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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(1 to 40 of 183)

 Posted: 9/10/2019 

My motor runs just fine, however after it's been running for a few hours if I turn it off to empty the basket when I turn it back on it hums. What could cause that?
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InyoPools Product Specialist  Posted: 9/12/2019 

Humming is a sign of a failing capacitor.
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 Posted: 6/13/2019 

My pool pump won’t turn on at all. There is no humming sound. The box is getting power but it seems that the timer motor is not working. Could that be the problem?
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InyoPools Product Specialist  Posted: 6/13/2019 

What is the catalog or part number from your motor's label?
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 Posted: 5/30/2019 

Well....replaced the top cap (think is the run cap?)....and nothing....like dead....think it could be the start cap?? Thanks for any help
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InyoPools Product Specialist  Posted: 5/30/2019 

It could be a start capacitor issue. Take a look at this guide for troubleshooting: How to Test a Pool Pump Capacitor
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Anonymous  Posted: 5/17/2019 

When I turn it on My Polaris motor will hum for about 10 seconds or so then it will shut off. What could be causing this?
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InyoPools Product Specialist  Posted: 5/20/2019 

It could be a bad capacitor or one of the things mentioned in this troubleshooting guide. What troubleshooting steps have you completed so far?
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 Posted: 5/9/2019 

My pump shuts off randomly, usually every 10-15min, then turns back on after about 30sec. It's been an ongoing issue over the past few years, last year it didn't happen at all from what I remember, but in years before it has happened with varying frequency. The pump has been replaced within those years, but it didn't seem to make a difference. It doesn't seem to be related to heat, pump doesn't seem overly hot, or weather (hot summer days or cool spring/fall days). I'm have a easytouch system (about 10 years old) and century 1 1/2hp motor (2-3 years old). Any ideas why this is happening?
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InyoPools Product Specialist  Posted: 5/9/2019 

Hello Kelvin - My first thought was that the windings in the motor are going bad and that is causing it to randomly shut down. If the windings are bad, the motor should be replaced. Another possibility is that the relay that controls the pump is going bad. That or the wires at the relay are loose.
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 Posted: 6/1/2019 

I replaced the relay and so far it seems to have fixed the problem. Thank you for your help!
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 Posted: 4/29/2019 

I replaced my start capacitor. Turned to power on, it popped and tripped the breaker Now it doesn't come on at all Now what?
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InyoPools Product Specialist  Posted: 4/29/2019 

I would confirm the capacitor was hooked up correctly, then test it to determine if it is still good. 
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 Posted: 4/7/2019 

My pool motor runs during a quick bench test. But there is no re-action when it is installed on the pump. I measured 220v at the input. I have a Sta Rite Pentair pump and USQ 1152 motor. My next guess is the bearings but I can't understand why there is no noise and no movement at all when it is installed on the pump.
 Reply

InyoPools Product Specialist  Posted: 4/8/2019 

Joe - have you checked that the impeller and the diffuser are not blocked or locked up? Is there scoring on the impeller, diffuser, or seal plate which might be a sign of rubbing?
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 Posted: 4/8/2019 

There is 220 VAC at the input. But still nothing, no noise , no struggling, no hum, There is one thing different when testing on the bench. I didn't want to play with 220v so I switched the control knob to 115v just for the bench test. Then I turned it back to 220v. But I get no reaction when the motor is installed on the pump.
 Reply

InyoPools Product Specialist  Posted: 4/9/2019 

Have you tried applying switching the motor to 115 and applying 115-volts to the motor when it is installed on the pump?
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 Posted: 4/10/2019 

Thank you for the follow up. Today I turned the AC switch to 115 VAC while the motor is installed. And it tried to run. It sounded almost normal with 115 vac. It was trying to run the pump. The AC switch is very difficult to turn and I'm concerned about breaking it. So, does this new indication mean that the AC switch is bad or could it be the motor wingdings? Maybe I can wire the 220 vac directly and bypass the black control knob. What are your thoughts?
 Reply

InyoPools Product Specialist  Posted: 4/11/2019 

I sent your question to a senior Century Motor's technician, and received this reply:If the motor is tested on a bench with no load, it will start if 115 volts are applied, regardless of the setting of the voltage change device.  If the power supply to the motor is checked across the two leads, it would read approximately 115 volts if that is the power supply.  If the power supply is approximately 230 volts, that would be the reading between the two leads.  If the power supply is approximately 230 volts, and the motor voltage change device is set to 115, the motor will burn out immediately. If the voltage change device is set to the voltage being applied, even if the pump was locked up, the motor would attempt to start, and then trip the internal overload.  After it cools down, it would attempt to restart.  The voltage change device is not easy to turn.  A wrench is the best way to rotate the device, while holding the terminal board with the other hand, so it doesn’t break. Is this a new motor that is being installed, or an existing motor that has a problem?
 Reply

 Posted: 4/8/2019 

The diffuser is brand new and the o-ring is brand new with Magic Lube. The PS-201 seal is also brand new and so is the starting capacitor. The impeller is clean and fine. The motor runs during a bench test but there is no action when it is installed.
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 Posted: 3/29/2019 

I have a Hayward pool pump mod # UST1102. The pump has been off for a couple of months. I turned it on and then looking through the cover, I noticed there was no water in the pump container. I shut off it off and filled the container with a hose. I turned the pump back on, and nothing... No noise, no hum and no pumping.
 Reply

InyoPools Product Specialist  Posted: 4/1/2019 

Hello  Tom - have you checked the pump circuit's voltage? This will determine it is getting enough electricity to run. Also, depending on how long your pump ran dry, your motor may have overheated and needed time to cool down. I would give it 15 minutes to a half hour and then give it another go. If after the motor cools down, and it still will not turn on, and the voltage is normal, the motor may need deeper troubleshooting.
 Reply

Anonymous  Posted: 3/27/2019 

My motor makes a buzzing noise and won't turn on. I can turn it with a screwdriver on the tail end of the motor without any problem, assuming it wasn't rusted inside? Do you think the capacitor, likely the problem? Also do you guys sell the capacitor cover with the screws for an Emerson EB841? The guy who came to give me an estimate broke the cover and the screws to open the cover. And quote me $900 to change the motor. If its problem is only the capacitor, then it will save me loads of money. But will have to find a way to extract the broken screws and find the replacement cover.
 Reply

InyoPools Product Specialist  Posted: 3/28/2019 

It very well could be a bad capacitor. For information on how to check it, read this guide: How to Test a Pool Pump Capacitor.
 Reply

 Posted: 2/15/2019 

Hi. My motor will not always start. When it will not start, if I give it a little turn with a screw driver it will then run fine. I replaced the start capacitor. What should I check next?
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InyoPools Product Specialist  Posted: 2/18/2019 

Hello James - Have you tested the circuit's voltage? Has the motor gotten noisier recently, like a grinding noise?Do you have the part, catalog, or model number from the motor label? Just want to determine which motor we're discussing.
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 Posted: 2/12/2019 

Hi I ordered a new pump motor from you guys last week (Order #917261) and replaced the old pump motor with the one you sent me. When I go to turn the pump on, nothing happens, at all. I checked with a volt meter to make sure I am getting electricity to the motor and verified that I am getting power. But like I said, literally nothing happens at all. Timer is on as well as all breakers. Any suggestions?
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InyoPools Product Specialist  Posted: 2/13/2019 

Hello Joseph - The motor is set at the factory for 230v. Are you supplying 230v or 115v to the motor?
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 Posted: 2/13/2019 

Hi Robert, yes the motor is switched to 230v and that is the power I am supplying.
 Reply

InyoPools Product Specialist  Posted: 2/13/2019 

You ordered the B2853. This is a 1HP uprated motor with a total HP of 1.25. If the old motor was the same rating, you may have a defective new motor. If the old motor had a higher total HP, the new motor may have burned up attempting to run. Either way, call our customer support at 407-834-2200. They can initiate the replacement process.
 Reply

 Posted: 1/31/2019 

I have a weird problem i can't pin point. I got this spa for free awhile back and have since been replacing parts to get it to run right. I don't know the brand or model, but the circuit board is a spabuilders one and there's a date of 07/2005 on the tub itself, so it is quite old. I have gotten the tub to cycle and heat up fine, but when the motor is running on high, the motor itself shuts off after a few seconds of running. I tested for power and it is still receiving power from the relay when the motor shuts off so i would assume that my issue has been something inside the motor the whole time? The only thing i replaced on the motor was the starter cap because it never used to start from a stop when i got it. This happens throughout all temps of the motor as well. I have left the tub unplugged for a week so the motor is dead cold, (40f or so) and it'll still shut off and shut off faster when the motor is warmed up. Is there something inside the motor i could fix or replace or would I be better off replacing the motor as a whole? Thank you.
 Reply

InyoPools Product Specialist  Posted: 2/4/2019 

Hello Bailey - It sounds like it could be the windings. We would recommend replacing the motor. What is the catalog or part number of the motor?
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 Posted: 1/21/2019 

My pressure pump motor hums. I have changed capacitor but no change. I have turned the motor over by hand at motor end using screw driver and although it turned, it was not easy. It has been in place for almost 15 years so am I right in saying it's time to get a new one?
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InyoPools Product Specialist  Posted: 1/22/2019 

Hello Stel - The fact that it's hard to turn by hand and that a new capacitor didn't work, signifies that a new motor is likely needed.
 Reply

 Posted: 1/13/2019 

My pump shut off this morning after running just fine. The breaker for the pump in the breaker box near pump and the main house breaker box pool equip breaker both tripped for the pool pump. I flipped them back on, and they stay on, but the pump appears to be getting no power. Not sure what to do at this point.
 Reply

InyoPools Product Specialist  Posted: 1/15/2019 

Hello Steve - We would recommend using a voltage meter to make sure that power is getting to the pump motor. If it is, we recommend replacing the motor. If not, we recommend contacting an electrician to diagnose the problem.
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 Posted: 1/9/2019 

My pool pump motor is not coming on during the auto programming. I can put it in service mode on the main panel and use the control on the top of the pump and it works. Do you think there is a problem with the main panel causing the pump not to engage during the normal programmed settings?
 Reply

InyoPools Product Specialist  Posted: 1/10/2019 

Hello Todd - What is the make and model of your pool pump motor and control system?
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 Posted: 11/1/2018 

I have a Jandy RS4 system. My filter pump won't start from the remote unit, but will start from the power panel when the unit is in service mode. Since it starts at the local button, does that rule out the relay? Should I be troubleshooting the remote unit and the board? Thanks for any help.
 Reply

InyoPools Product Specialist  Posted: 11/2/2018 

Hello Matt - You are correct. It doesn't sound like a relay issue. We would recommend looking at the board and remote/receiver.
 Reply