last year when I knew even less about these things than I know now, I had to get a CH man in to deal with a bunch of stuck (closed) thermostatic valves on a system that had not been run for some time. I was intrigued to discover that his hammering, seemingly quite gentle, worked a treat on all the valves. Having resolved to make sure that all valves were fully open during the summer I overlooked one of them and sure enough it's stuck.
The CH man charged his minimum call out fee so I'd like to take the hammer to this myself. Is there a knack? - I suspect there is, at the very least it probably requires a conviction that one is capable enough to do it. I lack this at the moment and am concerned that I damage the valve.
I've removed the unscrewable controller. I've tapped around the valve with the metal end of a pair of pliers (can't find the hammer) but I wonder, should one actually tap the pin sometimes or should all action be around the solid metal parts of the valve? Heavy or light action?
thanks for any encouragement.