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  1. #1

    Humming sound, but things seem to be working.

    I've got a quiet humming sound coming from my furnace when heating and cooling systems are not running. Every thing seems to work right now. The blower turns.

    There's a light-switch mounted to the side of the furnace. If I flip that off, the sound stops. It seems to be coming from the duct underneath the furnace, where I think the cooling coil is.

    Anyone have an idea what this humming might be?

  2. #2
    Join Date
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    Arnold mo
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    Transformer.
    An answer without a question is meaningless.
    Information without understanding is useless.
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  3. #3
    Join Date
    Dec 2002
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    Houston,Tx.
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    Quote Originally Posted by tipsrfine View Post
    Transformer.

    What he said up there.
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

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  4. #4
    Join Date
    Jul 2004
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    Massachusetts
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    What they said.

  5. #5
    Join Date
    Nov 2006
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    Southeastern Pa
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    Yes.

    If the transformer is terribly loud, a tech could probably try to isolate it from its mounting panel.

    But, chances are this requires no further action.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

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  6. #6
    OK, thanks.

    Why would the system need to allow the transformer to draw energy when it's not running? It seems inefficient. Is it to avoid a time delay?

  7. #7
    Join Date
    Jan 2008
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    2,058
    The transformer is always on because power is always applied to the unit, so it is always ready to go, and power your t-stat, if it's that type. It uses very little power.
    I suppose if you really want to, you can go the the unit, turn the power off, and turn it back on each time you need heat or cool.
    "Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler

  8. #8
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    Quote Originally Posted by horseatingweeds View Post
    OK, thanks.

    Why would the system need to allow the transformer to draw energy when it's not running? It seems inefficient. Is it to avoid a time delay?
    ...because you don't want to go to the unit every time you want heat or cooling.

    The idea is that the power is always there waiting, so the thermostat can route it correctly for the desired function.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







  9. #9
    Join Date
    Aug 2011
    Posts
    568

    Hmm

    Quote Originally Posted by horseatingweeds View Post
    OK, thanks.

    Why would the system need to allow the transformer to draw energy when it's not running? It seems inefficient. Is it to avoid a time delay?
    the amount of power it uses is a blip on the radar, and i do mean a BLIP!

  10. #10
    Join Date
    Jan 2009
    Location
    South Georgia
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    Quote Originally Posted by horseatingweeds View Post
    OK, thanks.

    Why would the system need to allow the transformer to draw energy when it's not running? It seems inefficient. Is it to avoid a time delay?
    As i thought about this my head began to hurt.... but your computer and its monitor probably burned more energy typing your post than the transformer will burn over the course of a week... it would be interesting to see if something more efficient could be designed... i'm gonna go lie down now and try not to think of all those cell phone chargers plugged in with no phone attached.

  11. #11
    Join Date
    Mar 2009
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    Triad - North Carolina
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    Quote Originally Posted by horseatingweeds View Post
    OK, thanks.

    Why would the system need to allow the transformer to draw energy when it's not running? It seems inefficient. Is it to avoid a time delay?
    The transformer powers the thermostat which is needed to turn on the system. Power consumption is minimal compared to the computer you are using right now!
    Yes, I've seen that before and it doesn't mean I like it.

  12. #12
    Join Date
    Feb 2011
    Location
    North East Ohio
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    776
    Someone explain this to me. How can a cell phone charger plugged in with no phone connected to itbe drawing power? What is pulling amps on that circuit?

  13. #13
    Join Date
    Aug 2011
    Posts
    568

    Hmm

    Quote Originally Posted by NCHeat View Post
    Someone explain this to me. How can a cell phone charger plugged in with no phone connected to itbe drawing power? What is pulling amps on that circuit?
    the charger its self, thats why the goverment wants you to disonect if not actually charging the phone! once you plug it in its working and sending amp/volts to the end that plugs into your phone, it cant see that your phone isn't attahed, though they might come out with one that can sense the phone is attached then it'll turn on!

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