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Boiler Expansion Tank Leak- Picture of it!

bschroed Member Posts: 2
edited December 2018 in THE MAIN WALL
Have a Navien boiler and the expansion tank has been for 2 years, and started leaking, and looking like this. Any ideas what can cause this before I install a new one. It is an EX30 Amtrol, which is a good product.


  • bschroed
    bschroed Member Posts: 2
    I will look
    Dan Foley
  • Jamie Hall
    Jamie Hall Member Posts: 23,675
    OK -- what hit it? That looks like damage from the outside...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • GroundUp
    GroundUp Member Posts: 1,959
    Looks kinda like external damage, but where is it located in relation to the circ? What is the system pressure? Even Extrol can't out-engineer a poor install
  • kcopp
    kcopp Member Posts: 4,452
    What is the rest of your system composed of?
    Is there pex tubing in it? Radiant floor? Staple up? What type of tubing is in the system?
    What is you water like?
    What temperature does the system run at?
  • Alan (California Radiant) Forbes
    Could be oxygen intrusion from non-barrier PEX.

    If so, replace it with a potable X-tank.
    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