Investigating and Solving Noise Problems Caused by a Broken Sewage Pump Impeller - A Case Study


Pump Model: LFP-3335-F / 3.00 HP / 3 PHASE / 3" OUTLET


Client: Residential Society at Varanasi, Uttar Pradesh.


Lubi Drainage sewage pump waste water pump
Lubi Sewage Pump (LFP Series)



In Varanasi, Uttar Pradesh, a densely populated residential society faced the critical need to effectively transfer wastewater from their premises to the municipal sewer line. To address this challenge, they made the decision to install our powerful LFP-3335-F sewage pump, a sewage pump specifically designed for such demanding scenarios.


Being situated on lower ground compared to the municipal sewer line, the residential society faced a unique topographical challenge. In this uphill battle, our exceptional pump became the unsung hero, tirelessly propelling the water upwards, defying gravity, and ensuring a seamless flow towards the municipal sewer.


After smoothly operating for several months, the pump operator felt some sound emanating from the pump. Concerned about this unexpected development, the operator immediately notified the management, who promptly reached out to us via our toll-free helpline to register a formal complaint.



  1. Customers can register a complaint by calling our toll-free number, after which they will receive a text message with information about the complaint as well as the contact details of our service engineer.
  2. Our Engineer usually calls up to fix an appointment as per the electricity schedule of the area - as there are frequent power disruptions in some places. 


Our service engineer reached the site as per the pre-scheduled appointment.  



Upon reaching the site, our service engineer immediately commenced the inspection to validate the reported problem and identify its root cause.


  • To diagnose the problem, our engineer performed a series of standard checks, commencing with an evaluation of the power supply. Using a clip-on meter, he accurately measured the supply voltage to ensure it was within the required range. 
  • Subsequently, our engineer proceeded to assess the cable's continuity using a megger meter.  
  • After completing the cable continuity check, our engineer requested the operator to disconnect the pump from the delivery pipeline and remove it for further examination. 
  • The operator agreed and disconnected the pump from the delivery pipeline and removed it. 


After safely removing the pump from the underground tank, our engineer sought approval from the management to transport the pump to our nearby service center for a comprehensive inspection and essential maintenance to ensure its peak performance.


Once the necessary approvals were obtained, our engineer, accompanied by the operator, transported the pump to our service center. 



While conducting the pump inspection, our engineer observed that the power supply voltage was within the appropriate range.


During the inspection, the engineer conducted continuity testing and observed that the continuity readings were within the specified range, indicating proper electrical connectivity throughout the pump system.


Upon reaching our service center, our technicians carefully opened the pump's casing and discovered a broken impeller. This damaged impeller was identified as the cause of the noise experienced.


Broken Impeller
Broken Impeller


The technicians showed the broken impeller to the operator and advised them to seek management's approval to get the damaged impeller replaced with a new one.



After obtaining the necessary approval, our technicians proceeded with the replacement of the broken impeller, and carefully fitted the new impeller into the pump's casing.


Following this, our engineer conducted an operational / functional check (without any load or resistance) to ensure proper functioning. 


After returning the pump to the society, our engineer recommended to the operator that they should ensure the water being pumped is free from any “solid” particles (metal pieces / stones etc) that could potentially harm the impeller.


With the necessary precautions taken, our engineer reinstalled the pump, and upon the operator starting the system, the pump exhibited flawless performance, operating smoothly and without any noise.



  1. The recommended power supply for a three-phase LFP-3335-F Sewage pump is 380 to 415 Volts.
  2. Prior to the installation of the pump, it is advisable to manually inspect and verify that the pump is free from any obstructions or jams, ensuring smooth operation from the start.
  3. Before installing the pump, it is highly recommended to utilize a megger meter to assess the continuity of the winding insulation, ensuring the integrity of the electrical components and minimizing potential risks.
  4. During installation, it is crucial to securely tighten the delivery flange and bolts, providing a reliable and leak-free connection for efficient operation.
  5. When it comes to LFP-3335-F sewage pumps, it is essential to understand that there is no need to fill water in the winding. These pumps are specifically designed to handle sewage without water entering the winding. However, it is essential to ensure that the sewage pump always remains submerged in water to ensure its effective functionality.
  6. When lowering the pump, please avoid using the pump's cables for lowering purpose. Instead, it is recommended to utilize a sturdy rope. This ensures a safe and proper lowering of the pump into position, reducing the risk of damage to the cables or other vital components.
  7. To achieve maximum efficiency, it is crucial to operate the pump within the duty point specified by the manufacturer. For detailed information regarding duty points and their significance, please feel free to reach out to our dedicated customer support team.
  8. Conducting regular inspections and servicing of the pump is highly recommended as it enables early detection of potential issues, allowing for timely maintenance and prevention of major problems. By prioritizing regular maintenance, you can enhance the reliability and longevity of your pump while minimizing unexpected downtime.


For smooth and uninterrupted working of your pump, always follow the instructions and standard operating procedure issued by the manufacturer in the user manual.