Seven common solutions for water pump malfunctions

Answer to the heat generated by the water pump

Reason: Bearing damage; The clearance between rolling bearings or bracket covers is too small; The pump shaft is bent or the two shafts are not concentric; The tape is too tight; Lack of oil or poor oil quality; The balance hole on the impeller is blocked, causing the impeller to lose balance and increase the thrust to one side. Exclusion method: Replace the bearing; Remove the back cover and install a gasket between the bracket and the bearing seat; Investigate the pump shaft or adjust the concentricity of the two shafts; Adjust the tightness of the tape appropriately; Add clean butter, which accounts for about 60% of the clearance inside the bearing; Clear the blockage in the balance hole.

The answer to not being able to absorb water

The reason is that there is air inside the pump body or air accumulation in the inlet pipe, or the bottom valve is not tightly closed and the water supply is not sufficient, the vacuum pump packing is severely leaking, and the gate valve or flap valve is not tightly closed. Exclusion method: First, increase the water pressure, then fill the pump body with water, and then turn it on. At the same time, check whether the check valve is tight and whether there is any air leakage in the pipeline and joints. If any air leakage is found, apply lubricating oil or blending paint to the joint after disassembly, and tighten the screws. Check the oil seal ring of the water pump shaft, and replace it with a new one if it is severely worn. Pipeline leakage or air leakage. The nut may not be tightened during installation. If the leakage is not severe, cement can be applied to the leaking or leaking area, or cement slurry mixed with asphalt oil can be applied. Temporary repairs can be done by applying some wet mud or soft soap. If there is water leakage at the joint, a wrench can be used to tighten the nut. If the water leakage is severe, it must be disassembled and replaced with a cracked pipe; Reduce the head and press the pipe mouth of the water pump 0.5m underwater.

Answer to Insufficient Traffic

This is because: the power speed is not matched or the belt slips, resulting in a low speed; The installation angle of the axial flow pump blades is too small; Insufficient head, long pipeline or right angle bend in pipeline; High suction range; Partial blockage or damage of the bottom valve, pipeline, and impeller; The water outlet pipe is leaking severely. Exclusion method: Restore the rated speed, remove oil stains from the belt, and adjust the belt tightness; Adjust the blade angle, lower the installation position of the water pump, shorten the pipeline or change the curvature of the pipeline; Seal the leakage point of the water pump and tighten the packing; Remove blockages and replace impellers; Replace the leak reducing ring and block the leaking area.

Deep well submersible pump does not supply water or has a small water volume

First, let's take a look at how much the current of the water pump is different from the current during normal operation. If the current is lower than usual (basically 2-3 times the normal current), there may be problems such as impeller wear and blockage of the check valve at the top of the pump head. If the current is as high as usual, it may be due to issues such as pipe gasket leakage, pipe leakage, or pump body leakage. If the current is higher than usual during operation, it can be basically determined that it is a problem of wear and tear of vulnerable parts. Additionally, if the cable is damaged, the amount of water will be the same as usual, but the current will increase. The current of three 380V motors is generally 2.2A. The above reasons can be identified by maintenance personnel who frequently repair deep well pumps.

Solution for unable to start

Firstly, the power supply situation should be checked: whether the connector connection is secure; Is the switch contact tight; Is the fuse blown; Whether the three-phase power supply is equal or not. If there is a circuit break, poor contact, blown fuse, or phase loss, the cause should be identified and repaired in a timely manner. Next, check if it is a mechanical failure of the water pump itself. Common causes include: too tight packing or blockage between the impeller and the pump body due to debris; The pump shaft, bearings, and leakage reducing ring are rusted; The pump shaft is severely bent, etc. Exclusion method: Loosen the filling material and unclog the drainage channel; Disassemble the pump body to remove debris and rust; Remove the pump shaft for calibration or replace it with a new pump shaft.

Answer to severe vibration of water pump

There are several main reasons: unbalanced electric rotor; Poor coupling connection; Bearing wear and bending; Loose or broken parts of the rotating parts; Reasons such as unstable pipeline supports. Measures such as adjustment, repair, reinforcement, straightening, and replacement can be taken to handle it separately.

The above situations are common causes of water pump failures, not all of them. In practice, when dealing with faults, the principle of "external first, internal second" should be followed based on actual analysis, and blind operation should be avoided.

Answer to the cavitation phenomenon of water pump

The cavitation of a water pump is caused by the vaporization of water, which is the process of water transforming from liquid to vapor state. The vaporization of water is related to temperature and pressure. At a certain pressure, water only begins to vaporize when the temperature rises to a certain value; If the pressure drops to a certain value at a certain temperature, water will also vaporize, and this pressure is called the vaporization pressure of water at that temperature. If the pressure in a certain local area during the flow process is equal to or lower than the vaporization pressure corresponding to the water temperature, water will vaporize at that location. After vaporization occurs, many small bubbles of steam and gas mixture will be formed. When bubbles flow from the low-pressure area to the high-pressure area along with the water flow, the bubbles rupture under the action of high pressure, and high-pressure water flows towards the space occupied by these original bubbles at a very high speed, forming an impact force. The metal surface is severely damaged due to fatigue caused by water hammer pressure. Therefore, we refer to the entire process of bubble formation, development, and rupture leading to material damage as cavitation phenomenon.

Overheating of supporting power motor

There are four reasons. One reason is related to the power supply: if the voltage is too high or too low, under specific loads, if the voltage fluctuation range should be outside+10% to -5% of the rated value, it will cause the motor to overheat; Asymmetric three-phase voltage of the power supply, with a phase to phase imbalance of more than 5%, can cause winding overheating; Due to phase loss operation, experience has shown that over 85% of agricultural motors being burned out are caused by phase loss operation. Therefore, it is necessary to install phase loss protection devices for the motors. The second reason is related to the water pump: the selection of power is not matched, the small horse pulls the big car, and the electric motor runs under overload for a long time, causing the temperature of the electric motor to be too high; Motors that start too frequently and have a short-term or intermittent working system are continuously operated. The number of starts should be limited, thermal protection should be selected correctly, and it should be used according to the rated value on the motor. The third reason is due to the motor itself: incorrect connection, mistakenly connecting the △ shape to the Y shape, causing the temperature of the motor to rise rapidly; The stator winding may have phase to phase short circuits, turn to turn short circuits, or local grounding. In mild cases, the motor may overheat locally, and in severe cases, the insulation may be burned out; The squirrel cage rotor has broken bars or defects, and the temperature of the iron core rises rapidly when the motor runs for 1 to 2 hours; If the ventilation system malfunctions, check whether the fan is damaged, whether the rotation direction is correct, and whether the ventilation duct is blocked; Bearing wear and rotor eccentricity can cause metal collision sounds between the stator and rotor cores, leading to a rapid increase in core temperature. In severe cases, the motor may smoke or even burn out the coils. The fourth reason is related to the working environment: the motor winding is affected by moisture or dust, oil stains, etc. adhere to the winding, resulting in a decrease in insulation. The insulation resistance of the motor should be measured and cleaned and dried; The ambient temperature is too high. When the ambient temperature exceeds 35 ℃ and the inlet air temperature is high, it will cause the temperature of the motor to be too high. Efforts should be made to improve its working environment. Such as setting up shelters for shade. Attention: If there is a malfunction due to electrical reasons, it should be repaired by an electrician who has obtained a professional qualification certificate. People with limited knowledge should not blindly repair to prevent personal injury accidents.