To not really understand how radiators worked

[HowDidINotKnowThis]

I always thought that when you turned the individual radiator thermostats down, it just meant the radiator came on at a lower temperature. But no!
Each number represents a temperature, and when the room reaches that temperature the radiator turns off.

0 = OFF
(*) = 7°C
1 = 10°C
2 = 15°C
3 = 20°C
4 = 25°C
5 = 30°C

I always thought mine were faulty as they always stayed really hot.

It’s not quite like that unless you have thermostatic valves.

In simplest terms, the valve is a tap. If you have the valve fully open (5) you get more hot water in the radiator, giving out more heat. If the have the valve partially closed (2) you have less hot water so less heat.

So, you thought it was the opposite?

Oh I guess I do mean thermostatic valves. I think they come on at the same temperature but just turn off when the room reaches the right temperature. The hot water just stops flowing in to them, until the room cools down enough for them to turn back on.