How your toilet works

How your toilet works.

Two assemblies are concealed under the lid of a toilet tank; a ball cock assembly, which regulates the filling of he tank, and a flush valve assembly, which controls the flow of water from the tank to the bowl. When someone presses the flush handle, the trip lever raises the lift wires (or chain) connected to the tank stopper. As the stopper goes up, water rushes through the valve seat into the bowl via the flush passages. The water in the bowl yields to gravity and is siphoned out the trap.
Once the tank empties, the stopper drops into the flush valve seat. The float ball trips the ball cock assembly to let a new supply of water into the tank through the tank fill tube. As the tank water level rises, the float ball rises until it gets high enough to shut off the flow of water. If the water fails to shut off, the overflow tube carries water down into the bowl to prevent an overflow.