertiWooster]

I set my radiator valve to say number 2 setting - i then increase the setting to number 4 and the radiator gets hotter .
Does it get hotter because the amount of water going into the radiator , increases between setting number 2 and 4 ?

[BertiWooster]

So , the lower the number you set the radiator valve at , the lower the amount of water goes into the radaitor .

Therefore the lower the amount of water going into the radiator , the less water there is in the radiator to lose heat from .

So , the water circulating goes back to the boiler at a higher temperature which means that the boiler does not have to use so much gas to re heat it to the temperature to which the boiller is set .

The above is therefore why turning the radiator valve down saves money .

Am I correct ?