Which valve should be open during P-100 pump startup?

During the startup of a pump like the P-100, it is essential to ensure that the discharge valve is open. This is because the discharge valve allows fluid to exit the pump and enter the system. By keeping it open, the pump can operate effectively, maintaining proper flow and preventing excessive pressure buildup within the pump itself.

Opening the discharge valve ensures that the pump is not dead-headed, which occurs when there is no path for fluid flow, potentially causing damage to the pump due to pressure surges. Additionally, having the discharge valve open assists in venting any air that may have accumulated in the system during startup, thus preventing cavitation, which can lead to operational issues and reduced efficiency.

In contrast, having the intake valve or drain valve open during startup may not be appropriate, as it could lead to operational inefficiencies, loss of prime, or unintended fluid discharge. The bypass valve also plays a different role, often used for management of flow around the pump rather than for direct fluid discharge. Therefore, ensuring the discharge valve is open is crucial for a safe and effective pump startup.