Radiators boiling hot!

Hi there
I\\\'ve moved to a property with a Halstead Quattro Gold. The room thermostat is set to 21 degrees but all the radiators in the house remain so hot you can\\\'t touch them. When the thermostat valves are turned down on the radiators, they just go off. The hot water is also scorching hot when it\\\'s on. What\\\'s going on??!!
Any help much appreciated

Most people complain about it being cold..

Anyway Im only a diyer, but whilst you wait for the pros.

I dont know if this boiler supplies a tank for hot water, if it does is there a t/stat if yes turn it down, if not fit 1..if you do not have a tank I would guess there is a t/stat for the boiler.
As far as the rad temps, when you close the valve partialy it will take a long time for the water to cool.

I would suggest turn rad valve off, then just open 1/2 a turn & see how it goes then adjust it from there.