Five reasons why the pump does not produce water after starting?
1. There is air in the water inlet pipe and pump body
(1) The water pump is not filled with enough water before starting. Sometimes it seems that the filled water has overflowed from the vent hole, but the pump shaft is not rotated and the air is completely discharged, resulting in a little air remaining in the water inlet pipe or pump body.
(2) The horizontal section of the water inlet pipe in contact with the water pump should apply a descending slope of more than 0.5% against the direction of water flow, and the end connected to the water pump inlet should be high, not completely horizontal. If it is tilted upward, air will remain in the water inlet pipe, which will reduce the vacuum in the water pipe and water pump and affect water absorption.
(3) The packing of the water pump has been worn out due to long-term use or the packing is too loose, causing a large amount of water to spray out from the gap between the packing and the pump shaft sleeve. As a result, the external air enters the interior of the pump from these gaps. Affecting water extraction.
(4) The water inlet pipe has been lurking underwater for a long time, and the pipe wall is eroded to form holes. After the water pump works, the water level continues to drop. When these holes are exposed to the water surface, air enters the DPP from the holes.
(5) Cracks appear in the elbow of the water inlet pipe, and there are tiny gaps in the connection between the water inlet pipe and the water pump, which may allow air to enter the water inlet pipe.
2. The water pump speed is too low
(1) Human factors. Some users randomly installed another motor to drive it because the original motor was damaged. As a result, the flow rate was small, the head was low or even no water was supplied.
(2) Mechanical failure of the water pump itself. The fastening nut between the impeller and the pump shaft is loose or the pump shaft is deformed and bent, causing the impeller to move more, directly rubbing against the pump body, or the bearing is damaged, which may reduce the speed of the pump.
(3) The power machine is not properly maintained. The electric motor loses its magnetism due to the burning of the windings. The number of winding turns, wire diameter, and wiring method changes during maintenance, or the failure to completely eliminate the faults during maintenance will also change the speed of the pump.
3. The suction range is too large
Some water sources are deep, and the outer terrain of some water sources is relatively flat, and the allowable suction range of the water pump is ignored, resulting in less water absorption or no water absorption at all (public account: pump pipe). You must know that the degree of vacuum that can be established at the suction port of the water pump is limited. The suction distance to the vacuum is about 10 meters of water column height, and it is impossible for the water pump to establish the right vacuum. Moreover, if the vacuum is too large, it is easy to vaporize the water in the pump, which is detrimental to the work of the water pump. Therefore, each centrifugal pump has its maximum allowable suction, generally between 3-8.5 meters. When installing a water pump, don't just think about convenience and simplicity.
4. The resistance loss in the water flow in and out of the water pipe is too large
Some users have measured that although the vertical distance from the reservoir or water tower to the water surface is slightly less than the water pump lift, the water lift capacity is still small or no water can be lifted. The reason is often that the pipeline is too long, there are many bends in the water pipe, and the resistance loss of the water flow in the pipeline is too large. The reason is often that the pipeline is too long, there are many bends in the water pipe, and the resistance loss of the water flow in the pipeline is too large. In general, the resistance of 90-degree elbow is greater than that of 120-degree elbow, and the head loss of every 90-degree elbow is about 0.5-1 meter, and the resistance of every 20 meters of pipe can cause about 1 meter of head loss. In addition, some users also arbitrarily use the diameter of the inlet and outlet pipes of the water pump, which also has a certain impact on the lift.
5. Influence of other factors
(1) The bottom valve cannot be opened. It is usually because the water pump has been left for too long, the bottom valve gasket is stuck to death, and the bottom valve without gasket may be rusted to death.
(2) The filter net of the bottom valve is blocked; or the bottom valve is hidden in the sludge layer in the water, causing the filter screen to be blocked.
(3) The impeller is severely worn. The impeller blades are worn out after long-term use, which affects the function of the water pump.
(4) If the gate valve or check valve is faulty or blocked, the flow rate will be reduced or even the water will not be pumped.
(5) Leakage of the outlet pipeline will also affect the amount of water lifted.
