De-mineralizing a hot water heater - a success story!

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by midwest_homeowner, Mar 9, 2006.

  1. midwest_homeowner

    midwest_homeowner New Member

    I have very hard well water (iron, calcium, etc), and have never flushed my 8 year old water heater (40-gal, natural gas). Needless to say, there was audible snap, crackle, pop, and occasionally boom sounds.

    Rather than shell out $$ for a new unit, I performed the following procedure last month with the help of an adventurous plumber:

    1. drain tank

    2. add two gallons of white vinegar

    3. wait 12 hours (at about the 6 hour mark, I ignited the burner for a minute or so)

    4. flush tank

    5. repeat steps 1-4

    It's been one month now, and still no noise!

    Just thought I'd share...

    Paul, Illinois
  2. hj

    hj Moderator & Master Plumber Staff Member

    Cave Creek, Arizona

    Call us again when the heater starts leaking and let us know how soon it happens.
  3. Phil P.

    Phil P. New Member

    Arlington, VA
    water heater "maintenance"?

    So, the basic advice re. water heaters is occasionally flush some water out the bottom, otherwise let sleeping dogs lie?

    I also saw the "This Old House" story where Richard the plumber changes out the anode rod thing, started wondering if I should do that, too.

    My gas fired 40 gallon unit is going strong after 14 years ... I guess I'd better keep the floor drain clear! Great info on this board ... Phil
  4. Gary Slusser

    Gary Slusser That's all folks!

    Phil, you can't flush much hard water scale out of a water heater tank; especially gas or oil fired types. Those snap crackle pop sounds are little steam explosions and have more than likely broken the 'glass' lining in the tank and that allows the water up against the raw mild steel of the tank. Vinegar is acidic, so it attacks steel. The water and acid causes rust and rust causes holes that leak.

    The best way to protect a water heater is to prevent hard water scale build up in it, and the only way to do that is with a water softener.
  5. SteveW

    SteveW DIY Senior Member

    Omaha, NE
    Check out a site all about WH maintenance: .

    They sell a book which claims you can keep a WH going for many, many years by inspecting (and eventually replacing) the anode rod, flushing the tank, and watching the dip tube.

    Make sure to check out the "fun stuff" pics -- esp. "Scary as ABC..."
  6. plumber1

    plumber1 Plumber

    I say good for you.....
    You can do a lot of things with that water heater and I don't believe your going to accomplish anything.
    Forget it and keep on using it.
  7. midwest_homeowner

    midwest_homeowner New Member

    Gary, I agree with your first sentence - regularly draining/flushing a water heater may only modestly help prolong tank life, as it will only rid the unit of suspended minerals, not minerals that have settled and bonded to the tank floor.

    However, prior to embarking on this project, I consulted with several plumbers, as well as Bradford White, and they all agreed that "snap, crackle, pop" is due to little steam explosions in the accumulated layer of mineral sediment on the tank floor. Had the noise been due to breaks in the glass lining, then vinegar wouldn't have any effect - in fact, it might make matters worse. Instead, what I witnessed was lots of dirty "apple cider" flowing out of my tank after the vinegar flush, and no more "snap, crackle, pop". Thus, I have to conclude that the noises were due to a layer of sediment buildup, that the vinegar successfully dissolved.

    Maybe northern Illinois well water has mineral composition that is susceptible to vinegar? The trap & jets in my newer American Standard toilet clog every six months or so, and an overnite vinegar bath (in the bowl) restores it to like-new condition. (Why didn't American fully glaze them in the first place??)

    Why not get a water softener? Because it is probably more maintenance, and anyway, my natual mineral water is cheaper and better tasting than bottled or softened water!! (Of course, that could be due to the leaking landfill about a mile from here...)
  8. when will it leak??

    now that you have basically cleaned out all
    the lime and sediment from the inside of
    the tank , and the bottom of the tank
    is clean as a whistle, I wonder how long it will be before
    the unit starts to leak???

    usually by de-limeing the heater,
    you expose to the elements any hair line cracks , poor welds ect
    that the sediment has sort of protected for a long while..

    so it will be interesting to see how much life you
    actually squeeze out of this puppy.....

    and how much time and money was invested in doing this??
    Last edited: Mar 11, 2006
  9. Gary Slusser

    Gary Slusser That's all folks!

    Midwest, I didn't say the explosions were due to the glass lining. I said they probably broke the glass lining and that allows water to get to the mild steel of the tank. That is what happens and then the water rusts holes in the tank.

    With gas and oil heaters, the heat is applied on the outside bottom of the tank on bare steel. The scale is on the glass lining inside the tank. There has tr obe substantial scale to cause steam explosions but, mostly they will be under the scale at the glass or between it in the scale. Either way, steam is powerfull and the force goes out in all the directions it can.

    The best protection for a water heater of any type is to keep the scale from forming in the tank. The only way to do that is to remove the hardness with a softener. The vinegar may have removed the scale but more likely it softened it and steam is unable to form in or under it now.

    Have you ever seen the inside of a heater with scale in it? With gas and oil heaters the scale is not only on the bottom, it's on the walls and the flue pipe. In an electric heater the scale forms on the elements, then in some cases it breaks off them from their expansion and contraction (on/off heating) and falls to the bottom like little half circles. They are hard to drain out if not impossible.
  10. midwest_homeowner

    midwest_homeowner New Member

    it's been an interesting experiment...

    Thanks for the clarification, Gary. I misread your post.

    Well, it's been an interesting experiment anyway. I've been laid off for a few months now and can't afford a new water heater + installation, so in the meantime, $8 worth of white vinegar and a $13 relief valve may have bought me some time.

    I'll try to remember to re-post in 6 months or so and give an update.

  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    New England
    If you either bookmark this thread or search for it later on, it will move to the top of the queue when you add a new posting. The history will make it more useful to others at the time.
  12. dubldare

    dubldare Plumber/Gasfitter

    An interesting FAQ on, AOSmith's webpage:
  13. Gary Slusser

    Gary Slusser That's all folks!

    A softener does not reduce conductivity of the water. Actually in most cases it increases it silghtly. Conductivity is based on the TDS, total dissolved solids, not hardness content although hardness adds to the TDS. When hardness is removed with a softener, sodium is added at the rate of two ions per ion removed; hence the slight increase in TDS of softened water.

    Their layer of scale wouldn't be needed to "protect" the tank material IF their glass/epoxy lining was intact BUT... the anode rods are sacrificial and designed to protect the tank from electrical induced corrosion, not rusting of the steel due to water caused corrosion.

    Plus the fact that as little as 1/16 to 1/8" of scale can cause an increase in fuel cost to operate a water heater by 20-30%.

    BUT... how do you limit scale formation in a water heater to 1/16"?

    So chose yer poison, pay higher fuel costs for hot water or for a new anode rod every few years or a new water heater. In the mean time, if you don't have softened water, you suffer all the other hidden costs of using hard water like damaged water using appliances, clothes and plumbing fixtures etc.. Proving there is no free lunch but a new water heater every 10 years or more costs the least of all the choices.
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