Air handler blower motor

Discussion in 'HVAC' started by natev, Aug 8, 2012.

  1. Aug 8, 2012 #1

    natev

    natev

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    My air handler blower motor started "stuttering" last week. It's keeping the house cool but it will start up fine blowing air & then randomly stop for a second and start up again and stop for a second - sometimes a few times in a row & sometimes it stops for a longer period but never more than a second or two before it gets going again. .
    There's no pattern to it - it's completely random & there are no "bad sounds" or smells...

    Is this most likely the motor or could it be the fan relay? How do I test that?

    I opened the air handler & it's horizontally mounted (mount is on the left) & it almost looks like I have to remove the heat pump element & electrical connections to get the squirrel cage out if I need to replace the motor - is there an easy way to get it out or does it just look more complicated than it is?

    I'd like to figure this out before it stops completely & we're stuck with no AC in 100+ degree weather.

    Any help would be greatly appreciated. I believe it may be Lennox or Carrier (outside unit is a Lennox but the only tag I was able to find near the motor was the fan wheel which is a Carrier wheel)
     
  2. Aug 8, 2012 #2

    kok328

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    If you have the capability, check the motor's capacitor. If not, it is a inexpensive first guess to fixing the problem.
     
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  3. Aug 9, 2012 #3

    natev

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    Could the behavior of the motor I described (stopping & starting randomly) be a symptom of the capacitor going bad?
    The capacitor is not mushrooming or anything I can see visually, unfortunately I don't have a meter that can test ferads.
     
  4. Aug 9, 2012 #4

    kok328

    kok328

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    yes, this is sometimes a symptom. Perhaps, you could have it tested or just replace it for around $20 or less.
     
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  5. Aug 9, 2012 #5

    natev

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    So I went to Grainger this morning & picked up a replacement capacitor for $6. Took me 7 mins to replace it & it's been through 2 cycles now without messing up! Hopefully that was what it needed - thanks for the replies!
     
  6. Aug 9, 2012 #6

    kok328

    kok328

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    Successfully troubleshooting HVAC without seeing, hearing or touching isn't easy.
    An educated guess at best.

    Congratulations !!
     
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  7. Aug 9, 2012 #7

    natev

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    One more question - what's the difference between a cap that says 50/60 Hz & one that says 60/50 Hz?
    The guy at Grainger said it didn't matter since the voltage (370 VAC) & microferads (7.5) were the same...
    Just wondering if that would affect anything...

    Also - I better check with you to see if on a single run capacitor (the one with just 2 terminals) does it matter which brown wire goes to which terminal? Ie...does the one with the white stripe need to be on a specific terminal & the one without the white stripe on the other - only 2 terminals & only 2 wires...wondering if it matters which is which)

    Thanks!
     
    Last edited: Aug 9, 2012
  8. Aug 9, 2012 #8

    kok328

    kok328

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    No difference between 50/60 Hz & 60/50 Hz, it's just the order that the manufacturer decided to print it.
    In the USA, we are 60Hz.
    Wire and terminal connections do not matter on this particular cap.
     
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  9. Aug 9, 2012 #9

    natev

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    Thanks again! Just wanted to make sure I wasn't going to blow anything up :)
     
  10. Aug 10, 2012 #10

    natev

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    Ok - worked great yesterday & now it's doing the same thing this afternoon...could I possibly have gotten a bad capacitor then?
     
  11. Aug 11, 2012 #11

    kok328

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    Like I said, it's not easy providing an accurate diagnosis without being there.
    Test the capacitor, check the relay or bypass the relay and see how the motor responds.
     
  12. Aug 12, 2012 #12

    joechuckg

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    Sounds like a relay in the circuit board is going out might need to replace board
     
  13. Aug 13, 2012 #13

    kok328

    kok328

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    Boards aren't cheap, replace the relay instead.
     

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