What is the difference between water pressure upstream and downstream of a pump when it is not operational known as?

The difference between water pressure upstream and downstream of a pump when it is not operational is referred to as Total Static Head. This term encompasses the vertical distance water must be raised plus any additional pressure differences at the two points being measured. Essentially, Total Static Head represents the potential energy of water in the system when the pump is not in operation and aids in understanding the hydraulic characteristics affecting the operation of the pumping system.

When considering the other terms, Dynamic Head pertains to the energy of the moving water during pump operation, which does not apply when the pump is stationary. Static Head generally refers to the height of water above a reference point and does not specifically account for pressure differences across the pump when not in operation. Net Positive Suction Head represents the pressure available to avoid cavitation within a pump, which is unrelated to the static conditions being measured in this scenario.

Thus, Total Static Head is the most appropriate term when considering the pressure differential across a non-operating pump.