Pump Discharge Pressure Problem

Gradual drop in discharge pressure of a centrifugal pump:

• drop in rpm
• drop in suction pressure (level in suction vessel)
• increase in internal clearances
• increase in roughness of wetted surfaces
• decrease in diameter of impeller vanes
• reduction in piping resistance of the downstream system (opening of control valve, leaking relief valve etc)

Sure there are more but that is a start.

Could also be the wrong oil in the system.

As the viscosity changes, the pressure drops.

I would check this first as it could be a VERY easy fix.

what repairs? pump losing pressure..... questions we need to consider * speed constant * filters/strainers clean * oil viscosity * temperature discharge is dropping is the suction steady? -have you already addressed these points?