Installation and Operation Manual
SA-07-11-87, Rev A
52
January 2019
Situation/Symptom
Possible Cause
Investigative/Corrective Action
Mechanical failure in driver or pump.
Remove driver and check for freedom
of rotation, correct spacing
of pump shaft assemblies.
Remove fluid end and search for any
mechanical failure.
Corrosion pitting on surface of diffuser cover
or diffuser, adjacent to impeller blades.
Head rise is also reduced by this condition.
Disassemble pump and inspect.
Rough or pitted surfaces can cause
friction losses which will significantly
increase horsepower consumption.
Clean these areas of all obstruction
and restore surfaces to a smooth
polished finish. Check diffuser throat
area at the inlet; erosion or corrosion
resulting in roughness or increased
area
will
increase
horsepower
consumption. Note: A larger throat
size than design will allow a higher flow
and horsepower for a given head rise.
Excessive
discharge pressure
pulsations.
Flow rate too low.
Increase flow rate through pump. Add
bypass to suction tank if necessary.
Insufficient NPSH available.
Refer to solution for insufficient NPSH
under “No flow, no pressure at
startup,” above.
Defective flow control valve.
Check control valve.
