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  1. #40
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    Quote Originally Posted by Hvac216 View Post
    That would be a lot of jugs or a heck of a tree. 5 gauges high and low side.
    One of the manifolds is hooked to a jug of R-410A, then all of the manifolds are hooked to each other.
    The refrigerant jug was sitting in the sun, so was a little warmer than the piece of copper.

    There is about an 8 year spread in instrument age in the picture, but all are reading within about 1 psig of each other, and the temperature probes are all within 1F of each other.
    If more government is the answer, then it's a really stupid question.

  2. #41
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    Quote Originally Posted by mark beiser View Post
    One of the manifolds is hooked to a jug of R-410A, then all of the manifolds are hooked to each other.
    The refrigerant jug was sitting in the sun, so was a little warmer than the piece of copper.

    There is about an 8 year spread in instrument age in the picture, but all are reading within about 1 psig of each other, and the temperature probes are all within 1ºF of each other.
    That's impressive that there still all that accurate. I've had my sman3 for almost a year and I'm getting real tired of calibrating the temps every time. Other than that they've been flawless. I'm considering either ak900 or a 550 or 570.

  3. #42
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    Quote Originally Posted by mark beiser View Post

    You can't stop at just one!
    <img src="http://hvac-talk.com/vbb/attachment.php?attachmentid=375481"/>
    Since I would only be able to afford one for now, then how do you address dealing with multiple refrigerants without cross contamination? Do I have to nitrogen purge them every time? Use different manifolds when charging/recovering,etc?
    Ron

  4. #43
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    Quote Originally Posted by Ron223 View Post
    Since I would only be able to afford one for now, then how do you address dealing with multiple refrigerants without cross contamination? Do I have to nitrogen purge them every time? Use different manifolds when charging/recovering,etc?
    No, just burp a little refrigerant through them like you would when hooking up any manifold and hoses.

    If you follow good practices when disconnecting from systems, you should never have more than a very thin film of oil residue in your manifold and hoses anyway.
    Assuming you use some sort of low loss fitting, at least on your high side hose, before disconnecting from a system crack the valves on your manifold open just enough to allow liquid refrigerant to bleed from the high side to the low side of the system through your manifold and hoses, then disconnect from the high side.
    Let the system pull the remaining liquid refrigerant out of your manifold and hoses, then disconnect from the low side.
    Do this every time you disconnect from a system and you will never have an accumulation of oil in your manifold and hoses.
    If more government is the answer, then it's a really stupid question.

  5. #44
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    Quote Originally Posted by mark beiser View Post

    No, just burp a little refrigerant through them like you would when hooking up any manifold and hoses.

    If you follow good practices when disconnecting from systems, you should never have more than a very thin film of oil residue in your manifold and hoses anyway.
    Assuming you use some sort of low loss fitting, at least on your high side hose, before disconnecting from a system crack the valves on your manifold open just enough to allow liquid refrigerant to bleed from the high side to the low side of the system through your manifold and hoses, then disconnect from the high side.
    Let the system pull the remaining liquid refrigerant out of your manifold and hoses, then disconnect from the low side.
    Do this every time you disconnect from a system and you will never have an accumulation of oil in your manifold and hoses.
    Ok... I've always had one question regarding bleeding over like that. So, I've hooked up, my low and high side are now pressurized. I close the ball valve on my liquid hose and let it pull back into the vapor line, what's to stop it from pulling the air out of the charging (center) hose as it does this?
    Ron

  6. #45
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    Quote Originally Posted by Ron223 View Post
    what's to stop it from pulling the air out of the charging (center) hose as it does this?
    There not being air in your center hose!
    If more government is the answer, then it's a really stupid question.

  7. #46
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    Quote Originally Posted by mark beiser View Post

    There not being air in your center hose!
    So are you filling it with liquid also before sucking it back in through the suction side?
    Ron

  8. #47
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    Quote Originally Posted by Ron223 View Post
    So are you filling it with liquid also before sucking it back in through the suction side?
    Vapor when hooking up to a system.
    When disconnecting, a few drops of the liquid fed from the low to the high side may dribble into the center hose before it flashes off.

    Since I have multiple sets of digitals, I use different sets for R-22 and R-410A, and keep a little refrigerant vapor pressure in my manifold and hoses, <30 psig.
    With my hose setup, I typically only have to purge the air out of a 6 inch hose on the low side, so only loose a miniscule amount of refrigerant connecting to and disconnecting from a system.
    If more government is the answer, then it's a really stupid question.

  9. #48
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    Quote Originally Posted by mark beiser View Post
    Vapor when hooking up to a system.
    When disconnecting, a few drops of the liquid fed from the low to the high side may dribble into the center hose before it flashes off.

    Since I have multiple sets of digitals, I use different sets for R-22 and R-410A, and keep a little refrigerant vapor pressure in my manifold and hoses, <30 psig.
    With my hose setup, I typically only have to purge the air out of a 6 inch hose on the low side, so only loose a miniscule amount of refrigerant connecting to and disconnecting from a system.
    I'm really not trying to give you a hard time personally, as I'm sure many guys do this. As its being explained, I'm just really having a hard time digesting this as being "according to best practices" as a term I hear used a lot. Which I'm also not clear where that term comes from... Where can I find something defining "best practices"? Or maybe it's just a general term for doing things? In such case I've always been told to use different gauges for different refrigerants. Even doing it as described, it seems inevitable there will be, given time, some cross contamination. This being the only thing keeping me from pulling the trigger on some SMAN4's. I would certainly like to be enlightened on the subject enough to feel comfortable using one manifold on multiple refrigerants.
    Ron

  10. #49
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    Been doing this since 1972, using procedures much like what Mark described. I have never had a problem with cross contamination. "YET"
    I do wonder though about the new oils. Not enough to worry about though. I also wonder when PVE oils will become the standard. Then we won't have to worry about that.

    Quote Originally Posted by Ron223 View Post
    I'm really not trying to give you a hard time personally, as I'm sure many guys do this. As its being explained, I'm just really having a hard time digesting this as being "according to best practices" as a term I hear used a lot. Which I'm also not clear where that term comes from... Where can I find something defining "best practices"? Or maybe it's just a general term for doing things? In such case I've always been told to use different gauges for different refrigerants. Even doing it as described, it seems inevitable there will be, given time, some cross contamination. This being the only thing keeping me from pulling the trigger on some SMAN4's. I would certainly like to be enlightened on the subject enough to feel comfortable using one manifold on multiple refrigerants.

  11. #50
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    Quote Originally Posted by Ron223 View Post

    I'm really not trying to give you a hard time personally, as I'm sure many guys do this. As its being explained, I'm just really having a hard time digesting this as being "according to best practices" as a term I hear used a lot. Which I'm also not clear where that term comes from... Where can I find something defining "best practices"? Or maybe it's just a general term for doing things? In such case I've always been told to use different gauges for different refrigerants. Even doing it as described, it seems inevitable there will be, given time, some cross contamination. This being the only thing keeping me from pulling the trigger on some SMAN4's. I would certainly like to be enlightened on the subject enough to feel comfortable using one manifold on multiple refrigerants.
    Two manifolds might be sustainable for a residential AC guy.

    A refrigeration guy, on the other hand...

    A typical day might see me working on anywhere from 2 to 5 or 6 different refrigerants.

    I've never had a problem with cross contamination by using the same manifold on over a dozen different refrigerants and 4 different oil types.


    Cross contamination is an over-blown fear given the actual amounts of refrigerant contained in your hoses. Think about it...

  12. #51
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    So for clarity, your purging vapor through your charging hose when you hook up, then bleeding your liquid side/charging hose back Into the suction side when your finished?
    Ron

  13. #52
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    Yeah what He said, I work on so many refrigerants. I do carry multiple sets of Gauges, But not really for different refrigerants, I have a set that I use on Prep Tables, A set for A/C work,and a set for remote refrigeration. Basically just different size Hose configurations and low loss fitting configuratons
    Quote Originally Posted by jpsmith1cm View Post
    Two manifolds might be sustainable for a residential AC guy.

    A refrigeration guy, on the other hand...

    A typical day might see me working on anywhere from 2 to 5 or 6 different refrigerants.

    I've never had a problem with cross contamination by using the same manifold on over a dozen different refrigerants and 4 different oil types.


    Cross contamination is an over-blown fear given the actual amounts of refrigerant contained in your hoses. Think about it...

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