What would cause low flow under all test pressures when testing for pump efficiency?

Low flow under all test pressures when testing for pump efficiency is primarily caused by pump inlet restriction. This occurs when there is an obstruction or limitation in the pathway leading to the pump, which can be due to factors such as a blocked inlet screen, a clogged filter, or kinks in the suction line. When the inlet is restricted, the pump cannot draw in the required amount of fluid, leading to a consistently low flow rate regardless of the pressure levels being tested.

This relationship is critical in understanding the performance of hydraulic systems and ensures that technicians can diagnose flow issues effectively. Ensuring that there is proper fluid access to the pump is vital for maintaining efficient operation and pump longevity.