What is the recommended procedure for shutting down a large centrifugal pump?

The recommended procedure for shutting down a large centrifugal pump is to slowly close the discharge before shutting off power. This approach is crucial because it helps prevent a phenomenon known as "water hammer," which can occur when sudden changes in flow cause shock waves in the piping system. Gradually closing the discharge valve allows the pump to decelerate smoothly, reducing pressure surges and protecting both the pump and the piping system from potential damage.

Additionally, slowly closing the discharge valve maintains the hydraulic balance within the system, allowing the pump to operate at a reduced capacity without causing cavitation or excessive wear. This procedure also ensures that the pump can be safely stopped without the risk of backflow or other complications associated with abrupt changes in operation.

Maintaining proper shutdown procedures is essential for the longevity and reliability of the pump and the overall water distribution system.