If a centrifugal pump with high flow and low static head begins overheating, what should the operator do?

The correct action when a centrifugal pump experiences overheating, especially under conditions of high flow and low static head, is to reduce the flow exiting the pump.

In a centrifugal pump, an excessive flow rate can lead to a condition known as "cavitation," where vapor bubbles form and collapse within the pump, causing damage and increasing thermal stress. Additionally, operating a pump beyond its optimal flow range can result in the pump running dry or reduced efficiency, leading to overheating. By reducing the flow, the operator allows the pump to operate within its optimal capacity, improves its efficiency, and helps dissipate heat more effectively.

Other options are not advisable: increasing the speed of the pump can further exacerbate the issues, thickening the fluid may increase the load on the pump making it work harder and potentially increasing the temperature even more, and fully opening the inlet valve could lead to even more flow entering the pump than it is designed to handle, thereby worsening the overheating problem.