Seven Common Faults of Pipeline Pumps and Booster Pumps and Efficient Solutions

Pipeline pumps and booster pumps, as indispensable core equipment in modern industrial, agricultural and civil water supply systems, are widely used in pressurization and water delivery scenarios due to their compact structure, convenient installation and maintenance, and stable and reliable performance. However, various faults are inevitable during long-term operation. Timely and accurate identification and resolution of these problems are of crucial significance for ensuring the stable operation of the system, extending the service life of the equipment and reducing operating costs. Combining the professional theories and practical experience of the Teffiko technical team, this paper deeply analyzes the seven most common faults of pipeline pumps and booster pumps, and provides detailed troubleshooting steps and efficient treatment methods, aiming to provide important reference for the majority of users.

I. No Water Discharge from Pipeline Pumps and Booster Pumps

The failure of pipeline pumps or booster pumps to discharge water normally is usually the most direct and urgent problem in the system. The causes may involve the pipeline, pump body, electrical system and other aspects.

Common Causes and Troubleshooting:

1. Blockage of Inlet and Outlet Valves and Pipelines:

• Phenomenon: No water flows out or the flow rate is extremely low after the pump is started.
• Troubleshooting: Check whether the inlet and outlet valves are fully open, and whether there is scale, debris or foreign matter blocking the inlet and outlet pipelines and impeller flow channels.
• Treatment: Remove the blockage and readjust the valve opening.

2. Motor Rotation Direction and Electrical Problems:

• Phenomenon: The motor rotates but the pump does not work, or the rotating speed is significantly low, which may be accompanied by noise.
• Troubleshooting: Check whether the motor rotation direction is correct (especially for three-phase motors, which cannot discharge water normally if reversed), whether there is phase loss operation, or whether the rotating speed is too low.
• Treatment: Adjust the motor wiring to change the rotation direction, fasten the motor wiring, and ensure the balanced three-phase power supply.

3. Poor Sealing of Suction Pipeline:

• Phenomenon: The pump cannot suck water, or there is a bubbling sound in the suction pipeline.
• Troubleshooting: Check whether there is air leakage at each sealing surface of the suction pipeline.
• Treatment: Tighten each sealing surface, exhaust air, and ensure the good sealing of the suction pipeline.

4. Air in the Pump Cavity:

• Phenomenon: The pump cannot build suction after startup, or the water discharge is intermittent.
• Troubleshooting: The pump is not completely filled with liquid before startup, resulting in air in the pump cavity.
• Treatment: Open the pump cover or exhaust valve, exhaust all air in the pump cavity, and ensure the pump is filled with liquid.

5. Insufficient Inlet Water Supply or Excessively High Suction Lift:

• Phenomenon: The pump idles for a long time, or the water discharge flow is unstable.
• Troubleshooting: Check whether the inlet water supply is sufficient, whether the suction lift exceeds the allowable range of the pump, or whether the foot valve leaks (especially prone to occur when used in grid-connected tap water pipes and with suction lift).
• Treatment: Stop the pump for inspection, adjust the water supply conditions, reduce the suction lift, and repair the foot valve leakage problem.

6. Excessively High Pipeline Resistance or Improper Model Selection:

• Phenomenon: The pump operates normally but the flow rate or head fails to meet the requirements.
• Troubleshooting: Evaluate whether the pipeline design has excessive bends, valves or too small pipe diameter, and whether the pump model is mismatched with the actual working conditions.
• Treatment: Reduce pipeline bends, optimize pipeline design, and reselect a more suitable pump for the working conditions if necessary.

II. Insufficient Outlet Pressure of Pipeline Pumps and Booster Pumps

The core function of a booster pump is to provide stable system pressure. If the outlet pressure fails to reach the expected value, the use efficiency of terminal equipment will be directly affected.

Common Causes and Troubleshooting:

1. Air in the Liquid:

• Phenomenon: Fluctuating outlet pressure, or accompanied by bubbling sound.
• Troubleshooting: Check whether air is mixed in the liquid, which will affect the normal operation of the pump.
• Treatment: Exhaust all air in the liquid and ensure the pump sucks in pure liquid.

2. Insufficient Rotating Speed or Damaged Impeller:

• Phenomenon: The pump operates but the pressure is low, or accompanied by abnormal noise.
• Troubleshooting: Check whether the pump speed reaches the rated value and whether the impeller is damaged due to wear or corrosion.
• Treatment: Check and increase the pump speed, and replace the worn or damaged impeller.

3. Excessively Large Opening of Outlet Valve:

• Phenomenon: The system pressure cannot be established effectively.
• Troubleshooting: The excessively large opening of the outlet valve leads to insufficient system resistance, and the pump cannot work at the designed head point.
• Treatment: Appropriately reduce the opening of the outlet valve to make the pump operate closer to the rated working conditions.

III. Insufficient Flow Rate of Pipeline Pumps and Booster Pumps

The pump can start and operate normally, but the actual water discharge flow rate is significantly lower than the designed value, indicating that the conveying capacity of the pump is limited.

Common Causes and Troubleshooting:

1. Flow Channel Blockage and Valve Opening:

• Phenomenon: The flow rate remains low.
• Troubleshooting: Check whether the flow channel and impeller part of the pipeline pump are blocked (such as scale deposition), and whether the valve opening is insufficient.
• Treatment: Remove the blockage, readjust the valve opening, and ensure the smoothness of the pump and pipeline.

2. Too Low Rotating Speed:

• Phenomenon: The pump operates weakly with insufficient flow rate.
• Troubleshooting: Check whether the motor speed is normal and whether there is a problem such as low power supply voltage.
• Treatment: Increase the rotating speed of the water pump shaft and ensure the motor operates at the rated speed.

3. Impeller Wear:

• Phenomenon: The flow rate gradually decreases after long-term operation.
• Troubleshooting: The gap between the impeller and the pump casing increases due to long-term wear, resulting in reduced efficiency.
• Treatment: Replace the worn impeller.

4. Excessively Large Opening of Outlet Valve:

• Phenomenon: The flow rate is lower than expected.
• Troubleshooting: The outlet valve opening affects the system flow rate.
• Treatment: Appropriately adjust the opening of the outlet valve.

5. Low Voltage:

• Phenomenon: The motor operates weakly with reduced speed.
• Troubleshooting: Check whether the power supply voltage is lower than the rated value.
• Treatment: Take voltage stabilization measures to ensure the motor obtains a stable voltage.

IV. Overheating of Booster Pump Motor

Abnormal temperature rise of the motor during operation will not only accelerate insulation aging and shorten the motor life, but also may cause safety accidents such as fire.

Common Causes and Troubleshooting:

1. Poor Environment and Heat Dissipation:

• Phenomenon: Excessively high temperature of the motor housing.
• Troubleshooting: Check whether the ambient temperature of the pump installation is too high, whether the motor heat dissipation fan is damaged, and whether the heat sink is blocked by dust.
• Treatment: Improve environmental ventilation, clean the motor heat sink, and ensure the normal operation of the fan.

2. Excessive Motor Load:

• Phenomenon: The motor current exceeds the rated value.
• Troubleshooting: The pump operates for a long time under working conditions exceeding the rated flow rate or head, resulting in motor overload.
• Treatment: Check the mechanical parts, adjust and handle them in a timely manner, adjust the outlet valve to make the pump work near the rated flow rate and head, and avoid overloading operation.

3. Abnormal Voltage or Phase Loss:

• Phenomenon: Severe motor overheating, which may be accompanied by abnormal noise.
• Troubleshooting: Check whether the power supply voltage is too high, too low or there is phase loss (for three-phase motors).
• Treatment: Ensure the stability of the power supply voltage and check the balance of the three-phase power supply.

4. Water Ingress into the Motor:

• Phenomenon: Humidity inside the motor with reduced insulation performance.
• Troubleshooting: Check whether the motor is flooded due to poor sealing or humid environment.
• Treatment: Dry the motor thoroughly and repair the cause of water ingress.

V. Water Leakage of Pipeline Pumps and Booster Pumps

Water leakage at the pump body or joints not only causes the loss of valuable medium, but also may corrode equipment, pollute the environment and even cause electrical short circuits.

Common Causes and Troubleshooting:

1. Wear or Damage of Mechanical Seal:

• Phenomenon: Liquid seeps out at the joint between the pump shaft and the pump body.
• Troubleshooting: The mechanical seal is the most common water leakage point of centrifugal pumps, and long-term operation wear or impact may lead to failure.
• Treatment: Replace the worn or damaged mechanical seal.

2. Sand Holes or Cracks in the Pump Body:

• Phenomenon: Liquid seeps out on the surface of the pump body.
• Troubleshooting: The pump body casting may have defects (sand holes) or cracks due to external impact or corrosion.
• Treatment: Weld and repair sand holes or small cracks, and replace the pump body in case of severe cracks.

3. Uneven Sealing Surfaces:

• Phenomenon: Leakage at flanges or joints.
• Troubleshooting: The sealing surfaces at the joints such as the pump cover and flange may be uneven due to improper installation or deformation.
• Treatment: Trim the sealing surfaces to ensure their flatness.

4. Loose Mounting Bolts:

• Phenomenon: Leakage at the joints.
• Troubleshooting: The fastening bolts at each connection part of the pump body may be loose due to vibration or long-term operation.
• Treatment: Check and evenly fasten all loose mounting bolts.

VI. Vibration or Abnormal Noise of Pipeline Pumps and Booster Pumps

Abnormal noise or severe vibration of the pump during operation is often a precursor to internal structural or installation problems of the equipment, which must be highly valued.

Common Causes and Troubleshooting:

1. Unfirm Unit Installation:

• Phenomenon: The whole pump shakes, and the vibration is transmitted to the foundation.
• Troubleshooting: Check whether the pump installation foundation is firm and whether the supporting part at the pump flange is stable.
• Treatment: Reinforce the supporting part at the pump flange to ensure the stable installation of the unit.

2. Air Leakage of Suction Pipe or Insufficient Submersion Depth:

• Phenomenon: Cavitation sound and vibration in the pump.
• Troubleshooting: Air leakage of the suction pipeline or insufficient submersion depth of the suction pipe orifice leads to air suction by the pump and cavitation.
• Treatment: Block the air leakage point or lengthen the submersion depth of the suction pipe to ensure the pump sucks in pure liquid.

3. Cavitation of Impeller:

• Phenomenon: A noise similar to "popping beans" in the pump, accompanied by vibration, and the decrease of flow rate and head.
• Troubleshooting: The pressure on the suction side of the pump is too low, and the liquid vaporizes in the pump to form bubbles, which then rupture to produce shock waves and damage the impeller.
• Treatment: Lower the pump installation height, increase the suction pipe diameter, or increase the inlet pressure to improve the net positive suction head (NPSH), and replace the damaged impeller.

4. Deviation from Operating Conditions:

• Phenomenon: The efficiency of the pump decreases and vibration may occur when the pump operates at non-design points.
• Troubleshooting: The pump operates at a large flow point for a long time or deviates from the high-efficiency zone.
• Treatment: As far as possible, adjust the valve and other methods to make the pump operate in the high-efficiency zone (rated point) and avoid operating at a large flow point.

VII. Excessively High Power of Pipeline Pumps and Booster Pumps

Abnormally increased power consumption of the pump during operation not only means a waste of energy, but also may indicate internal problems of the equipment and accelerate component wear.

Common Causes and Troubleshooting:

1. Use Beyond the Rated Flow Rate:

• Phenomenon: Excessively large motor current and heavy pump operation load.
• Troubleshooting: The pump operates under working conditions far exceeding the designed flow rate, leading to increased hydraulic loss and heavy motor load.
• Treatment: Adjust the flow rate, properly close the outlet valve, and make the pump work near the rated flow rate.

2. Excessively High Suction Lift:

• Phenomenon: Insufficient pump suction and increased motor load.
• Troubleshooting: The excessively high installation height of the pump leads to an excessively large suction lift, and the pump needs to consume more energy to overcome the suction resistance.
• Treatment: Lower the pump installation surface and reduce the suction lift.

3. Bearing Wear:

• Phenomenon: Overheating at the motor or pump body bearing, accompanied by friction sound.
• Troubleshooting: The bearing is worn due to long-term operation, poor lubrication or improper installation, resulting in increased friction and motor load.
• Treatment: Replace the worn bearing.

Conclusion

The stable operation of pipeline pumps and booster pumps is the foundation for the efficient operation of various systems. Through in-depth understanding and systematic troubleshooting of the above seven common faults, combined with the specific treatment methods provided in this paper, users can significantly improve their fault diagnosis and resolution capabilities. Regular preventive maintenance, strict installation specifications, reasonable model selection and matching, and timely response to abnormal conditions are the keys to ensuring the long-term, stable and efficient operation of Teffiko pump equipment. It is hoped that this guide integrating professional knowledge and practical experience can provide a comprehensive and valuable reference for your pump equipment maintenance work.

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