Bingo! It works almost every time. If that doesn't work, close and open the thumb screw & thump it again. It probably won't make any difference but at least you tried. If it doesn't there's just no choice that I know of other than remove & replace it. It's such a rare event I don't think I'd try to remove to just clean it or fix it....chances are if it stuck any repair will be temporary & you don't want to go back there again.
I first thought about the hammer but didn't want to bust anything apart. I tend to over do things........
But eventually I got out the smaller hammer and started tapping around it. Finally got the valve to start working again. At least it shut off the flow of water through the pipes. Mother in law was relieved and that makes wifey happy so my life becomes a lot better !!!!!
I told everyone to just "chill out" until the spring/summer season.
I will be disassembling refurbishing, and replumbing the entire system. This year it seems like the old gal, (the AA Fred) is starting to tell me that it is time for a little work. The acidic water is starting to take its toll on everything.
And its not like I don't have anything to do..........................
meanwhile -- back at the ranch - Tonto disguised as a toilet seat is getting more tail than the Loan Ranger!
When you have the opportunity but before you let the system go cold - or once you restart for good NEXT season - dump a can of R6 Barr's stop leak in the system and let that circulate not only will you have a minimal leak prevention agent in play -- the contents will scrub the circulator impellers clean and clean that pesky sticky flapper valve - this will help prevent it from sticking again