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Cleaning deposits in DHW tank-in-tank, TT Prestige Excellence

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oak
oak Member Posts: 22
I am finding that my 110 Prestige Excellence is working more often on the DHW cycle. We are on a well, and we get calcium-magnesium deposits on everything. It even sticks to a glass container when I boil water in my microwave for a coffee. The Triangle Tube tech support says: "No way Ca and Mg can stick to a stainless steel tank. The problem must be something else".

Should I flush this tank with a solvent? It's getting old now (maybe 12 years). We flush the boiler annually and I am always surprised how dirty it is but no Ca Mag build up there. What solvent is recommended?

Thanks

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 23,419
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    Domestic hot water? Do not use anything other than vinegar. But -- you can try vinegar.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Grallert
  • HVACNUT
    HVACNUT Member Posts: 5,860
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    Be careful. I don't know which order it is but one bladder can't have pressure without the other.
    I know on initial fill, it must be done in a particular order.
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,327
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    Hello, AO Smith used to have a product called Mag Erad, which was a food-grade, citric acid descaler. If you can find some, that would be good. Otherwise, white vinegar is fine, though make sure to let the tank vent as hydrogen gas can be generated.

    Yours, Larry
  • MikeL_2
    MikeL_2 Member Posts: 494
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    We use Rydlyme, a non toxic descaler by Apex Engineering. They will provide technical data, support, and concentration needed depending on the application.
    Hvacnut is correct; the inner tank should be filled before pressurizing the outer tank.......
  • psb75
    psb75 Member Posts: 843
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    The problem is that the TT tank-in-tank doesn't have a bottom drain to properly flush the domestic potable water side (inner tank) where the deposits would settle. But I wouldn't think that deposits on the inner tank bottom would inhibit hot water production, given that the whole inner tank is surrounded by hot boiler water.
  • hot_rod
    hot_rod Member Posts: 22,251
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    Maybe consider cleaning both the boiler side and the potable side. Scale on the outside (boiler side) can also lower the transfer efficiency. Get a hydronic cleaner form Rhomar, Fernox or others and clean the boiler loop.

    Plenty of off the shelf safe cleaners for the potable water side, follow the mixing instructions.

    When you hit a metal surface with boiler temperatures like 180° you get increased mineral precipitation. Scale is forming from dy one, yes even on stainless metals.

    Have you tested your water? What is the hardness number?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • psb75
    psb75 Member Posts: 843
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    Probably not much mineralization on boiler side because of finite amount of hardness in a (relatively) closed system. Potable side is always open to new hardness being added all the time.
  • hot_rod
    hot_rod Member Posts: 22,251
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    both of these boilers were filled one time, no addition feed water added!

    I think it is cheap insurance to run a cleaner, fill with treated water, and add a hydronic conditioner on the boiler side.

    No doubt the potential for scaling is much higher on the potable side.

    It would be nice to add a circulator or use a tankless descale kit to move some flow up inside the tank. Moving the descaler fluid in the tank would do the best job.

    Remove the H&C and use a tankless cleaner kit. These kits are handy for cleaning 3 way mix valves also.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Solid_Fuel_Man
  • psb75
    psb75 Member Posts: 843
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    Agreed. Mo' cleaner = mo' bettah. Pumped.
    Both sides.
  • 23Bob
    23Bob Member Posts: 3
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    Mag-Erad Water Heater Cleaner is easily found as sku 6831000 in the new 2 pound more economical package with the new United States Patent at Menards. A. O. Smith also is working on the new size upgrades and the sister product for those million BTU type heat exchangers is the A. O. Smith Un-Lime Delimer. Note that the National Codes have been changed. Temperature and Pressure Relief Valves on potable systems must be removed and waterside inspected for clogs and fallen off or corroding probes and the CSA NOT NB/ASME rating used because potable water is 20-80 pounds and the ASME Rating is 150 Pounds, or 360 degree Fahrenheit Water, clearly dangerous. The CSA rating assures the water never exceeds 210', remains under boiling, does not expand double nitroglycerine as water does when it flashes to steam as the pressure drops to under the boiling point of the superheated water. Mag-Erad is at Menards and that is a lot of locations nationally, more coming.
  • 23Bob
    23Bob Member Posts: 3
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    Someone several entries above talks about a rid product that comes as a liquid. The Safety Data Sheet for the same amount of muriatic acid found in Lysol Toilet Bowl cleaner shows severe eye damage, burns and so forth. Anyone can write any thing the OSHA people do not check the accuracy of SDS Sheets that is something we do in Court when injured by inaccurate and misleading SDS Sheets. Muriatic acid stress corrosion cracks stainless steels and dissolves copper and sets up permanent corrosion cells in glass lined tanks. You did not know that did you? I even caught a solder company that left out a toxic component in their solder, in 16 hours they rewrote the SDS sheet for fear of the consequences. Only Factory Approved Mag-Erad a fully concentrated food grade highest quality available ingredients product is without question the most recognized safest product for your use and for what it can do to preserve equipment. It just received another brand new United States Patent and part of the Patent is it MUST be only comprised of food grade materials. It is in the Patent! Mag-Erad - Specifications of Food Grade in the United States Federal Government Patent. Who watches out for your kids, your family, the water supply, you? Mag-Erad does. The updated instructions on the 2 pound new package save lives from other Codes we got passed Nationally.