| No. | Forms of failure | Possible reasons | Solutions |
| 1 | Bearing is running hot | 1. Inconsistent unit centers; | 1.Check and adjust the alignment between pump and prime mover; |
| 2.Too much or too little lubricating oil; or impure lubricating oil; | 2.Adjust or replace the lubricant; | ||
| 3.The bearing is worn; or water enters the bearing bush; | 3.Replace bearings or lubricants; | ||
| 4.Vibration of the machine set. | 4.Check the rotor balance or run at a small flow point. | ||
| 2 | Insufficient flow or head | 1.The impeller is damaged; | 1.Replace the impeller; |
| 2.Air leakage into the suction pipe; | 2.Plug the leakage; | ||
| 3.There is a blockage in the pipeline; | 3.Clear the blockage; | ||
| 4.The rotating speed is reduced; | 4.Increase the speed as required; | ||
| 5.The submerged depth of the inlet pipe is not enough; | 5.Increase the submergence depth of the inlet water pipe; | ||
| 6.The inlet and outlet valves are not fully opened; | 6.Fully open the valve; | ||
| 7.The head is not consistent with the pump head. | 7.Choose a larger impeller. | ||
| 3 | Vibration and noise | 1.The rotating or fixed parts are worn; | 1.Repair the worn parts; |
| 2.There are sundries in the pipeline or pump; | 2.Check and remove sundries; | ||
| 3.Poor alignment of shaft and motor center; | 3.Adjust and align the center; | ||
| 4.Loose anchor bolts; | 4.Tighten anchor bolts; | ||
| 5.Bearing is worn; | 5.Replace the bearing; | ||
| 6.The shaft is bent; | 6.Replace the shaft; | ||
| 7.Pump cavitation; | 7.Reduce the installation height or thicken the inlet pipeline; | ||
| 8.The rotating part is out of balance; | 8.Check the reason and try to eliminate it; | ||
| 9.The inlet valve is not open enough; | 9.Open the inlet valve and adjust the outlet valve. | ||
| 4 | Serious leakage | 1.The friction pair is severely worn; | 1.Replace with a new mechanical seal; |
| 2.The dynamic ring or static ring is broken; | 2.Replace with a new mechanical seal; | ||
| 3.Uneven seal compression; | 3.Re-adjust the sealing combination; | ||
| 4.The O-ring is damaged. | 4.Replace the O-ring. | ||
| 5 | The pump cannot pump out the liquid | 1.There is air in the suction line or the pump; | 1.Fill with liquid and expel air; |
| 2.The inlet or outlet valve is closed or the pipeline is blocked; | 2.Open the valve and clear the blockage; | ||
| 3.The actual head is higher than the maximum head of the pump; | 3.Replace the pump with high head; | ||
| 4.Air leakage from the pump suction pipe; | 4.Prevent leakage on the inlet side; | ||
| 5.The water suction height is too large; | 5.Reduce the pump installation height, and increase the inlet pressure; | ||
| 6.The suction pipe is too small or blocked by debris; | 6.Increase the suction pipe diameter and eliminate blockage; | ||
| 7.Impeller steering error. | 7.Correct the direction of motor | ||
| 6 | The pump does not rotate. | 1.The impeller reverses and loosens, resting on the front guard plate; | 1.Check the steering and adjust the clearance; |
| 2.Impeller and pump body are blocked by solid materials. | 2.Remove silted materials. | ||
| 7 | Motor overload | 1.The pump and motor are out of alignment; | 1.Make sure the alignment of pump and motor; |
| 2.The relative density of medium is too large; | 2.Change the operation process; | ||
| 3.Friction occurs in the relative motion part; | 3.Repair the friction part and adjust the gap; | ||
| 4.The resistance of the device becomes lower, and the operating point is biased towards the place of large flow. | 4.Check and adjust the pressure of suction line and discharge line. |
