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Roth Radiant Panels, PEX-al Tubing vs pex expansion rates

heathead Member Posts: 234
Installing a Roth radiant panel system that is supplying heat to a sometimes used room.  The room will be set back to 45 when not in use.  Question is Roth doesn't make a 3/8 pex-al pipe.  The o2 barrier pex they carry is 3/8 and has a expansion capacity of 1" for every hundred feet.  at 10 deg.  The pipe is going to expand when the systems turns on taking the tempatures  from say 50 deg to 120 the design temperature, Max loop lengh is 156 feet. Max run is only 22 feet long straigh line then turning around at end( going to silicone pipe in turns).  So expansion lengh is only 1.4 inches for each lenght before making a turn.  I am thinking about using a Watt pex-al than has much lower expansion rates and better o2 barrier. Has anyone used the 3/8 watts pex-al in a roth panel or other system that the pex-al needs to be pressed into.  I know one would normally do an outdoor reset that would take the tempatures up slowly, but the homeowner wants to be able to turn on the heat and have it ready to use in about 2 hours.    Any thoughts on the watts pex-al?  I normally like to keep things installed with the same manufacture for a job.  Thanks


  • NRT_Rob
    NRT_Rob Member Posts: 1,013
    no problem

    we use Mr. Pex PAP in Roth.
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
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