How do I remove the head off this Giacomini thermostatic radiator valve?:
I was expecting part of the white bit to twist off easily, to reveal the inner pin on the valve. It looks like there might be some trick to it, e.g a release mechanism by poking something through the holes. But the bottom white bit is metal and rock solid. Do I need to use wrench to unscrew it? I don't want to remove the valve (gets messy) just the valve head.
My actual problem is that the radiator has simply stopped working, but I'm told it's likely to be the thermostatic valve is broken. By removing the valve head I hope to determine whether this is the case.