Is it worth changing the water heater anode on older unit?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by golem, Aug 1, 2013.

  1. golem

    golem New Member

    Messages:
    18
    Location:
    VA
    I'm confident the correct solution for prevention would be to replace the water heater as a whole but have to ask...

    My current gas fired Kenmore PowerMiser 8 has a warranty expiration date of 2004 so pretty sure it's probably at least 12 years old and considered geriatric. I'm positive no maintenance has been performed on the unit in its lifetime therefore wondering if there is any worth in changing out the anode? Maybe even flush it while she's pressure relieved.

    Also out of curiosity -- Water heaters I've seen leaking do so in a pinhole type slow drip manner. What is the likelihood that a tank lets go catastrophically? I don't mean explode but more like a crack that allows for larger volumes of water to escape before becoming aware of the failure?
  2. leejosepho

    leejosepho DIY scratch-pad engineer

    My wife and I have a gas-powered water heater my in-laws purchased used and had someone install a little over 20 years ago, and I have the same kinds of questions you are asking! I know it is a matter of when, not whether, and then how badly or even violently it might fail. I purchased a new anode rod for it about a year ago, but decided not to stress the heater with an impact wrench while removing the old one. So, I have a used electric heater with a new rod I can install at least temporarily if the gas unit stops working or begins leaking before we can afford a new heater, but I would not mess with the old one even if it was all we had.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,258
    Location:
    Cave Creek, Arizona
    In 60+ years I have "replaced" about 4 anode rods, but have removed many of them and substituted a brass plug. As for my own heaters, I have never replaced one of their anode rods.
  4. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,311
    Location:
    Maine
    I concur with HJ'S, and every time if tried to change one the damn thing was rusted so tight that I had to use an electric impact wrench to get it out. To worth the time and effort.
  5. golem

    golem New Member

    Messages:
    18
    Location:
    VA
    Thanks for the replies!

    My one concern (if I were to replace the anode) seems to be echoed by you gentlemen -- I was dreading the thought of corroded/encrusted threads making removal a PITA. Even using an impact is scary because I can just imagine the vibrations taking my leak fears to fruition. Anyhow, it's sounding like I should just leave well enough alone. When the pucker factor sets in a couple years from now I'll know it's time for replacement or install of a tankless.
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,258
    Location:
    Cave Creek, Arizona
    In theory, the anode rod is to "coat" any exposed steel that the glasslining did not cover. That being the case, by the time the anode rod is "depleted" all exposed steel should be coated.
  7. golem

    golem New Member

    Messages:
    18
    Location:
    VA
    Not sure that is correct hj. Anodes are considered "sacrificial" due to the fact the alloy they're made of is more electrically conductive therefore attracting the always present and corrosive electrical reaction occurring when metal is submerged in water. The anode is designed to "sacrifice" itself. As soon as it is fully consumed the corrosion process will continue on to the next available candidate which in this case would be the tank and/or fittings. I've never heard anodes being described as similar to vapor coating.
  8. leejosepho

    leejosepho DIY scratch-pad engineer

    That is how things work with sacrificial anodes on boat rudders and such.
  9. asktom

    asktom Member

    Messages:
    589
    Location:
    Victor, MT
    I agree anodes are sacrificial. I also agree about no changing them (except in special cases) - especially in a water heater almost a decade out of warranty.
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