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Antifreeze & corrosion

Lynne Member Posts: 50
i will be sure it's O2 barriered; hoping that is. The antifreeze is old, and there are crawl space areas, so the system really does need it. The fluid ph is 7, which told us it's time to change it. And it is a Buderus cast iron boiler. so the next concern is distilled water; thanks for your input; and i think we should do the rhomar cleaner rather than just flush the system and replace antifreeze; Thanks hot rod


  • Lynne
    Lynne Member Posts: 50
    antifreeze & corrosion

    We have a hydronic system that has gone through 3 expansion tanks in 19 months. The tanks have pin holes right through them. System has antifreeze that we need to flush and replace, question is, should we clean and treat with a product like Rhomar as well? we've used Rhomar when we've had particles of iron present; this sytem fluid seems particle free.
  • Darrell
    Darrell Member Posts: 303

    Yes, you should clean and flush the system. Probably if you check your system PH it is about 6 and eating everything in sight. You may also have oxygen being ingested into the system fluid via a leak, constant fill, or non-barrier tubing.

    The flushing protocol that I wass taught it to flush each zone or piping system with clean water until it runs clear, and then continue to flush for three times more. For instance, if it takes twenty minutes for a zone to run clear, continue to flush for sixty more minutes. Then put in a boiler cleaner, your choice today, I use a Hercules product because that's what's available to me. Let it run for a couple of days or a week and do the flush again into a white bucket, (so you can see the quality) and through a paint seive, (so you can see any solids). If it is dirty this time, do it again. I just did a system at the local sewer plant that I had to flush three times. Once with clear water, and twice with cleaner, before I put new antifreeze in. When you put the new antifreeze in, don't put in any more than you have to for safety. Too cold equals too thick, and it tends to burn and go bad more quickly.

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  • hr
    hr Member Posts: 6,106
    any non barrier tube

    in the system? If so the O2 ingress will require constant maintenance of the inhibited glycol. It's the oxygen ingress that(uses up) the conditioners in the glycol. Test and boost as needed.

    Higher operating temperatures increse O2 ingress also.

    Another possibility is extreme temperatures breaking down the glycol. Insufficient flow through the boiler heat exchanger could cause this. Is it a copper tube boiler by chance?

    Regardless, if the ph of the glycol falls below 7 or so I'd remove it and use the Rhomar cleaner to clean out all the old fluid, flux, oil, etc. then start anew.

    It is also critical that you use DI water to blend the glycol. Bad water will once again deplete the inhibitor package in the glycol. Some manufactu7res offer pre-mixed glycol thayt doesn't require onsite blending. Rhomar does, Nobel also I believe.

    Is it imperative that you have glycol in the system? It does bring some baggage :)Unless you have piping on outside walls or the home is left unoccupied in the freezing months, glycol may not be needed?

    Of course if you do have a non barrier system or other means of o2 ingress you will still risk pin holeing expansion tanks.

    Rust never sleeps :)

    hot rod

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  • Tom Wackerman
    Tom Wackerman Member Posts: 2
    hydronic radiant ceiling panels

    I am looking to represent a line of quality radiant ceiling panels for Manitoba, Canada. Can anyone recommend a line?
  • ALH_4
    ALH_4 Member Posts: 1,790
    New Topic

    nm ;-)
  • Lynne
    Lynne Member Posts: 50
    boiler cleaner seems necessary

    So chemical treatment we will do, thanks for your stories of experience. Have you put in a product after flushing along with the antifreeze like Rhomar?
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