The diverter valve I've ordered for my shower has threaded inlets. My question is, should I screw in the adapter first and then solder the pipe or vice-versa. Also do I apply anything to the threads on the adapters before screwing them in?
solder mip's on to pipe first,then cool down with water. Then apply tape and dope then thread into valve. If you have to solder close to valve after that soak a rag in water and place over valve closest to the side you are soldering.
You need to be absolutely certain that you can plug off the unused outlet on the diverter like that. Many diverters require you to pipe all outlets to something, even if that gives you a redundant function.
Lake County, Florida plumber
Springtime Plumbing Services, LLC