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  1. #1

    Question about rumble sound...

    I have a Rheem Package unit that was installed 6 months ago. I have a loud low freq rumble sound that seems to be coming out of the return filter. I thought maybe the duct they installed was to small causing the sound but if I turn on only the fan I do not have the noise. It happens if the heat or cooling is running.

  2. #2
    Join Date
    Oct 2009
    Raleigh, NC
    Is it gas fired?

  3. #3
    Quote Originally Posted by MicahWes View Post
    Is it gas fired?

    No, it is a 3 ton unit with a heat pump with heatstrips. It is a scroll compressor and doesn't seem real load out side. There is 18" flex running to the return box that is located in a hall way. The sound is a low freq rumble and carries through the house very loudly. I did go out next to the unit and noticed that the ground is vibrating around the unit. They set it on a plastic pad. If I go under the house and put my hand and ear on the flex I can hear and feel the roar / rumble sound. It does not do it with just the blower running. Any ideas or things I shouls check?

  4. #4
    Join Date
    Jan 2004
    Fan only speed may be much slower then heating or cooling speed.
    Contractor locator map


    How many times must one fix something before it is fixed?

  5. #5
    Quote Originally Posted by beenthere View Post
    Fan only speed may be much slower then heating or cooling speed.

    How can I tell that for sure? The model number off of the badge is RQNM-A036JK010.

    Looking at the duct work it has a 20X30 Return grill and 18" flex for the return. I then has a short piece of 18" flex to 18" round pipe with 5 6" flex runs off of it. Then it necks down to 14" pipe with 5 6" flex run off of it. I checked the fan and it is set on the low tap. The manual shows 1050/1350 (Min/Max) CFM. The noise is coming from the return side, I do not hear it on the supply side if I stick me ear to a vent or trunk.

  6. #6
    Join Date
    Jul 2000
    Northern Wisconsin
    Would another sound you'd equate it to be a pulsation?

    Return flex will sometimes cause a pulsation noise. It can be caused by air flow through it that is close to if not beyond it's rating OR it can be because of bends or droops in the flex run. The inner flexible tubing will slightly collapse as the air volume moves through it at very fast speeds. By collapsing slightly the characteristics change for the better and the conditions allow it to relax and ......... this process once started usually continues and generates a low frequency pulsing or fluttering sound that can be heard at the return grill. Sometimes hard pipe is the better option.

    You said it was a filter grill, correct? Try removing the filter and see if the noise goes away. If it does you can always try using a less restrictive filter if one is available. I would suggest you call back the installer and explain what you're hearing and explain that the noise is not acceptable and you'd like it resolved.
    Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.

  7. #7
    Join Date
    Aug 2010
    West Monroe, LA
    I would call your installing company back and explain the nosie you are hearing and ask to have a tech come out and look at it. Any good company shouldn't have a problem in doing this.

    It can be many diffrent things as others have stated but without your installer looking at it you want know for sure. Call them and have them come out.

  8. #8

    I could never get the installation company to do much about it.
    The low freq rumble carried through the house and was way to loud. It only made the rumble when the compressor was running. The flex running to the return box was pretty much straight, so I went and bought some more. I added it to the run and made a few bends in it. It got rid of the loud rumble sound......

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