A pump (10") including: a housing defining a pair of chambers (18, 20); a first diaphragm separating one of the chambers into a pumping side and a pumped side, the first diaphragm being movable between a first position and a second position, thereby forcing fluid from the pumped side of the one chamber; a second diaphragm separating another of the chambers into a pumping side and a pumped side, the second diaphragm being movable between a first position and a second position, thereby forcing fluid from the pumped side of the other chamber; an air piloted supply valve in flow communication with a supply of pressurized fluid, the supply valve being movable between an opened position wherein pressurized fluid flows to the pumping side of one of the chambers (18, 20), and a closed position wherein pressurized fluid is inhibited from flowing to either of the chambers (18, 20), the supply valve having a first port in flow communication with the supply of pressurized fluid and a second port; wherein the supply valve is configured to be in the opened position when the pressure at the first port is larger than the pressure at the second port; and a mechanical controller including a pressure regulator having an input in flow communication with the supply of pressurized fluid, an output in flow communication with the second port of the supply valve and a port in flow communication with the supply of pressurized fluid via a restriction which causes the initial pressure at port of the pressure regulator to be less than the pressure provided by the supply of pressurized fluid, and which allows the pressure at port to build up by pressurized fluid bleeding past the restriction; wherein the pressure regulator is configured to allow pressurized fluid from the supply of pressurized fluid to reach the second port of the supply valve for shifting the supply valve to a closed position when the pressure at port reaches a predetermined level. a housing defining a pair of chambers (18, 20); a first diaphragm separating one of the chambers into a pumping side and a pumped side, the first diaphragm being movable between a first position and a second position, thereby forcing fluid from the pumped side of the one chamber; a second diaphragm separating another of the chambers into a pumping side and a pumped side, the second diaphragm being movable between a first position and a second position, thereby forcing fluid from the pumped side of the other chamber; an air piloted supply valve in flow communication with a supply of pressurized fluid, the supply valve being movable between an opened position wherein pressurized fluid flows to the pumping side of one of the chambers (18, 20), and a closed position wherein pressurized fluid is inhibited from flowing to either of the chambers (18, 20), the supply valve having a first port in flow communication with the supply of pressurized fluid and a second port; wherein the supply valve is configured to be in the opened position when the pressure at the first port is larger than the pressure at the second port; and a mechanical controller including a pressure regulator having an input in flow communication with the supply of pressurized fluid, an output in flow communication with the second port of the supply valve and a port in flow communication with the supply of pressurized fluid via a restriction which causes the initial pressure at port of the pressure regulator to be less than the pressure provided by the supply of pressurized fluid, and which allows the pressure at port to build up by pressurized fluid bleeding past the restriction; wherein the pressure regulator is configured to allow pressurized fluid from the supply of pressurized fluid to reach the second port of the supply valve for shifting the supply valve to a closed position when the pressure at port reaches a predetermined level.