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100 percent antifreeze

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aperson
aperson Member Posts: 66
in THE MAIN WALL
What will happen to a hot water boiler system that has 100 percent antifreeze in the heating pipes? I mean no water just antifreeze. 

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  • mattmia2
    mattmia2 Member Posts: 9,670
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    Nothing good. The heat transfer is somewhat less, propylene or ethylene glycol are fairly corrosive and need inhibitors that must be maintained, they are more viscous so they require more pump for the same flow. unless you are in the arctic or antarctic you don't need that concentration.
  • HVACNUT
    HVACNUT Member Posts: 5,841
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    38 percent Polypropylene is good to 0°F so, why? 
    SuperTech
  • Tom_133
    Tom_133 Member Posts: 884
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    I agree with the above comments, more is not better in this case. Use the percentage you need. You will gain efficiencies, that will save money up front and on the fuel use. Its even worth paying someone else to come fill the system if you dont have a pump or tester
    Tom
    Montpelier Vt
  • pecmsg
    pecmsg Member Posts: 4,861
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    HVACNUT said:

    38 percent Polypropylene is good to 0°F so, why? 

    X-2

    W H Y

    ? ? ?
    SuperTech
  • hot_rod
    hot_rod Member Posts: 22,158
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    Pump and expansion tank would need to be upsized.
    I think above about 64% the freeze protection does not increase. All the Dow charts end at 64 or 65%?
    Pretty much all glycol you buy is pre-blended to some degree so you would need to know exactly what was or will be put in.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Zman
    Zman Member Posts: 7,569
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    I once got a little greedy trying to increase the concentration in a large system. When the slug of ~100% glycol hit the big system circulators it turned into a big foamy mess. It was a PITA to get the air out and get it all mixed evenly.
    There is basically no upside to concentrations above 50%.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    TinmanSuperTech
  • aperson
    aperson Member Posts: 66
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    Answers are awsome. I am going to turn my neighbor on to this site.
  • HomerJSmith
    HomerJSmith Member Posts: 2,441
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    The glycol manufactures will love you!
    SuperTech
  • bucksnort
    bucksnort Member Posts: 167
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    Maybe because 100% glycol freezes at 10 degrees?
  • Derheatmeister
    Derheatmeister Member Posts: 1,544
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    aperson said:

    Answers are awsome. I am going to turn my neighbor on to this site.

    And when you dilute the Glycol it is better to use deionized water vs. just regular tap water!
  • SuperTech
    SuperTech Member Posts: 2,166
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    Glycol also has a lower viscosity than water. I've seen boilers with high concentrations of glycol leak from the seals on zone valves and from the flanges of the circulators. Its really nasty when a boiler has too much glycol and its been in the system too long. Ball valves and gate valves become locked up and corroded, boiler drains and air vents start to leak....
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,528
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    Mechanical seals on pumps are also a concern. Mechanical seals lubricate by leaking water, which then evaporates once passing across the seal surfaces. Glycol doesn't readily evaporate, so it builds up and makes a mess.
    Retired and loving it.

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