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Expansion tank thread size question

STEAM DOCTOR
STEAM DOCTOR Member Posts: 2,256
in THE MAIN WALL

#90 expansion tank comes with 1/2" male threads. The equivalent floor standing model comes with 1" threads. Just wondering about the reason for the difference. Thanks

Comments

  • 109A_5
    109A_5 Member Posts: 2,095

    I would say it is the pipe size of the most common pipe size for the system application type.

    image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    LRCCBJ
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 2,256

    The ex-90 is 14 gallon, with 1/2" male threads. The sx-30v is also 14 gallon, but free standing, with 1" female threads. And good reason not to bush down the 1"? Is there any reason the free-standing would need larger pipe size?

  • Intplm.
    Intplm. Member Posts: 2,416

    A good question that I have often wondered about as well. I have often seen and installed with the lesser diameter size pipe bushed down or a reducing coupling used. Is it anything more than what @109A_5 says.

    It might be that simple, but are there some type of load requirement besides system size?

  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 2,256

    Or tank design? The physics of the freestanding tanks seem to be the same as those mounted to the system piping. But that's just a guess

  • psb75
    psb75 Member Posts: 980

    So…does anyone know the answer?

  • hot_rod
    hot_rod Member Posts: 24,332
    edited February 9

    the Amtrol engineering book explains it well. It depends on the amount of expansion you need to accommodate, and the piping distances also. It is a free download that evert hydronics involved person should read

    amtrol engineering handbook

    IMG_1035.png
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 2,256

    Thanks. Will certainly take a look

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 17,131

    In the Amtrol example they are talking about a system with 100 psi.

    I don't think in a residential install the pipe size is critical.

    A little common sense and it will be fine

    Intplm.ethicalpaul
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 10,075
    https://forum.heatinghelp.com/discussion/comment/1841542#Comment_1841542

    Where can I send folks to take that course Ed? Common Sense 101

    I have heard that you can't fix stupid, but duct take can muffle the noise.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    jesmed1PeteAdelcrossvIntplm.
  • mattmia2
    mattmia2 Member Posts: 11,610
    edited February 9

    perhaps the floor mount version is a well tank with a different label and fewer coating processes?

    1/2" is even bigger than needed for an expansion tank.

    EdTheHeaterMan
  • jesmed1
    jesmed1 Member Posts: 964
    edited February 10

    @EBEBRATT-Ed said:

    "In the Amtrol example they are talking about a system with 100 psi."

    You forgot to mention the 7,000 gallons water volume and the 270 degree max average temperature. 😅

    PeteAEdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 10,075
    https://forum.heatinghelp.com/discussion/comment/1841549#Comment_1841549

    I remember a installing a wall hung boiler that was imported from Europe and rebranded by Hydrotherm. It was called the Celtic. The expansion tank was included within the cabinet and has a 1/4" OD copper line connecting the tank to the system.

    So, "All expansion tanks are not connect equal" how unAmerican.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    mattmia2
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 17,131
    edited February 10

    As the boiler heats from a cold start expansion is gradual. It's not like the tank has to suddenly accept a ton of water.

    Anything 1/2" or larger would be fine.

    At least for residential

    mattmia2Intplm.

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