What To Do if the Outlet Pressure of a Split Case Pump Drops?

Split case pumps are widely used in industrial, municipal, and commercial applications. A sudden drop in outlet pressure can affect system performance. This guide explains common causes and recommended corrective actions to restore normal pump operation.

Common Troubleshooting for Split Case Pump Issues

#	Problem	Possible Cause	Corrective Action
1	Motor Reversal	Wiring issues may cause the motor to rotate in the wrong direction.	Always check rotation direction before starting. If reversed, swap any two motor terminal wires.
2	Operating Point Shifts to High Flow / Low Head	Reduced system backpressure causes the pump to operate in the low-head, high-flow region.	Slightly close the discharge valve to restore normal pressure.
3	Pump Speed Reduction	Pump head is proportional to the square of the speed; any speed drop reduces outlet pressure.	Measure actual pump speed, find the cause, and restore the correct speed.
4	Inlet Cavitation	Suction pressure below liquid vapor pressure causes cavitation.	Check for blockages, ensure inlet valve is fully open, or raise suction tank liquid level.
5	Internal Leakage	Excessive gap between rotating and stationary parts reduces discharge pressure.	Inspect and repair/replace worn parts, such as impeller wear rings.
6	Impeller Flow Path Blockage	Partial blockage hinders flow.	Disassemble to remove debris; consider installing a suction strainer.

Conclusion:

Timely diagnosis and preventive maintenance are crucial. Regular inspections, correct installation, and adherence to manufacturer guidelines will help maintain optimal pump performance.