Abstract: A motorless carbonator including a double acting diaphragm type pneumatic water pump is connected between a carbonator tank and a water supply. The pump is driven by the carbon dioxide fed to the carbonator tank. Control of the pump is by way of an electrically operated shut-off valve which is opened and closed in response to a water level sensor in the carbonator tank. Coupled between the carbonator tank and the pneumatic pump is a spring biased diaphragm valve assembly which is normally biased closed, but is opened when the pump is actuated to feed water into the carbonator tank.