sand pump motor

Troubleshooting Low Flow in Centrifugal Pumps

When a centrifugal pump isn’t delivering adequate flow, it can impact both the pump itself and downstream process equipment. Use this guide to troubleshoot low flow conditions, so you can maintain optimal pump performance and protect connected process equipment.

To troubleshoot low flow in centrifugal pumps, start by investigating these key issues:

Installation Issues

One of the most common yet overlooked problems is reversed impeller rotation. When initially wiring the pump motor, perform a “bump start” test with the motor disconnected from the pump to verify proper shaft rotation. Incorrect rotation can cause the impeller to loosen from the shaft, potentially resulting in severe internal damage.

Valve Position Problems

Always verify that discharge and suction valves are fully open. Additionally, check bypass valves to ensure flow isn’t being diverted through alternative paths. These simple checks are easy to overlook but critical to proper operation.

Flow Restrictions

Ensure the suction pipe is completely clear of debris. Restricted intake flow will directly limit the pump’s output capacity. In suction lift applications like self-priming pumps or vertical turbines, confirm proper fluid submergence to prevent vortexing, which can severely impact performance.

Impeller Obstructions

Debris lodged in the impeller eye reduces the pump’s ability to create the low-pressure zone necessary for proper operation. Regular inspection and cleaning may be required depending on the application.

Wear-Related Problems

Several types of wear can reduce pump performance:

Worn impeller vanes decrease hydraulic capacity

Deteriorated wear rings and plates increase internal recirculation

Excessive clearances for the pumped fluid lead to increased slip, causing fluid to recirculate within the pump rather than flow to the discharge