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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(121 to 160 of 176)

 Posted: 6/19/2016 

Hi,

my motor is on a timer. in the morning it hums and tries to start multiple times until it finally starts. Usually it feels like it tries to start approximately every minute or so, it hums for few seconds and then shuts off. Finally after multiple tries, it starts working. Is this capacitor too ?

 Reply

InyoPools Product Specialist  Posted: 6/6/2016 

gtfoxxsr - I'd look at the electrical motor parts under the back cover. See our guide on "How To Replace AO Smith Motor Parts - Overview". The motor windings might also be shorted out, in which case, you are looking at buying a new motor.
 Reply

InyoPools Product Specialist  Posted: 6/6/2016 

Uncle Don - Your motor may have two capacitors, a start capacitor, and a run capacitor. The start capacitor is in the back of the motor under the cap. The run capacitor is under the bump on top of the motor. Check both capacitors. Then make sure you supply voltage matches the voltage set up on your motor and that the connections are tight. Finally, check the other motor parts. See our guide on "How To Replace AO Smith Motor Parts - Overview".
 Reply

 Posted: 6/4/2016 

I have a Waterco 2hp pump,hasn't been used for (3) seasons, won't start or even hum, shaft turns freely,electrical supply fine...Any thoughts?
 Reply

 Posted: 6/4/2016 

Have Sta-Rite P6RA6G-207L. Motor trips breaker after 15 seconds. Capacitor was replaced. Shaft spins freely as does impeller.
 Reply

InyoPools Product Specialist  Posted: 6/2/2016 

silas - Circuit breakers sometimes fail. Check for power out of the circuit breaker. If none, you may have to replace the circuit breaker. Try swapping it with one of your other circuit breakers that you know works.
 Reply

 Posted: 5/31/2016 

I replaced the booster pump and the pool pump last year.It has been working well.All started well and a couple of days ago the pump can't start.I have checked and there is no power at the switch to the pump.the circuit breakers are on and I have checked everything else even the pool control box.No idea where I'm loosing power right before to the pump.
Pls help,any ideas.

 Reply

InyoPools Product Specialist  Posted: 5/24/2016 

buefordTJ - Your problem could be the 136VAC voltage. Voltage to the pump should be within +/- 10% of the pump's voltage on the motor label. If the voltage is listed as 115VAC, the voltage should not exceed 127 VAC. I don't understand how the voltage can vary between the circuit breaker and the house plugs. Someone has to check that. The circuit breakers do not affect the voltage level. They only determine how high the amperage in the line can go be tripping the breaker. 15 will handle up to 15 amps: 40 up to 40 amps. If the issue in not due to source voltage, it may well be your motor. It is well passed the time when most motors are replaced.
 Reply

 Posted: 5/23/2016 

Hi, have a 1.5HP Jacuzzi Magnum pump (A.O. Smith Centurion motor) that's about 10 years old. Always brought it in for the winter. Last summer noticed on warmer days that it would stop for 15 seconds, come back on for 1-2 minutes, stop, come back on, and this would repeat. Took it in to the shop and they cleaned it, changed a bearing and impeller and said it still works well. Tried it today and it started doing the same thing again. It's wired for 115Vac. I checked the voltage coming from the power outlet and it reads 136Vac. I checked other outlets in the house and am getting 115Vac. Could this be the reason? If so, is it just a matter of changing the breaker? I have a 40amp breaker from the panel that services the pump, and heater. At the pool i have a 20Amp breaker for the pump and a 30Amp for the heater. Had this configuration for the last 7 years.
 Reply

InyoPools Product Specialist  Posted: 5/23/2016 

Suze - Usually a humming motor is an indication of a bad start capacitor, but most above ground pumps do not have start capacitors. If it's not the capacitor, you may have a short in your motor windings which means replacing your motor.
 Reply

InyoPools Product Specialist  Posted: 5/23/2016 

Sandy - If your motor is humming, you can probably get by with changing the capacitor. If it was actually whining, your motor bearings are failing and you probably need to replace the motor. 10 years is a good life for a motor.
 Reply

 Posted: 5/21/2016 

Hello, I recently opened my above ground pool, I bought a new filter last year the Pentair PNCC0075OE116. The pump worked all day on the first day, I shut the pump off and went to turn it on the following day and now the pump will not turn on. I just hear a humming noise. The electrical outlet is suitable for pool use so I do not believe that is the issue. Any help would be appreciated
 Reply

 Posted: 5/21/2016 

Hello, I hooked up my pool pump Pentair PNCC0075OE1160 to my above ground it worked fine day 1 for 12 hours. Next day it just hums and will not turn over. No issues with the electrical outlet as the outlet is working fine. The pump is only a year old. Any help would be great, thank you
 Reply

 Posted: 5/21/2016 

Went to open my pool for the summer and when I tried to turn my pump on, all it did was whine for about 20 seconds and then go silent. No water moved at all, is this pump shot. It is almost 10 years old.
 Reply

InyoPools Product Specialist  Posted: 5/20/2016 

Renee - Does the motor start again after you let it cool off. If so the motor is overheating. Make sure any debris is cleared away from the bottom of the motor. If the motor just hums when you turn it on, you may have to change the start capacitor. If there is no sound, check the voltage to the back of the motor to make sure you are getting power to the motor.
 Reply

 Posted: 5/18/2016 

I was vacuming my pool and turned the switch off to go to backwash, I hit the switch to turn it back on and there was nothing! I've checked all the breakers and everything is good. It has just stopped and I have no power. I even turned it back to filter and tried the switch again there is NOTHING. Please help moter is only a couple years old.
 Reply

InyoPools Product Specialist  Posted: 5/18/2016 

sunbev - Problem may be in the circuitry before the pump. I would suggest calling the spa manufacturer and seeing if they can resolve your problem.
 Reply

 Posted: 5/17/2016 

Replaced the whole pump and motor assembly about 2 months ago and has been working fine until today when I wanted to start it up tried to hit the emergency switch to reset and I can hear a click from the electrical box under tub, but when I press the button to start it I just here a click for each stage but no engagement.
 Reply

InyoPools Product Specialist  Posted: 5/10/2016 

MULE - This is generally what happens when your pump is configured for 230V and you are hooked up to 115V. See instructions on the motor label for changing your pump's voltage configuration.
 Reply

 Posted: 5/9/2016 

my Hayward pump runs for about 1/2 min. then it shuts off what could be the problem
 Reply

InyoPools Product Specialist  Posted: 4/19/2016 

Dan - I would start at the last fix first. Check that capacitor was wired correctly and that leads are tight. Than you might have another bad capacitor. I'd replace it again. Make sure it is at least as large as the original one. Then you might consider replacing the Terminal Overload Protector. See our overview guide on "How To Replace AO Smith Motor Parts - Overview" for references to individual guides on replacing these parts.
Note: you may have to go online to purchase the Terminal Overload Protector.

 Reply

 Posted: 4/18/2016 

I have a Century 3/4hp booster pump for my pool sweep(4years old). About a month ago it stopped working and had the normal hum sound of a bad capacitor. Cap was bad and leaking oil. I installed new capacitor and worked as good as new. Yesterday pump quit. Nothing, no noise, no heat, nada. Checked all electrical connections and voltage going into pump and all is good. Did the motor just give up or did the new capacitor die again?
 Reply

InyoPools Product Specialist  Posted: 4/18/2016 

capacitor check - Sometimes if you tap the electrical end of the motor while it is humming, it may start up, then you can be pretty sure it is the capacitor going bad. Also look at the capacitor(s). A bad capacitor will sometimes leak or expand at one end. In any can, if the motor is humming at startup, I would try changing the start capacitor first - at the back under the end cover. It's an easy fix and inexpensive. Your other option is probably going to be buying a new motor. See our guide on "How To Replace a Pool Pump Capacitor" for more information.
 Reply

Anonymous  Posted: 4/18/2016 

Step 3 says to check to see if you have a bad capacitor. How do you know if it is bad? My motor hums and then shuts off after 6 seconds.
 Reply

InyoPools Product Specialist  Posted: 2/22/2016 

motor won't start - Take the input wires off of the motor and check across the two input wires to see if you have 220V coming into the motor. If you do, you probably have a bad motor. Check with the distributor. If you don't have 220V coming into the motor, there is something wrong with the supply wiring.
 Reply

Anonymous  Posted: 2/17/2016 

Motor is new and hooked up correctly to 220 voltage. Motor reset appears to be ok. No continuity across terminals. Have power to plug in but, doesn't even try to start???
 Reply

InyoPools Product Specialist  Posted: 2/9/2016 

Nealva - From your description it sounds like your hi-speed windings are shorted. See our guide on "How To Use a Multimeter to Test a Pool Pump Motor - Winding Resistance" to test the windings.
 Reply

 Posted: 2/6/2016 

I was pumping water from my pool today dud to the heavy rain that we had and the pump motor just stopped. I thought the the electricity to the house had gone out but when I checked it had not. The motor tried to start again and hummed/buzzed but did not start and clicked off again. this time I noticed a little smoke. I I switched the speed to low and it started and ran. I turned it off, switched it back to hi and turned it on and it hummed/buzzed and a cloud of smoke formed around it and I turned it off immediately. I opened the end of the motor and there are some windings (start windings I assume) that are burned looking. Is my motor ruined? How can I tell for sure. My pump is a Hayward Super II 2-speed.
 Reply

InyoPools Product Specialist  Posted: 9/10/2015 

low voltage - Overheating is probably due to low voltage as you suggest. These motors’ are designed to operate at 115V +/- 10% - that's about 104V on the low end. Check your wire size between the breaker box and the motor. Here's a link to Recommended Wire Sizes. If it is too small, it will drop voltage across the length. Also check your supply voltage during the period of high power usage in your area. Voltage will drop when everyone is pulling power for their A/Cs. Check for obstructions in your motor, like debris around the impeller or for a loose impeller or diffuser rubbing on the inside of the housing. Make sure your motor has adequate ventilation.
 Reply

Anonymous  Posted: 9/7/2015 

I thought I needed to replace my 3/4 hp polaris booster pump because it was tripping the breaker. I'm on my second replacement pump and having problems because they overheat and shut off. I'm running it on 115v and it is wired for 115 as directed on the outside of the pump. My reading at the timer is 109. At the outlet where the pump plugs in in the shed the reading is 106 and the reading at the end of the wires for the pump plug is also 106. When I attach the wires for the plug to the pump the reading when the pump is running is only about 84. Any ideas as to what the problem is?
 Reply

InyoPools Product Specialist  Posted: 7/23/2015 

Shane K. - Your problems are most likely with the motor. If it is making load screeching noises, your motor bearings are failing. Check to make sure that your impeller is not clogged or rubbing on the inside of the pump housing. Check that all your electrical connections are tight. Check that there is no breaks in your power cord to the pump.
 Reply

 Posted: 7/21/2015 

I have a 1 horse motor it's been working for 2 years with know problem but now when I turn it on it runs 5 sec and turns off. Could it be the timer box are would you say it's most likely the motor?
 Reply

InyoPools Product Specialist  Posted: 7/2/2015 

motor hums - I would check your motor's start capacitor, usually under the electrical cover. See our guide on "How To Replace a Pool Pump Capacitor". Also while you are in that area, check to see if the governor is stuck open. See step #4 of our guide on "How To Replace AO Smith Motor Parts - Overview".
 Reply

Anonymous  Posted: 7/1/2015 

My pump, 1 hp Hayward, was working well until a couple of days ago. When I turned it on, it would hum for about 10 seconds and would shut off. Do I really need to replace it? or is there something I can do to fix it.
Please help.

 Reply

InyoPools Product Specialist  Posted: 6/9/2015 

1blondgal33 - Generally this is a wiring problem. Check to make sure the supply wire are connected to the right terminals and that they are tight.Use a meter to verify that you are getting power at the motor terminals. If you have 115V power make sure the motor is configured for 115V. If 230 volts coming in, motor should be set up for 230V. Occasionally you might get a bad motor. Check with your supplier for more information. If we sold it to you, please call us at 877-372-6038.
 Reply

 Posted: 6/8/2015 

Installed a brand new motor. It had power just doesn't start? Have no clue why. Please help.
 Reply

InyoPools Product Specialist  Posted: 5/20/2015 

Chuck - Could be that your supply voltage is not matched to your motor configuration. If your have 115V coming in, your motor should be set for 115V. Same for 230V. Also check that your pump's impeller is not jammed.
 Reply

 Posted: 5/19/2015 

I just completed replacement of the motor on my Hayward Super pump, a job made much easier by your hoe to guide(Thanks). The problem is when I turn it on it only runs for 2-3 seconds before switching off and then immediately back on and then off again continuously. Any ideas?
 Reply

InyoPools Product Specialist  Posted: 4/27/2015 

Justin - Sounds more like a problem with your 2-speed switch. Check the connection to the switch to make sure they are tight. Have you changed anything since your pump worked at both speeds. If so, recheck that.
 Reply

 Posted: 4/27/2015 

I have a pool pilot controlling my pool, pool pump shuts off when you select high. Motor is less than 1 year old, is this a capacitor issue or a pool pilot issue?
 Reply