Before starting a positive displacement pump, which of the following is the correct procedure?

Before starting a positive displacement pump, the correct procedure involves opening the inlet valve and the discharge valve. This is important because positive displacement pumps require fluid to be present on both the inlet and discharge sides to avoid damage and to ensure proper operation.

When the inlet valve is open, it allows the pump to fill with the fluid being moved, creating necessary suction. Opening the discharge valve allows the fluid to flow freely from the pump once it starts. If the discharge valve were closed when the pump was started, it could create excessive pressure, leading to potentially damaging conditions such as pump failure or pipe bursts.

Overall, ensuring both valves are opened provides a safe operational environment for the pump and supports its efficiency in transferring the wastewater.