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Fosta Pex w/Fintube

MikeyB Member Posts: 696
Looking to install a Home Run Manifold system w/3/4" fintube, what be be a better option 1/2" Fosta Pex, or go with 3/4" Fosta Pex for each section of fintube, There will be 3 bedrooms and one bathroom, Acording to Slant Fins Heat Loss Explorer the heat loss in btu/hr for each room are, 4509, 3450, 2841, 1272, Thanks for you help guys


  • hot_rod
    hot_rod Member Posts: 21,800
    small pex

    1/2" can move about 1.5 gpm or 15,000 btu at 20 degree delta T.

    Heck, 3/8 may be large enough depending on run lengths. Small diameter copper and pex is commonly used for panel radiator runs.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • MikeyB
    MikeyB Member Posts: 696
    edited August 2009

    Thanks HR,  I was hoping to install panel rads but have to settle for fintube instead.The runs wont be that long at all, the house is pretty small, I will go with the 1/2" Fosta Pex, Tech Support from Viega metioned that I should use 3/4" Fosta Pex, which I thought was a bit much considering the loads and legth of run
  • Steve Ebels_3
    Steve Ebels_3 Member Posts: 1,291
    Love the stuff

    We use 1/2" all the time for panel rads and BB zones. 3/4" would only be used if you are feeding a load above 15K or if head was a factor with the smaller diameter.
  • MikeyB
    MikeyB Member Posts: 696
    Fosta pex/fintube

    Thanks Steve, I appreciate it. Now it looks like the home run system might get shot down, and just go with a series loop.
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