What is the most important rule when operating a positive displacement pump?

The most important rule when operating a positive displacement pump is to ensure a flooded suction. This means that the pump must be primed and that there is a continuous supply of liquid at the pump's inlet. A positive displacement pump operates by trapping a fixed amount of fluid and forcing it out through the discharge. If the suction is not flooded, the pump may not be able to draw in fluid properly, leading to cavitation, excessive wear, or even damage to the pump.

When the suction line is not adequately flooded, the pump can run dry, which can cause overheating and failure. Flooded suction ensures that the pump is always maintaining an appropriate pressure difference at the inlet, allowing for efficient operation and longevity of the pump. Overall, maintaining a flooded suction is critical to ensure that the pumping system functions properly and efficiently.