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Why do water pumps fail - Diagnosis & Solution

Posted: 10/03/2021
Category: Wastewater Pump

Very often when a water pump fails, the common misconception is that the pump is the trouble maker.

As one of the top water pump manufacturers in India, we have helped our clients in diagnosing the root cause of pump failures. In this guide, we share our experience and help you in finding the root cause of pump failures.

Operating a Damaged Pump can hurt the Entire System

Operating a Damaged Pump can hurt the Entire System

Operating a failed pump without determining the root cause of failure can lead to bigger troubles down the line. With water pumps playing a critical role in several industries, pump operators need to learn how to troubleshoot failures to resolve the root cause.

Finding the root cause for pump failures is easier than you think. In fact, leading water pump manufacturers in India, like Sintech offer extensive after-sales support to clients to help them troubleshoot any issues they face down the line. Our pump experts are always on hand to assist with and provide guidance on analysing the reason for pump failures so that you are not troubled with repetitive failures.

How to diagnose pump failures?

How to diagnose pump failures

The first step is to investigate symptoms like excessive vibrations, abnormal noises, etc. Once you identify what’s the trouble, you can very well find out the cause.

Pump failures can be broadly classified into two categories:



Isolating the Electrical Troubles

Isolating the Electrical Troubles

Erratic power supply can cause pump motor failures. So, the first step is to monitor your power readings. Check with the voltage and amperage are within the normal range. Look for any voltage imbalances between the various phases.

Voltage imbalance can cause the following troubles:

Rise in the temperature of the motor

Short motor life

Even a 1% voltage imbalance can increase motor temperatures by 18% which results in shortening motor life. Voltage drops and the corresponding increase in current flow also has a negative impact on the VFDs attached to the pump.

Identifying the Mechanical Troubles

Identifying the Mechanical Troubles

To identify mechanical issues, you need to understand where the pump is operating on the curve. The duty point of a pump is the intersection between the pump curve and the system curve.

Initially, when the pump is installed it is designed to operate as close to the system curve. Over time, due to various factors like air entrainment, sedimentation build-up, scale build-up, the system curve changes. Changes in the pump operational curve can further lead to various mechanical troubles that can damage the pump system.

How to determine the actual operation curve of the pump?

Pump operators can take the help of flowmeter readings to find the actual flow rate of the pump. This gives a clear idea of where the pump is operating when compared to actual design conditions.

In the absence of a flowmeter, a drawdown test can also be used to determine the actual flow rate of a pump.

In several cases, when the pump is not operating as per specifications, determining the actual pump flow gives an insight into pump health. The actual pump flow helps to identify the root causes for pump failure.

You can identify the root cause of pump failure by digging deeper down this checklist:

Is the check valve not opening fully?

Is there more head on the pump than what’s specified in the pump manual?

Is there cavitation due to inadequate NPSHA (Net Positive Suction Head Available)?

Is there enough NPSHA?

Is there a clog in the piping?

Does the impeller show signs of premature wear and tear?

Is air trapped inside the pump?

Do the measured pressure and flow match the pump curve?

Go for Diagnostic Testing

Go for Diagnostic Testing

If you have checked these basic steps but still unable to identify the problem, you can consider pump diagnostic testing. In diagnostic testing, water pump manufacturers in India or a full-service testing organisation will bring diagnostic equipment to your place to measure pump output, vibrations and other factors to determine the root cause of pump failures.

Check if the VFDs are the Reason for Pump Failure

Check if the VFDs are the Reason for Pump Failure

Variable frequency drives are used in pumps because they help in operating the pump at various flows. VFDs can alter the pump curve with speed regulation. While VFDs are beneficial in several ways, they come with their own set of troubles that can lead to pump failures.

Some of the common VFD-related pump troubles include:

Low operational speed – If the pump is oversized then the speed of the pump will be reduced.
Low operational pump speed can lead to other troubles like build-up formation in the eye of the impeller. If this is the problem, try running the pump at full speed for a short while to flush out the build-up.

Final Thoughts

While most industrial pumps are designed to offer maximum output and can last for years, when operated incorrectly, it can lead to drastic system failures. If your pump fails, take the time to identify the root cause and correct it. Running a damaged pump can prove to be costly in the long run. So, it’s best to investigate the reason for pump failure and eliminate it as early as possible to improve outputs and savings.

If you have any other queries on pump failures, reach out to our pump experts at Sintech. As the No.1 water pump manufacturers in India, we can assist you in identifying and eliminating pump troubles.

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