What Do I Need to Know About My Spa Pump?

When we get calls from customers looking for help, we get more calls about spa pumps than anything else we sell. There are a few things you should know about your pump that will help you when trying to restore/ replace it.

A very common problem in older spas is the failure of the hot tub pump. Restoring your pump can give you many more years of enjoyable use out of your hot tub.

First of all let’s start with the anatomy of the pump. The pump has two main parts the “wet” end and the “dry” end. The pumps wet end houses the impeller which moves the water; the dry end houses the electric motor which moves the impeller.

As these two parts are separate it is possible to replace just the wet end or the motor, however if your entire pump is more than 2-3 years old we recommend replacing the entire thing. Replacing the entire spa pump will save you headaches in the future.

If you are going to replace the entire hot tub pump there are a few things you will need to know when looking for a new pump.

· What is the horsepower of the pump that you are replacing? Although you can use a different horsepower pump than what was originally used, it would change the pressure of the water flow coming through your jets. When the manufacturers choose a pump they base the horse power on the number of jets being serviced. It is recommend that if you choose to use a different horsepower that you do not increase by more than one level. Therefore increasing from a 4 HP to 4.5 HP, or 2 HP to 3 HP, should be okay but you would not want to go from a 1 HP to a 4 HP, as this could cause you problems later on with your equipment.

· What is the speed of the pump? Generally your pump is either going to be a 1 speed or a 2 speed. If you cannot locate the speed on the pump you can tell by how the pump normally supplies water to your jets. If you push the button once do your jets come on low and then pushing it again takes them to a higher speed? If so this would be a 2 speed. If you are still not sure check the AMPS listed on the pump, if only one number is listed chances are you have a 1 speed, if two numbers are listed, it most likely a 2 speed pump.

· What is the frame of your pump? The “frame” means where do the bolts fit that attach the wet end to the motor. Most of the time you can find the frame listed on the label as either 48 or 56. Often with an F indicating that is the “frame” size. If you cannot find an indication of frame size you can measure between the thru-bolts on the pump. A 48 frame will be less than 4 inches between the bolts; a 56 frame will be more than 4 inches between the bolts.

· What is the voltage of the pump you are replacing? The best way to know this is to consult the label on your current pump or your hot tub’s owner’s manual. This is important to check because not all spas that are wired for 240V use 240V pumps some only use 120V pumps.

· The last thing you need to determine is what is the size of the plumbing in your spa? Both the plumbing that takes the water into the pump and the plumbing that takes the water out of the pump. It is common for people to get confused here and want to measure the size of the hole on their wet end---DO NOT do this! You need to look at the PVC pipe within your spa and see what the diameter of the pipe is. This is the size that you will want to use when finding a pump or pump fittings. Most spas will be the same size for both the intake and outtake pipe but be sure to double check just in case yours is one that is not.

After determining all of this information about your pump you are now ready to shop for a replacement. Here at Hot Tub Warehouse we have a large selection of replacement hot tub pumps and any other spa parts you may need.

18 thoughts on “What Do I Need to Know About My Spa Pump?”

  • bob davies

    I just had a 650 gallon swim spa installed with 18 5/16" rotational jets ,so I am not using it as a swim spa but rather a regular spa, my old spa had 8 jets and the pump was a standard 2 hp. with my new 18 jet spz the pressure at the jets is mimimal do I need a high pressure pump and if so what one, thanks PS all piping is 2"

    • Kasey

      After speaking with one of our techs, he would probably recommend the Waterway Viper that is 2.5" but made specifically for swim spas. The largest pump we sell for 2" plumbing is the. It may also be a good idea to ask the swim spa manufacturer what they would recommend. Thanks!

  • Jerald

    I have a hot tub, it did not come with the motors. I have no clue what I need... Can anyone help?

    • hottubwarehouse
      hottubwarehouse April 23, 2014 at 9:20 am

      Hi Jerald. It is very difficult to recommend the correct pump if you have no information about the previous one and as we are not there to look at your tub. I would recommend either having a local spa technician come take a look to let you know what you need or if you know who the hot tub manufacturer is you could also contact them for information about what size pump goes in that tub. Once you are able to determine what kind of pump you need we are happy to assist you in finding it.

      Thank you.

  • bob

    Hi, I need to replace my two spa pumps. The first was a 6HP one speed pump. The second was a 6 HP two speed pump. I was told that I could downgrade the 6hp two speed to a 3.5 hp two speed. Does this make sense? I was told the 6hp pump was overkill. I was concerned because the original pumps came with the spa.


    • hottubwarehouse
      hottubwarehouse October 8, 2014 at 1:01 am

      You want to keep your pumps as close to the originals as possible in terms of water flow they can produce. The other tricky part is that a lot of pumps are considered 6HP are really only 3 or 3.5 HP. The 6HP rating could be the brake horsepower and the continuous would be 3 or 3.5. You want to look to see if there is a sign for the continuous HP with a 3 or 3.5 next to it on the label.

      I would assume the 6HP is the Brake HP since I don't know of any of the major brands of pump manufacturers that make a 6HP. A lot of spa brands will list the spa pumps Brake Horsepower to make it look bigger and better but the continuous horsepower is truly what your pump is running.

      I hope this helps.

  • Greg

    My 2004 Marquis Euphoria hot tub has two pumps (Ultra Jet MP130 and MP160) What is the purpose of a two pump system? Does one pump serve different zones that the other? Or do they work in series somehow? I'm trying to figure out why one of my zones seems to have only about half the waterflow as it did when new. The other zones seem to have waterflow similar to when the hot tub was new. I've requested a plumbing diagram from the manufacturer, but was informed they don't have those available to customers.

    • Angie Treasure

      Hi, Greg. Hot tubs often have multiple pumps to handle the workload of all the jets in order to keep maximum circulation. It's most likely that the zone that has a lesser waterflow is not being fed properly by the pump. I found an online manual of the pump system for the 2004 Marquis Euphoria (on page 50) if that will help you solve the problem. Good luck!

  • Bassam

    Hi there, I'm buying the jets and the pump for my outdoor concrete spa, the design accommodate 5 seats, thus we agreed on 10 jets, my first question is shall we make it 2 for each seat (one for the back and one for the feet) or the best practice is to use more number of jets per seats (what is the normal efficient number of jets and the diameter of each jet)
    second question is about the calculation of the right pump according to the designed jets, I mean how to determine the capacity of the pump according to the number of jet, they told me things has to be determined according to gpm for each jet multiplied by number of jets, but not one told me how to pick the right pump accordingly
    thank you in advance

  • Andrew

    My pump will click on and hum for a second and then shut off without doing anything. It's also very warm to the touch. What could be wrong?

    • Kasey LaRose

      I would recommend you have a service tech take a look at it, but based on your description it sounds like the problem could be the capacitor. Keep in mind, it's impossible for us to diagnose from here, but hopefully that gets you on the right track.

  • Kyle F

    I purchased a used spa without a pump on it. The owner did not know if it was a 48 or 56 frame pump. It's a 220V, 1.5HP, 2 speed pump. Does it matter if I put in a 48 or a 56 frame? I know sizing is a little different but I can alter plumbing to make either fit. So if it originally came with a 48 frame, would it do any harm to rig in a 56 frame?

  • Mike

    My spa currently has a Ultra jet pump and i need to replace it. Can it be replaced with any brand as long as the specs and inlet/outlet are the same?

  • Darlene

    I have a 2up pump on my hot tub can I use a 5 up pump?

  • Jarrett

    Hi.. I recently bought a used, 2001 Catalina model hot tub. When I started it I noticed the the jets on one side in lounger area were not working, after investigation , I found out that one pump was not working, the system has three pumps in total.. the pump that doesn't work however is on the opposite side of the lounger where the jets aren't working.. do this sound like the failed pump is responsible for the jets not working?

  • Steve

    Can you put a 3HP wet end thats fits on a 2.5HP dry end if it's your only option. Could this potential work?

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