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  1. #66
    Join Date
    Jul 2012
    Location
    North west Arkansas
    Posts
    86
    Post Likes
    I have limited space available in my service van, and with tools, parts, and cylinders of refrigerant as well as reclaim cylinders there's not a lot of room,, I work on everything at these Subways,, so I carry tanks of CO2 already for beverage systems, and it's what I use to purge and pressure test,,, it's never caused me any issues, and I use a filter drier,,
    Haven't used it in anything larger than a 5 ton ac, so can't tell you about effects when used in very large systems,, for what I do, it's been fine..

  2. #67
    Join Date
    Feb 2015
    Location
    Waterdown, Ontario, Canada
    Posts
    4
    Post Likes
    Quote Originally Posted by jpsmith1cm View Post
    I have used both and I cannot tell a difference between the results.

    Some try the argument that CO2, in the presence of water, forms carbolic acid. This is true. Since we're evacuating the system to remove moisture, I don't see this as a major issue.

    Depending on the CO2 grade that you buy, it may or may not have a significant quantity of moisture in it.

    I like CO2 because there is a LOT more of it per can. I DON'T like it because that thing is HEAVY dragging it up to and across the roof.
    Hate to be a stickler for details, but CO2 plus moisture does not form carbolic acid. It forms carbonic acid, which is a weak acid.
    Nitrous

  3. #68
    Join Date
    Feb 2010
    Location
    In a boiler room
    Posts
    7,463
    Post Likes
    Just when you think it's dead, it comes back to life!

  4. Likes Mike19 liked this post.
  5. #69
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    26,290
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    Quote Originally Posted by Nitrous View Post
    Hate to be a stickler for details, but CO2 plus moisture does not form carbolic acid. It forms carbonic acid, which is a weak acid.
    Nitrous

    Appreciate the correction, Sir.

  6. #70
    Join Date
    Jul 2012
    Posts
    1,888
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    According to the tree huggers co2 makes "global warming". Using that would be defamory to using 410A environmentally friendly gas lmao

  7. #71
    Join Date
    Feb 2008
    Location
    Waffleville
    Posts
    10,459
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    Quote Originally Posted by Capz View Post
    Show me documentation where it states it is okay to use co2 as a brazing purge gas.

    Do a search "co2 corrosion carbon steel".

    CO2 is not an inert gas.

    Maybe my terminology was a little strong. Unless somethings have changed, I read in one of my books never to introduce co2 into refrig systems. Having pulled high vacuums on the shells of many large cryogenic vessels, I can verify that it is much easier & faster to remove nitrogen with a vacuum pump than it is co2, air or any gas with a moisture content. Boiling off moisture is what delays busting below 500mi. I needed to get below 100mi on perlite tanks, and 10mi on super insulated mylar tanks.

    CO2 will also react to high heat such as it does in the GMAW.
    Read about it here.
    http://en.wikipedia.org/wiki/Gas_metal_arc_welding
    Guess CO2 rack systems are just all wrong...

  8. #72
    Join Date
    Feb 2008
    Location
    Waffleville
    Posts
    10,459
    Post Likes
    Quote Originally Posted by Phase Loss View Post
    Yeah, I've seen that too...even on 40 year old stores.

    that can't still possibly be soot from not flowing.

    It's more likely burnt oil from high discharge temps.

    And no, I'm not joking. I've never flowed nitro during a service situation. you're talking about a handful of braze joints at best.

    IE: replacing a TXV, 3 joints, don't even wrap the valve with a rag...never had one fail....ever. Use a rose bud tip too, on full blast...for everything.
    Amen! Someone finally tells it like it is!

    No textbook fairies on this site in 2013!

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