| To provide the forceful volume of water needed for | | | | A diaphragm valve is recognizable by its one-piece, |
| flushing action directly from a water supply system, | | | | rounded cover, which is nearly twice as large as the |
| rather than from a storage tank, a pressure-flush | | | | pipe leading to it. The cover of a piston valve is |
| valve toilet must be connected to a larger-than-usual | | | | slightly larger than the pipe containing the valve. |
| pipe, 1 or 1.5 inches in diameter. It lets water flow at | | | | Fix leaks or other malfunctions by replacing worn |
| 30 gallons per minute, and this high flow rate can lead | | | | parts. Since parts made by different manufacturers |
| to waste or, if parts fail, flooding. | | | | are not interchangeable, be sure to note the maker's |
| A pressure valve toilet contains three mechanisms: a | | | | name; it is clearly stamped on the device, usually on |
| built-in stop valve to shut off water quickly in an | | | | top of the pressure valve. |
| emergency, a handle assembly and the valve itself. | | | | The flow rate of a diaphragm-type valve is regulated |
| Handles and stop valves are essentially the same on | | | | by adjusting the stop valve. The diaphragm |
| all toilets. There are, however, two distinct types of | | | | automatically regulates the duration of the flush cycle. |
| pressure valves, one employing a diaphragm | | | | On a piston-type valve, both the flow rate and the |
| mechanism and the other a piston. The two types | | | | flush cycle are regulated by turning a screw on top |
| can be easily identified by their outside profiles. | | | | of the valve. |