The American Standard Champion flush valve has a diameter of 4 inches, whereas the industry standard is 2 inches. A larger flush valve translates into more force and speed during each flush for potentially more efficient evacuation of the bowl.
The American Standard Champion flush valve is central to the American Standard Champion 4 flushing system. The flushing system is siphonic, which is most common in the United States. Siphonic action flushing utilizes gravity and entails water from a tank essentially pushing downward the contents of the bowl.
The Champion 4 flushing system combines the larger opening of the 4-inch flushing valve with a piston that delivers a 360-degree flow of water at speeds up to twice as fast as a 3-inch valve. The valve allows about 1.6 gallons of water to fill the bowl, and channels beneath the bowl rim direct water to a jet within the S-shape of the lower bowl so that the Champion 4 flushing system clears the bowl with a single flush.
The subsequent force and speed potentially moves masses that are up to roughly 70 percent larger than the sizes of masses that industry standard valves typically move. At 4 inches, the American Standard Champion flush valve is the largest on the market as of 2016.