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Commercial DHW storage tank

bburd
bburd Member Posts: 332
edited April 13 in Domestic Hot Water
I live in a 128 unit condo building constructed in 2008. Our domestic hot water is provided by two 500,000 Btu natural gas boilers and a 400 gallon steel storage tank.

The hot water has been rusty for a year or two. Our new mechanical contractor opened the tank for cleaning and told us it is rusted inside, has not been well-maintained and we need to replace it before larger chunks start getting into our plumbing. This will require removing part of the wall of the rooftop boiler room and hiring a crane, since the tank won’t fit in the elevators. We will probably have to have aerial power lines taken down and put back to get the crane in. It’s a costly project that we don’t want to have to do again any time soon.

Are other types of tank available that will last longer than the approximately 15 years we got out of this one? I think the original is glass lined, but do not know if it has  an anode that should have been checked regularly. Perhaps that is the key to longer life? Whatever happened to more durable materials like Monel?

Bburd

Comments

  • hot_rod
    hot_rod Member Posts: 16,332
    Correct, the enameled steel tanks need anode maintenance.
    All metals and alloys have a weak spot. Have a detailed water analysis done to see what tank metal works best. Stainless tanks need attention to chloride levels.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    bburd
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,549
    Hi, As far as I know all glass-lined tanks have anodes. A few thoughts. I've been able to get fifty years from glass lined tanks by regularly replacing anodes. Another thought is to use powered, or impressed current anodes. This way, they should seldom or never need replacing, al;though it's good to check on them to be sure they are still working. One more thought is to put anodes into the present tank as done right, they will stop further rusting. In worst case, they'll simply buy you time. I'd also look at using smaller tanks, ganged together, so you just might not need the crane. Also, the old tank could be cut up and removed in pieces, again preventing the need for the crane.

    Yours, Larry

    Ps, Monel seems to have left the building...
    bburdrick in AlaskaAlan (California Radiant) Forbes
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 12,021
    You might want to put in (4) 119-gallon tanks if you have some room. Viessmann has some nice ones.

    They could cut the old tank up to remove it and take it down the elevator. Hire a welder who knows how to cut with a torch or maybe a junkie will remove it. You could skip the expensive crane work if the Viessman's will fit the elevator there not very heavy and all stainless steel, I think.

    You will have a little more piping to do but it can all be PP copper.

    I will post a picture of one I did if I can find it.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 12,021



    bburdAlan (California Radiant) ForbesGGross
  • Zman
    Zman Member Posts: 7,334
    I would cut the old tank into pieces to remove and then install smaller tanks.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    bburd
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 12,021
    @Larry Weingarten

    You type fast!!! Beat me to it!!!

    @bburd

    The Viessman's have good capacity. You probably wouldn't need 4 of them.

    Just one option
    Larry Weingarten
  • tim smith
    tim smith Member Posts: 2,460
    There always is the possibility of having the tank relined. You would have to talk to a reline company. They would probably sand blast and epoxy line it. Also just having tank cleaned and close check of walls of tank might gain insight into whether tank is really rusted or just surface muck.
    Good luck,
    Tim
  • retiredguy
    retiredguy Member Posts: 607
    My only 2 questions are; #1) do you have softened water and #2) if you have softened water do you store it above 140 degrees F. Softened water above 140 F will ruin any epoxy lined tank quickly.
  • bburd
    bburd Member Posts: 332
    Our municipal supply is mostly surface water and relatively soft. there is no softening or additional treatment in our building. 

    Bburd
  • jumper
    jumper Member Posts: 1,849
    tim smith said:

    There always is the possibility of having the tank relined. You would have to talk to a reline company. They would probably sand blast and epoxy line it. Also just having tank cleaned and close check of walls of tank might gain insight into whether tank is really rusted or just surface muck.
    Good luck,
    Tim

    In my day cement lining was available. How long it protects steel I was never told.
  • tim smith
    tim smith Member Posts: 2,460
    I was thinking maybe 3 119s. What kind of boiler heats the tank, important piece as to what type of tank you use.
  • bburd
    bburd Member Posts: 332
    We have two 500,000 Btuh Lars natural gas fired boilers. Copper fin I believe.

    Bburd