Centrifugal pump with its simple structure, easy maintenance, high efficiency and become the most widely used in agriculture, a pump, but also because sometimes mention the water and make you feel annoyed. Now on the water to mention the reasons for the failure to be analyzed. There is air in the water inlet pipe and pump body: some users do not fill enough water before starting the pump, and sometimes it appears that the filled water has overflowed from the bleed hole, but the air is completely discharged without rotating the pump shaft, causing a little air to remain in the inlet pipe Or pump body; the horizontal section of the inlet pipe in contact with the pump applies a descending slope of 0.5% or more to the direction of the flow of water, and the end connected to the pump inlet is the highest, not completely horizontal. If upward tilt, there will be air intake pipe, reducing the vacuum hose and pump, affecting water absorption; pump filler due to long-term use has been worn or packing pressure is too loose, resulting in a lot of water from the packing and pump shaft As a result of the external air from these gaps into the interior of the pump, affecting the water; the water pipe due to long-term potential underwater, wall corrosion holes, the water pump work continues to decline, when these After the hole is exposed, the air enters the inlet pipe from the hole; there is a crack in the inlet pipe bend, and a slight gap at the connection between the inlet pipe and the pump may cause the air to enter the inlet pipe. Pump speed is too low: artificial factors. A considerable part of the user due to damage to the original motor, coupled with another motor driven, the result of a small flow, low lift or even the consequences of the water; belt wear. There are many large-scale centrifugal pump transmission, due to long-term use, transmission belt wear and relaxation, a slip phenomenon, thereby reducing the pump speed; improper installation. Two pulley center distance is too small or two axes are not parallel, the drive belt mounted to the top, resulting in the package angle is too small, the two pulley diameter calculation error and the coupling shaft pump two eccentric eccentricity will result in larger Pump speed changes; pump itself mechanical failure. Impeller and pump shaft loose nut or shaft deformation bending, causing the impeller to move more, directly with the pump body friction, or bearing damage, are likely to reduce the pump speed; power engine failure. Motor due to the winding burned, and lost magnetism, the maintenance of the winding turns, diameter, wiring changes, or maintenance failure is not completely ruled out the factors that will change the pump speed. Suction too much: some deep water, some water outside the flat terrain, while ignoring the allowable suction pump, which resulted in less water or not absorb the results of the water. To know the pump suction port can establish a degree of vacuum is limited, the absolute vacuum suction is about 10 meters high water column, 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 3-8.5 meters. Do not install the pump only easy and simple. Water flow resistance of the inlet and outlet pipe 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 a small amount of water 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 elbow bend than the 120-degree bend resistance, each 90-degree elbow head loss of about 0.5-1 meters, 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 tube diameter, which also has a certain impact on the lift. Effect of other factors: Bottom 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. Bottom valve filter is clogged; or Bottom valve potential water in the sludge layer caused by filter plugging; Impeller wear serious. Impeller blades wear and tear after long-term use, affecting the pump performance; gate valve can check valve failure or blockage will result in reduced flow or even pumping out of water; outlet pipe leakage will also affect the amount of water.