I thought I could upload a picture to this site--but it looks like I can only point to a url...
the valve in question attaches to male threaded end of elbow whose other end I believe to be unthreaded and know to be female. That then attaches to the pipe that goes to the basement to the main. there is another valve on the pipe right at the main.
So perhaps I could 'sweat' the elbow off of the pipe that goes to the basement, screw on the new valve, then sweat back on after having sanded and fluxed the surfaces.
To answer another question, there is a bleed screw in the basement on this pipe in question--so I believe I can simply let the water drain out of that bleed screw as well as have the sprinklers blown out and that should eliminate any freezing concerns.
Does that seem right?
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