One of my rad stats has stuck shut so have cold radiator. Looking at
previous posts on this site, you can unstick it by "pulling up pin
with a pair of pliers".
Looking at mine, if you prise the plastic top off the control, there
is a chrome knob about 12mm in diameter, which you can depress & it
bounces back up. Is this the pin? Not sure of make but says Concerto
Any help appreciated - I'm not competent to drain system & muck about
with it, but if there's a quick fix I'd like to know!