Pump hums and might start.....or not

[Victor Newman]

Inground pool, StaRite 2 speed (2hp and 1/4hp). I like to switch the motor on once in awhile, just because. Couple of days ago I did this and pump hummed for 3-5 seconds and clicked off. Breaker did not trip.

So, I have been testing. It appears that when pump is on high, per the panel switch, that is when the humming starts. It appears that when the pump is on low.....it starts up as usual.

It has been cold here lately. 25 to 30 degrees at night. I also have a freeze control unit that overrides the timer. I read a lot of the threads on motor humming. Lots of good info and I will start by trying to turn the impeller (power off, breaker off). Read that it could also be centrifugal start switch is not working or the windings are shot. I might carefully test the capacitor.....except I thought I saw that only an analog meter will do the trick. I only have a digital multi-meter (but I thought I read they can test resistance, also) ?? I am an electrical and mechanical dunce.

My main question now, is: If the freeze control comes on at night and the motor fails to go on.....what is the worst that can happen? Will it hum for a long time and burn something up? Will it eventually trip the circuit breaker ?

Thanks

 

[Divin Dave]

Hi Victor,
usually there are 2 reasons why a pump hums and wont start going.
1 - It has a bad capacitor
2 - Bad bearings that have seized up.

Before troubleshooting, turn off the breaker to the pump.

If you are a little handy and have a volt meter, you can test the capacitor.
The capacitor is under the big hump cover on top of the motor. Remove the cover and disconnect the capacitor. Here is a video on how to check it with a volt meter.
https://www.youtube.com/watch?v=FDuN7QHn1-s

Bad bearings will seize the motor. To check if this has what's happened, remove the fan cover from the back of the motor, If you can spin the armature shaft with your fingers, then the bearings are ok. If not, then it's seized.



Since you mentioned the pump will sometimes run, Im leaning towards the capacitor being bad. Its a common thing that happens.

Hope this helps

 

[Victor Newman]

OK, I tried to get my fingers to the impeller after removing the strainer basket. No good. Need LONGER fingers. A wood stick did not seem to turn the impeller. Took off the metal end cap. I could see the end of the shaft but no way for me to turn it. It was covered up by what I think might be the centrifugal start switch (too dumb to post a photo). There is a small "start capacitor" here. It looked OK, I did not fool with it.

Took the large capacitor cover off. It looked OK, I did not fool with it or try a multi-meter. Wrote down all the numbers on both capacitors in case I have to call a repair person. They can bring correct replacement.

A bit more testing revealed a 3-5 second hum.....and then the motor kicked in.

I really need to know.....if the motor goes on at night via the freeze control and hums and hums...will the motor burn up? I also noticed a 5 second hum and a "click". Hum stopped. After 20 seconds, I can start the motor as usual. Is the "click" a overload shutoff or relay or some safety device?

 

[Divin Dave]

Hi Victor,
If its the capacitor, then no, the motor wont burn up if freeze protection kicks in.
It just wont come on.

 

[Victor Newman]

Had to get a new AOSmith/Centurn 2-speed motor. New start capacitor no help. It was the windings.

Thanks for your help....