I must be getting weak in my old age because I cannot unscrew the threaded fitting on the half inch valve where it is threaded onto the copper water pipe(which comes up through the floor in my house). I put a large crescent wrench on the flat part of the valve and a large pipe wrench on the copper water pipe. It won't budge. Any suggestions before I call a plumber? I tried tapping the fitting pretty hard. I bought a quarter turn halve inch valve to replace the old because the old one is leaking water out the handle. The metal in the old valve is in bad shape so I would not want to try to replace the rubber bushings and re-use it.
Bill