1. Spa Pump Voltage (v)

This is an extremely important first step.  Installing a pump with the incorrect voltage can either work in a diminished capacity, not work at all, or cause severe damage to the new motor, and/or your spa control system.  Voltage ratings can be found on the pump motor spec sticker.  They are usually identified by “Volts” or “V” and labeled as 115v or 230v.

Can be found on motor spec sticker.

Finding Voltage on Your Spec Sticker

Finding Amperage rating on Your Spec Sticker

2. Spa Pump Amperage

Every model of motor is tested and rated for how much power it will draw while operating.  The amperage rating is a true measurement and far more accurate than a horsepower rating.  (See “Horsepower vs Voltage/Amperage”) for more information.  Amperage can be found on your pump’s motor spec sticker and usually indicated by “Amps” “SFA” or simply “A”.  Single voltage dual speed pumps will show 2 amperage ratings for example, 12.0/3.5. The larger representing high speed and the smaller will represent the low speed.  Dual Voltage (115v & 230v) will also show 2 amperage ratings. Although they are single speed, the 2 amperage ratings will reflect how much power is being drawn when wired 115v, or 230v.  230v usually pulls about half the amperage of 115v.

Can be found on motor spec sticker.

3. Spa Pump Frame Size

For our purposes, frame size refers to the mounting size of the motor.  It does not refer to the diameter of the motor, power capabilities, or any other aspect.  Although larger frame motors tend to be larger overall than smaller sizes, this is not always the case.  It’s not uncommon to find pumps that share the same overall specs available in multiple frame sizes.  Selecting the wrong frame size when choosing your new spa pump can result in installation problems, incorrect plumbing alignment, and other issues.

Frame size is usually stated on the motor spec sticker; however, you can also measure your existing pump to determine exactly which you should choose.  Using a tape measure or ruler, measure center to center between the top 2 mounting posts.  The mounting posts are part of the wet end that extend out to connect to the motor with 4 long “through bolts”. This is the most accurate way to determine frame size. 48 Frame = 3-5/8”     56 Frame = 4-1/4”

Can be found on motor spec sticker & physical measurement.

5. Spa Pump Plumbing Connection Size

Plumbing connection size is also very important when choosing your replacement spa pump.  Make a mistake, and the plumbing simply will not connect.  With just a couple of simple steps, determining your connection will be fast and easy.

The most effective way to determine connection size is to measure the outer diameter (outside thread to outside thread) of your pump wet end intake and discharge.  It is important to remember that some models of spa pumps contain different size connections for each.  For example, you may find that your suction is 2.5” and the discharge is 2”.  To make it even more confusing, there are different types of threads that will physically measure differently than how they are labeled. For example, a 2” Buttress Thread physically measures 3”.  Buttress threading is common on most spa pumps.  Buttress connections utilize a threaded union to attach the pump wet end to the plumbing.  To measure, close valves to isolate pump, or drain the spa.  Unthread the unions and measure the diameter of the male threaded connections on the pump wet end.  Be sure to measure both the intake, and the discharge.

** Be sure to always use the Buttress Measurement when choosing your pump connection size ***

Can be found by physically measuring.

6. Original Manufacturer of Spa Pump

It may not seem important to know the original manufacturer of your pump, however it can be extremely helpful when it’s time to replace it.  Most manufacturers tend to stick to the same types/sizes of plumbing connections; however, the overall size of the wet end can vary.  A good example of this is if the height of the intake from ground level differs from your existing, it can make it very difficult or impossible to use as a replacement.  Variations in height, width, and diameter all play a part in what will line up with your existing plumbing.  This is almost always the case when the plumbing in your spa is extremely rigid, meaning it cannot move at all to align with a different size and shape wet end.  Most pump brands will be sure you know exactly who produced it.  Typically, manufacturers will mold their logo on to the wet end, or place stickers on either the motor or the wet end itself. 

*** Be sure you are retrieving the manufacturer of the pump as a whole, and not the manufacturer of the motor itself. ***

Can be found on pump label.

7. Spa Pump Model and Serial Number

Knowing the model number of an existing pump can help in the search for your new spa pump.  Manufacturers tend to reproduce the same models year after year, and very rarely make major changes to an existing line.  The amperage ratings, or flow information may change, however physical changes are rare.  Matching the exact model or another brand that is considered a substitute, can make the process a bit easier.  It is also important to know where to find the serial number of a pump.  Typically, it won’t be helpful unless there is a warranty issue.  Serial numbers are not normally published publicly, so using it during your search will not yield the results you are looking for.

*** After purchasing your new spa pump, be sure to write your model and serial number down and keep in your records. ***

Can be found on manufacturer pump label.

Finding your Model and Serial Number