What to Do When a Centrifugal Pump Makes Abnormal Noise During Operation

Centrifugal pumps are widely used in industrial and water systems. If a pump produces abnormal noise during operation, it usually indicates a problem in the pump or the system. Ignoring these sounds can lead to reduced efficiency or even pump failure. Here’s a detailed guide to identify and resolve the issue.

1. Cavitation or Insufficient Suction

Symptoms: Humming, buzzing, or metallic knocking sounds
Causes: Air in the suction line, low liquid level, partially closed valves, or insufficient suction pressure
Solutions:

• Inspect the suction line for air leaks and ensure it is properly sealed

• Check the liquid level and maintain adequate fluid at the pump inlet

• Adjust suction valves to achieve the designed flow rate

2. Worn or Poorly Lubricated Bearings

Symptoms: Humming, friction noises, or clicking sounds
Causes: Bearing wear, insufficient lubrication, or poor-quality lubricating oil
Solutions:

• Check bearing temperature; overheating indicates wear

• Add or replace lubricating oil

• Replace bearings if damaged

3. Impeller Damage or Contact with Pump Casing

Symptoms: Unusual noise and excessive vibration
Causes: Worn or broken impeller blades, or too small clearance between impeller and casing
Solutions:

• Stop the pump and inspect the impeller; repair or replace if necessary

• Check axial and radial clearances and adjust pump shaft position

4. Foreign Object Blockage

Symptoms: Knocking sound or vibration
Causes: Solids or debris inside the pump or piping
Solutions:

• Stop the pump and clean the impeller, strainer, and pump casing

• Install filters or strainers to prevent foreign objects from entering

5. Resonance or Pipeline Vibration

Symptoms: Noise changes with pump speed
Causes: Insufficient pipeline support or loose pump installation
Solutions:

• Check pump foundation and ensure it is securely fixed

• Add pipeline supports or vibration dampeners

✅ Recommended Procedure for Troubleshooting:

1. Stop the pump immediately to prevent further damage

2. Check and rule out the above common causes one by one

3. Record the abnormal noise characteristics for technical analysis