American Standard Selectronic 3-in. Flush Valve Assembly with Flapper for 4019 Toilet Tank - AMS-738921-101

Yes. The 738921-101 flush valve assembly is the American Standard Selectronic 3-inch valve built for the 4019 toilet tank, and it is specified for use with American Standard Cadet 3 toilets. If the tank on the fixture is a 4019, this is the matching valve. On a Cadet 3 with a different tank number, check the tank casting before ordering, since American Standard uses different valve assemblies across tank models.

The flapper is included. The 738921-101 is sold as a complete flush valve assembly with a chemical resistant flapper, so a maintenance tech replacing a leaking valve gets both parts in one box rather than sourcing the flapper separately.

That failure is usually the flapper, not the valve body, and the flapper in the 738921-101 assembly is a chemical resistant type. In buildings where housekeeping drops in-tank chemical cleaners, that is the part that degrades first and causes phantom flushing. Replacing the whole valve assembly rather than just the flapper also resets the seat, which is the other common source of a slow leak-by on an older Cadet 3 tank.

Flush volume delivery rate. A 3-inch valve, like the one in the 738921-101 assembly, opens a larger port so the tank dumps faster into the bowl, which is what American Standard calls an oversized valve for a stronger flush. A 2-inch valve is the older standard and moves water more slowly. The two are not interchangeable: the valve size has to match the opening in the tank bottom and the flapper seat it sits on, so a 3-inch replacement goes into a tank designed for a 3-inch valve.

Repair part. The 738921-101 is the flush valve assembly that sits inside the toilet tank, the tower and seat the flapper seals against, plus the flapper itself. It is not a fill valve, not a trip lever, and not a tank or bowl. If the complaint is a tank that will not fill or fills forever, that is the fill valve, a different part.

No finish choice applies. The 738921-101 ships in one configuration only, part number 738921-101.0070A, because the valve lives inside the tank where nothing is visible. Order the single version and you have the right one.

No specialty tooling. American Standard rates the 738921-101 as easy to install: the job is shutting off the supply, draining the tank, pulling the tank off the bowl to reach the valve nut and gasket, then setting the new valve and reseating the tank. For a property manager doing several units, the work is routine plumbing hand tools plus a fresh tank-to-bowl gasket and bolts if the originals are corroded.