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  1. #1
    Join Date
    Mar 2008
    Park City, Utah

    Default Flex duct connections

    Is it acceptable to connect 6 inch flex duct to 8 inch with a "splice" like this.

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  2. #2
    Ron Bibler's Avatar
    Ron Bibler Guest

    Default Re: Flex duct connections

    Did it have a metal Y duct ?



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  3. #3
    Join Date
    Feb 2008
    Chicago IL

    Default Re: Flex duct connections

    Whether it is acceptable or not isn't exactly the best question. Can you splice two runouts off of a feeder trunk, sure. Can you splice two 6" off of one 8" maybe, maybe not. It depends on many factors. As Ron mentioned obviously is the connection sound and with proper fitting.
    Other important factors would include, what are the runouts feeding, what are the CFM requirements for those spaces, are they the only supplies, how long is the run for each length of pipe, etc?
    To really determine whether it is acceptable or not you would have to do at least two primary things, run a Manual D load calc for the ducts and rooms and take CFM readings at the registers. Neither of these are part of a normal HI. So what to do?
    I'm assuming you are running the system during the HI. Do the rooms come up or down to temp, is there decent air flow from both registers?
    I check for decent airflow. If I'm suspicious I'll take multiple temp readings during the HI in those rooms to doc whether the rooms are coming up or down to set temp. I also have a CFM meter with me to take readings if need be.
    Hope that helps.
    "The Code is not a ceiling to reach but a floor to work up from"

  4. #4
    Join Date
    May 2007
    Frankfort, KY

    Default Re: Flex duct connections

    It's acceptable but very rarely works as intended.

    Measured Performance more than just a buzzword


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