Fault
Cause
Remedy
The system pressure exceeds the shut-off
pressure.
•
Increase the liquid level on the inlet side.
•
Open the isolating valve in the inlet pipe.
•
Check system head curve vs.
performance curve.
The speed of rotation is too low.
Reestablish the correct speed of rotation.
The suction lift is too high, or there is
insufficient NPSH.
Reduce the suction lift or restore the required
NPSH.
The strainer or the impeller is clogged.
Clean the strainer and the impeller passages.
Wrong direction of rotation.
Reestablish the correct direction of rotation.
The joints are leaking.
Tighten the joints.
The shaft or coupling are broken.
Repair or replace damaged parts.
The inlet valve is closed.
If the inlet valve is closed, open it slowly.
There is not enough inlet pressure for hot or
volatile liquids.
Reestablish required inlet pressure. Check
NPSH.
The foot valve is too small.
Replace the foot valve.
Worn or damaged hydraulic parts.
Repair or replace the worn parts.
Excessive clearance between the wear
surfaces.
Repair or replace the wear rings.
The pump loses its prime after starting.
Joints are leaking.
•
Tighten the joints.
•
Tighten the packing.
•
Check o-ring between sleeve and shaft.
•
Replace the gaskets.
The suction lift is too high, or there is
insufficient NPSH.
Reduce the suction lift or restore the required
NPSH.
Excessive power is required.
The speed of rotation is too high.
Reduce the speed of rotation.
The pump is operating beyond its
recommended performance range.
Set the duty point in accordance with the
recommended performance range.
The specific gravity or viscosity of the
pumped liquid is too high.
If less flow is sufficient, reduce the flow on the
outlet side, or fit the pump with a more
powerful motor.
The shaft is bent.
Replace the whole rotation element, and
possibly the pump.
The stuffing box is too tight.
Retighten the stuffing box, if possible.
Alternatively, repair or replace the stuffing
box.
The impeller clearance is too small causing
rubbing or worn wear surfaces.
Adjust the impeller clearance, if possible, or
replace the wear ring.
There is an electrical or mechanical defect in
the motor.
Contact your local service center for
diagnostics.
The pump is restricted in its rotation.
Remove any obstacles, or replace any worn
parts.
Incorrect lubrication of the motor.
Reestablish correct lubrication of the motor.
21
English (US)
