Why must a pump be primed before it operates?

A pump must be primed before it operates to ensure that all the air is evacuated from the pump's suction line and the pump itself is filled with liquid. If there is air trapped in the suction line or the pump casing, it can prevent the pump from generating the necessary suction required to move the fluid effectively. This is crucial because most pumps are designed to move liquids and rely on the creation of a pressure difference to function properly.

When a pump is not primed, it may run dry, leading to inefficiencies, potential damage, and failure to deliver the required flow. Priming ensures that the pump is filled with the working fluid, which improves operational efficiency, reduces cavitation risks, and enhances the overall performance of the pumping system.