Possible Corrosion Problem Waiting

Discussion in 'Maintenance and Troubleshooting' started by osok, Sep 2, 2011.

  1. osok

    osok New Member

    Should the water in my closed loop system be treated to prohibit any future corrosion problem inside the unit? If so what type of corrosion inhibitor and at what ratio. I live in the south so not concerned about freezing. I'm concerned about rusting internally.
  2. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Leave it be.
  3. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Leave it be.
  4. osok

    osok New Member

    I was thinking maybe it needed protection since you can never fully remove all air from a system. But thanks for the replies and I'll leave it be.

  5. My thought

    I deal a lot with commercial. When you order a typical geo heat pump, I think the two options on heat exchange coils are copper or cupra nickel. Cupra nickel resists corrosion better. You can lose a copper coil in beach or ocean areas in two years.

    I agree with the previous two comments IF the water put into the system is NEUTRAL PH. Where I live, the water is so pure it errs on the acidic side. What does that mean? It means that standard copper pipes will perforate in 20 years time. One professional geo installer whom I trust locally would probably "truck in" a more neutral water in my case.

    Or you take a sample and have a professional chemical company ( the ones that do commercial water treatment: large tonnage water towers and so on) give an opinion on a sample you give them. There are legitimate additives that can be added to make water that is on either extreme of PH, neutral. Water that is neutral pretty much stays neutral unless there is some other outside acting influence.

    Hopefully your professional is using a multi thousand dollar flushing machine which would remove 99.5% of any air.

    Water is popular and safe, and cheap but make sure it actually is neutral. In moderate climates, it is preferred because of superior heat transfer and flow characteristics. That's my take.
  6. Looby

    Looby Member Forum Leader

    Do you mean domestic potable water, or "dead water" in a closed loop?

    I'd expect water in a closed loop to rapidly become "inert" after depleting
    whatever corrosive potential it might have had initially. That's certainly
    my experience with a 60-year-old all-copper hot water/baseboard system
    that we had before the geo retrofit.

    Our domestic well was/is slightly acidic -- enough so that I got tired of
    repairing/replacing pinholed copper pipes, and gradually converted the
    domestic water plumbing to 100% CPVC.

    OTOH, the hydronic copper piping and fin-tube copper radiators were
    corrosion-free and like new when we removed them after 60 years of
    service -- even though they'd been on a slightly leaky system (boiler
    blow-downs, circ pump seepage, etc.) with an auto-fill valve refilling
    them from the slightly acidic domestic water supply.

    Executive summary: Leave it be.

    Last edited: Apr 4, 2012
  7. reply


    I have had to replace all my original domestic water copper piping at my house because of pinhole leaking. I have now have pvc/cpvc. The downside? cpvc becomes brittle. You can't actually snap cut it. It just fractures.

    I work for an institution with many buildings having 27 years + copper domestic piping. Until they decide to replace the whole darn thing, we use pressure clamps. In fact we use hundreds of them. So much for lifetime copper!

    I daily deal with commercial water treatment. I still say if water is neutral, fine, if it is not neutral.....? One of the functions of water treatment in commercial is to add oxygen inhibitors, essentially chemicals that absorb free oxygen. Done correctly, pipes 60 years old will look fine on the inside, why because there is no reaction or corrosion taking place.

    All I'm saying is that before I circulate a lot of water through loops with copper, I would test the water I intend to add to my house.

    Some of the chemical guys that analyze our stuff have chemistry degrees. I listen to them.
  8. Looby

    Looby Member Forum Leader

    Funny thing 'bout that, so do I.

    Maybe a good idea, maybe not. Corrosion chemistry is a very specialized
    field. After 9 years of undergraduate & graduate chemistry, I know enough
    to know that I'm no corrosion chemist. Not even close.

    RE: brittle CPVC -- warm it up with a hair dryer or heat gun. Works great.

    ...now an escaped chemist,


    "Anyone dumb enough to take chemistry can't possibly be smart enough to pass."
    -- First Law of Undergraduate Survival
    Last edited: Apr 4, 2012
  9. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    @ Lobby.

    I, at 62, am just learning the stuff they taught me in college.

  10. Looby

    Looby Member Forum Leader

    @ Mark.

    Me too, but you must be a quick study. It took me 5 years longer.


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