1. Main reasons

(1) The inlet valve of the pump is not open or the opening degree is insufficient

(2) The gate of the pump inlet valve has fallen off

(3) The pre pump filter is blocked by debris

(4) The inlet pipeline of the pump is blocked by debris or silt

(5) During the trial operation of the new production, the flange gasket of the pump inlet valve was not perforated

2. Handling method

(1) Firstly, fully open the inlet valve of the pump. If it still cannot be eliminated, the pump should be stopped and the inlet and outlet valves as well as the outlet valve of the water storage tank should be closed. The pump outlet vent valve should be opened for pressure relief and venting, and the pre pump filter drain valve should be opened to drain the water stored in the pump and inlet pipe section

(2) Inspect and repair the inlet valve of the pump

(3) Remove blockages and debris from the pre pump filter, and clean the filter screen

(4) Check, dredge, and flush the inlet pipeline for sediment and debris

(5) Dismantle and inspect the flange gasket of the imported valve, and re drill or replace the gasket