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Replacing Buderus ST120 Indirect with failed coating

Jeffj Member Posts: 3
When we were ready to replace our heating system 12 years ago, we went with a Buderus Boiler & Indirect installed by Tom Schwarz. Tom's expertise and skill made us confident in our choice. Sadly Tom passed away, and his business was taken over by our oil supplier. Recently we noticed that our hot water appeared discolored, and flushing the ST120 I found a good deal of residue. The pressure relief valve also vented behind the boiler. I vented it further to bring the pressure down, but it is slowly climbing again, even with the intake line turned off. I was told that Buderus would not honor a warranty claim unless the Anode was inspected every year. (Tom checked it twice, but his last visit was in 2012) - further I was told that it is a pro-rated warranty applied against the full list price of the new tank, so it's of dubious benefit. I'm looking for a contractor who can install a new indirect tank in the Melville area. Thing about the SuperStor with its stainless tank. Any suggestions?


  • Big Ed_4
    Big Ed_4 Member Posts: 2,697
    Here on Long Island our water is high in iron and would come out of solution with temperature set point higher then 120* .... Maybe all you need to do is flushing out the tank ? It will be an brown red color .. Stainless always sounds like an great idea but a **** to weld ...I condemned more then I would like to ... I wound recommend an Buderus over most other units .. You have a glass spun steel tank ..The glass is porous and sucks in water when you first fill it up .. that layer of water looses it's O2 or sting ..It acts like an protective barrier ... If broken the fresh water seep in and rot the steel .. This use to happen with an direct fired unit and with a build of of iron laying on the bottom of the tank with an 2000* flame underneath ....With lack of water it superheated and cracked the glass ... Cant see this happen with an indirect ... Are your aerators plugging up with whitish fiber ?
    I have enough experience to know , that I dont know it all
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,537
    Stainless doesn't hold up any better under Long Island water conditions. High chlorides.
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • kcopp
    kcopp Member Posts: 4,393
    Pretty typical on Buderus s120.... HX tend to fail before the warranty is up. anode is usually fine.... Its just not a good unit.

    Try the Bradford White Powerstor.
    3 anode rods. "lifetime warranty"

  • Jeffj
    Jeffj Member Posts: 3
    Our tank is running at 120 degrees, and yes the water when I flushed it was brown-red. There was also enough sediment to clog the drain valve as I was flushing the tank - I'm guessing that was part of the coating from the HX?. Our water comes from the South Huntington Water District, and according to their report the level of Chloride is from 2.8 to 69.1 mg per liter. and for Iron it is 170 ug per liter. I don't know if those levels mean SS is not a good option for our home. Looking into the Bradford White indirect, thanks! Jeff
  • Jeffj
    Jeffj Member Posts: 3
    The contractor suggested raising the temperature to 140 and adding a mixing pump, but would that increase the amount of iron that would separate out in the HW tank?
  • hot_rod
    hot_rod Member Posts: 21,857
    All water conditions considered, a quality glass lined tank should last a long time

    Anode upkeep is critical. Wide and high temperature swings do put glass lined tanks to the test, most manufacturers suggest below 180 temperatures

    The quality of the water and the amount that flows through the tank are part of the equation

    New chemicals are being used by water companies to keep the water safe and clean. In some cases poly phosphates are added to treat high iron content water High tank operating temperatures can cause that red sludge formation that you see when you drain the tank

    The treatment chemicals added are to keep water safe for consumption, but not always safe for all metals. Pay attention to acceptable chloride levels with stainless. You may not have any warranty from day one if they exceed levels on the installation guide
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream