How does rad control work?

Live at Three

We have the new low energy rads upstairs with stats in each room also. Just wondering what is the purpose of the 1-5 dial on the rad, how does this work in tandem with the stat. What is the point of a dial on the rad when the stat is going to control the temp of the room anyway?
We have the bedroom stats set to 19 degrees. How should we leave the dial on the rads?
Thanks

Wearb

I don’t know your setup, but generally where there is a room stat, any radiator valves in that room should be at maximum.

Skatedude

They are thermostatic valves, so each level turns off the valve at a set temperature.

In degrees Celsius.
1=12 celsius
2=15
3=18
4=21
5=25 or 28(depending on make)

But they vary slightly by manufacture

Live at Three

Thanks.
Its air to water heating with underfloor downstairs and rads upstairs.

There is actually only 1 stat upstairs and its in the master bedroom, so the temp of that room controls the heat in all bedrooms. Child's bedroom always feels cooler than master bedroom. I have a feeling that this is not an ideal setup although perhaps someone could explain to me why it is.
I know these type of rads don't heat up like the old ones, but these don't even feel warm to the touch.

There is a rad in the hall in an open area adjoining downstairs, some in bathrooms and 1 in hot press. Should these be left up to 5 too, even though not really required for much heat?

Skatedude

If you use thermostatic valves on the rads and a wall mounted thermostat in the same area, then that will confuse the system. I'd also recommend getting a plumber to balance the rads, simple procedure