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Heatway Onyx....

kcopp Member Posts: 4,432
I have a customer w/ a 12 year old system. It has a WM gv boiler, a super stor, and 2 zones of heatway Onex.... The last few years  the system has had maintenance issues. Whenever I go to work on this system I notice that there is a good deal on rust on the inside of the piping, the flow checks and the mixing valves. I realize the issues that the entran piping had.... is it possible that they still have  not figured out an O2 barrier w/ the Onyx tubing too? ty,kpc


  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    They will not acknowledge there is a problem...

    and in my professional problem, and other professionals like yourself, there IS a problem.

    My theory is this. The aluminum/mylar film that they are using for an O2 barrier DOES stop O2 transmission at a right angle to the tubing profile. It has to, because 02 can't penetrate a metal surface.

    But, and this is a BIG but, where ever the tubing is cut, and placed on a barbed fitting, there is a parallel path for 02 to travel along the inner tube lining, between the barbed fitting and the mylar barrier and into the water. The more tube cuts, the more parallel paths for 02 to travel into the working fluid.

    Other than treating the water in the system as an open system, and maintaining the proper pH for the connected equipment, I have no good solutions to the problem.

    Interestingly enough, the Watts PAP tubing has a special cap that is placed on top of the cut tubing before being placed upon the receiver fitting. I think they are attempting to avoid possible fluid impingement onto their aluminum barrier, and associated corrosion.

    If they used something similar to this on the RAR tubing, it MIGHT slow the transmission of 02 through the inner tubing path.

    The next step in the degradation process is the accumulation of "gunk" in lower level, low flow tubing which has been known to block off circuit flows in smaller diameter tubing (3/8" and 1/2" in particular).

    I'd hate to see this degrade into another E2 legal action...

    But I am aware of some legal beagles who are keeping a very sharp eye on the subject...

    Rhomar cleaning products are compatible with rubber products. Keep the pH high (8.5) for ferrous components and the rust should subside.


    There was an error rendering this rich post.

  • Greg Maxwell
    Greg Maxwell Member Posts: 212
    Heat Exchanger

    A brazed plate heat exchanger will remove any further corrosion issues, but I would only do that in this case only after you have removed any possibility that the corrosion is being caused by another source. We have branches that sell a fair anount of that product, and I am unaware of any problems with it. That does not mean that they dont exist, of that there wasnt a problem 12 years ago, but I would eliminate any other possibility first.
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