⚙️ Troubleshooting of Pumps – Common Problems and Solutions
Pumps are critical components in industrial plants, water treatment facilities, HVAC systems, and chemical processes. When a pump fails to perform as expected, it can lead to downtime, energy losses, and costly repairs. Effective troubleshooting helps identify the root cause of problems such as excessive power consumption, insufficient pressure, or low discharge flow.
This blog explains the most common pump issues, their causes, and practical solutions.
🔹 Excessive Power Consumption
Excessive power consumption can result from mechanical or hydraulic problems. If not addressed, it can lead to motor overload, pump seizure, or bearing failure.
Mechanical Causes
- Imminent bearing failure.
- Pumping elements rubbing against casing.
- Poor shaft alignment.
- Bent shaft or binding rotating elements.
- Stuffing boxes too tight or worn wearing rings.
Hydraulic Causes
- Fluid viscosity or specific gravity higher than design.
- Pump running at too high speed.
- Discharge pressure higher than calculated.
- Rotary lobe pump: discharge pressure too high → motor overload.
- Centrifugal pump: too high capacity (too low discharge pressure) → motor overload.
Other Causes
- Electrical or mechanical defect in submerged motor.
- Improperly adjusted packing gland (too tight).
- Incorrect lubrication of driver.
- Solution: Check pump alignment, verify fluid properties, inspect bearings and seals, and ensure proper lubrication.
🔹 Insufficient Pressure
Insufficient pressure is often linked to cavitation, caused by inadequate system inlet pressure. Cavitation damages pump components and is usually accompanied by noise, vibration, and discharge pulsation.
Causes of Insufficient Pressure
- Impeller installed backwards.
- Impeller speed too low.
- Worn wearing rings or mechanical defects.
- Impeller diameter too small.
- Air or gas entrained in liquid.
- Excessive lift on rotor element.
- Fluid supply exhausted or overheated (vaporization in inlet line).
- Wrong direction of rotation.
- Loss of prime due to suction line air leaks.
- Inlet restrictions: clogged strainers, debris, or rags.
- Fluid cooler than design → viscosity too high.
- Solution: Inspect impeller installation, check suction line for leaks or blockages, monitor fluid temperature, and ensure correct rotation.
🔹 Insufficient Discharge
Low discharge pressure is caused by loss of flow. Pump discharge pressure depends on the system’s resistance to flow. If the pump is not delivering rated flow, or if flow is bypassing, discharge pressure drops.
Causes of Insufficient Discharge
- Cavitation restricting flow into the pump.
- Pump worn or damaged, reducing rated flow.
- Flow bypassing instead of entering the system.
- System resistance lower than anticipated.
- Solution: Check for cavitation, inspect pump internals for wear, and verify system resistance.
🔹 Key Takeaways
- Excessive power consumption → caused by mechanical defects, misalignment, or fluid properties.
- Insufficient pressure → often due to cavitation, impeller issues, or suction restrictions.
- Insufficient discharge → linked to flow loss, pump wear, or bypassing.
- Regular inspection, alignment, lubrication, and monitoring fluid properties are essential for pump reliability.
