Boosting Submersible Monoset Pump Discharge: A Troubleshooting Case Study with Effective Solutions


Client: Manager of a residential flat at Bengaluru, Karnataka


Horizontal Multistage Submersible Pumps (LHMS series)
Horizontal Multistage Submersible Pumps (LHMS series)


A residential society located in the Bengaluru district had recently upgraded their water supply system by installing our LHMS-1B Submersible Monoset Pump, in order to meet their daily water requirements.

However, upon attempting to start the pump, the pump operator noticed that the discharge was significantly lower than that of their previous pump.

Suspecting a manufacturing defect in our pump, he promptly shut it off and brought the matter to the attention of the society manager.

Recognizing the urgency of the situation, the manager sought our assistance in resolving the issue by calling our toll-free helpline to register a 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. 


Nameplate Of The Pump
Nameplate Of The Pump


Upon arriving at the location, our service engineer promptly initiated his inspection to diagnose the reported issue and determine the underlying cause.

  • To begin the diagnosis process, our engineer conducted a series of standard checks, which included examining the power supply.
  • After checking the power supply, he moved on to inspect the wiring of the pump.
A glimpse of the pump from the site
A glimpse of the pump from the site


  • The engineer examined the main power supply to identify if there was a problem with the power provided by the distribution company. However, he did not find any issues.
  • During the inspection, our engineer conducted an ampere reading on the panel and observed that the pump was operating at a suboptimal amperage level, falling below the rated value of 5 Amps.
  • Further examination revealed that the wiring had not been installed correctly, likely causing the low power output.


Most submersible pumps usually come with three insulated wires - Red (R), Yellow (Y), and Black (B). These wires are designed to connect the pump to an external panel that receives power from the main power supply.

Efficient functioning of submersible pumps is contingent upon proper wiring. This entails the connection of the Red wire to Red (R-R), Yellow wire to Yellow (Y-Y), and Black wire to Black (B-B) for optimal performance.

In this case, the wires were not connected properly, as they were haphazardly connected to Red-Yellow (R-Y), Yellow-Black (Y-B), and Black-Red (B-R) instead of the correct connection of Red to Red (R-R), Yellow to Yellow (Y-Y), and Black to Black (B-B).

Incorrect wiring can cause the submersible pump to rotate in the reverse direction, leading to a reduction in discharge and low amperage consumption.

To rectify the issue, our engineer carefully reconnected the wires in the proper manner.

After doing so, he started the pump and observed that it was operating at full RPM and efficiently pumping water.

The pump operator also confirmed the improvement in performance.



  1. The recommended power supply for a three phase LHMS-1B, Submersible Monoset Pump is 380 to 415 Volts.
  2. As the LHMS-1B, Submersible Monoset Pump is a water-cooled pump, do make sure that the pump body is filled with water to avoid overheating.
  3. Power fluctuations can cause serious damage to all electrical appliances. Use a stabilizer if you are witnessing voltage fluctuations.
  4. In cases where changes are made to the supply lines by the electricity board, immediate changes should be made to the pump panel and the pump terminal accordingly.
  5. The suction and delivery flange bolts must be properly tightened.
  6. Do make sure there are no leakages in the pump apparatus or the suction or delivery pipeline.
  7. Use good quality cable for wiring to avoid voltage loss and pump performance issues.
  8. Make sure your pump operates at the duty point declared by the manufacturer for maximum efficiency. Please contact our customer support team to learn more about duty points.
  9. Test the motor’s continuity, insulation, and resistance using Ohms and Megger Meters.
  10. Regular inspection and servicing of the pump can help detect debris in the strainer or other issues beforehand.


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