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anti-freeze in boilers

brad johns
brad johns Member Posts: 5
in THE MAIN WALL
We just replaced a Weil-McLain boiler that was leaking because the system also uses a chiller, so the customer used regular automotive anti-freeze in the system, when we changed the boiler we flushed the system so it now has regular water in it. I think I read years ago that the anti-freeze makes a gas right near the burners where it is heated most in the heat exchanger. Could someone here refresh my memory on why you can't use ethyl glycol, I'am sure there are many other reasons as well. Thanks in advance for any and all info.

Comments

  • Plumdog_2
    Plumdog_2 Member Posts: 873
    The biggest reason of all

    Auto anti-freeze is EXTREMELY toxic. Call poison control to confirm this. If you have physical connections between your boiler "liquid" and the potable water supply, you are always at some risk of the two liquids mixing. For example: the boiler fill assembly and the coil inside your Indirect Water Heater.
  • hot_rod
    hot_rod Member Posts: 23,405
    ethylene glycol

    can be used in hydronic systems. Generally large hydronic systems will use EG as it is a better heat transfer fluid and less expensive.

    It also bio-degrades quicker in the enviroment, if dumped (1 less carbon).

    It needs to be a hydronic fluid like Dow's DowTherm EG, as the automotive EG fluids contain silicates which WILL sludge up the system after time.

    As Plumbdog mentioned EG fluids are a higher toxicity than PG and spills can be an issue.

    hr
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
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