Has anyone ever seen one of these?
Just moved into a new house and several radiators have these on teh outlet end (they have TRVs on the inlet side. One of the radiators is cold at the bottom and I wanted to remove it and take it into the garden to try to flush it through and get any sludge out. But how do I isolate the radiator as this valve doesn't appear to have any way to shut the valve off!