A big thank you to all those who chipped in on this one. The radiator now appears to be working normally again – and not a moment too soon in the current weather conditions! :)
Thanks namsag. After mucho fiddling I found a sort of peg thing in the lower black ring of the valve head. When this was prised out I was able to twist the ring and pull the valve head off the rad to reveal the pin. The pin was not seized and when I pulled it out water spurted from the valve...
One of the radiators in my house has stopped heating up. It was working fine until last week; now it doesn't heat up regardless of the setting on the Danfoss thermostatic valve. The inlet pipe gets warm but that's all. I am assuming that the valve is stuck in the 'closed' position. How can I...