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  1. #1

    Buzzing noise from circuit breaker

    An office has a 2.5 ton Trane R-22 10 SEER condensing unit and a fixed orifice metering air handler, both installed in 2001. The office is a ground floor unit of a two story building and the condenser is on the roof of the structure. The space cools as it should, but when the compresser starts, a buzzing sound can be heard from the circuit breaker panel. The buzz is usually less than a second, but sometimes can last 1-2 seconds. The owner said this has been happening, on and off, since he took the space (2002). I was on the roof near the compressor when it started and did not hear anything unusual. However, there is definitely a buzzing sound coming from the breaker panel.

    The owner says the breaker has been replaced and the wiring to the unit has also been replaced, both of which seemed to be the case when I checked. The connections also seemed tight. Also, according to the owner, a hard start kit was connected and then removed, the condenser fan motor was replaced, gas was added and removed. I'm sure other "service" was performed as well.

    What kind of electrical problem could this be?

  2. #2
    Join Date
    Jan 2003
    Location
    San Jose, Ca
    Posts
    2,089
    Sounds like something is loose in the panel. An electrition needs to check the panel out.
    Old snipes don't die they just loose their steam

  3. #3
    Join Date
    Sep 2008
    Posts
    15
    I would check the current draw of the unit. It could be at the verge of tripping the breaker and causing it to chatter.

  4. #4
    Join Date
    Sep 2008
    Location
    Mesquite Tx.
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    374
    I agree with the electrician part. Since they changed the breaker, I would look at the buss connectors under the breaker, or the buss its self. Just my two bits.

  5. #5
    Join Date
    Jan 2008
    Location
    melbourne aus
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    80

    Thumbs up buzz bar

    i also agree with the electriian could be a relay buzzing or if there is another contactor in there which could be making the buzzing noise
    you will be able to tell which one one it is if you tap the side with an INSULATED SCREWDRIVER. the change it.

  6. #6
    Join Date
    Jul 2008
    Location
    Northwestern Va.
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    15
    Arcing..plain and simple. Or arcing inside of conduit...makes the same kind of noise.

  7. #7
    Join Date
    Nov 2006
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    Southeastern Pa
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    Yes, check and make sure that the current is not so high that it is on the verge of tripping the breaker.

    Very often, it is the press-in breaker that makes the noises folks hear in service panels. Specifically, the type produced by ITE and their licensees. I have had all of my noisy breaker, burning buss bar problems from the ITE design.

    Inspect the line side tines of the breaker, and make sure they are still clean and smooth. If not, start this with a new breaker.

    Move the breaker to another available space and use a blank out for front panel safety protection. Get some no-al-ox or equivalent and lube up the line tines on the breaker, and install on a fresh spot.

    When you remove the breaker, you will very likely see a mark on the buss bar where the arcing was simmering.
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  8. #8
    Join Date
    Dec 2006
    Location
    Middle Tennessee
    Posts
    11,347

    *

    Quote Originally Posted by timebuilder View Post
    Yes, check and make sure that the current is not so high that it is on the verge of tripping the breaker.

    Very often, it is the press-in breaker that makes the noises folks hear in service panels. Specifically, the type produced by ITE and their licensees. I have had all of my noisy breaker, burning buss bar problems from the ITE design.

    Inspect the line side tines of the breaker, and make sure they are still clean and smooth. If not, start this with a new breaker.

    Move the breaker to another available space and use a blank out for front panel safety protection. Get some no-al-ox or equivalent and lube up the line tines on the breaker, and install on a fresh spot.

    When you remove the breaker, you will very likely see a mark on the buss bar where the arcing was simmering.

    are you teaching DIY now?



    .

  9. #9
    Join Date
    Jun 2008
    Location
    Apopka, Florida
    Posts
    110

    Buzzing noise from circuit breaker

    Taking into consideration, what is the size of the breaker, what is the gauge of the wire, what is the length of run on the wire, you could have a voltage drop if it is close to max run of the wire causing you to have the buzzing that you are experiencing.

  10. #10
    Join Date
    Nov 2006
    Location
    Southeastern Pa
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    18,812
    Quote Originally Posted by Airmechanical View Post
    are you teaching DIY now?



    .
    No, I don't think so.

    From what I am able to understand from the original post, this is not the "owner" posting, so he is not "doing it himself." The poster is working this problem because the owner has called him in, and since this is a rooftop unit, it is reasonable to me that the poster falls into the category of "technician."

    In fact, this does not appear to be an HVAC problem.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







  11. #11

    Buzzing noise

    OVER AMP DRAW

  12. #12
    Join Date
    May 2001
    Location
    Western Wa
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    1,843
    The buzzing is the first stage of the fire alarm.
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