How To Troubleshoot a Pool Pump Motor - Motor Shuts Down

WRITTEN BY:  Inyo Pools

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If your pool pump motor starts but shuts down unexpectedly it is probably overloaded and the thermal overload protection device has tripped. This guide discusses what to look for to correct this issue.

Step by Step


Step 1

CHECK VOLTAGE - Measure the voltage level to the motor terminal. It should be within 10 percent of the voltage listed on the motor label. If it is too high call the local Power Company. This picture shows measuring the voltage across the two output lines to the pump.

Step 2

CHECK AMPERAGE - Measure the amperage to the motor terminal. If high, find out if the pump impeller was recently replaced (it could be sized incorrectly). Remember, motor horsepower times the service factor = total horsepower. Total horsepower must be equal to or greater than the impeller rating. If the impeller is too large for the motor, it will be trying to push more water than the motor can handle and the motor will overload, get hot, and shut down.


(1 to 40 of 75)

Inyopools  Posted: 09/25/2017 13:17 PM  Inyo Product Specialist

Doug - If it worked well before being submerged and doesn't now, the water probably damaged some of the electrical circuits. Try taking the motor into a pool store to see if they can test it for you. Here is a guide on "How To Replace AO Smith Motor Parts - Overview" that shows you what electrical parts may be involved. Also, look at our guide on "How To Use a Multimeter to Test a Pool Pump Motor - Winding Resistance" to check out the motor windings.

Doug  Posted: 09/23/2017 12:42 PM 

I have a roaring river 1hp pump that when its under load it shuts off after 4 sec when not under load runs fine the pump is 3 months old it ran dry during the hurricane and got submerged for two days pulled it out dryed it out now it comes on but shuts off under load worked fine before the storm

Inyopools  Posted: 07/30/2017 13:43 PM  Inyo Product Specialist

Charles - If your motor's thermal breaker is tripping frequently, this is an indication that your motor is running too hot and its current level is too high. Look for easy fixes first like blocked air vents or a bad capacitor. See our guide on "How To Troubleshoot a Pool Pump Motor - Motor Overheated". However, if this overheating issue has been a problem for awhile, chances are high that it has caused shortages in the windings which escalate the current problem and eventually leads to total failure.

Charles  Posted: 07/28/2017 17:16 PM 

I have a jandy 1 1/2 HP single speed pump. I have gotten so the thermal breaker is tripping. The unit is 3 years old and runs year round in that we have water features with our pool. We also have an electric Heat pump heater as well as a Solar Attic Solar system in the loop. we have had no issues with the system until recently. I am thinking of making a change to a 2HP 2 speed system (Jandy flopro) ... What would cause the current motor to trip. I have cleaned the filter checked the flow etc.

Inyopools  Posted: 07/27/2017 17:45 PM  Inyo Product Specialist

Carol - Check that your new motor has the same total HP [HPxSF) as the old motor. They could both say 1 HP but if the product of HP times service factor (SF) is not the same, you might have substituted a smaller motor into your pump. Since the impeller did not change, it would be trying to push the same amount of water through the pump as the bigger motor, and it would overheat.

Carol  Posted: 07/26/2017 18:24 PM 

Just replaced motor on pool. Hayward super pump 1.0 to a new pump with same specs. Motor keeps overheating and shuts down. Volt and amp are good. Ideas?

Inyopools  Posted: 07/09/2017 16:07 PM  Inyo Product Specialist

Al - If it is humming, you may have a bad start capacitor. Try replacing that first. See our guide on "How To Replace a Pool Pump Capacitor". If that doesn't work or your pressure is still high, see our guide on "How to Reduce High Pressure in Your Pool System".

Al  Posted: 07/04/2017 14:38 PM 

I have a Hayward powerful LX pump. It ran at the start of the season but the pressure was too high and it was really difficult to bump.i took it apart and cleaned the fingers, replaced it and it ran for about 20 seconds and shut down. It tripped the breakers and every tone I try to restart it it continues to trip . Any ideas? Now it just hums then trips

Inyopools  Posted: 06/30/2017 11:50 AM  Inyo Product Specialist

brainfart - If your motor was running dry for three hours, it may have been permanently damaged. It does have a thermal protector that shuts the motor off as it heats up then allows the motor to restart after it cools. If this cycle happened many times over the 3 hour period, it finally stops working. I'd take the motor into a place that can check it to see if it is damaged beyond repair.

brainfart  Posted: 06/28/2017 12:21 PM 

I took my TurboCell in for testing (it's dead) and did not disengage the auto on switch before my motor. I was planning to put it right back on but didn't get to it until this morning and the pump had been attempting to run for about 3 hours. It was doing nothing when I went out there and now with the TurboCell back on, the motor starts and shuts down after about 20 seconds. Am I screwed? It seems like it is trying to run as normal for those 20 seconds.

Inyopools  Posted: 06/24/2017 13:26 PM  Inyo Product Specialist

Anonymous (stuck motor) - I'd check the capacitor again. Also, check that the governor is not stuck open. It disengages the start switch when the motor gets up to speed. See our guide on "How To Replace the Governor on an AO Smith Motor". Then, do a continuity check on the motor winding to make sure they don't have a short in them.

Anonymous  Posted: 06/22/2017 20:12 PM 

I am having a problem with my motor, it just hums and won't start. However if I turn the shaft it will start up and run all day. I have changed the start capacitor and verified that the starter switch is working fine. I am at a loss, the motor ran fine last year when I bought it, this year it ran fine for a couple of weeks than all of a sudden it would not start. Nothing is jammed, the shaft spins freely. Anybody got any ideas ?

Inyopools  Posted: 05/30/2017 20:21 PM  Inyo Product Specialist

charles - You probably should have changed the pump's impeller and possibly its diffuser. When you downgraded your pump's motor that had a total HP of 1.125 (3/4 HP x 1.5 SF) to a motor with a THP of 3/4 HP (3/4 x 1.0) without changing the impeller, the smaller motor had to do the work of the larger motor and probably failed. Not sure why this occurred when you changed filter modes. Did you remember to turn off the pump before you changed modes?

charles  Posted: 05/30/2017 18:40 PM 

I recently replaced my pump. Now when I switch from one setting to another (rinse / backwash / filter) the fuse trips. From previous comments it sounds like the impeller. I didn't change the impeller. The old pump was 3/4HP with SF of 1.5. The new pump is 3/4HP with SF of 1. Do I need to change the impeller?

Inyopools  Posted: 05/29/2017 21:42 PM  Inyo Product Specialist

DAVID - I do not understand the correlation between the multiport valve (MPV) on the filter and the pump shutting down. The pump should be off when you rotate the handle on the MPV. When you try to turn the pump back on after changing to backwash, does it fail to start?

Inyopools  Posted: 05/29/2017 18:52 PM  Inyo Product Specialist

Smoked - Check the gauge of wire between your pump and the circuit breaker. If you have a long run, you may have to go up a gauge of two. If that's good, you may have to invest in a new motor.

DAVID  Posted: 05/27/2017 18:10 PM 

We have an Hayward SP1580X15 Power-Flo LX 1.5hp pump. When I go to backwash the filter pump shuts down. I replaced the pump thinking it was bad. The new one is doing the same thing. We have a sand filter and no pressure gage. Any idea's as to what could be the problem?

Smoked  Posted: 05/26/2017 21:21 PM 

I have a 1.0 HP Hayward Superpump that's about 5 years old or so. Recently, it got hot and shut down. It's plugged into a GFCI, which was blackened around the plug. The wiring inside the junction box at the pump got hot enough to melt one of the wire nuts in half, causing it to fall off. I cut the wire back and re-wired the pump. It clicked a few times and then was silent. Is it fixable or is it more cost effective to replace the pump motor?

Inyopools  Posted: 05/03/2017 11:25 AM  Inyo Product Specialist

JR - If you replaced the impeller recently, I would concentrate on that. Make sure you have the correct replacement impeller. It has to match the total HP calculated for your motor, not the HP. Total HP rating is calculated by multiplying the listed HP on the motor label with the motor's Service Factor (SF). If the impeller is a size larger than the original, it will require greater torque than the motor can deliver and overheat quickly. Also, check that the new shaft seal was seated correctly. If it is not on straight, it will add friction to the rotating motor and cause it to overheat.

JR  Posted: 05/02/2017 12:48 PM 

Have a Century AO Smith B849 that was replaced about 3 years ago, and the impeller was replaced just a couple months ago. Pool ran fine for a while then recently it started doing a start loop. It tries to start up, I can immediately see water moving in the clear top pump filter basket, but then stops within a few seconds. Then it tries again in a few minutes, but never gets actually running. Pool man says I need a new pump, but the first pump lasted 16 years, and the same pump (B849) the 2nd time lasts only 3 years? Doesn't seem right?

Inyopools  Posted: 03/06/2017 11:10 AM  Inyo Product Specialist

Voltboy - Sounds like an issue with your Jandy RS control board. You will probably have to call Jandy (now Zodiac) on this one. Their number is 800-822-7933.

Voltboy  Posted: 03/02/2017 17:28 PM 

Ok check this out. When my epump starts up on its normal daily time it knocks my RS control panel offline. at the end of the time it turns off like normal and shows my panel back online and I can use any of the other pumps of features again. but while my main pump is on I can't do a thing on my iaqualink or the board. Wifi is showing still connected on the iaqualing box.

Inyopools  Posted: 01/25/2017 10:09 AM  Inyo Product Specialist

MickeyGzzz - If your motor just hums and won't turn over, it's probably due to a bad start capacitor. I would replace the start capacitor. If that doesn’t work, you may have a short in the motor windings.

MickeyGzzz  Posted: 01/25/2017 2:39 AM 

I have a pump with a start capacitor on the rear end of the motor and have a run capacitor on the top of the motor.
I swapped out the run capacitor on the top motor gets juice but only humming. Impellers are free moving
Would my next step to replace the start capacitor?

Thank you

Inyopools  Posted: 10/11/2016 12:51 PM  Inyo Product Specialist

Bob - Sorry for the delay. we had a system issue. The replacement speed controller for your VS JEP1.5 pump is not in our system yet. I will see if is available and get back to you.

Inyopools  Posted: 10/11/2016 12:02 PM  Inyo Product Specialist

glurge - Does the motor just hum when you turn it on? If so, you may have a bad start capacitor. See our guide on "How To Replace a Pool Pump Capacitor".

Glurge  Posted: 10/10/2016 10:39 AM 

I have a US Motors 1081 Pool Motor 1.0 HP Model C55CXKMB-5012. It is fairly new only a few months in service. Today I tried to run it and it comes on for a few seconds, sounds like nothing is spinning and then cuts off. Any idea what is happening. It was working fine the previous day??

Bob  Posted: 10/04/2016 13:14 PM 

I just spoke with Jandy tech support. They said there's no replacement parts in the speed control box on the motor. It's a Gen II model JEP 1.5, by the way. Also said the speed control is now available without the motor, and to see about getting one installed. Would not sell me one. It's a recent release, part number R0688600. Can you give me a quote for one? I included my email address. Thanks again!

Inyopools  Posted: 10/03/2016 12:46 PM  Inyo Product Specialist

Bob - Your pump problem could well be that you run capacitor is starting to fail. They are fairly inexpensive. I would try replacing it. As the capacitor fails, the terminal end of the capacitor starts to bow out.

Bob  Posted: 10/01/2016 21:24 PM 

I have a 1.5 HP motor Jandy Stealth pump with an AO Smith motor, about 4 years old. It was running fine, but then started running at varying speeds and stopping. It does not trip any breakers. If left alone it will start and run and pump, then stop after about 45 seconds. I've checked and there are no blockages, it seems electrical or controls related. Could this be due to the run capacitor going out? Thank you for offering all the advice to everyone!

Inyopools  Posted: 09/07/2016 13:21 PM  Inyo Product Specialist

pump stumped - Check to make sure you are getting 220V to the pump motor. If you have an older pump, it might be time to replace it. However you only have to change the motor. According to your specs, here is a link to your replacement motor.

pump stumped  Posted: 09/05/2016 16:52 PM 

I have a 1.5 Hp xp2 flow-master 220 volt pump . This is the main circulation pump in my bull Frog Spa. The pump is getting very hot and cycles off and back on once it cools down. I have switched the power from pump 1 and 2 on the circuit board and the other pump works fine so I have ruled out a relay I am guessing. Is their anything else I can do before I replace the entire pump? Any info would be appreciated .

Inyopools  Posted: 08/30/2016 10:22 AM  Inyo Product Specialist

1.5 HP impeller - If the pool service guy thinks it's the impeller, I would have that looked at first. They are relatively easy to replace and much cheaper than a new motor. See our guide on "How To Replace A Pool Pump Impeller".

Anonymous  Posted: 08/29/2016 17:28 PM 

My pool motor Hayward C4812N134C1 1.5 hp was put in 4 years ago, now not working my pool service guy said it is the impeller but said it is better to replace than repair as it may be something else. I changed my filter to 150 SQF clean and clear 3 months ago. Any suggestions if should consider fixing or replacing pump?

Inyopools  Posted: 08/16/2016 9:42 AM  Inyo Product Specialist

2HP Jandy pump - When you shelter the pump, leave enough room around it for ventilation. Also, you might consider elevating the pump with additional pavers to help keep the motor vents free of debris. One customer did this and found a significant reduction in motor heat.

Anonymous  Posted: 08/15/2016 19:07 PM 

Thanks for your prompt response. I think rather than pay $100 to have it checked and then an inflated price for a new motor, I will simply buy a new motor and put it in. I find 6 years on a motor a bit short but hot environment, rain, and direct sun is probably a harsh environment. I think I'll cover the equipment to see if I can get a longer life. Thanks again!

Inyopools  Posted: 08/15/2016 14:05 PM  Inyo Product Specialist

2HP Jandy pump - If your pump is pushing water for even a second, you are past the startup circuits. I don't think a bad thermal protector would let your motor start, and if it did, it wouldn't overheat in a second. Low voltage might have been a problem, but you checked that. 6 years is an average life for a motor, so you may be due for a replacement. You might have the motor checked at a pool or engine store to see if they can find an answer.

Anonymous  Posted: 08/13/2016 16:52 PM 

2hp switchless Jandy pump just stopped working. It hums for 1 sec and shuts off. It does move water during that second. Motor shafts spins freely as does impeller. Capicator checked ok but replaced with new one anyway. Voltage to pump ok. Still same behavior.

Can you help? Any thing else to check. Is it possible thermal protector is bad or must I replace a motor after only 6 years?


Inyopools  Posted: 08/10/2016 9:23 AM  Inyo Product Specialist

Beyondfustrated - It sounds like your impeller is too big for your new motor and is overworking the motor - trying to push more water than the motor is designed for. Your pump id of S2444T is really the designation of your filter, so I don't know what pump you have. I guessing it is a Hayward Super Pump. If you have a 1 HP Super Pump with a Service Factor (SF) of 1.1 (on the motor label), you have an uprated motor and your impeller should be SPX2607C. See our guide "How To Understand True Pump Horsepower - Up Rated vs Full Rated" for an explanation of an "uprated motor".

Beyondfrustrated  Posted: 08/09/2016 14:25 PM 

We have a Hayward S244T Pro Series 1HP pump. Every year the motor goes out and we have it replaced The service company cannot tell me why this is happening. This last time they replaced the impeller and now the motor overheats within several hours and shuts off after it cools off it can be restarted. This has never happened before in the past. I have had an electrician out and he tells me it is not electrical. The motor is a century 1hp as well. Any insight on what the possible cause of our motor issues could be?