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Glycol-The mystery

Joe at krahezfoo@aol.com
Joe at krahezfoo@aol.com Member Posts: 60
in THE MAIN WALL
sorry it took so long to get back to you. Didn't get a response from Interstate Chemical, but my customer did. I guess the problem with mixing the two is with the inhibitors that are added. guess they create havoc in the system. Will try Interstate again Monday; and get some answers. The pressure is on now, the temperature up here has dropped almost 30 degrees in the last day. Time to retire the vacuum pump and gauges and get out the boiler analyzer; at least for this upcoming week. Keep in touch!

Comments

  • hr
    hr Member Posts: 6,106
    Glycol mixes

    I visited a glycol recycler last week. They collect automotive anti freeze from quick lube joints. They claim the new automotive propylene glycols are drained and mixed with the EGs all the time. The PGs are all red colored in automotive and the EGs green.

    They allow the stuff to settle in tanks then run it through filters and RO it comes out perfectly clear! Then they re-inhibit it to the different manufactures specs. They process 1200 gallons a day.

    They sold me 5 gallons of EG, uninhibited (clear) I will add the hydronic inhibitors and install it in an old E-2 snowmelt system.

    If you ever come across an E-2 DON'T drain the fluid!

    I'll try and e-mail me chemist friend at Dow today to get his opinion on blending PG and EG. I'm certain you wouldn't want to mix automotive with hydronic anti freezes due to the inhibitor make up. But I'm not sure about blending hydronic PG and EG.

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  • Earthfire
    Earthfire Member Posts: 543
    what

    is E-2 am familiar with PG, Eg, Methanol, Ethanol & environol but don't know ? E2 , and why not drain?
  • hr
    hr Member Posts: 6,106
    E-2 =

    Entran 2. The rubber tube sold under the Heatway name. On some batches the plasticizers would come out of the tube. If you drain the fluid you further risk the tube getting hard.

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  • hr
    hr Member Posts: 6,106
    Glycol compatiability

    My sources tell me EG (ethylene glycol) and PG (propylene glycol) can be mixed without a problem. In rare cases the inhibitors may not be compatiable, but the glycol base product is compatiable.

    The inhibitors in Dowfrost (PG) and Dowtherm SR-1 (EG) are compatiable and may be mixed. I would not recommend mixing automotive anti freezes with hydronic. Automotive antifreeze use silicates which could coat and plug HX surfaces in a hydronic system.

    They cautioned me that PG is more viscous than EG and below 20 degrees it is tough to pump. At 0 degrees straight PG cannot be pumped with centrifugal pumps.

    I have had some problems with electric boilers and copper tube not being able to "make" the flow switch contacts due to the thick PG at low temperatures in snow melt applications. This is one reason the copper tube manufactures recommend 35% glycol max. in their boilers.

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