Self-Priming Centrifugal Pump Seal Replacement | Video

MP Pumps demonstrates how to replace a mechanical seal and set the impeller to wear-plate clearance on an MP Pumps Flomax pump. This procedure may be necessary if there is any leaking around the mechanical seal. This video includes how to disassemble a centrifugal pump, how to reassemble a centrifugal pump, how to inspect and clean important parts, how to replace the mechanical seal on the pump, and how to set impeller clearance on a centrifugal pump.


Centrifugal pumps work by spinning a shaft-driven impeller extremely fast inside a casing. When fluid is introduced to this impeller, the centrifugal force generated by the rotation expels the fluid through a suction port, which leads to the outside of the casing. The fluid then exits a discharge port, and the velocity received from the impeller is then changed into pressure.

How does a Centrifugal Pump work? What makes a Self-Priming Centrifugal Pump different?

Self-priming centrifugal pumps are different from non-self-priming centrifugal pumps in that self-priming centrifugal pumps do not suffer from air binding like a typical centrifugal pump will. Self-priming pumps mix air and water together to do this, creating a fluid that acts much like regular water. Excess air is then removed, allowing the pump to move only water. This happens only during the priming cycle, the process will stop during pumping.