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Pump Troubleshooting Guide: Common Issues, Causes, and Solutions
LG Series Vertical Multistage Pump – High-Rise Water Supply Type
This technical guide provides a structured overview of common pump failures, their potential causes, and recommended corrective actions. By identifying issues early and applying the proper solutions, operators can ensure stable pump performance and reduce downtime.
1. Pump Fails to Deliver Water
Possible Causes:
- Inlet valve not opened, or suction/discharge pipelines blocked
- Impeller passage clogged
- Incorrect motor rotation direction or motor running at low speed due to phase loss
- Air leakage in the suction pipeline
- Pump not fully primed; air trapped inside the pump chamber
- Insufficient inlet water supply, excessive suction lift, or leaking foot valve
- Excessive pipeline resistance or improper pump selection
Recommended Solutions:
- Inspect and clear any blockages in pipelines or impeller passages
- Correct motor rotation direction and secure motor wiring
- Tighten sealing surfaces to eliminate air leakage
- Open the pump cover or air release valve to remove trapped air
- Shut down the pump to check suction conditions and adjust accordingly
- Reduce pipeline bends or redesign piping; select a suitable pump model
2. Insufficient Pump Flow
Possible Causes:
- Any causes listed in Issue 1 may also lead to insufficient flow
- Pipeline, pump passage, or impeller partially blocked; scale buildup
- Low supply voltage
- Impeller wear
Recommended Solutions:
- Follow the troubleshooting steps from Issue 1
- Remove obstructions and readjust valve openings
- Stabilize supply voltage
- Replace worn impeller
3. Excessive Power Consumption
Possible Causes:
- Operating beyond rated flow
- Excessive suction lift
- Worn pump bearings
Recommended Solutions:
- Adjust pump flow and partially close discharge valve
- Reduce suction lift
- Replace worn bearings
4. Abnormal Noise or Vibration
Possible Causes:
- Poor pipeline support
- Gas mixed in liquid
- Cavitation occurring
- Bearing damage
- Motor overloaded
Recommended Solutions:
- Reinforce pipeline supports
- Increase suction pressure and remove trapped air
- Reduce vacuum level to eliminate cavitation
- Replace damaged bearings
- Adjust system load to prevent motor overload
5. Motor Overheating
Possible Causes:
- Excessive flow leading to overload
- Localized friction within pump or motor components
- Motor bearing failure
- Insufficient supply voltage
Recommended Solutions:
- Reduce flow by partially closing discharge valve
- Inspect and remove friction points
- Replace damaged motor bearings
- Stabilize system voltage
6. Pump Leakage
Possible Causes:
- Mechanical seal worn or damaged
- Pump casing defects such as sand holes or cracks
- Unflat or damaged sealing surfaces
- Loose installation bolts
Recommended Solutions:
- Replace the mechanical seal
- Repair or replace the pump casing
- Rework sealing surfaces for proper flatness
- Tighten installation bolts
Conclusion
By understanding the typical failure modes of pumps and applying the correct corrective actions, operators can significantly improve system reliability and reduce maintenance costs. For unresolved or complex issues, consultation with professional technicians or the pump manufacturer is recommended.