How Does a Pool Pump Really Work?

One of the greatest parts about doing pool maintenance yourself—other than saving money and gaining a bit of know how—is how routine the process becomes. All that skimming, scrubbing, and chemical balancing can become second nature. But eventually, the time might’ve come when you opened up your pump to clear out its skimmer basket, paused, and thought, That’s interesting. You might’ve even come to the realization that although you run your pump every single day, you don’t actually know how the thing works!

Other than the simple fulfillment of knowing how something you use every day operates, understanding your pump can also help you make smarter decisions about getting your circulation system in optimal shape—and by smarter, I also mean you can save yourself some serious cash. I’ll explain what your pump does and how, as well as how the pump fits into the greater circulation system, and the one thing every pool owner should do for their pump to cut costs. Let’s get moving.

I Don’t Have All Day. What Does a Pool Pump Do?

Alright, I get it. You want to know enough about your pump to make smart decisions about yours. But you’re not interested in the nitty gritty details. That’s actually a fine approach. Here’s the short answer: your pool pump is what moves water through your greater circulation system. Using power, it moves water from your pool, through the pump and filter, through any other accessories you have, like a heat pump or waterfall, and back into the pool. When your pump is running for the proper amount of time every day, it repeats this process a few times on the daily. How much horsepower and how fast your pump needs to run—these are different—can vary based on the size and needs of your specific pool.

Your Pool Pump: The Heart of Your Circulation System 

If your circulation system was a human body, the heart would be the pump. It’s what gets everything moving—and without it, your pool is in serious trouble. Your pump gets the wheels going to keep the bad guys out of your pool, and keep your pool water clean and safe for swimmers. 

That’s exactly why it is a big deal to not run your pump, even for just a few days: it’s the hub of how your circulation system works to filter out debris and microscopic bacteria. Without your pump running, all that bad stuff is able to fester and run amok. The result isn’t pretty. Running your pump for the right amount of time every day? It just makes all the difference.

So How Does a Pool Pump Really Work?

Now we’re going to get a little technical—but don’t worry, this is super simple stuff when you really look at it. Pumps work on a concept called centrifugal force, which basically just means that water moves away from its center force. That’s why you might see pool pumps referred to as “centrifugal pumps.”

Every pool pump has an inlet and an outlet, so that water can both enter and leave its chambers. Pool pumps also have two halves: the electric motor, and the hydraulic “wet end.” The motor is where the power lies, and the wet end is where water moves through the pump before heading off to your pool filter and back to your pool. Still with me? Let’s go a little deeper. 

The energy from your pump’s power source is converted into mechanical movement. How? Well, the pump’s electric motor powers the impeller, which can look a little like enclosed bottom blades of a blender and spins an attached part called the volute—fast. The volute is connected to the hydraulic wet end, so the water is then propelled at a high velocity toward the outer edge of the impeller. That movement of water away from the impeller is centrifugal force in action, and it creates an area of negative pressure, or a vacuum. (The vacuum is super important here and requires a perfectly sealed pump—otherwise, your pump would be pushing air as well as water, which is never okay.) Once your volute creates enough energy, it changes velocity, which pushes water to flow out of the pump.

And when I say it pushes water, I mean that it pushes water. We already know that pool pumps are nifty and essential devices—and better yet, they don’t suck in any way! This can be confusing because the part of the pump where water comes in is often referred to as the “suction side” of the pump. But actually, the pressure there is lower than the atmospheric pressure, which creates that vacuum we talked about and pushes water through the pump. Kind of like using a straw! 

Do you have a variable-speed pool pump yet—and the lower monthly energy bills to show for it? The Blue Torrent 2 HP Variable-Speed Pump is the one to try—it’s ultra-powerful, allows for more thorough circulation, is eligible for rebates, and pays itself off in under a year in energy saved. As customer Dave Schmidt says, “My pool has never looked cleaner. I am pleased with my new pump!”

Your Pump’s Power? It All Lies in its Parts

So now you know how your pump works—it’s all in how its different parts interact. But here, we’ll break down those specific parts even further. This section is for those willing to get the most advanced understanding of that unit working in their backyards every single day. But again, it’s really easy stuff once we get down to it. We’ll be working from the electrical side of the pump to the hydraulic wet side of the pump. 

The pump motor is the most complex part of your pump. It contains a motor shaft, a skinny metal piece that sticks out of the motor and connects to and spins the impeller, which we’ll get to in a few. When the pump motor is open, you can also find end bells, which are metal brackets built into the pump. They’re also called end shields or cover plates, and are used to support the bearings. The bearings are enclosed in a sleeve called a bearing shield, and is responsible for allowing the motor shaft to spin smoothly. If your pump ever gets too hot, worn bearings could be the culprit. In addition to connecting to the impeller, the motor shaft is also connected to the rotor inside. The rotor works to power that shaft. And now we’re back at the beginning of the process!

The impeller is the most important part of your pump. It’s also the only part that actually moves, since we’re not counting the water. It’s what propels your water at a super high velocity. There are actually two different types of impellers used for pool pumps: semi-open face impellers and closed face impellers. Semi-open faced impellers are typically used in older pool pumps, and are less efficient than closed-face impellers. Closed-face impellers, in addition to being found on newer pumps, also are the easiest for lifting and priming. Plus, they have a higher flow rate. You can expect a closed-face impeller to flow up to 50% more water in any given time than a semi-open faced impeller.

The pump seal is a ceramic and graphite unit that sits at the motor shaft and prevents water from leaking out of the pump at the motor shaft. This seal is spring-loaded to adjust for improper alignment, and depends on water (and only water, not air) to keep it cool. Pump seals are one of the most popular replacement parts for pool pumps, and without a functional one, your pump could start pumping air in addition to water, which is a recipe for disaster.

The pump housing and strainer contains the pump basket, which we’ll get to next. It’s the section of the pump in which water moves, and it has a rubber O-ring seal to prevent air from entering the pump.

The pump basket collects debris, such as leaves and twigs, from the water passing through. It looks just like a basket, with holes for the water to come through but a grid to stop large debris from heading toward your filter, as well as clogging.

Is your pool pump powerful enough to support one of the best accessories known to pool owners? The Energy-Saving ComforTemp Pool Heat Pump 95,000 BTU to heat 18,000 Gallons extends your swim season, all while working powerfully and reducing energy costs. According to customer Steve, “Simple install and simple set up. Heated my pool from 66 to 82 degrees in about 2 complete days.”  

Pump Circulation 101

So how does your pool pump fit into the greater circulation system? First, it draws in water from the pool through the skimmer. Your pool skimmer is a rectangular built into the side of your pool, and you might have more than one. Your pool water should always reach about halfway up your skimmer, so that it can pull water in efficiently. The skimmer also has a basket that catches debris. Next, water moves through the pump itself, and comes into contact with the second basket that will catch debris, this time in the pump’s housing. Then, the water is pushed out of the pump to your pool’s filter pump, which catches microscopic debris. If your pool has a water heater, a salt water generator, or any other accessories, the water is then pushed through them and returns back to the pool through the return jets, cleaner than ever. 

That’s Not All—It Can Get Even Better 

Pool pump efficiency goes way beyond having an open-faced or closed-faced impeller. It’s also about the pool pump itself. And thankfully for pool owners everywhere, the technology has come a long way from the first pool pumps.

The smartest decision any pool owner can make is getting a variable-speed pump, and the sooner the better. Instead of running at full horsepower like single-speed pumps, variable-speed models allow you to control how fast your motor runs according to your pool’s specific needs. The result? A crystal-clear pool and a full wallet.

Save Some Cash

Some pool owners put off buying a variable-speed pump because they’re initially more expensive to buy than the standard single-speed model. But within around one year, variable speed pumps will save you more than the difference of cost. This is because they significantly cut your energy bill—and save you money every single month.

Help the Environment

Variable-speed pumps are about to essentially become federal law, and not just because the government cares about your wallet. They’re also the most environmentally-friendly. So in addition to being the best crafted, most reliable pumps on the market, they’re also endorsed by the American government and benefit all.

Get Early Bird Benefits

Before federal law makes it illegal to buy single-speed pumps or parts, the government is also incentivizing pool owners to buy variable-speed pumps with rebates, sort of like you can get with an environmentally-friendly car. This makes perfect sense, since these types of pumps use the same advanced battery technology as electric cars. Access the PoolPartstoGo Rebates Calculator to discover just how much cash you’ll get back, depending on where you live.

Looking for the best variable-speed pump on the market? The right one will not only keep your pool clean, but it’ll also help you save big. The Blue Torrent 2 HP Variable-Speed Pump is ultra-powerful and reliable, comes with a lifetime warranty, is eligible for rebates, and pays itself off in under a year by energy saved. As customer Bill Britton says, “Runs great. Super quiet.”  

You’re Pumping!

Look at you! You just learned everything you need to know about your pool pump—and stuck through the technical parts. Now you can make the best decisions about what type of pump you should be using, and your wallet will thank you. And with your next swim, you’ll be all the more appreciative of that crystal-clear water flowing out through your return jets. Enjoy.


Related articles:

Ideal Schedule for Your Variable Speed Pool Pump

What To Do When Your Pool Pump Won’t Turn On?

How To Fix An Overheating Pool Pump?

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