General Pumps demonstrates how to completely service and diagnose almost any plunger pump. Many plunger pumps share the same basic design, so actions shown in the video are applicable to most plunger pumps. The video includes how to disassemble and reassemble a plunger pump completely, how to inspect each individual part, how to service and repair those parts, and how to diagnose problems with your plunger pump.

Plunger pumps are a type of positive displacement pump that operate by expanding and contracting a cavity within the pump. First, the cavity is expanded as a plunger rod moves away from it. This opens an inlet valve which introduces a fluid into the cavity. Then, the cavity is contracted as the rod moves back in. This closes the inlet valve and opens a discharge valve. The water in the cavity is pressurized and exits the cavity through the discharge valve.