Most Commonly Asked Questions about Centrifugal Pumps and Their Answers

Centrifugal pumps are among the most common pump types in use today, with various configurations available on the market. They are popular because of their simple design, ease of maintenance and operation, as well as smooth flow rate.

Here are some of the FAQs about centrifugal pumps and their answers that can give you a better idea of how the pumps work.

What is cavitation?

The increase in speed of water getting into the pump causes pressure to drop. If it drops too low, vaporisation can happen. Bubbles may be entrained in the liquid. The bubbles will collapse with force as they get to areas with higher pressure. This will then result in noise and vibration coming from the centrifugal pump.

How do you tell if there is cavitation in the pump?

You will know if the pump is cavitating if you hear vibrations and knocking sounds when the pump is working. Other signs include faulty power consumption and reductions or fluctuations in the output of the pump.

If running backwards, will a centrifugal pump still work?

The pump facilitates water off the impeller vanes’ tips. Even if the impeller is running backwards, centrifugal forces will continue to accelerate the water, but at a much lesser level of efficiency. A pump that runs backwards will consume less power, and operate at a lower pressure. This will result in the delivery of less water.

What’s the relationship between pressure and low flow?

When the flow rises, the pump’s discharge pressure drops. When the flow drops, the discharge pressure rises.

My pump continues to start and stop. Will this affect the motor?

Yes. Starting the motor frequently can lead to heat buildup. This can result in damages to the motor. Each time the motor starts up, there is an inrush of current that is 10x the nameplate amps. The pump’s motor disperses the energy inrush as heat.

Where should I install the isolation valve for controlling the flow?

If there is a need for flow control, you can use a valve on the pump’s discharge side. Don’t utilize a valve on the pump’s suction side.

These are some of the most frequently asked questions related to centrifugal pumps.