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Hot Water Heating System Sealant...

Andy_d Member Posts: 10
Is there a Hydronic system sealant for pex pipe. I know there is for boilers, but i have a customer asking me if there is. We have a digester that is wrapped in pex and pinholes have developed. Without going into more detail, all i need to know is if anyone has heard of such a product. I haven't seen anything in my 30 years of plumbing wholesale, but maybe I've missed something.


  • Big Ed_4
    Big Ed_4 Member Posts: 2,687
    Hmmmm , neither did I...
    I have enough experience to know , that I dont know it all
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,229
    Hello, Might it be time to go into more detail? I'm curious to know what's causing pin-holing in PEX. Perhaps we can try to address the root cause. ;)

    Yours, Larry
    delta T
  • hot_rod
    hot_rod Member Posts: 21,818
    I've used the Fernox brand sealers in rubber tube in slab that had small leaks, pin holes I assume. Sometimes it works sometimes not, really depends on the size, number of, holes and I suspect expansion and contraction causing the hole size to change.

    The stuff i used is a milky white product, almost looks like diluted Elmers glue :)

    I suspect some insect was boring it to the tube for a source of water or warmth, as it was in a greenhouse application.

    When we finally chopped open the slab, in the case where the sealer did not work the tube looked like it has bore or chew marks.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream