| Possible causes | Recommended action |
| Excessive rotation speed. Wrong Pole number of electric motor. | Check nameplate and replace the motor. |
| Higher voltage | Check the power supply |
| 50Hz pump is running in 60Hz area | Check nameplate and replace the motor. |
| Pump head is low. Excessive discharge quantity. | Close discharge valve to the specified water level. |
| Bearing is damaged. | Replace the bearing. |
| Roatating part contacted.Or shaft is bent. | Repair at a specialized factory |
| Excessive specific gravity and viscosity of the liquid. | Review the plan |
Rotating, but water does not come out. Discharge quantity is not enogh to specified capacity.
Excessive water leakage from stuffing box
Electric motor does not work well with noise.
Water comes out at first, but it doesn't come out soon.