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Thread: Pump not starting - even with new capacitors

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    Pump not starting - even with new capacitors

    I'm wondering if anyone has seen this issue. Our 2 speed pump (third season on our 24' AGP) would not start last night. Motor just hums - breaker would not trip. Did a little research, then pulled both the start & run capacitors. I suspected the start one might be bad, but the run capacitor looked a little rugged. So this afternoon, with two new capacitors installed, the motor still just sits and hums. But a little twist on the slotted motor shaft (exposed when the end cover is off to access the start capacitor) will get the motor running. Ran it for 5 minutes - stopped it - would not start. Got it running again by manually spinning the shaft and let it run for two hours. Still no go on its own. Is it possible that Grainger sold me a bad start capacitor? Should I get another start capacitor? Could this problem be caused by something else? Thanks for any help / suggestions you can provide!
    24' x 54" Sentinelle AGP (New in April 2011) // 1.5 HP two-speed pump // 22" sand filter (150#) // Aqua Rite SWG

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    nedchavez's Avatar
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    Pump not starting - even with new capacitors

    Sounds like the centrifugal switch is bad. This switch puts the start winding and start capacitor in the circuit to give it the extra torque the motor needs to start, then removes them from the circuit when the motor is up to speed.

    Can you post a picture of the motor nameplate?
    16' x 32' IG vinyl liner w/ hopper bottom (12,500 gal), Single-speed 1 HP Sta-Rite pump, and 300# Cristal-Flo sand filter, TF-100 test kit

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    Re: Pump not starting - even with new capacitors

    Quote Originally Posted by nedchavez
    Sounds like the centrifugal switch is bad. This switch puts the start winding and start capacitor in the circuit to give it the extra torque the motor needs to start, then removes them from the circuit when the motor is up to speed.

    Can you post a picture of the motor nameplate?
    OK - I'll try to post a picture of the nameplate. Hope it is clear enough. Thanks for your input.

    [attachment=0:3o2uwl2u]pump-motor.jpg[/attachment:3o2uwl2u]
    Attached Images Attached Images
    24' x 54" Sentinelle AGP (New in April 2011) // 1.5 HP two-speed pump // 22" sand filter (150#) // Aqua Rite SWG

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    Re: Pump not starting - even with new capacitors

    I agree with nedchavez, your centrifugal switch is probably hung up. Turn off the breaker, open the back and look at the centrifugal switch. Try to manually operate the switch and if you find it is binding put a little oil on the pivot points. It's worked for me on a couple of motors.
    16x32 Oval In-ground Vinyl, ~17,000 gallons, Hayward 1hp Superpump, Hayward S245T Sand Filter

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    Re: Pump not starting - even with new capacitors

    OK, I took another picture, this time with the end cover pulled and the capacitor off to one side. Is the centrifugal switch connected to the start capacitor (red wires)? Is there a simple way to test the centrifugal switch? Are the pivot points visible in this picture or do I need to remove the end plate? Thanks again for your help!
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    24' x 54" Sentinelle AGP (New in April 2011) // 1.5 HP two-speed pump // 22" sand filter (150#) // Aqua Rite SWG

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    nedchavez's Avatar
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    Re: Pump not starting - even with new capacitors

    Well, I'm sorry to say, I missed in the initial post that it was a two speed motor. You have what is referred to as a PSC motor. Permanent Split Capacitor. These have no centrifugal switch. This would mean a capacitor is bad or a motor winding is bad. I would take it to a motor repair / rewind shop and see if it is repairable or if it needs to be replaced.
    16' x 32' IG vinyl liner w/ hopper bottom (12,500 gal), Single-speed 1 HP Sta-Rite pump, and 300# Cristal-Flo sand filter, TF-100 test kit

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    Re: Pump not starting - even with new capacitors

    Quote Originally Posted by nedchavez
    Well, I'm sorry to say, I missed in the initial post that it was a two speed motor. You have what is referred to as a PSC motor. Permanent Split Capacitor. These have no centrifugal switch. This would mean a capacitor is bad or a motor winding is bad. I would take it to a motor repair / rewind shop and see if it is repairable or if it needs to be replaced.
    I am able to get the pump started in both low speed and high speed settings. All I have to do is twist firmly with a screw driver in the slotted shaft that you can see in the second picture. Does that clarify things at all? I'm tempted to get another start capacitor and try that. For the moment I can run my pump and my SWG and keep the pool clean and "not green."
    24' x 54" Sentinelle AGP (New in April 2011) // 1.5 HP two-speed pump // 22" sand filter (150#) // Aqua Rite SWG

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    nedchavez's Avatar
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    Re: Pump not starting - even with new capacitors

    Quote Originally Posted by fiftyhertz
    I am able to get the pump started in both low speed and high speed settings. All I have to do is twist firmly with a screw driver in the slotted shaft that you can see in the second picture. Does that clarify things at all?
    That is a symptom of the start winding not working ie bad winding / bad cap / bad centrifugal switch (where used).

    I'm tempted to get another start capacitor and try that.
    I would try it. I just doubt the new one you already have is bad. Do you have access to a multimeter to check it?

    For the moment I can run my pump and my SWG and keep the pool clean and "not green."
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    16' x 32' IG vinyl liner w/ hopper bottom (12,500 gal), Single-speed 1 HP Sta-Rite pump, and 300# Cristal-Flo sand filter, TF-100 test kit

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    Mod Squad Bama Rambler's Avatar
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    Re: Pump not starting - even with new capacitors

    It looks like water has been up in the bottom of that motor. I'd pull the bell end off and see what it looks like in there.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Pump not starting - even with new capacitors

    Update:

    Last night I went out to start the pump manually. It was after dark, and of course I had to pull the end cover off to turn the shaft. Using my flash light I took a long look at what I could see through the partial openings in the bearing end cap. I thought I could see what looked like part of a centrifugal switch. I used my screw driver to try to move the switch arm. Well - that was not a good thing to do. Now the motor would not start with a manual boost - in fact after about 20 seconds of power to the motor the breaker tripped! So I plugged in my electric drill - I was going to give the shaft a real good boost to get it turning. About 1/2 second after pulling the trigger on my drill I got a good spark - and a very hard trip of the breaker. Time to regroup!

    So after work this evening I pulled the pump/motor off the sand filter base and took it up to the deck. I pulled the bearing end cap off and sure enough - it has a centrifugal switch. I have a digital multimeter - and from what I could tell the motor windings were in good shape. The centrifugal switch seemed to be ok. I could get the switch's pressure plate to move forward and back. The switches electrical contacts seemed to be ok as well - nothing appeared to be damaged. So I put everything back together and gave it a test - fired right up! Started on its own. Then put everything back in its place. Pumping well. The SWG is doing its job - and the pool is still "not green!"

    So - I think that the real problem all along was in the pressure plate part of the centrifugal switch. It became stuck/jammed and would not return to its "normal off position." There are some hinges in the pressure plate mechanism that must be sticky. The springs in the mechanism are supposed to return the pressure plate to its off position - but they must not have had enough force to overcome the "sticky hinges."

    I took a few pictures while I had the motor apart. The centrifugal switch has two main components, The pressure plate mechanism mounts on the shaft and is behind the bearing. The electrical and mechanical contacts are mounted to the motor end plate. While putting the end plate back on you have to be certain that you get the mechanical contacts set in correctly, behind the bearing and in contact with the pressure plate. With the motor powered off the springs are supposed to push the pressure plate towards the bearing. The plate pushes the mechanical contacts - which in turn closes the electrical contacts. With these contacts closed the start windings and ths start capacitor will "see power" up as soon as the power is turned on. Once the motor is turning fast enough the pressure plate drops away from the bearing and the switch opens - leaving only the run windings and the run capacitor in the circuit.

    I'll post another update if things change. For now I will keep a spray can of WD-40 handy. I also have learned which opening is best used to access the pressure plate if it gets stuck. That would be one of the lower openings - away from any of the wires and also away from the mechanical contact part of the centrifugal switch.
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    24' x 54" Sentinelle AGP (New in April 2011) // 1.5 HP two-speed pump // 22" sand filter (150#) // Aqua Rite SWG

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    nedchavez's Avatar
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    Re: Pump not starting - even with new capacitors

    Hmm, I don't understand why the motor showed as a psc type when I looked it up, yet it has a centrifugal switch? Oh well, glad to hear you got it working. Good job!

    Be careful with the wd40. Even though it uses CO2 for a propellant, it's probably flammable when vaporized. You probably shouldn't start a motor soon after spraying or the spark from the centrifugal switch could start a fire.
    16' x 32' IG vinyl liner w/ hopper bottom (12,500 gal), Single-speed 1 HP Sta-Rite pump, and 300# Cristal-Flo sand filter, TF-100 test kit

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    Mod Squad Bama Rambler's Avatar
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    Re: Pump not starting - even with new capacitors

    That switch is why I suggested removing the end bell. Those switches are notorious for sticking. Glad you got it remedied
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Smykowski's Avatar
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    Re: Pump not starting - even with new capacitors

    Good post. That info will for sure help someone in the future.
    33' round, 23,000 gal AG vinyl , 1HP 2spd PowerFlo Matrix downsized with 3/4HP impeller (X2), Hayward S180T 150# sand filter (X2), Hayward H250 NG heater Pool Store year 1 - $850 for 2 months; Pool Store year 2 - $440 for 2 months, TFPC year 1 - $170 for 4 months; TFPC year 2 - $95 for 4.5 months
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    Re: Pump not starting - even with new capacitors

    Quote Originally Posted by Smykowski View Post
    Good post. That info will for sure help someone in the future.
    This post helped me get my pump running, the day before listing my house! yay! I bought another house with a pool - Im an IDIOT! -

    Just thought I would say thanks
    16x32 in-ground vinyl liner, 17,500 gallons, sand filter, 2 outlets, BBB method, 8+ hours of daily sun, hayward super pump

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