American Standard Flash Shower Rough-In Valve With Universal Inlets/Outlets With Screwdriver Stops - AMS-RU101SS

The Flash RU101SS rough-in valve sets anywhere from 1-3/4 inches to 2-3/4 inches measured from the finished wall to the back of the valve. That one inch of play is what lets you use the same valve behind thin tile over backer and behind a thicker mud bed or a stone surround without re-plumbing. The plaster guard doubles as an installation guide for setting that depth, and on thin-wall work it can carry the mounting support.

Yes. The RU101SS has 1/2 inch male NPT / sweat inlets and outlets, so it takes 1/2 inch copper sweated directly, 1/2 inch iron pipe threaded on, or PEX and CPVC through the appropriate 1/2 inch adapters. One valve covers whatever the building is piped in, which is why it gets specified on multi-unit repipes where you hit copper in one stack and PEX in the next.

The valve body only. On the Flash RU101SS the cartridge ships with the trim kit, not with the rough-in, so you need to order a matching American Standard Flash trim separately to finish the shower. That split is deliberate: the rough goes in at plumbing top-out, the walls close, and the cartridge and escutcheon stay in the box until finish. The screwdriver stops are part of the rough-in valve itself.

That is what the flush plug is for. It stays in place of the cartridge so you never have to install and pull a cartridge just to test, and it blocks cross flow between hot and cold while you flush the lines of solder flux and debris. Test with air to 200 psi or with water to 300 psi through the flush plug. For a GC running a whole floor of showers, this is the difference between testing at top-out and waiting for finish trim to land.

No. The Flash RU101SS is a back-to-back capable valve, so hot and cold can be reversed at the valve without repiping. That matters on back-to-back bathrooms sharing a wall, where one of the two showers is always fed from the opposite side, and it saves the callback when a rough goes in mirrored.

It includes screwdriver stops, so a single shower can be isolated at the valve to change a cartridge or service the trim without shutting down the riser. In an apartment building or a hotel, that is the whole job: no notices to residents, no draining a stack for one leaking shower. The stops are integral to the rough-in valve, not a trim option.

The body is cast DZR brass, dezincification resistant, chosen to resist corrosion where water has high chloride content or a high pH. Dezincification is the failure that eats ordinary brass from the inside and shows up years later as a pinhole or a seized stop, so DZR is the specification institutional and multi-family buyers look for when the water quality is known to be aggressive.

The RU101SS has a flat back, so it sits flush against a 2x cross brace between studs rather than rocking on a curved casting. Screwing it tight to a flat surface is what keeps the valve from shifting when someone leans on the pipe later, and it makes setting the depth within the rough-in range repeatable across a run of identical bathrooms.

American Standard model RU101SS is the Flash shower rough-in valve with universal 1/2 inch inlets and outlets and screwdriver stops included. There is one configuration, supplied unfinished since it is buried in the wall, and the visible finish is decided entirely by the trim kit you pair with it.

No screws. A stainless steel retaining ring with flats secures the test cap and the cartridge, and the flats let you put a wrench on it to loosen the ring for insertion or removal. Stainless rather than plated steel matters on a part that sits wet inside a wall for the life of the building, and it means the finish plumber is not fighting a corroded fastener years down the line.