Common Faults & Solutions

Item

Failure

Possible Causes

Troubleshooting

1   Higher vibration noise   1. Air leakage or blocking occurs at the suction line or suction end.
   2. The suction height exceeds the self-priming capability of the pump.
   3. Bearing failure.
   4. The pump is not aligned with the motor.
   5. The mounting height is very high, resulting into cavitation of products in the pump.
   1. Eliminate air leakage or blocking.
   2. Reduce the suction height or pipe resistance.
   3. Replacement of bearing.
   4. Correct the concentricity.
   5. Lower mounting height or reduce speed.
2   Large pressure fluctuation   1. Air leakage or blocking occurs at the suction line or suction end.
   2. The suction height exceeds the self-priming capability of the pump.
   3. The pressure relief valve is not well adjusted or the operating pressure is too high, resulting into the repeated open and close of the valve.
   1. Eliminate air leakage or blocking.
   2. Reduce the suction height or pipe resistance.
   3. Adjust the pressure relief vale or reduce the operating pressure.
3   The flow rate of pump drops down   1. Large mechanical wear.
   2. Air leakage or blocking occurs at the suction line or suction end.
   3. The suction height exceeds the suction lift of the pump.
   4. The pressure relief valve is in leakage
    
   1. Replace the consumables.
   2. Eliminate air leakage or blocking.
   3. Reduce the suction height or pipe resistance.
   4. Grinding the sealing surface for the valve.
4   No oil supplied to pum   1. The inlet valve is not opened.
   2. Air leakage or blocking occurs at the suction line or suction end.
   3. The suction height exceeds the suction lift of the pump.
   4. The screw liner wears.
   5. The motor is in wrong direction of rotation.
   6. The medium is of large viscosity.
   7. No medium in the pump for lubrication and seal.
    
   1. Open the valve.
   2. Eliminate air leakage or blocking.
   3. Reduce the suction height or pipe resistance.
   4. Replace the worn part.
   5. Adjust the direction of rotation for the motor.
   6. Heat up the medium.
   7. Fill in the medium.
5   Power increased   1. The transmission medium is in large viscosity.
   2. Serious wear in the pump.
   3. The pump is not centered with the motor.
   4. The outlet pipe is blocked.
   1. Reduce the viscosity by increasing temperature.
   2. Repair or replace the worn part.
   3. Correct the concentricity.
   4. Eliminate the blocking.
6   Pump gives out heat   1. The transmission medium is of large viscosity.
   2. Severe wear in the pump.
   3. The pump is not centered with the motor.
   4. The outlet pipe is blocked.
   5. The cooler is in failure and the oil temperature is much high.
   1. Reduce the viscosity by increasing temperature or reduce the speed.
   2. Repair or replace the worn part.
   3. Correct the concentricity.
   4. Eliminate the blocking.
   5. Reduce the oil temperature suitably.
7   Mechanical seal gives out heat   1. The returning port of mechanical seal is blocked.
   2. The medium is of large viscosity.
   1. Clean the returning port.
   2. Reduce the viscosity by increasing temperature.
    
8   Oil leakage   1. The returning port of mechanical seal is blocked.
   2. The seal gland is not flat.
   3. The seal surface of rotating
   1. Clean the returning port.
   2. Adjust the seal gland.
   3. Grind the seal surface or replace it with a new one.