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duct help

rich73 Member Posts: 1
I have a trane xv90 furnace and want to move it to another room. how can I find out what size flex hose to use to reconnect it.

my plan I have a bulding maint. man going to help me with the gas and ac unit line. I am a machine maint. so the wiring and things I can take care of.  I can't find a company that will do it. To big for some and to small for others.

 for the duct work going cap off the the old holes on the supply plentium and the return with sheet metal and duct seal and screws.

Supply  duct

getting a new supply plentium installed in the floor then from there I  want to use flex duct to go from new plentium to old plentium for the supply.

Return duct

tap in the top of the return manifold and run flex duct to the top back in to furnace.

how can i find out what size plentium and what size flex duct I need for this furnace? is 20" flex big enough?


  • Snowmelt
    Snowmelt Member Posts: 1,416
    edited June 2014

    Do you just have heat or do you have a/c,

    What's the existing duct work, I'm sure you must have a hvac supply house by you, or a duct metal shop, usually no job is to small. I would you rigid duct all the way.

    What you need is a duct-u-lator
  • Techman
    Techman Member Posts: 2,144
    duct help

    Using flex duct on the supply plenum , main trunk is not in your best interest.
  • Eugene_Silberstein
    Eugene_Silberstein Member Posts: 349
    Duct Help

    In a nutshell, you should definitely NOT use flex duct for what you are proposing. In addition to probably being a code/fire violation (depending on where you are) the resistance to airflow created by flex duct is very high. Using flex on both the supply and return ducts will very likely cause you have reduced airflow as well as nuisance high limit trips resulting from the overheating of the appliance.

    Trane requires that duct installation be in accordance with NFPA 90.

    There was an error rendering this rich post.