Identifying Spa Pump & Motor Replacements

Identifying a correct motor or pump replacement for a spa can be a tricky business: motors come in various sizes, pumps can have non-standard (up-rated/brake horsepower) ratings, sometimes the horsepower rating will be blank. Correct identification can make the difference between a profitable parts sale/service call and an expensive mess.
Lets cover some of these terms:

Up-rating – The practice of labeling a motor at higher then its traditional horsepower rating. For example changing a 2 HP pump into a 3 HP pump by only changing some of the ratings on the sticker.
Brake/SPL “Special” Horsepower – These are commonly used for even bigger “up-ratings” a 2 HP pump can change to 4.5 HP merely by changing the sticker on the motor.
Frame Size – Motors come in different sizes, we define these standard sizes by motor frame numbers. Unfortunately these motor manufactures do not agree on the terms they use for these frame sizes. For simplicity we refer to standard spa motors as 48Y and 56Y, but motor manufacturers call them all sorts of things. Some motor manufacturers even call the 48 frame motors 56 and vice versa.With horsepower ratings you cannot trust and frame sizes called all sorts of different things – what are you to do? The best weapon in our quest to identify a correct replacement is careful observation. We can identify frame size with a ruler and noting where the bolts are, we can get an idea for the horsepower by observing the amperage & voltage and find out one speed or two speed with the RPM rating. Everything we need to know is at hand you just need to know what to look for.
Below is a checklist of things we use when identifying a pump. We do not always use all of these, but the more of them you know the more likely it is you get it right.
Pump ID checklist

RPM rating
Pump brand
Pump model
Motor diameter
Impeller part number
Pump casing part numbers
Number of screws that hold the pump wet end together
Shape of the pump faceplate
Distance between motor thru-bolts and the head size.
Position of motor thru-bolts
Pump discharge location
Pump suction location
Outside thread diameter of suction and dischargeWhat do we do with all that?

Amperage and voltage – Normally the correct replacement will be the same voltage and near the same amperage.
RPM Rating – A 3450/1725 rating means you have a 2 speed motor, a 3450 rating means you have a standard 1 speed motor, a 1725 rating means you have circ pump motor, ratings of 2850 or 1425 mean you have a 50 hertz overseas motor.
Motor diameter – 48 frame motors are around 5-1/2” in diameter, 56 frame motors are around 6-3/8” diameter.
Distance between motor thru-bolts – 48 frame motors have thru-bolts about 3-5/8” apart, 56 frame motors have thru-bolts about 4-1/8” apart.
Thru-bolt head sizes – 48 frame motors usually have 1/4” heads on the thru-bolts, 56 frame motors usually have 5/16” heads.
Pump brand/model – Replacing a pump with exactly the same pump will ensure a good fit. With most pump models only one motor size fits, eliminating a lot of the frame questions.
Pump case/impeller part numbers - These will usually lead to a particular pump model, and the impeller numbers to a model and horsepower. If there are no part numbers we can use basic shape and number of screws to try and narrow down to a pump model.
Outside thread diameters (where the plumbing hooks up) - The common thread sizes are 1.5” Buttress = 2-7/16” diameter, 2” Buttress = 3-1/16”diameter and 2.5” Buttress = 3-11/16” diameter.
Thru-bolt locations – most motor bolts that attach pump and motor are located at 11:00, 1:00, 5:00 and 7:00 O’clock. If yours are located elsewhere, ask before ordering a motor.
Pump discharge location – some pump discharges are located directly in-line with the motor shaft (they may be straight up or point left or right) we call these “center discharge” pumps, some pump discharges are set off to the right side of the wet end we call these “side discharge” pumps.
Pump suction location – most pumps have the suction is in the center of the wet end, 100% Drain pumps have them lowered to the bottom.As you can see there are a number of things to consider when selecting spa pumps and their parts, if you follow the guidelines above you will find it is not hard to get it right. If you need assistance call our dedicated expert support team at Spa Parts Plus, we are here to help.

This is but one of the problem areas customers find themselves faced with when trying to make a repair themselves.

What I will need to schedule your Appointment

First of all in most cases serial numbers will not help me over the phone.The Industry has never published a cross reference on spa matching serial numbers to manufactors products. The biggest single helpful information is "WHO MADE THE SPA" the second is the year it was made. Having been in business for over 25 years I have a library on spas as well as an extensive database. Given proper clues  I can usually identify what you have. Lastly a discription of the Control panel on top of the spa helps greatly narrow things down.

The Day of the Appointment

In most cases I will need the spa filled with water. Unless you have a monster leak and water gushes out as fast as it goes in this rule is designed to save me time and you money.. Have someone there that can make decisions about the spa. If your household Circuit breaker panel is located inside the home or inside the garage access will need to be granted should that become necessary. And because appointments vary wildly it might be usefull to have your schedule clear should more time be required to make the repair.


 In most every case the spa is refilled and tested. I have found that much like cars the repair needs to be tested. This checks to make sure it does not leak,the heater comes on and the pumps all work. That having been said it takes sometimes 24 hour for the spa to go through it's first cycle after the repair is made. anything can happen and generally does. That is where my Warranty comes in


Astricts (from Above)

​ * The Reset button on a plug in style gfi restores power the test button turns power off

​** Power Fuses are large, normally Green and Silver or Orange and Silver in color.Logic fuses are Glass style fuses.

​*** Air can enter the pump and prevent the pump from priming.This happens on draining.Until the air is removed the spa might make a humming sound but there will not be water going through the filter or the jets.

What to do before the repairman comes

First of all check the Obviuous. Cord plugged in the GFI reset* In some cases there were door switched installed that disabled the spa (Pre 1995 models) if the door was opened.  If you feel brave there might be fuses inside the control box that need replacing**. Does the pump try to come on? Was the spa drained recently*** is there more than one circuit breaker for the spa?

On one brand of G.F.I. breaker the test button can hangup in the test position. Gentle pry up this test button with your fingernail and try to reset the GFI breaker. If the Breaker handle moves immediately to the trip position...Stop!

the spa may be unsafe to use. 

Android Text /Voice       916-532-2211    Fax 916-988-2729

​Folsom and Roseville 916-988-8606 and 916-850-2660

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