American Standard Flash Shower Rough-In Valve With CPVC Inlets/Universal Outlets With Screwdriver Stops - AMS-RU109SS

The Flash RU109SS has a rough-in range of 1-3/4 inches to 2-3/4 inches measured from the finished wall to the back of the valve. That one-inch window is what lets you use the same valve behind tile, backer plus tile, or a thin acrylic surround without repositioning the body. The plaster guard doubles as an install guide for setting that depth, and on thin-wall builds it can carry the mounting support.

Inlets are 1/2 inch CPVC, and the outlets are universal. The CPVC inlets let you solvent-weld straight to 1/2 inch CPVC supply without transition adaptors, which cuts out two joints per side and the leak paths that come with them. If you are piping in copper or PEX you will need the appropriate transition at the supply, since the valve itself presents CPVC sockets.

Yes, and that is the point of the flush plug. The RU109SS ships with a flush plug so you never have to pull a cartridge to test or flush: it blocks cross flow between hot and cold, and the assembly can be tested through it at 200 psi with air or 300 psi with water. The stainless steel retaining ring with flats holds the test cap in place without screws, and the flats let you back it off by hand tool for a quick swap to the cartridge at trim-out.

Yes. The Flash valve body has back-to-back capability, so hot and cold can be reversed quickly without a different part number. That matters on multi-family and hotel work where mirrored bathrooms share a wall and the supply sides flip from one unit to the next. You stock one valve for both orientations.

Not for the stops. The RU109SS includes screwdriver stops built into the valve, so you can isolate hot and cold at the valve through the trim to change a cartridge or work on the shower without shutting down the riser or the unit. On rental and hotel property that is the difference between one bathroom out of service and a whole stack of them.

The body is cast DZR (dezincification resistant) brass, chosen to resist corrosion where chloride levels and pH run high. That is the reason to spec it over plastic-bodied economy valves in hard or chlorinated municipal water, and it is why the retaining ring is stainless rather than plated steel.

The valve is rated for shower and tub applications. Whether the installation ends up shower-only or tub-and-shower is decided by the trim and diverter you pair with it, since the cartridge comes with the trim. The outlets are universal, which is what allows the same body to serve either configuration.