As on the picture.
Pump and motor assembly. Removed from the American Standard hot tub spa bath where the tub was damaged during shipment. Like new. Never run or used. Base, power cord and air switch included as shown on the picture.
Ultima II Pump, 1 speed, Part Number 752444-300, High Performance 1.1 rated.
CSA model number PUUTAS1198P,
UL model number PUUTSCAS1098BR,
Volts 115, HZ:60

GE motor A-C Thermally protected.
Mod: 5KH36JN3632BX
RPM 3450
A 9.9

Must use dedicated line, GFI (GFCI) protected. Copper conductor only. Grounding connector on top of the unit is copper.

Basic Spa Pump Design:

Basic Pump Operation and Description

Pumps used in pools and spas are centrifugal type pumps.  Water is pulled into the center end fitting, called the suction, and sent out through the exit fitting, called the discharge.  In virtually every implementation the discharge is at a 90 degree angle from the suction.  There are a few exceptions in this, namely the Aqua-Flo® pump that is used in older 'Mr Spa' applications, and some Acura® spa pumps.  The flow-isolator shown above, is not on all pumps, and is used to allow a higher pressurization of the pump cavity.  Without it, the output from the impeller will feed back into the suction, reducing pump output.

Rotation speed is counter-clockwise (viewed from the front), typically 3450 RPM in a single speed pump, and 1725 and 3450  RPM in a two speed version.

Pump motors are brushless, and the rotation speed is primarily dependent upon the line frequency of 50 or 60 Hz.  Because of this design, the speeds can't be changed since the pump is 'hardwired' for these specific speeds of operation.

The diagram above uses a 48 frame through bolt motor, which is the most frequently used in the spa industry.

Motor manufacturers: A.O. Smith®, Emerson®, Franklin Electric®, General Electric®, and Magnetek®.

The business end of the spa pump, the part that moves the water, is called the 'wet end'.

All 48 frame through bolt motors, with a threaded shaft, are generally interchangeable among different manufacturers.  That is, if you remove the wet end from a GE motor, you can re-install it on any of the other manufacturers pump motors with a similar horsepower rating.

The most commonly found problem in existing spa pumps, is the failure of the pump seal assembly, located between the impeller and the volute (back of the wet end).  The end result is usually the destruction of the impeller because of rust creeping back up the shaft, and in severe cases, the pump bearing will fail, requiring replacement of the bearing or the motor. 

The cause for seal failure is usually the lack of proper water quality management.

Pump FAQ

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I am in the process of replacing my pump assembly.  Can I replace my 3/4 horsepower pump with something bigger, such as a 1.5 or 2 horsepower?

Yes, however, you might think that having more output on your jets may be a good thing, it can also work against you... and the jets could end up almost being painful, or too strong that you can't sit in front of them for more than 2 or 3 minutes.

If you want to upgrade, then only go up one half horsepower from the current rating, Maximum!  So, in this particular case, I would go up no more than .25 horsepower, and install a 1 HP version.  You may find that even this increase may be too much sometimes, and will have to reduce the force of the jets by adjusting the air intake to the jets, or by closing the jet body itself.


I need to replace the motor on my pump assembly.  It is a 1 Horsepower, 2 Speed, 115 volt pump.  Can I go up to a 1.5 horsepower motor?

Sure, but you will notice virtually no difference in the output power of the pump.... That is, unless you also replace the wet end, or the impeller for the upgraded motor.  All ac motors like this will be rated for a rotational speed of 3450 RPM on high speed, or 1725 on low.  The trick is in the rpm... not the horsepower.  That being said... generally, a 1.5 horsepower motor will run with a lower heat and loss factor using a 1 horsepower wet end.



Can I replace my 115 Volt pump, with one rated for 230 volts?
Yes, in certain situations you can.  In the majority of cases, all you need to do is disconnect the white pump wire inside the control box from neutral.  Then reconnect it to L2, (usually the red power input).  However, if you ever plan on having this spa hooked up to 115 volts, you'll have to go back to the old pump motor voltage. 

I generally prefer 230 volt motors because they draw less current, put a lower load factor on the control relays and air switches, and will make them last longer.  The amperage draw of a 230 Volt 1.5 horsepower motor, at approximately 8 amps, will be half that of one connected at 115 Volts.  The start up current is less, and there is less of a voltage drop  through the wires and connections to it; so the benefits are obvious.

If your spa uses a digital control system, such as Balboa, Gecko, Hurricane, or MEI, then you may find that L2 is switched through a relay, and that particular L2 relay is where you need to make your 'common' connection with the white wire.



Why didn't they make this spa with 230 volt motors?  Why did they use 115 volt versions?  I've had my spa hooked up with 230 volt power ever since I've had it!

Yes, this is normal.  There are a couple of reasons for using a 115 volt motor...

1.  A 115 volt motor, on a spa control system with this kind of motor installed, is usually called a convertible spa, and can be usually be connected for 115 volt, 20 Amp current from the house, or 230 volt 40-50 amp service.  Quite a convenient and obvious selling point.

2.  Mass quantity purchasing by manufacturers.  It is usually cheaper for any spa builder to purchase 10,000 115 volt pump assemblies from the manufacturer, than it would be to split it up between 115 volt and 230 volt versions of the same pump.  It's a lot less paper work, and in house accounting and spa marketing becomes bit easier too.



My pump motor is making a lot of noise, and the bearings sound like they've gone bad.  Can I have this motor rebuilt, instead of replacing the entire thing... and save some money?

Absolutely.  Take your complete pump assembly to a local electric motor shop, and in most cases, you can have the motor rebuilt/reconditioned for less than $100.00 (us).  Many of them also carry the same seals that your pump assembly requires, and they'll usually do that for you as well.  Based on what I've heard from my own customers, smaller shops are better at customer service... that is, listening to YOU, and taking care of you, than the huge ones.  That is, don't be afraid to trust some guy operating a small - motor repair service out of the shop in his garage.  Just don't ask a spa technician or repair service to do this for you.  While some might arrange this, the majority of spa service companies will lose money in the long run actually having it done.



All my pump is doing is just humming when I try to energize it.  What's wrong with this thing?

Several options here:

1.  Armature shaft is just stuck.  With the power to the spa turned OFF, rotate it with a pair of pliers, your fingers, or other suitable tools to ensure that it will rotate freely.  If it's a little bit difficult to turn... then your bearings may be on the way out, and in which case, it's time for a rebuild, or replacement pump or motor.

2.  Starting capacitor defective.  These can be found at any motor repair shop.

3.  Centrifugal switch contacts are defective.  Time for a rebuild, or motor replacement.

4.  Motor is just dead... time to rebuild or replace.



The shaft on my pump is rusted, and I can't get the impeller off to replace the bad pump seal; also, the plastic shaft coming from the impeller looks like it's split.  Why did it rust up so much, and what do I do with this thing?

Well,  water quality is usually the number one cause of pump seal failure.  Not defective components.

The reason why your shaft is rusted is usually because brominated water creeped through the failing pump seal, and onto the pump motor shaft... then crept back up under the plastic socket for the impeller... causing the total freeze up.  If you can't remove the impeller with a pair of channel locks... (tempting the obvious fate of breaking the thing)... then you've basically got no other choice than to destroy the impeller, and replace it, and/or the wet end assembly.  There is an excellent instructional bit about this here.



My motor ran and pumped water fine for many years... but now it puts out so little water flow.  Do I need to replace the pump?

Probably not.  First and foremost, (with the power to the spa removed obviously) remove the suction end pipe of the wet end, and feel or look inside to see if anything has clogged any part of the impeller.  You'd be really surprised how much a small hair beret can stop water flow dead in its tracks. 

Remember, a centrifugal pump, to create suction must have discharge.  It takes very very little to stop the suction, and once that is blocked, then there's no discharge, which means, little or no suction force.  This is almost like the answer to the proverbial question... which came first?  The chicken or the egg?  In this case, the chicken.... that is, the suction, is dependent upon the ability of the water to LEAVE the impeller.  If there is nothing leaving, there won't be anything going into the suction either.  A small object.. can severly alter the ability of the pump to create a good flow.



I've been getting a FLO error on my control panel, but my circulation pump or main pump on low speed seems to work fine, and is pumping water.

Check the answer to the question above.  If this involves a small circulation pump, then you may only have to remove the suction line, and the static weight of the water will force water flow backwards through the wet end, and you might just see a lot of crud, grass, hair and other undesireables, come out of the suction end.  You'll want to double check to make sure nothing else is clogging the suction.  Otherwise, I'd check the flow/pressure switch.



The balance of troubleshooting...

When dealing with pump motors that are won't run, are noisy, etc, (particularly if they are more older), the best solution is to take it to an electric motor shop and have it professionally rebuilt, or just replace the entire motor. However, if you have a bit of finesse with these kinds of things, (as well as the time!), then the following troubleshooting guide should assist you.

Testing

When testing pump motors, do the following:

1. Always make sure that the pump motor frame is grounded!

2. If a 48 frame or through bolt pump is being tested, and the wet-end is not on the motor, install and tighten nuts on the thru-bolts to keep the motor together!

3. If the wet end is installed, do not run the pump dry for more than two or three seconds in a twenty minute period, or you will overheat the pump seal, and compromise its integrity! 

4. If testing with the wet end installed, ensure that the pump openings (suction and discharge) are clear and free of debris prior to applying power... and NEVER look into a pump opening when the pump is running! 

5. Install the rear electrical safety cover prior to applying power!

6. Ensure that the pump is anchored by adequate means, (at least two bolts through the mounting plate to a sturdy work surface).

7. Never try to "help" a pump motor start by turning the shaft with power applied! The sudden surge could mangle your fingers!

8. Never touch the pump motor with power applied!

9. Always use a rubber mat to stand on, and NEVER test the pump motor in a wet environment, you could be ELECTROCUTED!

Abnormal Operation Symptoms

Pump works, but strange things happen:

1. Noisy motor (check wet-end first), Usually caused by dry or worn bearings. I've seen motors with bad bearings run for two years or more. Eventually you'll need to rebuild or replace the motor though.

2. Starts when it feels like it; Starting capacitor worn out, Centrifugal switching contacts burned, Intermittent open circuit in stator. Stalled armature symptoms: "gunked" bearings, excessive resistance in wet end seal, rust accumulation around armature core. 

3. Motor dims lights in the house for a few seconds when starting, makes outrageous humming noise for a few seconds, power cord gets warm after several attempts to start. This can be considered normal in instances where the current surge lasts for less than a second, but anything longer than a second is reason to suspect the causes in the previous paragraph.

4. Having seen this a few times... Motor won't come up to full speed. Acts as if it's starting then coasting, starting then coasting, repetitively. You've probably got a 220 Volt pump motor hooked up in a 110 Volt Circuit.

Failures

Most pump failures can be attributed to the following:

1. Bearing failure due to chemical salts carried by moisture (A-Number One!). Check to see if the motor shaft will turn by hand. If not, then try to free it up using a wrench or screwdriver. If it turns freely, then try to re-energize the pump. If it operates then check for Abnormal Operation above. This "freeze-up" of the armature will also happen when an older pump has not been used in a while, and is caused by the bearing lubricants drying up. 

2. Bearings Okay, armature will turn by hand. If all you get is a hum with dimming house lights, you could have a defective starting capacitor, or defective switching contacts. If you get no hum at all, then you could have an open stator winding (replace pump), or defective thermal limit switch.

Use an ohm meter or continuity checker to determine the status of the respective component.

3. Fused, burned, or melted down centrifugal switch contacts. Usually caused by control system failure, sending hi and lo speed voltage to the pump simultaneously, a shorted starting capacitor, or a virtually direct lightning strike. 

Try to split contacts without bending copper support strips, apply power to only one speed to see if pump switch is still operable. Bear in mind that the switch contacts may not be reliable in the future if not replaced. Repair the cause of the simultaneous dual voltage application (usually a micro-switch failure on a relay or combination switch).