If a hot tub is like the human body, then its pump is like the heart. The spa pump’s job is to keep the water in the hot tub moving, so the heater can raise the water’s temperature before the water shoots out of the jets. Without the pump, the hot tub’s water stays cold and stagnant.
Some problems, such as air locks, are easy to fix. Screeching noises caused by bad bearings and weakened jet strength due to a broken propeller are more serious. These problems spell the end of a pump’s useful life.
No matter your diligence to its maintenance or the quality of the pump, spa pumps eventually wear out. You can hire someone to fix the pump, but you’ll pay triple the cost on the repair than the price of a new pump. In other words, replacing the hot tub’s pump makes more sense than repairing it.
The models we reviewed give you the most value for your money. Although spa pumps are not universal, most can fit a variety of hot tub setups. To make sure you choose one that will work with your hot tub, we also put together a buyer’s guide full of specification and sizing information.
This website is supported by readers. As an Amazon Associate we earn from qualifying purchases.
Best Spa Pumps
Spa Pump Buying Guide
Choosing a spa pump can be tricky. However, the pump you already have can give you a baseline of information that will help you pick your new one. Usually, all the specs are located on the pump’s label, including voltage and horsepower among other values.
For some specs, you do have a little leeway. With other factors, you must make an exact match. Our spa pump buying guide explains all the options you have, and it will show you how to size your new pump properly.
Some spa pumps operate on one speed while others can change between two speeds, which are expressed in RPM. To make sure the pump can keep up with the number of jets in your hot tub, it’s best to stick with the same speed as your old pump.
Push the jet button on the hot tub’s control panel twice to find out if it’s a one-speed or two-speed model. If the speed increases the second time, you’ve got a dual-speed spa pump.
Spa pumps produce anywhere from a fraction of a horsepower to 5 HP. If you feel that the jets’ water pressure is just right, stick with the same HP as your old pump has. If you want more pressure, you can safely bump the HP up to 1.0 with the new spa pump. Going above this slight increase may be too much for the hot tub’s piping system, causing leaks to occur.
Service Factor (SF)
If a service factor (SF) is listed on the spa pump’s label, you won’t be able to judge the pump’s horsepower at face value. Instead, you’ll have to multiply the written HP by the SF to find out the total brake power. The total break power is the pump’s true HP, and that’s the figure you need to compare.
There are a few factors to consider if you want to keep your electricity bill as low as possible. The higher the pump’s horsepower, the higher your bill. For that matter, the same rule applies to the voltage. A 240-volt pump requires more electricity than a 120-volt spa pump.
Another way to determine if a spa pump is a one-speed or two-speed model is to look at its amperage rating. If you see two amperage measurements on the specs sticker, you definitely have a dual-speed spa pump.
Keep in mind that although the electrical system can handle a higher amp load, a hot tub pump is engineered to perform at a specific amperage. You can get a higher-amp pump than the one you have, but don’t go overboard. Remember, the higher the pump’s horsepower, the more amps it will draw – This is yet another reason to slightly increase the HP, if you do so at all.
The spa pump’s voltage must be compatible with the hot tub’s wiring. Most hot tubs are wired for 240 volts, but there are some that use 120 volts. A 115-volt spa pump’s power supply will have two wires while a 230-volt model will have four wires. If you install a 115-volt pump in a 240-volt hot tub, the pump will not work.
When sizing a pump, you must consider the number of jets in your hot tub. The more jets the tub has, the higher the pump’s speed needs to be.
The spa pump’s flow rate is measured in gallons per minute, and the GPM must be high enough to meet the flow rate for the number of jets. The diameter of a jet’s opening determines its flow rate, and every spa jet requires a certain GPM level to function correctly.
As with the true HP, a simple multiplication formula will tell you the maximum GPM you need from your new spa pump. Add the number of jets in your hot tub and multiply that number by the flow rating for one jet. The answer is the GPM the pump must produce.
Wet End Discharge
The wet end of a spa pump is where the water exits the pump. Spa pumps with an adjustable discharge on their wet end are the easiest to install because you can situate the discharge port the way you want. If the wet end’s fittings aren’t one-size-fits-all, you may need to replace the unions when you switch out your old pump for a new model.
On a spa pump, the place where the pump’s motor connects to the wet end is called the frame, which comes in a size 48 or a size 56. These numbers correspond to the distance between the bolts that secure the wet end to the motor, and you must get the same frame size as you had before.
Usually, the label will have a 48 or 56 next to the letter F. If it doesn’t, you can measure from the far edge of one bolt to the far edge of the bolt below (or above) it. If the distance is fewer than 4 inches, the pump has a 48 frame size. If it’s 4 inches or greater, the frame size is 56.
Every hot tub has a filter, which is rated at a specific flow threshold. If the spa pump puts out too much water pressure for the size of the filter, the filter will cease to function efficiently and most likely fail prematurely. However, if your hot tub’s filter has a bypass valve, it can withstand the higher water flow that’s produced when a dual-speed pump’s impeller spins at its top RPM.
How Do I Measure the Spa Pump’s Discharge?
You want to make sure the spa pump will fit the hot tub’s existing plumbing network. To do so, all you need is a simple tape measure. Start from the outside diameter and measure across to the opposite end on the outside. The measurement will either be 2.5 inches or 3 inches. Take the measurement and subtract it by 1 – The answer should correspond to the pipe size of 1.5 inches or 2 inches.
How Do I Prime the Pump?
Air locks are an inevitable nuisance that prevents the spa pump from circulating the water. To remove trapped air and restore the pump’s functionality, you’ll need to prime the pump in one of two ways. Some spa pumps prime themselves. Usually, self-priming pumps don’t require human intervention, but sometimes they do.
One priming method involves the hot tub’s control panel. You can only try this method if the panel has a priming button. Activate the spa’s priming mode and turn on the jets for 20 seconds at the lowest possible speed. Then, crank up the water flow to the highest speed for an additional 20 seconds. Alternate between both speeds until the air bubbles and/or gurgling noises are gone.
The other way to prime the pump is to do it manually via the bleeder valve. Before you begin, turn off the circuit breaker. Next, close the discharge’s gate valve. Once you start turning the bleeder valve, you’ll hear hissing air. Your cue to stop turning it and tighten the valve is when that sound stops. After that, flip on the breaker and test out the jets.
How Long Should My Spa Pump Last?
Spa pumps are designed to last anywhere from 5 to 10 years. Debris is a pump’s worst enemy. To get as many years of useful life as possible from your spa pump, routine maintenance is a must-do.
Luckily, it isn’t hard to maintain your spa pump. Inspect and clean the filter regularly to prevent debris from damaging the pump’s impeller. Also, keep the water’s pH level balanced. If the pH is too high, the pump’s components will begin to corrode. If it’s too low, scale buildup will clog the filter and pump.
Finally, make it a point to check the pump for leaks every once in a while. If you spot a leak, replace the seal. As long as you stick to a regular maintenance schedule, you can maximize (and maybe even exceed) the spa pump’s lifespan.
Spa Pump Buying: Recap
Since it’s the center of a hot tub’s water circulation and jet pressure, the spa pump will make or break your hot tub experience. While all of the pump models on our list are excellent performers, only some may be suitable for your hot tub.
You must take into account the amperage, horsepower, frame, flow rate and voltage in order to correctly size your new spa pump. Once you figure out the specs you need, selecting one of the spa pump’s we’ve reviewed will be easy.