When should a positive displacement pump be operated?

A positive displacement pump should be operated when the suction and discharge valves are open. This is essential because a positive displacement pump moves a fixed volume of liquid with each cycle, and it requires an unobstructed path to intake the fluid through the suction valve and discharge it through the discharge valve. If either valve is closed, the pump could create excessive pressure that may lead to mechanical failure or damage to the system, and it would be unable to draw in fluid effectively.

In contrast, having these valves closed would prevent fluid flow, causing potential over-pressurization, while operating during specific hours or under certain temperature conditions is not a requirement for positive displacement pumps. These pumps are designed to operate continuously under normal conditions as long as they have the necessary fluid supply and the valves are correctly positioned to allow flow.