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transfer plates/radiant

Ray_6
Ray_6 Member Posts: 2
in THE MAIN WALL
Anyone have experience with Watts radiant Onix tubing? It's 3/8" and doesn't use transfer plates but does staple up right to the subfloor. Does this work? Other companies are using transfer plates with PEX. This is EPDM. Aluminum inside and bullet proof material. I'm about to put it in my house. Ray

Comments

  • Al Letellier
    Al Letellier Member Posts: 781
    radiant tube

    I have done a couple of jobs this way with no problems. Direct staple up with no plates, make sure tubing is in good contact with flooring (staple every 6") and use gap above insulation....no problem. Like the product for it's flexibility but is only available here from a supplier we never do business with, so we went to pex...not the tubings fault.

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  • Tony_8
    Tony_8 Member Posts: 608
    onix

    My 1st radiant job used Onix. 6000 ft. 12 ft basement ceiling. Whew!
    Staple like Al said, often. Onix seems to be hotter to the touch than pex, might be better transferring heat. Definetely costs more. Keep out the chemicals and antifreeze or you'll have a mess.
  • hot_rod
    hot_rod Member Posts: 23,405
    Fluid to wall temperature difference

    The Onix runs about 7 degrees cooler on the outer wall than the fluid inside. Pex, maybe 4-5 degree difference. Copper near zero, in underfloor (dry) applications according to my measurements..

    In a slab application, Siggy modeled Onix at 12.5 temperature difference (Watts Radiant calculated it at 13.098) as seen in a recent Watts Radiant article in PM Engineer mag.

    1/2" Pex in slab modeled by Siggy's FEA showed 5.3 degrees, Watts Radiant calcs showed 4.84 for the same assembly.

    It all has to do with the thermal conductance of the various materials as seen in these tables from the Watts Radiant article. Bottom line the thicker rubber takes a higher temperature. The numbers from Watts Radiant calcs, FEA modeling bt Siggy, and my IR testing all agree on this.

    Watts Radiant states " The reality is EPDM requires only a 5-6% higher water temperature than pex in a typical application"

    I suspect if pex had the same wall thickness as Onix the numbers would be very close.

    The rubber has gotten pretty chubby, in wall thickness, over the years with additional layers, compared to the original solar roll and original Entran products.

    hot rod
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • John Abbott
    John Abbott Member Posts: 358
    Onix

    > Anyone have experience with Watts radiant Onix

    > tubing? It's 3/8" and doesn't use transfer

    > plates but does staple up right to the subfloor.

    > Does this work? Other companies are using

    > transfer plates with PEX. This is EPDM. Aluminum

    > inside and bullet proof material. I'm about to

    > put it in my house. Ray



  • John Abbott
    John Abbott Member Posts: 358
    Onix

    I did a number of jobs with onix tubing and they worked well.I stopped using it due to the questionable survival of the company not any performance issues.Now that they have been aquired by Watts I don't think that is an issue.

    John
  • Tony_8
    Tony_8 Member Posts: 608
    must be

    a bad memory. maybe the water temp was higher on that job than subsequent projects. haven't had call one on it since installed in '97. see them regularly downtown and hear how comfortable they are. smiling customers are my favorite.
  • hot_rod
    hot_rod Member Posts: 23,405
    Oh, it can work

    just fine if designed and installed properly. I've done plenty of rubber staple up, including some in my own home.

    It tends to need higher supply temperatures than the other methods, except maybe supended tube.

    All the different applications have a limit. Work within their "comfort zone" and you should be fine :)

    hot rod

    To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • John@WattsRadiant
    John@WattsRadiant Member Posts: 49
    Anti-freeze okay with Onix

    Ethylene or Propylene Glycol is fine with Onix, as are most hydronic system chemicals. With antifreeze in any hydronic system,make sure you use at least 25-30% antifreeze so there is enough inhibitor to keep up with the gylcol as it turns acidic. Lower concentrations can actually increase corrosion. Of course, with Onix or Pex, stay away from any petroleum based chemicals.
    John
  • Art Pittaway
    Art Pittaway Member Posts: 230
    Good stuff, great people

    Worked with Onix on many, many jobs in No. Illinois and all problems came back to installation, or "Murphy". Contractor had a stapler go bad and he punched 50+ holes in the tube before he realized. Never once did I have Onix jump back and "Wup" me in the head like pex will do. Bend, fold and drive on it...no problem.
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