Know your hot tub; Know your pump

17 September 2021  |  Superior Wellness

Know your hot tub; Know your pump

Owning a hot tub is wonderful. The bliss of being able to switch it on and unleash the therapeutic power of the jets is something you can’t live without if you have experienced it. But there will come a time when something may go wrong. You may have had your hot tub for a few years. Either way, getting to know your pump, its specifications, capabilities and limitations is vital in enabling you to make the right choice when buying a new pump. It’ll save you money in the long run as well.

What does a hot tub pump do?

Basically, your pump is the beating heart of your hot tub set up. Your pump or pumps are responsible for circulating the water around your hot tub and powering your jets. If you have a two pumps, they will probably be single speed. One for circulation and one for powering your jets. If you only have one pump then it will be variable speed, powering both the circulation and jets. The speed of your pump is measure in revolutions per minute (RPM) and the amount of water they can shift is measured in gallons per minute (GPM). Typically, single speed circulation pumps use less power and move about 25GPM of water. In contrast, variable speed pumps vary in power, capable of moving 100 – 260GPM.

What are the parts of my hot tub?

Knowing your hot tub specification may seem a little dry but it is vital so that you can recognise when something is going wrong, and then make a judgement about whether or not it is worth repairing. On pumps over 5 years old, for example, it is often more cost effective to replace the entire pump rather than fixing the problem.

The specification of your hot tub is often found printed on a label on the side of your hot tub. Read it. It will also help you in that important process of replacing or upgrading your pump or pumps. The key parts you need to be aware of are:

Wet and dry ends
Horse power
Frame size

Wet and dry ends

Hot Tub Wet EndThe end of your pump that connects to the plumbing is the wet end of your pump. It contains the impeller, which pushes the water through your system and circulates it around your hot tub. The dry end is where the electrical components are housed that power the impeller. If water enters this end of the pump then the whole system will break down.

The impeller can be the source of some hot tub problems. It can get clogged or clocked with residue which can prevent circulation. This can be remedied by cleaning or replacing the impeller. However, in some cases it is wiser to replace the whole pump.

Horse Power

Like with your car, the horse power of your hot tub pump refers to the power output – how quickly it can push the water around the system. Most pumps have between 1hp and 5hp. Don’t be tempted to just buy a bigger pump. You need to make sure you have the right plumbing to harness that power of your pump effectively.

Frame Size

Pumps come in all shapes and sizes. Frame size refers to the housing around the pump and where the holes are to bolt it into your hot tub. Look at your set up carefully to make sure the pump you are choosing can be fitted securely into your set up. The two frame sizes on the market are usually 48 frame and 56 frame. On a 48 frame the fixing bolts holes are a little under 4” apart. On a 56 frame the fixing bolt holes are just over 4” apart.


This refers to the place from where on the pump the water is pushed. This is usually on the top or on the side, and with many pumps you are able to turn them so it fits the set up in your hot tub. Check your pump before you pick a new pump to make sure you can fir it into your system.


This is the final factor you need to consider before replacing or upgrading an old pump. The plumbing is the diameter of the pipes attach your pump to your system. The pipe sizes in your system can range from 1.5” to 2 5/8” so be sure to check these again as you may need to buy new unions so your pump fits snugly into your system. For more help with this have a look at our

Handy guide: Hot Tub Pump Unions

This blog article was written by Hot Tub Help - 17/09/2021 All rights reserved