I have three 120 gallon heaters

Discussion in 'Water Heater Forum, Tanks' started by Mad Plumber, Nov 20, 2008.

  1. Mad Plumber

    Mad Plumber Mad Skills

    Aug 13, 2005
    Got a question for ya. This is Bill Julian. (Plumber) How would I pipe 3 hot water heaters so I don't create a reverse loop and they draw equally together. I have 3 120 gallon heaters. I'm told by the inspector that I am over working one heater the system is not equally drawing. Said something about a reverse loop and the tees have to situated correctly.

    All the colds got in series all the hots come out in series I have the hot 3/4 tee to fixtures near the end of the 3rd heater.


  2. nhmaster

    nhmaster Master Plumber

    Jul 30, 2008
    Tech. Instructor
    S. Maine
    I would have a plumber tackle this.
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  4. Master Plumber Mark

    Master Plumber Mark Master Plumber

    Feb 6, 2005
    Sensitivity trainer.. plumber of mens souls
    indianapolis indiana - land of the free, home of
    what are you doing anyway?????

    I have always liked series the best.....

    parallell never draws off correctly and over time
    the lines get closed shut somewhere and it even draws worse

    what are you doing anyway, is this some sort of hotel???
  5. jimbo

    jimbo Plumber

    Aug 31, 2004
    San Diego, CA
    You say series, but it sounds like you mean the 3 tanks are parallel. In this case, the inlets and outlets must be manifolded so they are identical.

    MASTERPLUMB777 In the Trades

    Aug 6, 2007
    Retired Master Plumber
    3 120 gallon water heaters

    Sounds like you have eather A.O. Smith cyclone or STATE water heaters
    go to hotwater.com web site,
    for A.O. Smith and they will show diagram of the
    proper way to pipe as they are supposed to be per, mfg's spec's and plumbing code also you can call 1-800-527-1953 for tech, support ! !

    Do not forget to make sure you have the proper sized thermal expansion tanks
    installed for all three heaters
  7. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Nov 20, 2008
    Chicago Illinois Licensed Plumber
    Chicago, IL
    As Mark asked "what are you doing anyway, is this some sort of hotel??? " How many fixtures are in this building and how many people are in it? Three Gal heaters is insane. If it is a hotel or a place that needs real fast recovery why not use a 200 Gal storage tank a A.O. Smith Burkay boiler with a recirculate pump. I had a restaurant in Chicago that has this set up installed. I had to replace the 20 year old storage tank, once I refilled the system and fired it up they had 180 degree water in 12 minutes. Another option is tankless heaters.

    Here is a couple pictures showing tankless heaters installs one is gas other is electric. [​IMG][​IMG]

    With more information about the job like if your using gas fired heaters and the BTU's of each heater, or if they are electric, and how many fixture units is the demand on this place. Then we can give you a more accurate answer on how to install what you want.

    Here is a link to A.O Smith's recomended way to install mutiple heaters in parrell. But each manfold MUST BE EQUAL LENGTH or it will not work. http://www.hotwater.com/lit/piping/A2190.pdf
    Last edited: Nov 20, 2008
  8. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    You get either the State #27200 or A O Smith #70415 three tank manifold kits, or you get their specifications and make your own. Once you see the prices you will know why this is not a "by the seat of your pants" task.
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