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Underfloor radient off BB return

MikeGMikeG Posts: 150Member
<span style="font-size:12pt">Has anyone had experience with the Ultrafin product for underfloor radient?  I have family room with finned BB originally designed for 180 degree water.  The room has a fair amount of windows.  I’m now using a modcon with ODR so my water temps are lower.  The amount of BB just doesn’t provide the comfort.  Heat loss is  13K.  I have easy access to the crawl and want to take the return from the BB and run it through PEX under floor.  Floor is ¾” OSB with 5/8” maple flooring.  Protruding nails make plates impratical.  Currently the uninsulated ¾” copper supply and return lines run in an enclosed insulated joist bay.  The dog and cat have found that spot.  When I ran 180 degree water I had to insulate the pipes because I was getting some movement in the maple flooring.  I do not have that issue with the lower temps.  Is there a better way?  Thanks in advance.</span>


  • ErikVErikV Posts: 34Member
    edited December 2009
    Angle grinder

    You said easy crawl space access ... an hour or two with an angle grinder (edit: mounted with a cutoff wheel) and the surface in the joist bays will be nice and smooth for plates.  Well worth the effort.  I don't have experience with Ultrafin but I know it is expensive.
  • MikeGMikeG Posts: 150Member
    Wood movement

    That's a thought.  Another reason for no plates was the option to run slightly higher water if needed and still keep floor surface temps low enought to limit wood movement.  I didn't want to get into mixing valves or other equipment under the house.  The BB now does well to counteract the cold off the windows, but the comfort is not totaly there. Everything else is BB with individual circs.  I may look at grinding.  Just trying to look at all options.  Thanks
  • Chris_110Chris_110 Posts: 3,056Member
    Quick Question

    If the original baseboard heated the home with 180 degree water at design then why will it not heat the space with a mod/con if your curve starts at 180 degree water? Is the question, I am no longer using 180 degree water as my design water temp? Is the family room on its own zone? Who's mod/con?
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • MikeGMikeG Posts: 150Member
    Using Lower Temps

    Correct.  I'm trying to use lower temp water.  Even with 140 -150 degree water it does OK to counteract the cold air off the windows.  I just have the opportunity to add something under the floor to give it that added comfort.  Just the one joist bay that has the supply and return pipes in it is noticable to the touch.  The room is well insulated, good windows.   Two other zones in the house had way to much BB even for the old 180 degree system.  Lower water temps are working better, as I work on fine tuning things.  This room is on a separate zone.  The bolier is a Munchkin, capable of 180, but running more efficient at the lower temps.  I'm just trying to keep everything simple if possible.   Thanks  Mike
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