How To Determine Why a Motor Won't Start or Shuts Off

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This guide discusses the common problems related to a motor that won't start or once it does start shuts off after 5 minutes.

Step by Step

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Step 1

No power to the motor- Check for improper or loose connections, open switches or relays and blown circuit breakers or fuses. Check for broken power cords.

Step 2

Jammed motor - Check that the motor shaft rotates easily. If it's stuck, check that the impeller is not jammed with debris. Check that the impeller or diffuser is not broken. If the impeller is good, you problem may be bad motor bearings. Replace bearings/motor or impeller as required.

Step 3

Motor hums but will not turn over - Check for a bad capacitor. You may have two: a run capacitor and a start capacitor. Some motor have a governor at the electrical end of the shaft. Check that it is not stuck open. If your capacitor(s) and governor are good and the motor shaft rotates easily you probably have a burned out motor coil and you will need to repair or replace the motor.

Step 4

Motor gets hot and shuts down - Generally due to low voltage or being overloaded. Check that the motor is wired correctly. If the motor is configured for 230V and has 115V coming in, it will shut down after running 3-5 minutes. Check for loose connections. Check for undersized wiring. For a hook-up to the circuit box of under 50', pumps of up to 2HP wired for 230V need No. 14 size wire, For pumps wired for 115V, the wire size must be No. 14 for 1/2 and 3/4 HP; No 12 for 1 HP; and No. 10 for 1 1/2 and 2 HP. Check that the motor is not overloaded. Does the pump have the correct impeller and diffuser for this motor? Is the impeller worn and rubbing on the diffuser.

Step 5

Note: Most pump motors have Automatic Thermal Overload Protection. The motor will automatically shut off before the motor generates enough heat to damage itself. Once a normal heat level is reached, the motor will automatically restart. CAUTION: If the motor operates in this on/off mode for any length of time it will burn out.

Comments

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(81 to 120 of 181)

Anonymous  Posted: 1/7/2017 

Pool motor starts each morning (on a timer) fine. But if have to power motor off for maintenance for a few minutes (to clean filter, etc), it buzzes and will not restart. Have to leave it off for several hours (too cool down) before it will run again. Is this a capacitor or motor issue?
 Reply

 Posted: 12/26/2016 

If I understand the rep, it appears he is saying that there is a separate set of PSC windings for each speed. This would explain the symptoms. This motor (previous post) had the low speed cap burn out, so may have damaged the aux (start) winding. I'll check it out now that I think I understand the wiring better. In the end I may need a new motor, but may be able to nurse it through the cold days of winter.
What made this so difficult to understand was that all the PSC circuits shown online use one cap, and if multispeed use taps at different points on the main winding (either changing the poles or just adding resistance). It was assumed that the speed control relay on top was controlling these taps-- it now appears it switches between the two separate sets of windings in the single case. This appears to be a common spa motor setup (the one next to it, by a different manufacturer, looks exactly the same); why there is nothing specifically about them online is hard to explain.
I appreciate you taking the time to look into this puzzle, and over the holidays too! May be back in the Spring for a motor if it's not an easy fix.
Happy New Year,
GeorgeC

 Reply

InyoPools Product Specialist  Posted: 12/21/2016 

GeorgeC - We asked the Century motor rep for his insight and here's his response. "This is likely a PSC motor on both high and low speeds. If the low speed has either a bad main or phase winding, or capacitor, it will not start on low speed. If the motor is running on high speed, and it is switched to low speed, it may continue to run but may overheat since it is weaker without both windings. It is curious that the low speed has a 25 mf capacitor. If you have the part number, it may still be in the system to check."
 Reply

InyoPools Product Specialist  Posted: 12/19/2016 

SwampPool - See answer to Sean B comment.
 Reply

InyoPools Product Specialist  Posted: 12/19/2016 

Sean B - Your motor should have at least a start capacitor underneath the back electrical cover. If it also has a run capacitor, it will be under a bump out on the top of the motor. If you have a leak between the pump housing and the motor, you will have to replace the housing gasket.
 Reply

 Posted: 12/17/2016 

I have an in-ground pool that is about 18,000 gallons (using pool calculator) and my pool pump stopped working. The pump will start up and prime with water entering the pump and then it just stops pumping water and there is loud click noise that sounds like a switch or breaker inside the pump motor. The motor will “stay on” and make a humming noise. If I turn the pump off and then try to restart it, it will just hum and not “turn over” and the motor will heat up. The impeller turns freely so it is not jammed. I went to the pool store and they said I needed a new motor if I wanted to install it or I could just buy a new pump. I haven’t replaced the capacitor and I do not know if my motor has 2 or just 1 capacitors. Another thing I noticed was that when the pump is working for the first 30 seconds, there appears to be some water leaking where the housing attaches the motor. Check out this video I uploaded of the problem: https://www.youtube.com/watch?v=7lewXpPgbv0

My current equipment: 1) Jandy Stealth Pool Pump JHPU 1.0, this exact pump is discontinued and I think it is an “upward” flowing 2) Emerson EB654 C Flange Pool Motor 1 HP – replaced original motor more than 5 years ago 3) 2” PVC pipe with Jandy Valves 4) Jandy cartridge filter 580

Any thoughts on what the problem is with my pump? Do I need a new motor? New entire unit?

 Reply

 Posted: 12/17/2016 

I have a two speed 220v GE spa motor, starts/runs on high, only hums on low but will run on low if switched quickly after running first on high. 2 caps, both "run" values, 25-30 mf. No start switch or starting cap found--makes sense, motor code KCP indicates permanent split cap. Question is, why are there TWO caps? Cannot find any wiring diagram with two run caps anywhere. One cap shows hi volts on high, 0 on low; other cap = 0 no matter if running high or low. Want to understand-is driving me nuts! Thanks, GC


 Reply

 Posted: 12/16/2016 

My pool pump motor will start and will work fine for about 20 seconds. Afterwards, it clicks and stops pumping water and then it hums until kill the breaker. If I immediately try to restart the pump, it doesn't spin and just continues to hum. I don't know if my replacement motor, Emerson EB654 C Flange, on my Jandy Stealth JHPU 1.0 pump, has 2 capacitors or just one. Other troubleshooting info is that it appears to leak water in between the motor and pump. Please check out this video I posted on YouTube of my pump not working.
https://www.youtube.com/watch?v=7lewXpPgbv0

 Reply

InyoPools Product Specialist  Posted: 12/12/2016 

pump/timer issues - It sounds like your timer isn't supplying power to the pump. Check the output power on the timer. See Steps 2 and 6 in our guide on "How To Use a Multimeter to Test a Pool Pump Motor - Voltage". If your pump is set up for 115V, you would see 115V across terminals 2 and 4. Then check that your timer is wired correctly. See our guide on "How To Install an Intermatic T104 Timer". This guide is for a T104 timer for 220V. If you have a T101 timer you would check for 115V across the 2 and 4 terminals.
 Reply

Anonymous  Posted: 12/6/2016 

Installed new pool pump but it will not start and the timer is not working either. Any suggestionsm
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InyoPools Product Specialist  Posted: 11/21/2016 

pump wiring - It sounds like your pump motor is configured for 115V otherwise it would not run off a 120V outlet. Check the configuration of your motor. Instructions for changing the motor to 220V should be on the motor label.
 Reply

Anonymous  Posted: 11/20/2016 

I just replaced my 220 volt pump motor with an identical motor. New motor will not run, i am showing line voltages at 119 v and 113 v. It will run set on 120 with a cord plugged into a gfci 120v outlet. Any ideas would be greatly appreciated.
 Reply

InyoPools Product Specialist  Posted: 11/14/2016 

Wilkus - This is usually an indication that your supply voltage is different that your pump's configuration. If you are running off of 115V, make sure your pump is set for 115V and not 220V. Also, check that your motor shaft spins freely.
 Reply

 Posted: 11/13/2016 

Hello this is my problem. When i switch on the pool pump it turn 1second stops after 3 seconds it turns again then stops again thats all it does. My question now is what could be the problem?????
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InyoPools Product Specialist  Posted: 10/12/2016 

ahmad - When a motor hums, it is generally due to a capacitor going bad. If you motor has a capacitor, it would be in under the electrical cover in the back of the motor. See our guides on " How To Select the Right Capacitor For Your Pool Pump Motor" and " How To Replace a Pool Pump Capacitor". If you don't have a capacitor, you may have a short in your motor windings, and you may need to replace the motor.
 Reply

 Posted: 10/11/2016 

I have Pentair 2hp above ground pool pump, after storm it hums and wont turn, how can test the capacitor or what could be the problem
serial number 03062880701205, p/n 340219, pmp dynii-n1-2hp 3' std
any help will be great

 Reply

InyoPools Product Specialist  Posted: 9/26/2016 

Chris - Since there is no switch panel on the motor itself, I'm assuming that you have a separate switch box between the motor and the breaker box and that this switch is not working. I would recheck the wiring to and from the switch or possibly replace the switch.
 Reply

InyoPools Product Specialist  Posted: 9/26/2016 

SP3400VSP - I would check that the leads going out of the control unit and into the back of the motor are connected tightly at both ends. Then you are probably at a point where a professional would have to look at it.
 Reply

InyoPools Product Specialist  Posted: 9/26/2016 

motor won't start - When they ran the motor in the shop, was it running on 115V or 230V and was this different than your supply voltage. If you are seeing 128V on each lead, you should be running at 230V. Check that your motor is configured for 230V - see the knob on left side of the input terminal. If your voltage is right, the only other issue I can think of is the motor may be binding when you put in into the pump housing. When the motor is installed, does the motor shaft rotate freely?
 Reply

 Posted: 9/25/2016 

Have Motor 855B Century 2Hpr, can turn on & off from the circuit breaker, but will not turn off or on from switch panel. wired with correct configuration on motor. any suggestions?
 Reply

Anonymous  Posted: 9/24/2016 

I have a Hayward pool pump model SP3400VSP. Pump display says Drive ERROR! Pump has stalled. For this error, the instructions manual indicates that the drive was not able to start the motor after 3 attempts. It says, motor connections to drive should be verified. How do I check this? Or is this something a professional must do?
 Reply

Anonymous  Posted: 9/24/2016 

My pool pump motor won't start. I checked for voltage at the motor with the leads disconnected from the motor. The voltage is 128v at each lead.I disconnected the ground lead and did a continuity check back to the breaker panel, sat. I removed the motor and brought it to a motor shop and it ran satisfactorily, to my frustration. I reinstalled the motor back in the system.
 Reply

InyoPools Product Specialist  Posted: 8/30/2016 

UST1152 won't start - It sounds like the start capacitor on your motor has failed. See our guide on "How To Replace a Pool Pump Capacitor" for the location of this capacitor and steps for replacing it.
 Reply

Anonymous  Posted: 8/30/2016 

I have a Century UST1152 pool pump that's on a timer. 2 days ago the pump did not turn on. Checked the common problem, tripped circuit, etc. Decided to try turning it back on/off several times and it finally kicked on. Same issue today. Once I get it to kick on it runs all day without a problem. The pump is only 2 years old. Any idea what I should check first?
 Reply

InyoPools Product Specialist  Posted: 8/29/2016 

Nut 3 - It sounds like the start capacitor on your motor has failed. See our guide on "How To Replace a Pool Pump Capacitor" for the location of this capacitor and steps for replacing it.
 Reply

 Posted: 8/28/2016 

I have a Pentair WhisperFlo WFE-4 pump. Pump has always run great. It was making a little bit of noise this morning and I went to clean out the filter and when I turned the pump back on it just hummed. power was getting to it but it wouldn't "turn over." How do I troubleshoot it? Thanks!
 Reply

InyoPools Product Specialist  Posted: 8/19/2016 

JIM D - Sounds like your motor wires may have been hit during the storm. Take the back cover off and see if there is any visible damage to the wires coming into the motor. See if you have power coming to the motor. It is likely that the windings in the motor are damaged and you may need a new motor. The cheapest approach would be to take the motor into the pool store or a motor shop to have them test it out. Don't spend too much. A new replacement motor is $130 - A.O. Smith 1 HP Round Flange Up Rate Motor - UST1102.
 Reply

 Posted: 8/17/2016 

Motor is 1 year old. Has worked perfectly until Aug 16 2016 when it shut off unexpectedly during a storm in FL. Does not hum . The timer is working but the wiring is really old. It has thermal overload protector. It's a AOSMITH HST 110. The pool place that installed it is 4 blocks and they want 85 dollars just to show up and can't come til next week. Should I call an electrician ?
 Reply

InyoPools Product Specialist  Posted: 8/1/2016 

Sandra - Check to see if your timer is working. Dial should move enough to see in 10 minutes. If it isn't working, you could change either the timer motor or the timer mechanism - motor plus gears. I see no reason to replace the timer with a switch. If the pump is running off an extension cord, check that the cord is heavy enough to carry the voltage. See this chart on Wire sizes. If the cord is not heavy enough, you could be dropping voltage before it reaches the pump which will degrade your pump over time.
 Reply

 Posted: 7/29/2016 

I went to turn the pool pump motor on. When I pressed the button in the timer box, I heard a pop, almost like a fuse burning out. Got a pool tech guy out. He replaced the motor and said the wiring was all jacked up and I would need an electrician to come out. In the meantime, it's plugged in with an extension cord. It's been running this way for the 16 years we've lived here. And I know my husband has replaced the motor once during that time, wired the same way. The tech also suggested getting rid of the timer box and just going to an on/off flip switch. My original suspicion was that the wind and rain that blew the cover open on the timer box somehow shorted it out. But when he said the motor needed to be replaced, I didn't question. But now since he suggested doing away with the timer box, I wonder if it was the timer box all along. Thoughts?
 Reply

InyoPools Product Specialist  Posted: 7/25/2016 

Bill213 - I'd take the motor out to see if the impeller is clogged or rubbing on the side of the pump. See if the shaft still rotates freely. Other than that, 14 years is a very good life for a motor. It probably needs to be replaced.
 Reply

 Posted: 7/22/2016 

I have a 14 year old 2 Hp Century motor that just started intermittently shutting off. After a 5-10 minutes it restarts and runs fine for hours on end. It suspect it's over heating given the symptom. I leave the motor running from the opening in spring until I close the pool Sept Oct. Been really dependable. Is it dying a slow death? Anything I should check out? Just trying to be prepared for what I fear might be the end for this motor.
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InyoPools Product Specialist  Posted: 7/19/2016 

motor shut off - There is not reset button on a motor. If this is an older motor, the "loud" noise may be due to the bearings starting to fail. If so, it's probably time to replace the motor. If your motor hums and has a start capacitor, try replacing the capacitor. I assume that this motor has been running in the past, so you probably have the right voltage going to the pump.
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InyoPools Product Specialist  Posted: 7/19/2016 

moisture in motor - That's a good question. There is no seal between the cover and the electrical end of the motor. Perhaps the cover is generally on tight enough that a seal is normally not required.
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Anonymous  Posted: 7/16/2016 

Is there any type of reset button on the motor. I have power to the motor, all breakers are on, lights to GFI outlets are on. The pool pump was running but sounded loud. I turned it off, cleaned out filter, and replaced everything as usual. I flipped the switch and it had power for about 1 second, then shut off.
 Reply

Anonymous  Posted: 7/15/2016 

Our pump motor started right up at the beginning of the season. After it rained it tripped gfi and shut off. My husband is an electrician and checked all the normal electrical things. He bypassed the gfi to see if it wood run without tripping it. It did run. After trial and error we figured out that it is getting moisture inside at the motor assembly. Like the area in your step 3 where the yellow sticker is. He put some silicone over the top part of that joint and it has worked fine since. My question is this- is there a seal or o-ring in that joint that can be replaced or why is water getting in there?
 Reply

InyoPools Product Specialist  Posted: 7/11/2016 

Mike - Yes, the thermal overload protector will not protect the pump from overvoltage. If you connect an 115V motor to 220V, the motor windings will fail.
 Reply

 Posted: 7/10/2016 

Hi,
So it means the thermal overload protector cannot protect the pump from overvoltage?
Thanks

 Reply

InyoPools Product Specialist  Posted: 7/8/2016 

bt - This is typically the symptom of a wrong voltage problem. Check your supply voltage. If your pump is set up for 220V and your supply voltage is 115V, the motor will overheat and shut off in 10-15 seconds. If your pump is configured for 115V and you have 220V coming in, you may have blown the motor.
 Reply

 Posted: 7/6/2016 

PB4-60 Polaris booster pump. It comes on for about 10-15 seconds & the Polaris in the pool works, then the motor shuts off. What's the dang deal?
 Reply