Fixing a Noisy Hot Tub Pump Motor

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Is your hot tub is making a loud buzzing or grinding noise? Bad news: it’s probably the motor. Besides being obnoxious, this sound also an indicates your hot tub will soon be out of service. Lets walk through the steps to pinpoint the cause of the noise and how to fix it below.

Nothing beats a fresh new pump, especially if your old one is kaput.

My Breaker is Tripped

Tripped breakers are usually the result of a bad heater or a bad hot tub pump. To determine the cause of the tripped breaker, try disconnecting the heater first, and then flip the breaker. If the breaker still trips with the heater disconnected, disconnect the pump and flip the breaker again. If the breaker does not trip with the pump disconnected, you’ve found the source of the problem – a bad spa pump.


NOTE: If your breaker is tripped but the pump does not hum when you flip the breaker back on, it could just be a bad fuse. In this case, use a multi-meter to test the fuse(s).

Fuse Testing
Always remove fuses from circuit before testing.

If all fuse(s) check out ok, testing the voltage on the back on the motor will verify if the motor is bad. If the motor gets the correct voltage, but doesn’t run, it’s bad.

Pump Voltage Testing

My Pump is Buzzing/Humming

A steady or intermittent buzzing/humming noise can be an indication of a seized hot tub pump. When the pump is seized, you’ll observe the following:

  • Tub will not heat
  • Topside shows a code of OH, DR, FLO, or DRY (codes vary depending on equipment system)
  • Tub will not circulate

A pump will commonly seize due to worn out bearings or trapped debris/foreign objects. The remedy is replacing the spa pump.

My Pump is Making a Loud Grinding Noise

Motors producing a loud grinding or screeching noise usually have bad bearings. Bearings go bad over time due to wear, tear, and water intrusion.

A loud pump will eventually stop working completely, so order a replacement sooner rather than later to avoid down time.

Note: There are companies that rebuild motors and/or offer rebuild kits. These are often just as expensive, or more, than purchasing a new complete pump and motor.

Spa Pump Lifespan

The average hot tub pump lasts 4-10 years depending on pump quality and how well the water chemistry has been maintained. Low pH, alkalinity or excess bromine/chlorine can all cause early pump failure.

Test and balance your water weekly to protect your spa equipment from unnecessary damage.


Replacing your Hot Tub Pump

Finding a replacement hot tub pump may seem difficult, but it is actually pretty simple. The label on your current spa pump will usually tell you everything you need to know. Gather this information:

  1. Voltage
  2. Amperage
  3. Frame size
  4. Discharge orientation
  5. Plumbing size
  6. Any name brands on the assembly
All the pumps a hot tub could want!

Some pumps have non-standard plumbing, so you may have to do some fiddling to get a standard pump to fit. If ever in doubt, email us a photo of your motor data label and the pump attached to the motor. We’re always happy to help you find the correct replacement.

When shopping for a replacement pump and motor, pick a well-known brand. Waterway and AquaFlo pumps are best known for quality and durability, but HydroMaster high performance spa pumps take reliability and durability to a new level and are cheaper to boot.

Looking for more information? Read our Complete Guide on Spa Pump Replacement.

Have questions or comments? Post a Comment below!


  1. Helpful info i need to know the diff between frame 48 and 56 as
    I have two pumps in my spa one of each also neither one has hp listed on label

    Liked by 1 person

  2. Hi Tony,
    The best way to find the frame size is by measuring the distance between the through-bolts. Less than 4″ is a 48 Frame, and a 56 Frame will be more than 4″.
    For horsepower, it may be better to find a replacement based on amperage. Here’s a link to our pump article with some images on frame size, a chart at the bottom with pump amperage and other factors, and more info on pump selection and replacement:
    Let me know if there is anything else I can help you with.
    Thank you,

    Liked by 1 person

  3. Hi Tony,
    My Aqua-Flo circulation pump finally packed up after about 7 years although I had the bearing replaced. However, the brand new Aqua-Flo circulation pump is very noisy and in my mind running hot. it is too hot to hold one’s hand on the case. I measure the outside case temperature which was about 67 Degrees Celsius. I then checked with the supplier who verified that this was within an acceptable operating range so let it be. I also think that the flow seems stronger than from what I recall with the previous pump but cannot be sure. It is still very noisy which is a nuisance. Any suggestions will be appreciated.

    Liked by 1 person

  4. I have a Noise that seems to be coming from the heater tube. there are no error codes on, the tub is heated, both pumps are working. I don’t get it. I have not ever had one do this. it;s pretty loud when the tub is heating during the cycle. it does seem to be coming on more frequently also.

    Liked by 1 person

  5. The noise could be coming out of the heater, and if it is the element inside may be rattling against the heater tube. That’s pretty rare, and would sound more like a rattling noise. If it sounds like a grinding noise, or a bad electrical noise (for lack of a batter way to phrase it), it would likely be the barrings in your motor. If you can give us a call, we’ll be happy to listen to it and let you know exactly what it is. Please call our tech support when you’re next to the tub. Our number is 800-823-3638 M-F 6am-5pm Pacific Time.

    Liked by 1 person

  6. Hi Kevin,
    If the sounds is a buzz or a humming and the jets do not turn on, that is likely a locked up motor and it will need to be replaced.

    Liked by 1 person

  7. Hi Kelvin,
    If the air bubbles that are usually in the water jets are no longer their, you will need to replace one or more of the air control valves on the top rail of your hot tub. If you turn the bubbles on with a button, that is an air blower motor. Your blower motor could be bad, or you could have a blown fuse in your spa pack. If you have a multi-meter and you’re able to troubleshoot yourself, you’re welcome to call our tech support if you have questions. If not, it’s best to hire a spa tech so you don’t waste your money replacing something that does not need to be replaced. I hope this helps, and please let me know if you have any other questions!

    Liked by 1 person

  8. One of the pumps in my hot tub is making a loud screaching noise. The pump appears to be working fine, just really noisy. Do I need to replace the pump or is there a way to repair it? Thanks

    Liked by 1 person

  9. Hi Eric,
    Thank you for checking with us! The noise you’re hearing are the bearings in the motor going out. When they’re really loud it’s actually difficult to gauge how much longer they will work. It could be a week, it could be 6 months. If you’re comfortable replacing the bearings yourself, it would be less expensive than replacing the whole thing. You would have to contact a motor shop, as we do not offer just the bearings. If you need to bring the motor to someone for repair, I recommend buying a replacement pump instead. Our complete pump prices start at $209, so it is usually more economically sound to replace the whole thing instead of spending almost as much or the same amount fixing an old motor.
    I hope this helps, thanks!

    Liked by 1 person

  10. Thanks Mark,
    I am interested in replacing the pump completely, but want to make sure I order the correct one.
    The spa is 10 years old, so guessing I am on borrowed time!
    Sounds like I need to take a few measurements and get back to you.

    Liked by 1 person

  11. We just found 6 ball bearings in the bottom of the hot tub, we just replaced the motor last year. Why would this happen?

    Liked by 1 person

  12. Hi Tracy,
    Thanks for checking with us! The ball bearings are not from the pump, they’re from your jets. Most spinning jets have ball bearings in them, and after time the water eats away the bearing casings and the balls come out. If you would like to find the right replacement jets, please email photos of the faces and sides of the jets to We’ll get you what you need!
    Thanks again,

    Liked by 1 person

  13. When the high speed motor runs it starts and pumps water. When the high speed is selected off there is a loud clunk and the low speed motor continues. This is a new issue. (almost sounds/feels like water hammer) I noticed that the flow may be slightly lower at high speed..
    Cleaned filters but no change….could it be the pump shaft?

    Liked by 1 person

  14. Hi,
    If you’re noticing a reduction in flow, it’s worth removing the intake cover of the pump and checking inside for debris. The “Klunk” noise however may be a more complicated problem with the motor. Check the exterior of the motor and the motor shaft itself for corrosion or water spots. If you see signs of water, it typically means the motor shaft seal is leaking when the pump is under high pressure. Seal replacement will stop any further water damage to the motor, but will not resolve the noise issue. For that, you’ll either need to have the motor rebuilt or replaced. Our technicians are on hand to assist you if you run into any problems diagnosing the issue.


    Liked by 1 person

  15. Thanks for the info Brian.
    I did some further investigation after taking off the side panels and observing the pumps and heating system running in both Hi and Lo speeds. The “Klunk” noise does not appear to be at the pump, rather closer to the heater pack / fuse panel approximately 3 feet away from pump. There is no seal leak on the pump shaft at either speed and the pump runs and seems to sound normal in both speeds.(motor is separate from pump) If the flow became slightly reduced this has been basically a gradual decline and I’m not sure how different it is from the original flow but its seems odd that this noise just started out of the blue after so many years(6) of maintenance free service and only when the Hi speed is shutdown.
    Unfortunately its winter time here and not easy to drain the tub to open up the pump to see the impeller. Also I need the “circ” pump to keep the heater working and the water warm. (hoping to know whats going so I can Shutdown and fix it quickly)
    I really appreciate your help and if you can think of anything else I could try to narrow it down let me know.

    Q1 – Is it possible for the motor/pump to appear to be running fine but actually not be …. how can I check this ?
    Q2 – Could the noise be related to too much air in pipework from a broken air mixing valves or something in the heater?
    Q3- If the pump impeller was broken or loose could it make the noise when the press of the Hi speed mode was removed?


    Liked by 1 person

  16. Hi,
    There are a couple of more things to try, give us a a call at 800-823-3638 when you have a moment near the tub. It should only take a few minutes to correctly diagnose what’s actually going on with your tub.


    Liked by 1 person

  17. I have a 4 year old plug n play Lifesmart Retreat DLX 5 person 28 jet Spa. Every once in a while, when the pump turns on, it makes a high pitched whining noise and after maybe a minute or so, it will stop. The tub seems to be working fine, keeping the temp where it needs to be. Jets work fine, etc. I’m assuming it’s the pump? It’s a Watkins Whirlpool Bath Pump – Model # 1431501-03 115v 60hz
    Thanks for any help you can provide.

    Liked by 1 person

  18. Hi Craig,
    Indeed it sounds like the motor bearings are starting to fail. The noise you’re hearing will continue for longer after each start-up, and eventually, the motor will stop working at all. We’d be happy to help you get a replacement, just give us a call at 800-823-3638 6a-5p Pacific, Monday – Friday.

    Liked by 1 person

  19. I just got an 2002 Optima 850 series and filled the tub with water and ran it maybe 1/2 hour and the temp only went up 2 degrees ( It was sitting in the sunlight if that may have help raise the temp). The heater only ohms 2.5 and has no short to ground. I’ve read where they should ohm 9.0-15.0..does this reading mean it’s faulty? The filter is clean and I ohmed the flo switch and it opens and closes according to the meter.

    Liked by 1 person

  20. Hi Pat,

    If you have a 5500W heater, you should be able to measure around 10.5Ω, & higher for a 4000W heater. If you can’t achieve that measurement, and your spa will not heat 4° or more / hour, you’ll want to replace your heater.


    Liked by 1 person

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