What Should Be Done For The Maintenance And Upkeep Of Deep Well Submersible Pumps
Nov 04, 2025
Submersible pump is a widely used water treatment tool. Unlike ordinary water pumps, submersible pumps are directly connected to motors and pumps to work underwater. Submersible pumps can be divided into well submersible pumps, working face submersible pumps, submersible sewage pumps, sand discharge submersible pumps, mining vertical pumps, etc. This article combines our school's years of maintenance experience to discuss the common fault phenomena and analysis of deep well submersible pumps during use.
1 Working principle and performance characteristics of submersible pump
A submersible pump is a universal water lifting machinery that operates by directly connecting an electric motor and a water pump. Its working principle is that the electric motor drives the impeller to rotate at high speed through the pump shaft, and works on the liquid under the action of centrifugal force, converting mechanical energy into liquid energy. The liquid (water) flies away from the impeller and is ejected outward. The ejected liquid gradually slows down in speed and increases in pressure inside the diffusion chamber of the pump casing, and then flows out from the discharge pipe at the pump outlet. The design principle of submersible pumps is "no entanglement, no blockage".
Some models are also equipped with tearing mechanisms or cutting devices, which can tear and discharge long fibers, strips, and other materials in the water. The inherent weakness of submersible pumps is that the medium they pump is mostly soft, limiting the sand content in the water to within 3%. When the sand content is high, it is easy to damage the seal. Once the motor enters the water, the bearings and winding insulation are damaged, leading to motor burnout.
2 Installation and use of deep well submersible pumps
Submersible pumps generally have certain requirements for the deviation range of power supply voltage and frequency. For high-power submersible pumps, step-down starting or soft starting must be used to reduce the impact on the power grid or other electrical equipment, as well as the submersible pump itself. The installation and use of submersible pumps should be selected correctly according to the usage environment and pay attention to relevant matters.
2.1 Selection and Operating Environment of Submersible Pumps
The selection of submersible pumps should be based on the characteristics of the working conditions, and the selection should mainly consider flow rate, head, installation method, etc. Only when the selected head is close to the actual required head, can the water pump operate efficiently and energy-saving. Improper selection will have a great impact on the operation of the water pump.
Generally, the operating environment of deep well submersible pumps should meet the following requirements:
(1) A three-phase AC power supply with a power frequency of 50Hz and a rated voltage tolerance of ± 5%;
(2) The solid content (by mass) shall not exceed 0.01%;
(3) The inlet of the water pump must be below the water level of 1m, but the diving depth should not exceed 70m below the static water level. The lower end of the pump should be at least 1m away from the bottom of the well;
(4) Require the well to be vertical, the well wall to be smooth, and the well pipes to not be staggered.
2.2 Installation of deep well submersible pump
The installation of deep well submersible pumps first requires checking whether the power supply lines, grid voltage, frequency, and control switches meet the usage conditions; Secondly, the water pump must take good grounding measures; Check whether the installation of the electrical control cabinet is correct and well grounded; Check the lifting facilities for safety and reliability. The installation of the water pump should be carried out in the following order:
(1) Remove the water filter located in the middle of the water pump, unscrew the water injection plug and drain plug, fill the machine with clean neutral water, and then tighten the plug. Check if there is any leakage at the connection parts of the motor, and seal them if there is any leakage.
(2) Use a 500 volt megohmmeter to measure the insulation resistance of the motor, which should not be lower than 150 megohms, and use a screwdriver to pry the impeller to rotate freely without any jamming phenomenon.
(3) First, connect the short water pipe to the check valve body, install a pair of clamps under the upper flange of the short water pipe, and then gently lift the water pump and place it in the well, so that the clamps are seated on the well cover.
(4) Use another pair of clamps to lift the long water pipe and connect it to the short water pipe, then remove the * * * clamp to lift the other long water pipe, repeat the installation process, and then cover the well cover to fix the clamp on the well cover. Install the bent water pipe, valve, outlet pipe, and deep well submersible pump.
(5) During the installation process, a pipeline gasket should be placed between the two flanges of the pipeline, and the bolts should be tightened symmetrically. The cables should be tied in the grooves on the flange of the water supply pipe; Do not use the cable as a hanging rope, and do not damage the cable.
2.3 Precautions for the use of deep well submersible pumps
Attention should be paid to the installation and operation of deep well submersible pumps:
(1) When lifting, attention should be paid to protecting the cables to prevent damage. The lifting device used (such as tripod, hoist or electric hoist, etc.) should have a lifting capacity greater than the weight of the submersible pump and leave enough space. Before lowering, manually rotate the impeller to check if it rotates flexibly, if the contact of the main contactor is good, if there are any cracks or scratches on the cable and cable joints, if the grounding of the motor housing is reliable, and use a multimeter to check the continuity of the three-phase circuit.
(2) When starting the submersible pump, it should rotate smoothly without vibration or abnormal noise, and observe whether there is any significant fluctuation in the motor operating current and line voltage before and after starting. Note that for submersible pumps that are installed or operated after maintenance for the first time, they can only be started locally during testing for observation. If any abnormalities are found in the submersible pump, it should be stopped immediately to check whether the rotation direction is correct, whether the installation is appropriate, and to identify the cause and eliminate faults before operation.
3 Analysis of Common Malfunctions in Deep Well Submersible Pumps
There are six common faults in the use of deep well submersible pumps:
(1) Unable to pump water or severely insufficient head: In this case, the water pump may experience intermittent rotation, and there may be significant noise when the submersible pump is idling. This phenomenon is mostly caused by damaged bearings of the submersible pump.
(2) Poor sealing: The shaft extension end of the water pump motor has a double end mechanical seal component made of highly wear-resistant materials. After a period of use, the seal of the submersible pump may leak oil and water due to wear or natural aging. In addition, there are circular rubber sealing rings on each mechanical mating surface to form a sealing gasket to prevent water from seeping into the pump body. However, due to the high speed of the motor used in submersible pumps, severe wear of the mechanical seal end face is inevitable during long-term use.
(3) Damaged and leaking water outlet pipe: You can hear the normal rotation sound of the submersible pump impeller suspended in the deep well (the electricity meter also rotates normally), but you cannot pump water or only a small amount of water comes up. This situation is mostly due to the damaged water outlet pipe.
(4) Stuck pump: The water pump does not rotate, but a buzzing sound can be heard, which is mostly due to the impeller of the water pump being stuck by foreign objects. For example, due to geological reasons, the high sediment content in well water at our school can easily cause damage to the filter cover.
(5) Leakage: Leakage is one of the most common faults in water pumps. The fault phenomenon is that when the circuit breaker is closed, the leakage protector in the distribution room automatically trips. This is due to the leakage of the motor winding caused by water entering the submersible pump body.
(6) Starting capacitor failure: When connected to the power supply, a buzzing sound can be heard, but the submersible pump motor does not rotate; If the impeller is gently moved at this time and the submersible pump can immediately rotate, it can be judged that the capacitor is damaged.
4 Maintenance methods for deep well submersible pumps
In order to ensure the normal and reliable operation of deep well submersible pumps, extend their service life, and reduce accidents during use, it is necessary to strengthen the maintenance and upkeep of submersible pumps, regularly carry out comprehensive maintenance and upkeep of submersible pumps and their control systems, and conduct comprehensive preventive maintenance at least once a year.
4.1 Daily maintenance and upkeep of deep well submersible pumps
The maintenance of submersible pumps mainly includes mechanical and electrical aspects. The focus of mechanical maintenance is sealing and rust prevention, while the focus of electrical inspection is cable insulation and leakage prevention.
4.1.1 Daily maintenance of mechanical aspects
(1) Regularly check the mechanical seal of the submersible pump, and inspect various sealing components such as sealing rings, refueling screws, sealing boxes, etc. Worn parts and parts with poor sealing performance should be repaired or replaced in a timely manner. If loose parts are found, they should be tightened in a timely manner. If the seal is not firm, new parts should be replaced in a timely manner to ensure safe use.
(2) To prevent corrosion of submersible pumps, if the surface of the pump is damaged or stripped of paint, the rust should be promptly removed and rust proof paint should be applied for protection.
(3) Regularly inspect the bearings of the submersible pump to see if they are worn, if there is a lack of oil, if there is any running of the inner or outer ring, and if they need to be replaced.
(4) Submersible pumps generally require a comprehensive inspection and maintenance every two years of use, which can be initially checked for the normal functioning of various components of the submersible pump through the sound produced by mechanical operation. Check for wear or cavitation on the impeller, rust, deformation, or wear on the shaft, looseness of the internal and external fastening screws of the motor, and any sediment or blockage around the pump port.
4.1.2 Daily maintenance in electrical aspects
(1) Regularly check the insulation resistance of the submersible pump to the ground and inspect the cables for any damage; If there is any damage, it should be replaced in a timely manner to prevent electric leakage;
(2) Regularly check the operating voltage and current of the submersible pump, and use a voltmeter to measure the three-phase voltage, which should be basically consistent;
(3) During the operation of the pump, it is necessary to observe whether the instrument readings and the vibration and sound of the pump are normal. If any abnormal situations are found, they should be dealt with in a timely manner.
4.2 Maintenance of common faults in deep well submersible pumps
Due to the frequent operation of the deep well submersible pump used in our school, the working hours are relatively long every day. Therefore, the dismantling and maintenance of the lifting pump should be carried out once a year (in special circumstances, once per semester). For common faults, corresponding repairs should be carried out according to the following different situations:
(1) Unable to pump water or severely insufficient head: This is mostly due to the damaged bearings of the submersible pump. At this time, you can unscrew the upper and lower screws on the submersible pump, remove the water turbine blades and rotor, gently tap out the bearings, and then replace them with bearings of the same specification and model.
(2) Poor sealing: When the sealing box leaks oil, there will be oil stains at the inlet joint. You can unscrew the screws to check if the oil chamber has been filled with water. If the oil chamber has been filled with water, a new sealing box must be used. When replacing, first remove the pump cover, remove the impeller, rubber wood, gasket, water slinger and other accessories, then remove the inlet joint, remove the key and shaft sleeve on the shaft, and remove the fixing plate of the sealing box to replace the sealing box.
(3) Damaged and leaking water outlet pipe: Replace the water outlet pipe or take emergency measures to plug it.
(4) Starting capacitor failure: Replace with a capacitor of the same specification.
(5) Pump jamming: Most of the pump impellers are stuck by foreign objects. You can unscrew the center screw of the impeller and remove the impeller to remove sand, gravel, and other foreign objects.
(6) Leakage: This is caused by water entering the submersible pump body, resulting in leakage in the motor winding. Waterproof tape can be used to wrap it for waterproofing treatment, but it is important to soak it for several hours and check the insulation with a shaking table. Replace the main cable with insulation that does not meet the requirements or has no repair value.