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Best Practice for Bladder tank install

INLINE Member Posts: 2
Bladder-type expansion tank Best PracticeWhen installing a Bladder Expansion tank into a boiler piping setup, what is the best practice for piping size selection? There are 1/2" and 3/4" tanks available but it seems if the tank hangs 1' or more from its feed (from a T connector), the 1/2" could be an issue at some point. meaning if / when the bladder breaks down internally  and the tank fills with more water than when it was new, it would be much heavier. If 1/2 " copper is used, it seems the weight could break 1/2" piping joint easily if extended very far from the "T "of the feed., I am thinking 3/4" is better to support the tanks weight when compromised.. Are there any guidelines to review for piping specs on a given tank?  (maybe manufacturers)? Thanks in Advance!


  • Brad White
    Brad White Member Posts: 2,393
    edited October 2010
    Tensile Strength

    The tensile strength of copper will support more than you think, but the bending moment? Not so much.

    Two schools of thought, maybe three:

    1) Mount your tanks on the floor even remotely from the connection point. I use an old Wok ring as a floor support to keep them from tipping and use a 300 psi rated braided hose to connect it, if in close-confines. Makes it easier to move if you need to and no support issues.

    2) Hanging from the pipe, 1/2" should be fine, 3/4" even better. Talking #30 tanks here, not the large ones. Put pipe hangers on each side of the dropping tee though.

    3) Some installers put them in stem-down. I never have but there is merit to that. If you do go this way, use threaded Sch. 40 iron or brass pipe and support accordingly. I too would feel uneasy if just copper, unless the coupling distance was short and the main it attached to was 1-1/4" or larger. But Sch. 40, I would not worry about it.

    My $0.02

    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
  • kcopp
    kcopp Member Posts: 3,825
    another way ...

    I commonly use is a drop ear 90 w/ 3 ears run from the "airscoop" area w/ heat pex or Fosta pex, attached to a floor joist w/ long screws. This gets it out if the way of the boiler for future cleaning and allows it to be removed easier. 
  • Brad White
    Brad White Member Posts: 2,393
    I like that

    Kevin. Neat especially if near a wall.
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
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