Possible causes

Aspiration failure

1.The pump has not been filled before operation;2.The suction pipe of the pump is not full of fluid;3.The net suction head is not enough;4.There is too much air or gas in the fluid

5.There is no flowing air cavity in the suction pipe;6.The air leaks into the suction pipe;7.The air enters the pump through the stuffing box or mechanical seal;8.There is air in the source of the sealing fluid

9.The water seal pipe is blocked;10.The packing ring in the stuffing box is not installed properly;11.The suction pipe is not completely immersed in the liquid;12.There is eddy current at the suction inlet

13.When the pump is running,the suction valve is closed or partially closed;14.The suction filter is blocked;15.The suction pipe is blocked;16.The friction resistance of the suction pipe is too large

17.Impeller clogging


Other hydraulic problems

18.Wrong rotation direction;20.The instrument is not calibrated;21.The impeller diameter is smaller than the specified;22.The impeller diameter is larger than the specified value;

23.When the pump is running,the discharge valve is closed,and the bypass is not opened;24.Run the pump under the minimum flow;25.The friction loss of the system is greater than the calculated value

26.The maximum pressure head of the system is greater than the design head of the pump;27.The maximum pressure head of the system is less than the design head of the pump;28.The pump is operated in an excessive flow state(for a specific low-speed pump)

29.Operate the pump at too low flow rate(for specific high-speed pump);30.The specific gravity of the fluid does not conform to the design conditions;31.The viscosity of the fluid does not conform to the design conditions

32.The internal operating clearance is too large due to wear;33.The leakage pipeline of the balancing device is blocked;


Mechanical fault generality

34.Poor alignment;35.Insufficient rigidity of foundation;36.Missing foundation bolts;37.