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Sandwich Method Pex Not Flush

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clementine
clementine Member Posts: 6
in Radiant Heating
Hi there!
Installing 1/2” PexAlPex into Everhot Omega plates (Made for 1/2” tubing).
I stapled down plates in a few rooms and cut a test piece of the Pex only to find out the tubing doesn’t quite fit/sit flush with the subfloor. This will be an issue since I am installing engineered hardwood on top. 
Has anyone had this issue before? 
Just not saw some reviews on similar plates in which the customer had issues with it fitting as well- their solution was to slice the bottom of the plates and press the tubing down to fit. I’d be worried about doing that in case it causes tubing friction on the sliced edge with expansion/contraction. 


Comments

  • Dave H_2
    Dave H_2 Member Posts: 556
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    Use a heating pex, PAP has a larger diameter

    Dave H.
    Dave H
    mattmia2Rich_49
  • clementine
    clementine Member Posts: 6
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    Dave H_2 said:
    Use a heating pex, PAP has a larger diameter Dave H.
    Definitely sticking with PAP - more curious about plate suggestions to fit it properly for above floor install. Thx!
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,002
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    Make your own?
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • mattmia2
    mattmia2 Member Posts: 9,646
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    you would also need thicker osb/plywood.
  • hot_rod
    hot_rod Member Posts: 22,143
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    As @mattmia2 mentioned, the plywood needs to be at least as thick as the PAP diameter, plus a few thousands for the thickness of the plate. Even so, I doubt that plate you show would stretch deeper? :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • clementine
    clementine Member Posts: 6
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    hot_rod said:
    As @mattmia2 mentioned, the plywood needs to be at least as thick as the PAP diameter, plus a few thousands for the thickness of the plate. Even so, I doubt that plate you show would stretch deeper? :)
    Exactly- I cut the plywood plenty deep. The grooves on these heavy Omega plates are just too small of a diameter with zero stretch. Big gap between the bottom of plate groove to the bottom of my cuts. I’d be amazed if regular Pex would truly sink below floor level. So far, getting a refund on plates as they were specified to fit PAP- and ordered samples from a few other vendors. Doing 2400sqft of heat- so, glad I only stapled down two rooms before seeing the issue! But still 🥴
  • hot_rod
    hot_rod Member Posts: 22,143
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    PAP is usually .630, compared to Pex at .625 OD. Looks like more than 5 thousands in your pic? Unless it is an odd Euro metric size tube? Or the plates were undersized? The ASTM numbers on the tube will tell you the spec it is made to, including the dimensions. F1281 is the common PAP standard.

    Another method is the fin down first, C fin, sleepers fastened over it, then the tube installed, similar to this pic, it is a C fin instead of a U fin. Then the proper sleeper thickness would accommodate the larger tube diameter.

    That layer of wood over the fin actually spreads the heat with less striping, but costs you the R-value of the sleeper thickness.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream

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