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  1. #1
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    Is a 2.5 CFM vacuum pump enough for 410A?

    Just curious if my 2.5 cfm vacuum pump will pull down a 3/8 , 3/4 . 40 foot lineset for a 410a system. Should i buy a large CFM pump? What about a 2 stage pump? What does 2 stage really do and mean? Any help on this topic would be appreciated....

  2. #2
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    Apr 2011
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    Nashville,TN
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    I havbe a 3 and a 6 and have used both on 410a systems..biggest difference is TIME!!
    --Men fight for freedom, then they make laws to take it away from themselves!--

  3. #3
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    Apr 2011
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    Get a 600cfm and I was always told pumps NEED to be 2 stage to achieve a deep vaccum.

  4. #4
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    Quote Originally Posted by hvacguy14 View Post
    Just curious if my 2.5 cfm vacuum pump will pull down a 3/8 , 3/4 . 40 foot lineset for a 410a system. Should i buy a large CFM pump? What about a 2 stage pump? What does 2 stage really do and mean? Any help on this topic would be appreciated....
    Batman you need to get your post count up (if you're in the business) and apply for a Professional Membership. I'm going to guess you don't have a Micron gauge.

    And we really can't answer your question in this forum (it looks like a DIY question which is against the Rules).

    Pumps? I have 5 and use them all on 410a systems.
    Yes, I know I Shouldn't But I Just Can't Help Myself...

  5. #5
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    Jun 2011
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    MO
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    Im not sure if i understand home&marine's comment, i am new to this site and im in the hvac industry, just not in the residential field, i work in the DDC controls side of the hvac business. I have gone through tech school and have my EPA universal tech card. Im not a DIY home owner. I thought this was the site you should go to to ask fellow hvac tech's correct me if im wrong......

  6. #6
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    Sep 2009
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    S.C.
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    Post

    Quote Originally Posted by hvacguy14 View Post
    Im not sure if i understand home&marine's comment, i am new to this site and im in the hvac industry, just not in the residential field, i work in the DDC controls side of the hvac business. I have gone through tech school and have my EPA universal tech card. Im not a DIY home owner. I thought this was the site you should go to to ask fellow hvac tech's correct me if im wrong......
    No biggie "it" only happens about 7 or 8 times a week. First, please go back and Read The Rules... Then you'll understand. As a "New Guest" you are limited to certain areas. Once you meet the required amount of "posts" you Can Apply For A Professional Membership "if" you can prove you're in the business at that point you can post the same question in another area and get Help!
    Yes, I know I Shouldn't But I Just Can't Help Myself...

  7. #7
    Join Date
    Jul 2006
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    Virginia
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    4,512
    when you think about it how many cubic feet is actually in a ac circuit 10 maybe in a small residential system

  8. #8
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    Jun 2011
    Location
    Western MA
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    It's all about time and time is money. I have both a 5 and a 6 cfm two stage vac and I can pull a 40' system down to 500 microns in about 45min. Probably take you at least twice as long, and definitely get a good micron gauge if you don't already have one. Also, the 4 port manifold I have has a 3/8" vac hose instead of all 1/4" hoses. That makes a big difference.

  9. #9
    Join Date
    Dec 2007
    Location
    houston, texas
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    I think it's about 6 tons per cfm of pump. I have a 3 and a 6 and use the 3 most of the time. We're working with 20 ton units so they are 10 ton each ckt.
    I'm not tolerating Political Correctness anymore, from now on it's tell it like it is.

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  10. #10
    Join Date
    Feb 2010
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    In a boiler room
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    Take the square of the CFM rating of the pump and that will be the number of tons it will handle.

    Example: 3 cfm pump will be fine for up to a 9 ton system.

    For pulling down a lineset and coil you will notice little to no difference in evac time between a 3 cfm pump and a 6 cfm pump. Especially if you are pulling thru the manifold and 1/4 inch hoses. The hoses you pull through and whether you remove the core will make the most difference in evac time.

  11. #11
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    As someone mentioned if you don't have a micron gauge you will have no idea if you have a deep enough vacuum.

  12. #12
    Join Date
    Dec 2007
    Location
    houston, texas
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    "Take the square of the CFM rating of the pump and that will be the number of tons it will handle."

    I couldn't remember just what the formula was, thanks for that
    I'm not tolerating Political Correctness anymore, from now on it's tell it like it is.

    Veto Pro Pak - The best tool bag you'll ever own






  13. #13
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    Feb 2010
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    Quote Originally Posted by Josephs LLC View Post
    It's all about time and time is money. I have both a 5 and a 6 cfm two stage vac and I can pull a 40' system down to 500 microns in about 45min. Probably take you at least twice as long, and definitely get a good micron gauge if you don't already have one. Also, the 4 port manifold I have has a 3/8" vac hose instead of all 1/4" hoses. That makes a big difference.
    I can pull a 40 ft lineset and coil to 500 microns in less than 30 minutes with my 3 cfm pump. Usuall only takes 15 - 20. I don't pull through a manifold.

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