What is priming and why is it necessary for suction operations?

• A. Priming increases residual pressure in the line
• B. Priming fills the pump and suction line with water to create a vacuum seal, enabling the pump to develop suction when drawing from a static source
• C. Priming is the process of measuring pump capacity
• D. Priming reduces TDH by removing elevation head

Answer: (B)

Priming is filling the pump and suction line with water so there is a continuous liquid column that allows the pump to develop suction when drawing from a still or static source. When a pump tries to lift water, it lowers the pressure inside the suction chamber; if air is in the line, that air breaks the liquid column and the pump cannot sustain suction, causing little or no flow. By priming, you remove air pockets and saturate the suction line with liquid, enabling atmospheric pressure to push water up to the pump and let the impeller begin moving fluid. This step is essential for suction operations because a static source won’t supply a continuous flow on its own, so without priming the pump cannot initiate flow. The other statements don’t describe what priming does: it isn’t about increasing residual pressure, measuring pump capacity, or reducing total dynamic head by removing elevation head.