Water enters through diagonal punching around the rim of the bowl, creating a vortex that draws the water down into the rear trap with a swirling action that scours the walls of the bowl. Water strikes two parallel ridges and folds over forming a jet, producing siphonic action. Large water surface provides a very efficient and clean process, and the flushing is extremely quiet. This model is mostly of one-piece construction with a low profile. Expensive.
SIPHON-JET
Water enters through rim punchings and jets placed in an up-leg of the rear trap, filling the trapway and creating an instant siphon action without rise of water level. The result is quick water withdrawal. Large water surface provides an efficient and clean operation. With quiet flushing and moderate cost, this is the most popular residential model.
REVERSE-TRAP
WASH-DOWN
Water enters through an open rim, as though a bucket of water were dumped into the bowl, filling the front trapway and creating siphon action. This model provides quick removal of water with minimum water rise. Small water surface makes the model more vulnerable to soiling and clogging. This is the least efficient and most noisy type but lowest in cost.
PRESSURE/TANKLESS
PRESSURE/TANK
A steel tank is located inside the china tank. Uses pressure from the water supply system. A 1.5 in. water supply line provides 25 psi pressure, compressing trapped air in the tank. When flushed the compressed air forces the water out. The bowl is designed to accept the torrent of water. The crest of the surging water empties the bowl through the enlarged trap. Large water surface makes this model efficient. Design features make it suitable for residential use. Flushing is very noisy. Low water usage (1.5 gpf) helps conserve water. Expensive.
