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Commercial DHW storage tank

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bburd
bburd Member Posts: 930
edited April 2022 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: 22,467
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    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: 3,384
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    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) ForbesMikeAmann
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,829
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    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: 15,829
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    bburdAlan (California Radiant) ForbesGGross
  • Zman
    Zman Member Posts: 7,605
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    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
    bburdEdTheHeaterMan
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,829
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    @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: 2,774
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    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: 929
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    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: 930
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    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: 2,331
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    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: 2,774
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    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: 930
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    We have two 500,000 Btuh Lars natural gas fired boilers. Copper fin I believe.

    Bburd
  • bburd
    bburd Member Posts: 930
    edited September 2022
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    Update:

    I got the drawings for the building. The two boilers are 750,000 Btuh each. The storage tank is 550 gallons, epoxy lined. The manufacturer is still in business, but their website says they no longer offer epoxy lined tanks; just glass or cement lining.

    I suspect there was some kind of problem, since my understanding is that epoxy lining should last longer than glass or cement.

    The irony is that a new tank of that size costs very little, but getting it up to the roof and installing it costs a small fortune. We are seeking alternate bids that will not involve the use of a crane.

    Bburd
  • pecmsg
    pecmsg Member Posts: 4,949
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    bburd said:
     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.


    I love the architects and engineers that DON’T take this into account. 

    Now is the time to remedy that situation. It will have to be addressed again! 
    CanuckerbburdEdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,166
    edited September 2022
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    pecmsg said:


    I love the architects and engineers that DON’T take this into account. 


    Now is the time to remedy that situation. It will have to be addressed again! 
    I wonder what recourse a property owner has against an architect that is already paid, for their poor design choices! Has that Architect been notified of the issue?

    In olden times the architect of a building would have to stand under the arch he designed as the supporting structure was removed. If it failed, and he was under it, then he wouldn't be available for future mistakes. being crushed by his mistake I think that we should apply the same standard today.

    Edward Young Retired

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

    bburd
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,384
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    Hi @bburd , I'd be tempted to put some rough numbers together for the crane approach and the elevator approach and then have a talk with the owner, or whoever is paying the bill. I'd probably invite the architect to the discussion as well. Discuss short and long term costs and maintenance. Let your new friend, the owner, decide. o:)

    Yours, Larry
    bburd
  • bburd
    bburd Member Posts: 930
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    The design team may well have recommended doing things differently, but was probably overruled by the developer who wanted to save money. They had a crane on site during  construction for other purposes. Since the developer sold off the condos, it wasn’t going to be their long term problem.

    I did find out that the penthouse boiler room doors are big enough to get the tank out. We are left with the problem of getting it downstairs, and the new one in.

    Bburd
  • bburd
    bburd Member Posts: 930
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    Hi @bburd , I'd be tempted to put some rough numbers together for the crane approach and the elevator approach and then have a talk with the owner, or whoever is paying the bill. I'd probably invite the architect to the discussion as well. Discuss short and long term costs and maintenance. Let your new friend, the owner, decide. o:) Yours, Larry
    I am one of the owners, and act for all of them. The building is now owned by the homeowners’ association, and I serve on the board of directors. I’m the only engineer; the others are financial and management people. The building is now 14 years old, and things are reaching the end of their normal service life… so we have some challenges.

    Bburd
  • leonz
    leonz Member Posts: 1,179
    edited September 2022
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    (1)

    A simple yet proven way to do what you need is to employ a boom and winch system using a counterweight to hold the boom and winch in place from the roof.

    This requires both labor and the equipment needed to assemble the winch, counterweights and the erecting of the jib boom that will hang over the sidewalk and street and a temporary 3 phase medium voltage power hook up to operate the jib mounted winch.

    The taller the building the larger the winch drum must be to allow the wire rope to reach the street to provide the fleet angle to allow the winch cable to pay out properly through the sheave block on the Jib boom.
    The jib boom on the temporary winch must be long enough and far enough away from the building's roof edge and also be high enough to allow the old tank to be lifted slid forward to the end of the jib boom and then lowered reversing the process to bring the new tank to the roof and rolled into the boiler room.

    (2)

    BUT in saying that;

    The single day cost of a crane rental for lowering the old tank and lifting the new one to the roof and on furniture dollies will cost you less than hiring a steel erecting crew that specializes in lifting heavy equipment and process machinery to bring a heavy winch and jib crane to lift and then lower the old tank to the waiting steel scrap container.

    Your plumbers would bring laborers with them and the crane company would supervise the lift on the ground and the roof.

    Removing and lowering the old tank is done first and then the new tank is lifted to the roof could be done in one 8-hour day or less after all the permits for the cranes placement on the street are obtained if needed.

    Using a parking lot if available would only require the shutting down of the parking lot for that morning after the roll off container for the old tank and piping is dropped in place.

    The crane company would determine which crane to bring apply for permits and decide where to set up the crane to do the work and they would provide the lifting straps, wire rope slings and shackles to lower the old tank and lift the new one to the roof.

    With a small job like this parking the crane, extending the stabilizer legs, adjusting the stabilizer legs adjustable foot pads on the 4 stabilizer's floatation blocks, raising the boom and attaching all the straps, slings wire rope cables to do the work will take longer than raising the boom to the roof attaching the old tank to assure its safe to lift and lower and then attaching the cables to the new tanks lifting eyes and lifting the tank using people holding ropes attached to the tank to make sure the tank does not sway or wander will take longer than setting up the crane.

    (3)

    Using stairs will require more labor, more preparation and an electric winch with enough chain that will be able to pull the tank or tanks up the stairs IF the landings are large enough to allow the tank or tanks to be pulled up and then dropped down and turned twice to allow the tank to be winched up the next set of stairs to the next landing.

    AND IF there is no way to pull the tank up the stairs using an exposed anchoring point in the ceiling like an H or I beam where you can install a four wheel beam trolley to attach the electric chain falls that stops the job completely. The other thing is that the electric chain falls will need to be connected to an 12 /3 extension cord and an outlet that can tolerate a high amperage draw if a second chain sheave block is not used to increase the winch chains pulling power.

    Anyone who tells you that it can be done without an H or I beam to attach the chain falls is wrong.

    Using manual chain falls will require a great deal more time to pull the tank up the stairs if there is an exposed I or H beam with a beam trolley.

    I would compare a bid from a machinery moving company and a crane companies day rate before you open a check book to place a deposit for the work as the machinery mover will take much longer to do the work than a crane as the crane will only require two lifts to do the work where a machinery mover will be setting up and dismantling equipment at each staircase landing.

    The other thing is making sure the machinery movers have a total liability umbrella policy as well as workmans compensation insurance which the crane company will have as a matter of business.

    You are going to find that hiring the crane for one day and letting the outside plumbers hire the roll off container for the tank and the crane for that matter will cost you less money and worry about blocking fire stairs or using the elevator(s).

    If all you have is passenger elevators and they are not equipped with a large diameter hoist drum to reduce the fleet angle of the wire rope cable attached to the elevator car you will be behind the 8 ball so to speak as the electrical system may not be able to handle the lift and stress the hoist cable and its anchor swivel
    to the elevator car requiring adjusting it by increasing the torsion on the wire rope by taking it out of service for a day and lowering it to the bottom of the elevator shaft disconnect the electric power and lock
    out the power to the elevators and dismantle the hoist cable anchor assembly and increasing the torsion of the cable and then reinstall and test it.

    You have to understand that if the elevator is used the elevator company will have to become involved and
    certify it can be used for this and they may very well have to come back and service the wire rope hoist and
    the hoist cable and anchor as it would have to be adjusted by removing the cable anchor and twisted several times to take up the inherent slack in the hoist rope from lifting the new tank to the roof and lowering the old tank to the ground level.

    (4) In liu of all this it sounds like a flash boiler and a proper sized continuous circulator would cost less to install after the old tank is removed by cutting it up on the roof using chain saw powered cut off saws.

    Sorry about all the boring details.
    bburd
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,829
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    Cut the old tank up in pieces and take it down the stairs/elevator. If you have your plumber disconnect it you may be able to get a junk guy to remove it.

    Then you can replace it with multiple smaller tanks.

    You need to sit down and run the #s on this.

    Then compare it to the cost of a crane pick and a larger tank.

    There is no magic to it.

    You may find the crane pick cheaper
    bburdZman
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,384
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    Hi @bburd , One thing I'm unclear on is whether you have an elevator, and if it goes all the way to the roof. Also, what is it's capacity? That info could help drive the hot water design decisions.

    Yours, Larry
  • bburd
    bburd Member Posts: 930
    edited September 2022
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    Hi @bburd , One thing I'm unclear on is whether you have an elevator, and if it goes all the way to the roof. Also, what is it's capacity? That info could help drive the hot water design decisions. Yours, Larry
    We have a good sized elevator, large enough to take a three seat sofa standing up, and it goes all the way to the roof. Bidders will get a walk-through of the site and can take measurements.

    Bburd
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,384
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    @Bburd , That helps! It makes me want to manifold together a bunch of 105-gallon Marathon tanks. They are long-lived, lightweight, and well insulated. Tanks could be individually valved, so hot water to residents essentially never needs to be shut off for maintenance. No crane needed, ever again! B)

    Yours, Larry
    bburd
  • tim smith
    tim smith Member Posts: 2,774
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    How many units in building and # of baths per unit? Total # of people? I would not be surprised if way over sized and very likely the.multiple 119 gal tanks would be best bet. Cut up old tank then never need crane. 
  • bburd
    bburd Member Posts: 930
    edited September 2022
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    128 units, probably 200-225 residents. One full bath in most units, two in a few. All units have their own laundry, and dishwashers.

    Bburd
  • hot_rod
    hot_rod Member Posts: 22,467
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    Run the building through the new water calculator to get a realistic number on consumption


    https://www.iapmo.org/water-demand-calculator/

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    bburdLarry Weingarten