1、 Startup and operation failures

• Unable to start
  • reason
    • power issue: Power not connected, voltage too low or too high, fuse blown, etc. For example, if the power supply line breaks, causing the pump to be unable to obtain electricity; The voltage is unstable and exceeds the normal operating voltage range of the pump, causing the motor to fail to start normally.
    • Motor failureMotor winding short circuit, open circuit, bearing damage and jamming, etc. A short circuit in the motor winding can increase the current and burn out the motor; Bearing damage can cause the motor rotor to malfunction.
    • Impeller stuckThere are foreign objects stuck in the impeller inside the pump, such as large solid blocks, long fibers, etc. These foreign objects will hinder the rotation of the impeller and prevent the pump from starting.
  • solution
    • Check the power circuit to ensure that the power is connected and the voltage is stable; Replace the blown fuse.
    • Inspect and repair the motor, such as repairing windings, replacing bearings, etc.
    • Clean up foreign objects inside the pump to ensure that the impeller can rotate freely.
• Sudden shutdown during operation
  • reason
    • overload protectionThe load on the pump exceeds the rated power of the motor, causing the overload protection device to operate. For example, if the viscosity or flow rate of the conveyed medium is too high, it will increase the load on the pump.
    • overheat protectionLong term operation or poor heat dissipation of the motor can cause excessive temperature, triggering overheating protection. Damage to the cooling fan of the pump, blockage of the cooling channel, etc. can all cause the motor to overheat.
    • Electrical malfunctionControl circuit malfunction, such as contactor contact adhesion, thermal relay misoperation, etc.
  • solution
    • Check the load condition of the pump and adjust the viscosity or flow rate of the conveying medium; Check if the setting of the overload protection device is reasonable.
    • Clean the cooling channel of the motor, repair or replace the cooling fan; Ensure that the motor operates at the appropriate ambient temperature.
    • Check the control circuit, repair or replace damaged electrical components.

2、 Flow and head faults

• Insufficient traffic
  • reason
    • Impeller wearAfter long-term use, the blades of the impeller will be worn by the medium, resulting in a decrease in the impeller's drainage capacity. For example, when transporting wastewater containing a large amount of sand and gravel, the impeller will wear out quickly.
    • Import blockageThe inlet filter of the inlet pipeline or pump is blocked by debris, reducing the amount of medium entering.
    • Speed reductionA decrease in motor speed, such as a decrease in power frequency or motor belt slippage, can cause a decrease in pump flow.
  • solution
    • Replace the worn impeller.
    • Clean the debris on the inlet pipeline and filter screen.
    • Check the power frequency and motor transmission device to ensure that the motor speed is normal.
• Insufficient head
  • reason
    • Damaged impellerThe deformation and fracture of the impeller blades can affect the head of the pump.
    • Sealing leakageThe seal of the pump is damaged, causing medium leakage and reducing the effective head of the pump. For example, mechanical seal wear, loose packing seal, etc.
    • Insufficient rotational speedSimilar to the reason for insufficient flow, a decrease in speed will cause a decrease in pump head.
  • solution
    • Repair or replace damaged impellers.
    • Replace damaged seals and adjust the tightness of the packing seal.
    • Ensure that the motor speed meets the requirements.

3、 Vibration and noise faults

• Excessive vibration
  • reason
    • Unstable installationThe installation foundation of the pump is not firm, or the anchor bolts are loose, which can cause the pump to vibrate during operation.
    • Rotor unbalanceThe uneven distribution of mass in rotor components such as impellers and shafts results in unbalanced forces on the rotor during rotation, causing vibration.
    • Bearing damageBearing wear, excessive clearance, or poor lubrication can exacerbate pump vibration.
  • solution
    • Reinforce the installation foundation and tighten the anchor bolts.
    • Perform dynamic balancing test on the rotor and adjust the mass distribution of the rotor.
    • Replace damaged bearings and ensure good lubrication of the bearings.
• noise anomaly
  • reason
    • mechanical frictionAbnormal friction between internal components of the pump, such as impeller and pump casing friction, bearing wear, etc., can generate noise.
    • Cavitation phenomenonWhen the inlet pressure of the pump is lower than the saturated vapor pressure of the medium, the medium will vaporize and produce bubbles. When the bubbles burst in the high-pressure zone, they will produce impact and noise.
  • solution
    • Check the internal components of the pump, adjust the clearance, and eliminate abnormal friction.
    • Increase the inlet pressure of the pump to avoid the occurrence of cavitation.

4、 Leakage fault

• Mechanical seal leakage
  • reason
    • Wear of sealing surfaceAfter long-term operation, the sealing surfaces of the dynamic and static rings of the mechanical seal will wear out, leading to leakage.
    • O-ring agingO-ring will age, deform, and lose its sealing function under the action of the medium.
    • Improper installationDuring the installation of mechanical seals, poor coaxiality between the dynamic and static rings, or inappropriate compression, can cause leakage.
  • solution
    • Replace the worn sealing surface.
    • Replace the aging O-ring.
    • Reinstall the mechanical seal to ensure installation quality.
• Leakage of packing seal
  • reason
    • Aging of fillersUnder the influence of medium and temperature, fillers will age, harden, lose elasticity, and lead to leakage.
    • The packing gland is too looseThe packing gland does not tightly press the packing, causing the medium to leak from the packing.
  • solution
    • Replace the aging packing.
    • Adjust the tightness of the packing gland to ensure that the packing has appropriate clamping force.