How to Fix a Humming Pool Pump Motor

Written by Michael Dean
December 5, 2023

humming pool pump motor

Think of your pool pump as the heart of your swimming pool. It circulates the pool water, preventing it from stagnating, becoming green or murky. Without a functioning pool pump, you’d be swimming in some nasty, unsanitary water! So, if you one day hear a weird humming noise coming out of your pool pump motor, there is definitely a cause for concern.

In this article, I will go over how to fix a humming pool pump motor as well as other common pool pump problems. Let’s get straight into it!


Main Takeaways

  • If your pool pump is humming and not turning on, this could be due to a faulty capacitor, a blocked impeller, damaged bearings, a damaged pump shaft, or electrical issues.
  • Other pool pump issues you may come across include low water flow, leakages, air leaks, and loud, squealing motors.
  • With good care, a pool pump can last up to 12 years, but the actual lifespan will depend on a variety of factors.
  • Some signs you need to replace your pool pump include bad water flow, loud noises, frequent repairs, and unreliable performance.

Humming Pool Pump Motor and Not Working: Reasons and Fixes

When you turn on the motor, if you hear a humming or buzzing noise and the pump is not working, it means that power is reaching the motor but is having trouble functioning properly. There can be several reasons why this happens. Here are some possible issues and fixes for a murmuring pool pump.

Faulty Capacitor

Issue: The capacitor provides the first jolt of electricity for starting the motor. Sometimes, it might be faulty or damaged, preventing the motor from starting.

Fix: Open the side or back cover of the pump and look at the capacitors. If they’re bad and need replacing, they may be burnt or misshapen. If that’s the case, simply take them out and replace them. Make sure you get the correct specifications for your pump.

Blocked or Damaged Impeller

Issue: It’s quite easy for debris to get lodged in the pump’s impeller. If this happens, it can prevent it from turning freely, causing your pool pump motor to hum. Another reason the impeller may not be working is that it is damaged.

Fix: Disconnect power to the pump, remove the pump housing, and inspect the impeller. Clean the impeller and check for any damage. If the impeller is in good shape, simply put it back and restart the pump. If it’s damaged, replace it!

Damaged Bearings

Issue: If your bearings are damaged or worn out, it can cause the motor to hum and stall without starting. This is because the worn-down bearings can’t support the rotating motor shaft.

Fix: Unfortunately, if the bearings are worn out, they must be replaced entirely. While you can DIY replace your bearings, it is a difficult process, so call an expert if you are hesitant to tackle this yourself.

Damaged Pump Shaft

Issue: If the pump shaft is bent or damaged, it can obstruct the impeller from turning smoothly.

Fix: First, try turning the shaft manually with a screwdriver. Sometimes, all it needs is a little push to get unstuck. However, if you cannot turn the shaft or it doesn’t spin as it should, the shaft is likely damaged. Unfortunately, you may need to buy a new pump in this case.

Pump Not Primed

Issue: If your pump is turning, but there is still a humming or buzzing sound, your pump may have lost its prime. In other words, there may be air in your pool pump. If this happens, turn off your pump immediately! 

Fix: Naturally, you’ll need to prime the pump—this involves filling the inlet pipes and pump housing with water and then starting the motor. However, if priming doesn’t work, you may be dealing with a more difficult issue, such as a leak.

Electrical Issues

Issue: The problem might be as simple as a faulty electrical connection. A tripped circuit breaker or loose wires can cause the motor to hum without starting.

Fix: Have a look at all the electrical connections. Check the switches and wires—are they secure and in working condition? If not, you may need to replace them. I highly recommend contacting an electrician for any major electrical work. It is always safer to employ an expert, especially if you have little experience.

Motor Overload

Issue: The pump motor might be overloaded due to running at high speeds for extended periods. It might also be overworked because of excessive debris in the pool, causing it to overheat and stall. Imagine being forced to run as fast as possible for hours on end. Would you be exhausted? This is how your pump feels after hours of running at full speed.

Fix: Disconnect the pump from the power and allow the motor to cool down. While it cools, manually remove any excess debris from the pool using a net. Once the pool is relatively clean, run the pump again at a lower speed to check if it’s operating normally. Also, ensure the pool pump is the right size for your pool. If it’s not, unfortunately, you may need to buy a new one to avoid this problem in the future.

Other Pool Pump Problems 

Pool pumps are certainly not the most troublesome equipment in a pool (looking at you, pool filter…), but it is an essential part of your pool ecosystem. Besides a humming and stalled motor, there are other pool pump problems you may come across as a pool owner.

For example, your pool pump may not turn on at all due to overloaded voltage, loose connections, or a jammed motor. Or your pool pump may be suddenly turning off, which may be because of the pump motor overloading. Other common issues include:

If you’re experiencing any other trouble with your pump and looking for solutions, check out my pool pump troubleshooting guide.

How Long Do Pool Pumps Last?

Swimming pool pumps are long-lasting. Most typically stick around for 8 to 12 years, but several things can affect their lifespan. The quality and make of the pump, the frequency of use, water chemistry, and the climate all affect the longevity of your pump.

Regardless of what factors affect it, regular maintenance is the most essential cornerstone to a healthy lifespan of a pool pump. If the pump is not looked after, cleaned, lubricated, and generally well-cared for, expect it to need a replacement much sooner than you anticipate! Caring for your pool equipment (no matter what it is!) goes a long way.

Signs It’s Time to Replace Your Pool Pump

No matter how well you look after your pool and pool equipment, there will come a time when you need to replace your pool pump. But when do you know it’s time? Here are some signs to look out for:

Bad Water Flow

Have you noticed a significant decrease in water flow through the returns, skimmer, and/or pool jets? That could indicate that your pump can no longer circulate water effectively and has to be replaced. But, of course, try troubleshooting the issue by cleaning the filter and checking for blockages first!

Loud Noises

Loud, excessive, or unusual noises coming from the pump motor—grinding, screeching, or rattling—might signify serious internal damage. While these noises can suggest other issues, you may need to replace the pool pump if the issue doesn’t resolve after troubleshooting.

Frequent Repairs

If you find that you’re frequently repairing the pump or replacing any parts like seals, the impeller, or the motor, it would make more sense (and be more cost-effective) to buy a new pump altogether instead of continuing to repair an old, faulty one.

Leaking Water

If there is any structural damage that is causing your pump to leak, you may need to replace your pool pump entirely. However, with that said, a leaky pool pump can be fixed if the damage is not too extensive!

Unreliable Performance

If the pump constantly fails to start, shuts off unexpectedly, or is seriously overheating, it may be a sign that the motor or its electrical components are deteriorating and require replacement.

Old Age

As I mentioned above, pumps can last up to 8 to 12 years. So, if your pump has passed this point or is nearing the end of its lifespan, consider getting a new pump!

What About a Slow Pump Flow Rate?

Several things can cause a slow pool pump flow rate. For example, if the filter is dirty or the impeller is clogged with debris, the water flow might get heavily restricted, which also means poor water circulation. Other issues include an air leak in the pump lines or even an undersized pump that is unable to keep up with the amount of water that has to be filtered regularly. Finally, there could also be a technical problem with the pool pump itself, such as a worn-out bearing or a damaged shaft, causing a slow flow rate.

If you’re experiencing a slow pump flow rate, try the following:

  • Clean the filter: First of all, remove and backwash or clean the filter, depending on your filter type. If you have a cartridge filter, replace cartridges with new ones if needed.
  • Check the impeller: Remove the impeller and inspect it for any obstructions, blockages, or debris that might be impeding its movement. If the impeller is clogged, remove the blockage, reinstall, and run the pump.
  • Check for air leaks: If that still hasn’t fixed the problem, check to see if there is any air in your pool pump. Signs of air include air bubbles, loss of prime, and visible leaks. If you find any air leaks, fix them immediately.
  • Check the pump size: Is the pump big enough for your pool? Have you added any water features recently, such as a pool spa, that might be causing the pump to overwork? If yes, consider upgrading the size of your pump to one that is appropriate for your pool. And on the flip side, don’t go too big, as that won’t be very energy-efficient!

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Take Care of Your Quiet Pump!

And that’s all there is to it! Dealing with a humming pool pump motor can be a frustrating experience for any pool owner. However, knowing the common issues and fixes for this all-too-familiar problem can get your pool pump back in optimal condition! Remember, a humming pool pump motor is often a symptom of underlying problems such as clogged impellers, capacitor issues, or electrical faults. So, by addressing these issues, you may be able to keep your pool pump running for longer, saving you both time and money in the long run.

Any more questions about your pool pump? Let me know!

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