Central heating systems...

[iCraig]

Any of you guys know stuff about them?

Now and again the rad in my room gets very hot (as though it's on full) but it's turned off. The "dial thing" at the top is set to "Off"

After a few hours it cools back down, but why is it doing that? My room is hot enough in the summer months, I can't be doing with the bloody radiator coming on in the night.