How-To Guides | Spa Pump Repair & Replacement

A common problem with older spas is pump failure. We will guide you through spa pump replacement, restoring your hot tub for many years of enjoyment. If your system is more than 2-3 years old, replace the entire pump, not just the motor or wet end. You'll have fewer headaches in the long run.

Caution: Electrical repairs can be dangerous, especially around water. Repairs must be made by a qualified electrician or spa technician. Regardless of who performs the work, disconnect all electrical power to the spa prior to making any inspections or repairs.

Shut power off at the service panel, and as a secondary precaution, disconnect the power to the spa as well. Do not attempt to perform electrical repairs unless you are qualified.


Anatomy of Hot Tub Pumps

Pumps have two main components: the wet-end, which moves the water, and the electric motor, which drives the wet-end.

Symptoms of Spa Pump Failure

There are several signs of hot tub pump failure:

  • Humming noise from motor not turning, frozen shaft, bearings or impeller, or defective starting capacitor
  • Whining noise from worn bearings
  • Leaks under the pump from a failure of the pump seals.

You could replace these components by themselves if you can find the proper parts. But if your pump is older, replace the entire thing. As the other pump parts fail, you will have to replace each one for a higher total cost. You'll save money - and time - in the end.

Replacement Hot Tub Jet Pumps

Removing the Old Pump

Disconnect power & read safety warning!

Spa Equipment Access

The best way to pick the right replacement pump is to remove the old pump first. You will be able to make inspections and measurements for a correct match.

After unhooking the electrical power, remove the spa's access panel.

Some hot tubs will have two gate or slice valves installed at either side of the pump. If so, close these valves prior to removing the pump. If there are no valves, drain the spa.

Disconnecting the Old Spa Pump

  • Disconnect the bare copper bonding wire from the pump's ground terminal.
  • Unscrew the pump's two unions. Some remaining water will drain out.
  • Remove the mounting screws from the pump base bracket.

You can lift the pump out of the hot tub with the power cable still attached to the control system.

Cable Detachment

Reuse the old power cable* for the replacement pump if it is still in good condition.

  • Loosen the cable clamp screws
  • Remove the access cover with terminal connections inside at the motor end of the pump
  • Remove the cable, making a note of wire color codes and connections
  • Check if wire ends are clean. If needed, snip off an inch or two, and re-strip the wires

Most spa pumps are two speed units, with the low speed used for filtration and heating cycles. Two speed 240V pumps have 4 wires: red, black, white, and green. Red is normally low speed, and black high speed. The white wire is common and the green is ground.

*Note: If you are also purchasing a new spa control system from us, you can discard the old pump cable. A new one is provided with the new spa pack.

Determine Pump Voltage & Horsepower

While all 110-120V spas use 120V pumps,  not all spas wired for 220-240V use 240V pumps.  Some use 120V pumps.  So check your owner's manual, and look at the label on the old pump to determine the voltage.  The label should also indicate the horsepower and amperage.  See pump specs for a cross reference.

Some people desire to increase the spa jet action by upgrading to a larger pump.  As a rule, this is not a problem. Check the spa's control system and the electrical service though; to be sure it can handle the added amperage.

As a guide, do not increase the pump horsepower more than one level of magnitude.  For example, upgrading a 1HP pump to 1.5HP, or a 3HP pump to 4HP is within reason.  Avoid jumping from 2HP to 5HP, as such a large increase will cause problems. Excessive jet pressure, extra current draw, and pump damage are just a few examples.

Determine Form Factor: Side or Center Discharge

The two spa pump form factors refer to the outflow or discharge fitting on the Wet End. Your old pump will be either Center Discharge or Side Discharge.

Orientation of Wet End

Pump wet ends can be rotated in 90° increments.  Loosen the pump's four through bolts from the back of the motor and pull them back enough to disengage.  Then rotate the wet end to the desired position, realign and re-tighten the bolts.

In most cases you need to match the existing form factor to get the components to match up. If you can use either form, select Side-Discharge, which is more efficient than a Center-Discharge pump of the same horsepower. See Pump Selection Chart

24-HR Circ Pumps

In addition to the main pump, some spas also utilize a small 24-HR circulation pump.  Most spa circ pumps have 3/4" barbed fittings for flex hose, which makes replacement very easy.  See Circ Pumps

Motor Frame Size

The physical size of the spa pump motor is referred to as frame. Spa main pumps have a size of either 48 frame (approx. 5.5" diameter), or 56 frame (approx. 6.5" diameter). Check the old motor's ID plate for frame size.

If in doubt, you can easily determine a motor's frame size by measuring the spacing between the through-bolts.

Bolt spacing on a 48 frame motor will be less than 4 inches. A 56 frame motor's bolts will be spaced more than 4 inches apart.

Note: Because of their lower cost and compact size, most spa pumps in service are 48 frame. Larger 56 frame motors are a little more expensive and somewhat stronger. They tend to operate a bit cooler than 48 frame units, which can mean longer service life.

Determine Pump Plumbing Size

Plumbing size is very important, but a lot of people get it wrong and end up ordering the wrong pump. Most spa pumps use either 1.5" or 2" plumbing fittings, and a few have 2.5" intake suction. These are pipe call-out sizes, not fitting measurements.

With the pump unions removed, measurement is simple. The easy way to get it right for most* pump brands is by measuring the overall outside diameter (O.D.) of the pump's threads:

  • 1.5" Pump thread measures approx. 2-3/8" O.D.
  • 2.0" Pump thread measures approx. 3" O.D.
  • 2.5" Pump (intake) thread measures approx. 3-5/8" O.D.

*Most pumps normally have a 2.0" discharge thread fitting, which measures about 3" O.D. Some brands of pumps (such as Hayward, Jacuzzi, and Sta-Rite) use non-standard fittings with different dimensions. Please contact our Parts Technical Help for assistance with these if in doubt.

Installing the New Pump

The installation of your replacement pump is essentially the reverse of the removal process described above. Once again, verify that the power is disconnected from the spa before proceeding.

Connecting Pump Power Cable

Most spa pumps are two speed units, with the low speed used for filtration and heating cycles. As explained below, two speed pumps can easily be configured for single speed use.

  • Remove a wiring plug from the new pump motor end and install a cable connector clamp.
  • Remove the wiring access cover from the end of the new pump motor.
  • Attach the pump power cable wires and ground per pump's wiring diagram.
  • Replace access cover.
  • Tighten cable clamp.

Make sure the wire ends are clean for a good connection to your new pump. Our replacement pumps have a label diagram showing the wiring scheme.

Two-Speed Pump Configuration

A two-speed pump requires 3 line connections, plus a ground wire. The typical color coding is as follows:

  • White: common
  • Black: high speed
  • Red: low speed (left blank for 1-speed use)
  • Green (or bare): ground

Refer to the wiring diagram on your pump, as some equipment systems use different color coding. Wire orientation may vary on different pump brands.

One-Speed Pump Configuration

Two-speed spa pumps can serve single-speed duty, common in dual pump hot tubs. Simply use the common and high speed terminal connections, while leaving the low speed terminal blank.

Note: Your spa filtration or heating cycle should come on with high speed instead of low speed after pump replacement. If it does not, simply switch the high and low speed wires.

Setting Up the New Pump

  • Reattach the bare copper bonding wire to the pump grounding terminal.
  • Set the pump in place, carefully aligning it to the union connections.
  • Start the base mount screws, but do not tighten them yet.
  • Hand tighten the unions. Do not use a wrench.
  • Tighten the pump base screws.

You may be able to reuse your old unions, or you can order new ones to match your plumbing size.  We also have a special reducer union (#BX9924) which will convert a 2" pump to match 1.5" spa plumbing.

Most spa pumps are designed for below water level (flooded suction) installation, to make certain that they fill with water. Their unions are compression fittings. Correctly align the male wet-end threads with the union, allowing the integral O-ring to seat properly.

Flooding the Pump

If you have drained the spa, refill it with fresh water. After installation and wiring, but prior to powering-on the spa, open the valves, if so equipped, to flood the pump.

IMPORTANT:  Purge the pump of any remaining air pockets by loosening the pump unions until all air has escaped. Leave the union loose for 5-10 seconds, then hand re-tighten them.  Running a pump dry will cause damage and void the warranty.

Testing and Inspection

  • Inspect the installation to verify that everything is properly connected.
  • Mop up any spilled water.
  • Reconnect power source.
  • Operate spa for a few minutes and observe for leaks or air locks.
  • Replace equipment bay access door.

About Voltage Numbers

In the U.S., standard household voltage (the voltage at regular wall outlets) varies from about 110 to 120 volts.  TVs, computers, lights, etc. are designed to run at this range.

Major appliances like ovens and clothes dryers, are usually wired at double that amount, from 220 to 240 volts. Spa motors are designed for one of these two ranges.

A voltage specification of 115 volts means it will function correctly in the range of 110 to 120 volts. A device listed at 230 volts actually means it will function correctly in the range of 220 to 240 volts.

Watts = Amps x Volts. Amperage determines the size of wiring and circuit breaker/GFCI required. It is also a factor in what your equipment controls will accommodate.  Wattage is the total amount of power consumed.  Note that a 120-volt pump drawing 16 amps uses virtually the same wattage as a 240-volt pump drawing 8 amps.

Replacement Pump Specifications

Our replacement pumps are designed to equal or surpass OEM specifications. These 2-speed pumps are easily configured for 1-speed use if needed.

Pump Speeds:
Low 1725 RPM
High 3450 RPM

Pump HP Hi/Lo Amps In/Out Discharge Frame
Pump HP Hi/Lo Amps In/Out Discharge Frame
BX4118-S22.5 (4.0)12.02.0"Side56

*Specifications subject to change without notice.

Replacement Spa Pumps

"The new pump really made a difference in the hot tub's water flow and I will tell you we've noticed it also runs a lot quieter. My old spa is now purring like a kitten and getting good use once again. Thanks for all your help and for saving me $300+."

Terry Bacon
Toledo, OH

"I just wanted to post a little feed back, I am the type of person that let's businesses know when they do something right, or get it all wrong. I called one of the local franchise pool supply companies for a spa pump, the price they quoted me was over $100 more then the one I bought from you. Your free delivery was on time, and your website had exactly what I needed for wiring tips. I will definitely go to your site when I need a new spa power pack, and will tell my friends that own spas about you.

You got it ALL right."

Bob Link
Merritt Island, FL

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