A Case Study of a Centrifugal Monoblock Pump Failing Due to Damaged Bearing: Analyzing the Factors and Possible Solutions


Client: Car Wash Company, Delhi

Complain: Monoblock Pump not Working



Centrifugal Monoblock Pump
Nameplate Of Pump
Centrifugal Monoblock Pump
Lubi's Centrifugal Monoblock Pumpset


Centrifugal monoblock pumps (MDH Series) are powerful pumps which can be used for various purposes like car wash, irrigation of lawns and gardens, water supply of residential bungalows etc.



One of our customers installed our centrifugal monoblock pump in their car-wash center.

One day, their pump suddenly stopped working, and they called us up on our toll-free helpline number to register a complaint.



  • 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.
  • Our Engineer usually calls up to fix an appointment as per the electricity schedule of the area - as there are frequent power disruptions at some places.


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



Our service engineer reached the location and immediately began his inspections to verify the complaint and identify the root cause of the problem.


  1. Power Supply: As always, our engineer first checked the pump’s power supply if it was reaching the terminal of the motor. After verifying the connections, our technician turned on the power supply. As soon as he did so, it tripped.
  2. Pump Fan: After observing the tripping, our engineer tried to spin the shaft (motor fan) using his screw driver. Here, the fan was jammed (not able to rotate freely).


Note: Such a problem can arise if water enters the winding. But to confirm if the problem was with the winding or somewhere else, the pump had to be opened. So, our service engineer decided to send the pump to the nearest service station for further investigation. 


At our service station, our technicians checked the winding with the help of a megger meter. Luckily, there was no problem with the winding, but the water had damaged the bearing and that could be possible reason for the tripping. 


Note: The client avoided starting the pump as soon as the problem is noticed. This greatly reduced the risk of additional damage.



Our technicians replaced the bearing and dried the winding. Later they refitted the motor and checked if the shaft (fan) was spinning freely. After confirming it, our technicians then fitted the pump with necessary fittings to check it. This time it was working fine.


Centrifugal Monoblock Pump
New Bearing And Dried Winding


As the problems were resolved, our engineer took back the pump to the client’s site and refitted it again.


As soon as they ensured that everything was fitted properly, they switched on the power supply and the pump started discharging water, as it did earlier. 



  • Always check the movement of fan (behind the pump) before switching on the pump. It should not be jammed or obstructed in any manner and should rotate clockwise.



The following measures can ensure that your Centrifugal Mono block pump lasts longer with little or no downtime.


  • Power Supply: Always ensure your Self Priming Pumps get continuous (single phase) power supply of 180-230 V.
  • Wiring: The live wire must be connected to the live terminal and the neutral wire to the neutral terminal. Any mistake in wiring could result in major fault. 
  • Leakages or presence of any debris anywhere in the pipeline or the foot valve can impact the flow of water.
  • Always use the mono block pump in the direction of positive suction.         
  • Always fill the suction line with water (even if you have a foot valve fitted) before 
  • The motor may also not function if the capacitor is weak. However, such instances are rare with new pumps. 
  • Always run the pump at the duty point as declared by the company. 
  • Always maintain a cover over the centrifugal pump to keep water and other particles from getting inside.


Final Words:

Always follow the guidelines provided by the dealer while buying or repairing the pump. 
You may also refer our user manual or call our toll-free number for any assistance.