radiator temperature dial - All or Nothing

Hi

I have a number of radiators with there own temperature dial.
There are about 5 or 6 settings on each dial. However I cannot get ANY heat out of them unless i set them to the almost maximum setting (it varies slightly from radiator to radiator). Therefore, my house is either like a sauna or an ice box, there is no in between. Does anyone have any ideas what could be causing this and if there is anything i can check?
Thanks

Could be your radiator thermostat valve sticking with built-up of corrosion.Depend what type you've got,you can take the cover off(usually a allen key lock in somewhere) then you will find a pin which operate the valve.Pull it out slighty with a plier without taken it right out (careful not to damage the pin) and clean the pin with WD40 and rags or 00 steel wools,then see if you can move it backward and forward.Don't worry if the pin come out,it will go back in with some diffculty but water will dribble out.The way the thermostat works e.g. high setting pin out,lower setting pin in.I think what happening in your case the pin won't go in for lower setting therefore hot radiator.Best to get a plumber if you're not sure.

A couple of aspects to consider.
You will most likely have a room stat that switches the circulating pump on and off and when the set temperture is reached the pump stops.
You can appreciate that thermostatic valves are individually set (1/4 open 1/2 open 3/4 open fully open) but unless the pump is running they cannot function correctly, as hot water is not being pumped through them. Try the room stat at a slightly higher setting.
My second point. Prior to radiator stats each radiator had two lockshield valves fitted, one was used as an ON/OFF valve and the other adjusted to restrict the flow of water in order to achieve the desired temperture,now if any of these are almost closed and water flow restricted then it's pointless having radiator stat valve fully open