Suction too much Some deep water, some water outside the flat terrain, while ignoring the pump allowable suction, resulting in little or no water absorption of the results. To know that there is a limit to the degree of vacuum that can be established at the suction port of a pump, the suction at absolute vacuum is about 10 meters high and the pump can not establish an absolute vacuum. And the vacuum is too large, easy to pump the water gasification, the work of the pump negative. Therefore, the centrifugal pump has its maximum allowable suction, usually between 3 to 8.5 meters, not only when installing the pump is simple and convenient. Water flow into and out of the pipe resistance loss is too large Some users after the measurement, although the vertical distance from the reservoir or water tower to the water surface is slightly less than the head of the pump, but still mention the amount of water is small or mention the water. The reason is often too long pipes, pipe corners, water flow resistance in the pipeline is too large loss. The reason is often too long pipes, pipe corners, water flow resistance in the pipeline is too large loss. Under normal circumstances, 90-degree bend than the 120-degree elbow resistance, each 90-degree elbow head loss of about 0.5 to 1 meter, every 20 meters of pipe resistance can make head loss of about 1 meter. In addition, some users are also free to pump into and out of the pipe diameter, which also has a certain impact on the lift. Other factors (1) at the end of the valve can not be opened. It is usually due to the pump being left on for too long, the bottom valve gasket is stuck, and the bottom valve without gasket may rust out. (2) The bottom valve filter screen is clogged; or the bottom valve causes potential clogging of the filter screen in the sludge layer. (3) impeller wear serious. Impeller blades worn by long-term use, affecting the pump performance. (4) Gate valve or check valve failure or blockage will result in reduced flow or even pumping on the water. (5) The leakage of pipe leakage will also affect the amount of water.