We know that small submersible pumps have characteristics such as small size, convenient installation and maintenance, no noise, and stable operation. The application of this equipment can greatly simplify underground structures, reduce the total road area, and significantly reduce the cost of building wastewater treatment plants. So how to do a good job of its maintenance work?

Regularly add oil and change oil regularly. After every 1000 hours of operation, the submersible pump's sealing oil needs to be replaced, and the oil inside the motor should be changed annually. For small submersible pumps, the upper and lower end caps, bearing chamber skeleton oil seals, and lithium-based lubricating oil need to be replaced regularly to ensure good lubrication. For small submersible pumps with mechanical seals, lubricating oil should be frequently added to the sealing chamber's oil injection screw hole to keep the mechanical seal well lubricated and ensure its service life.

2. Replace the sealing box in time. If excessive water leakage is detected (normal leakage is 0.1mL/h), the sealing box should be replaced immediately, and the insulation resistance of the motor windings should be measured. If the insulation resistance is below 0.5 megohms, it needs to be dried, using the same method as for general motor windings. When replacing the sealing box, pay attention to the integrity of the outer diameter and the O-ring in the shaft hole; otherwise, water will seep into the submersible pump, damaging the motor windings.

3. Regularly measure the insulation resistance. Use a 500V or 1000V megohmmeter to measure the insulation resistance of the pump stator windings to the housing. The insulation resistance of the pump stator windings to the housing must be greater than 1 megohm (not less than 0.5 megohm) before use; otherwise, the windings should be repaired or dried to ensure safe use.

4. Proper storage. When not in use for a long time, the submersible sewage pump should not be immersed in water for extended periods and should be stored in a dry, well-ventilated room. When storing the submersible pump rubber cable, avoid sun exposure, as this can easily cause aging and cracking on the surface, leading to serious consequences such as winding ground faults or zero insulation resistance.

5. Timely anti-rust treatment of the surface of the small submersible pump. After one year of use, the small submersible pump should be painted and rust-proofed in a timely manner according to the corrosion condition of its surface. The internal paint to prevent rust depends on the type of pump and the corrosion conditions. Generally, when the inside is full of oil, it will not rust, and no paint is needed inside at this time.

6. Small submersible pumps should be maintained annually (or after 2500 cumulative operating hours), including: disassembling the pump motor, cleaning all parts, removing scale and rust, checking their integrity, repairing or replacing damaged parts in a timely manner; replacing the lubricating oil in the sealing chamber and motor; if the lubricating oil released from the sealing chamber is cloudy and the water content exceeds 50mL, the entire sealing box or the dynamic and static sealing rings need to be replaced.

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7. Pressure test. After overhauling the electric pump or replacing the mechanical seal, a 0.2MPa pressure test should be used to check for air leaks between the mating surfaces, O-rings, and the mechanical seal covers. Assemble or replace leaking parts.