Open Loop back-flush

Discussion in 'Open Loop' started by ciws14, Nov 5, 2010.

  1. ciws14

    ciws14 Member

    Has anyone had any experience with an older open loop that has not ever been back-flushed and cleaned? I have a customer with about a (5) year old system that has never been attended too. The water in that area is very high in calcium and areas where the system had small leaks had major deposits left behind. Is there any worry with chemically cleaning a system this old if it developing leaks in the coax? I planned on using something less harsh then ice machine cleaner to clean this system up with. Any thoughts?
  2. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    I recently had a very bad experience in regard to flushing an open loop. First and foremost make sure that the solution you are using is not detrimental to any of the componants of the system, not just the coax coil.
    I would determine the construct material for the coax first and then address the rest of it that will come into contact with the solution of choice.

    We tried an acid flush of the piping and multiple cubes in a commercial system that was choking on bacterialised iron. The solution effectively cleaned the coax and piping, BUT! it dissolved or caused failure to the solvent welded joints int the schedule 40 pvc that was used for unit piping the cubes. The damage did not present immediately. All the leaking came later! omg:eek:

    Flushing can be effective but treat with respect.
  3. ciws14

    ciws14 Member



    That is what I was kind of afraid of. I actually just back-flushed one of my shop units with a product I've never used before:

    Apex - Rydlyme is the world's leading biodegradable descaler, rydlyme is designedto dissolve water scale, lime deposits & rust deposits, but is not water treatment orwater conditioner.

    I was a little skeptical as one of my supplier's salesman was preaching about how great it was. At $26 a gallon, you can see my point. I was given a sample and was told to mix it 4 to 1 and did so in a 5 gallon bucket. I was pleasantly surprised to say the least. She cleaned up within a few minutes. They say it's non-hazardous, but it is very irritating if you get any on your skin. You can hear it sizzle when it hits the concrete. I splashed a little when I was pouring into the bucket. I was a little worried at first. But in the end, it seemed like a good product.

    I am going to do my other shop units and see how things go. I am looking to develop a waiver of some sort for customer's to sign that have systems that have not been cared for properly. Something to protect myself. Does anybody have anything like this?
  4. Looby

    Looby Member Forum Leader

    Not surprising; the MSDS says it's up to 10% HCl (a.k.a. hydrochloric acid,
    a.k.a. muriatic acid).
  5. ciws14

    ciws14 Member


    I saw that too. It appears that the terms "safe", "non-hazardous", etc are very loose terms...:confused:
  6. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    o.k. I will fess up. All muriatic acid is not created equal. The stuff at the big box store for etching and cleaning concrete is not the same as the stuff we got from a supply house in a big blue drum.:rolleyes:
    Be carefull with concentration levels.
  7. Looby

    Looby Member Forum Leader

    At worst, 10% HCl is only borderline "hazardous." It's a skin irritant,
    but not really "toxic", for example, stomach acid is about 0.5% HCl.
  8. greg quinn

    greg quinn New Member

    I worked as a mechanic in a cereal plant for 36 years. We circulated rydlyme thru our mills that had a lot of luck with it.
  9. mldncx

    mldncx Member

    I had planned to use Nucalgon 4287-34 Nickel Safe Ice Machine Cleaner on my daughter's Waterfurnace open-loop geothermal heat pump but, after reading this post, I'm more than a little hesitant. According to the MSDS, this product contains 15-40 percent phosphoric acid. I'm wondering if it will affect the solvent welds in the PVC piping that supplies water to the heat pump. Any idea?
  10. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    I do not have any experience with that product. I have a lot of experience on what not to do. The first thing is to identify what we are trying to remove. Is it scale build up due to minerals, or is it a organic fouling? Once that is determined I would call Coatey chemical. They have a lot of experience treating and removing a wide variety of "stuff" without damage to pvc solvent welds.
  11. mldncx

    mldncx Member

    Thanks, Eric. It did not occur to me to contact the solvent manufacturer.
  12. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I tried NickelSafe on a badly scaled (37 years in service, probably never flushed) open loop system Coax. Didn't work, but that was a heckuva scaled system.
  13. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Go find the Furnox dealer.

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