A drinking fountain valve is what controls the water flow.  VMS stocks self closing valves where you simply turn the handle to start the flow of water and then release the handle to stop, push button valves simply start the flow of water when the button is pressed and stop the flow when the button is released and air control valves that are used on all Haws freeze resistant drinking fountains; it is diaphragm controlled, supplied with an in-line mesh Y-strainer and 1/2" NPT inlet and outlet.
The bubbler cartridge or regulator is one of the most commonly replaced parts of a drinking fountain. This cartridge acts as an on/off valve. When pressed, the cartridge allows the water to flow, and when released, the self-closing action stops the water flow. Once the water is flowing, the cartridge acts as a regulator that controls how much water flows out of the bubbler. The height of the flow can be adjusted by turning the adjustment screw with a screwdriver.
VMS stocks both the green and red spring cartridges; green is used on both Elkay and Halsey Taylor coolers with a push bar.  However, the red cartridges can be used interchangeably.  The only difference between the two is the tension of the spring, cartridges with the green spring must have more tension applied to the push bar to actuate. 
VMS stocks valves and cartridges for the following brands; American Standard, Central Brass, Kohler, Elkay, Halsey Taylor, Ebco, Murdock, Oasis, Sunroc and others.