How to Troubleshoot Common Performance Issues in a Centrifugal Pump

​A centrifugal pump does not fail without warning. In most cases, the signs appear well before the pump stops working entirely. Flow drops. Noise increases. Vibration shows up where there was none before. For maintenance and operations teams in food and dairy processing plants, catching those signals early is the difference between a planned repair and an unplanned shutdown. This guide covers the three most common performance problems in a centrifugal pump and what to do about each one.

Cavitation: The Most Damaging Centrifugal Pump Problem You Can Hear

Cavitation is the most destructive failure mode a centrifugal pump faces. It occurs when inlet pressure drops below the vapor pressure of the liquid being pumped. At that point, vapor bubbles form inside the pump casing. Those bubbles then collapse violently as they move into higher-pressure zones, and each implosion sends a shockwave into the impeller surface. Over time, that repeated impact causes pitting and material loss on the impeller blades. According to Pumps & Systems, cavitation can reduce pump efficiency, cause vibration and noise, and lead to significant damage to the impeller, casing, shaft, and other internal components. The full technical breakdown is available at pumpsandsystems.com.

In food processing environments, cavitation most often traces to one of three causes: insufficient Net Positive Suction Head (NPSH), a suction line that is too long or too restrictive, or an operating point far from the pump’s best efficiency point. To troubleshoot, start at the suction side. Check for partially closed valves, clogged strainers, or excessive pipe runs between the supply tank and the pump inlet. In many cases, those simple checks resolve the issue without pulling the pump.

Seal Failure: A Small Problem With Large Consequences

Mechanical seal failure is the second most common centrifugal pump problem in sanitary processing environments. A failing seal shows up as visible leakage at the pump housing, often accompanied by a wet floor or product contamination in the seal area. In a food or dairy plant, that is not just a maintenance problem. It is a food safety issue that triggers immediate corrective action.

Seal failure in a centrifugal pump has several root causes. Running the pump dry, even briefly, generates heat that destroys the seal faces. Operating consistently below minimum flow starves the seal of the fluid film it needs to function. Misalignment between the pump and motor also accelerates wear by placing side loads on the shaft that the seal was not designed to handle. For that reason, alignment should be verified any time a centrifugal pump is reinstalled after service.

In sanitary applications, seal selection also matters. Product-contact seals must be compatible with both the process fluid and the cleaning chemicals used in Clean-In-Place (CIP) cycles. A seal rated for water may fail quickly when exposed to caustic or acidic CIP chemistry. Specifying the right elastomer at the outset prevents a recurring maintenance problem.

Bearing Wear: The Failure Mode That Builds Slowly

Bearing wear is the most gradual centrifugal pump failure mode, and it is often the last one operators notice. Early signs include a slight increase in vibration, a rise in bearing housing temperature, and a low rumble or grinding sound during operation. Left unaddressed, bearing wear progresses to bearing failure, which takes the shaft and seal with it.

The primary causes of premature bearing wear are inadequate lubrication, contamination of the bearing housing, and operating the pump well outside its design flow range. In food and dairy environments, wash-down water is a common contamination source. If water infiltrates the bearing housing during sanitation, it degrades the lubricant and accelerates wear. As a result, bearing housing seals and lubrication intervals deserve regular attention in any centrifugal pump maintenance program.

Vibration analysis is the most effective early detection tool for bearing wear. A baseline vibration reading taken when the pump is running correctly gives maintenance teams a reference point. Any deviation from that baseline, in amplitude or frequency, signals a developing problem. Catching bearing wear at that stage typically means a bearing replacement. Missing it means a shaft replacement and a much longer downtime.

When Troubleshooting Your Centrifugal Pump Points to a Deeper Problem

Some centrifugal pump performance issues trace back to the original pump selection rather than to a maintenance failure. A pump running far from its best efficiency point, handling a fluid it was not sized for, or installed in a piping configuration that creates turbulence at the inlet will cause recurring problems regardless of how well it is maintained. In those cases, the right answer is a system review, not another repair.

Pumps & Systems provides detailed guidance on common failure modes and their root causes at pumpsandsystems.com/pump-troubleshooting-problems-and-failures, a useful reference for maintenance teams building a structured diagnostic approach.

Koss Industrial stocks centrifugal pumps and components for the dairy, cheese, and food processing industries, including Alfa Laval models. If your current pump is showing recurring issues, the Koss team can help evaluate whether a replacement or system change is the right fix. Or, you can contact our team directly through the Koss Industrial contact page.