The centrifugal pump is unable to pump air and is not self-priming.

The centrifugal pump is unable to pump air and is not self-priming.

• A. True
• B. False
• C. It can pump air but not self-priming
• D. It is self-priming

Answer: (A)

A centrifugal pump moves water by turning rotational energy into the liquid’s kinetic energy, and it relies on a continuous column of liquid in the suction line to develop the suction that draws water in. Air in the suction breaks that liquid column, so the pump cannot develop enough suction to move fluid; it may cavitate or simply pump nothing. In other words, it cannot effectively pump air. Self-priming means the pump can evacuate air from the suction line and fill itself with water without external help. If a pump isn’t designed to be self-priming, you must manually prime it by filling the pump casing and suction hose with water before starting. Typical fire-service centrifugal pumps require priming, so they are not self-priming by default. Therefore, the statement that the centrifugal pump is unable to pump air and is not self-priming is correct.

A centrifugal pump moves water by turning rotational energy into the liquid’s kinetic energy, and it relies on a continuous column of liquid in the suction line to develop the suction that draws water in. Air in the suction breaks that liquid column, so the pump cannot develop enough suction to move fluid; it may cavitate or simply pump nothing. In other words, it cannot effectively pump air.

Self-priming means the pump can evacuate air from the suction line and fill itself with water without external help. If a pump isn’t designed to be self-priming, you must manually prime it by filling the pump casing and suction hose with water before starting. Typical fire-service centrifugal pumps require priming, so they are not self-priming by default.

Therefore, the statement that the centrifugal pump is unable to pump air and is not self-priming is correct.