| Possible causes | Recommended action |
| The pump is not primed. | Fill the pump and suction pipes with water before starting the pump. |
| Air intrusion. | Inspect and repair the suction piping and stuffing box. |
| Air is retained in the suction pipe. | Re-construct piping |
| Suction head is high. | Review the plan |
Rotating, but water does not come out. Discharge quantity is not enogh to specified capacity.
Over load (Overcurrent) occurs.