Bypass and demand pump and valve system for bypass and demand pump

A head for a diaphragm pump;

• the head comprising:
• an inlet port and an outlet port and defining an inlet side including a plurality of inlet chambers;
• a diaphragm;
• and an outlet side having a center outlet chamber intermediate the plurality of inlet chambers;
• a plurality of inlet valves, wherein each of the plurality of inlet chambers includes an associated inlet valve of the plurality of inlet valves, and the diaphragm is sequentially engaged by each of the inlet valves of the plurality of inlet valves;
• a single shutoff check valve controlling fluid flow from the center outlet chamber, the single shutoff check valve comprising a plunger in the center outlet chamber movable between a fully closed position and an open position;
• a single bypass valve within the center outlet chamber and in fluid communication with the center outlet chamber and each of the plurality of inlet chambers, the center outlet chamber intersecting each of the plurality of inlet chambers;
• a single shutoff switch, the single shutoff check valve being actuated by the single shutoff switch.