How does one cure the exhaust noise of a high-efficiency gas furnace?

Discussion in 'Off Topic' started by Thegonagle, Dec 7, 2007.

  1. Thegonagle

    Thegonagle Diamond Member

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    I have a "Ruud Achiever 90+" high-efficiency furnace installed in my home. This Ruud unit seems like a great product with good build quality, engineering, etc., except that the PVC pipes that vent it to and from the outside make a lot of noise whenever the burner is firing. It's a high-pitched, multi-frequency whine reminiscent of the transporter noise from Star Trek TOS.

    Anybody else ever deal with this? Are there mufflers or something else available? This noise keeps me up at night, and since the pipe exhaust pipe is aimed at my next door neighbors' bedrooms, they undoubtedly hear it, and would appreciate if it was quieter, too.

    What's the best way to quiet this thing down?
     
  2. jagec

    jagec Lifer

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    Sounds like some sort of resonance is occuring in the pipes. Touch the pipes while it's operating, and see if they're vibrating.

    One possible cure would be some sort of baffle at the end, to disrupt the air flow slightly and prevent the buildup of resonance.
     
  3. Squisher

    Squisher Lifer

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    Sounds like a Ruud is a either a re-badged Lenox or they're using the Lenox pulse air technology. I owned one for 20 years.

    Are you sure it is the intake and exhaust pipe? A Lenox will have that vibration throughout the system.

    If the sound is coming from the intake/exhaust, they do make mufflers that are supposed to be installed on the bigger units. Also, nothing is stopping you from insulating the pipes with pipe wrap or isolating the pipes in their own insulated structure.

    If the bulk of the noise is coming from through the vents then installing flexible insulated duct would be the best solution.

     
  4. dartworth

    dartworth Lifer

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    Ruud = Rheem
     
  5. prism

    prism Senior member

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    Why would you want to fix something that makes the Star Trek transporter noise?...
     
  6. Thegonagle

    Thegonagle Diamond Member

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    Because it sounds like one of those episodes where the transporter breaks, and Scotty has to "energize" it for 10-15 minutes at a time.

    The noise is from the draft-inducer fan. It's resonating through the PVC pipe. It's louder outside than inside. I was just wondering if there are accepted practices or parts available to address this issue.

    I've searched and have found very little info on the specific topic of noise from high-efficiency furnaces, except on Lennox Pulse models, which mine is not. Therefore, I'm not sure such info applies, because, near as I can tell, the Pulse design is fundamentally different from the design that I have.

    Anyone else have any ideas?
     
  7. alfa147x

    alfa147x Lifer

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  8. Sluggo

    Sluggo Lifer

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    I have the same furnace and have really never noticed it. My HVAC guys did kind of caution me about it when I bought it, but they said some people are more "tuned into it" than others.

    Mine has a very slight thrumming, but I really never notice it unless I specifically listen for it.

    I must say, I have never noticed any PVC pipes that vent it to the outside. The exhaust on ours is 4" galvanized pipe that vents straight up. The only PVC pipes are the upper and lower condensation drains.