Case Study of Low Discharge from Centrifugal Pump

 

Client: Private School/Hostel at Madgaon, Goa

Complain: Low Discharge from Centrifugal Pumps

 

         

Centrifugal Pump
Installed Pump On Site
Horizontal Centrifugal Pump
Lubi's Horizontal Centrifugal Pump
(MXF SERIES)

 

 

Situation:    

One of our clients had installed our Single Stage Horizontal Centrifugal Pump (MXF SERIES) at their school to irrigate their plantations and playgrounds. 

One day their worker noticed reduction in discharge of water and informed the administrative department about it. They called us up on our toll-free helpline number to register a complaint. 

 

Note:

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 at some places.
 

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

 

Observation:

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

  • Power Supply: As always, our engineer first checked the pump’s power supply. After inspecting the connections, our engineer turned on the power supply. He noticed that the quantity of water being fetched by the pump was very low. 
  • Pump Fan: After checking the power connection, our engineer inspected the shaft (motor fan) – but it was rotating in the right direction.

    Note: The direction of the normal rotation is usually engraved on the cover of the pump in the shape of an arrow. It is a good indicator of the normal functioning of the pump.
     
  • Leakages: After checking the power supply, our engineer moved on to check for any leakages - but he could not find any.
  • External Debris: Our engineer removed the pump from the pipeline to check if some external debris had accumulated in the pump, its valves or pipeline, but could not find any. 

 

Since the technician was not able to find any fault in the external apparatus, he decided to inspect the foot valve installed on the suction pipeline. 
 

He removed the suction pipe from the pump and poured water into it. On doing this, he found water leaking from the foot valve, indicating some problem with the tension of the foot valve spring. 

 

Note: Foot valves are installed at the bottom of the suction (inlet) pipeline. Foot valves keep the pump primed, enabling water to flow in but preventing it from flowing out again. Any kind of malfunction in the foot valve can have a significant impact on the performance of the pump.

 

Solution:

 

foot valve
Removed Old Foot Valve

 

As the foot valve was not working properly, our technician replaced it with a new one. He again filled the suction pipe manually with water to check for leakages from the new foot valve. This time, there was no leakages, which meant that the foot valve was working fine. 
 

He then refitted the suction pipe to the pump, and after confirming everything was fitted properly, restarted the pump.
 

The pump started discharging water properly, as it did earlier.