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  1. #1
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    Best way to recharge system when not using manifold during evacuation??????

    When evacuating a full system after a repair, what is your preferred method to recharge with refrigerant when you are not pulling a vacuum through a manifold but with 1-2 big hoses directly connected to your vacuum pump.

    With a new system or evaporator side repair, it is pretty easy to valve off your evacuation rig, release the charge and then add what you need while it is running.

    I'm wondering what is the best way to add refrigerant when you are doing a compressor or condenser-side repair, and have to fully recover the system, without compromising vacuum or risk getting atmosphere into the system.

    The only two ways I can think of is to attach a hose connected to a manifold or directly to a refrigerant tank and to the side port of your valve core remover before you start pulling a vacuum. I've done this method. I purge the hose with refrigerant and the hose I use has a ball valve at the end, so i am pulling a vacuum on the fitting and have refrigerant directly behind the valve. This seems like a good way to do it but when my vacuum isn't going well I wonder if it is because that hose fitting isn't vacuum rated.

    The other method I can think of is to pull your vacuum, isolated the valves on your valve core removers, remove your vacuum hoses, connect a refrigerant tank to the liquid line side via a purged hose, open the ball valve on the hose to allow refrigerant into the valved off core tool and back the hose off a little to purge refrigerant through that small, blanked off space on the core tool to get the air out. Then open up the valve and charge the system.

    Would this be considered a proper way to add refrigerant to an empty system and not risk adding atmosphere into the system with refrigerant and destroying a deep vacuum?

    Is there a better way that I am not thinking of?

  2. #2
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    I shut the valves on my core removers.
    “I haven’t failed. I’ve just found 10,000 ways that won’t work.” - Thomas Edison

    “It’s not whether you get knocked down, it’s whether you get up.” - Vince Lombardi

    "In this house we obey the laws of thermodynamics" - Homer Simpson

    Local 486

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  4. #3
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    I hook two hoses to my pump and a third hose to the discharge line port and connect that to a cylinder. Pull a vacuum on everything and when the micron gauge is showing what I want I break the vacuum with the cylinder. Then I will add what I can, start the system and finish adding through the suction port...

  5. #4
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    I use a yellow jacket shut off valve connected directly to the side port of my Appion VCR, have not had an issue yet with the shut off valve not being able to hold vacuum or leaking, but that is something I am keeping an eye out for ..... I keep a DEDICATED shut off valve just for this purpose ....

    just remove the vacuum gauge and install the charging hose ...... OR, have a shut off valve on each VCR, one for the vacuum gauge, one to charge, that may be even better .......... I also use a yellow jacket shut off valve on my inverted tank to allow me to better meter the refrigerant into the system .....

    I mainly wanted the shut off valve so I could isolate my vacuum gauge from seeing a positive pressure but it also turned out to be a good way to break the vacuum / charge the system without introducing air / moisture .....
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    Last edited by hvacskills; 08-04-2018 at 10:42 AM.

  6. #5
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    If your using 2 big hoses, use the core removers from appion, close the balls valves after vacuum attach your manifold, break the vacuum with refrigerant, after you have positive PSI, 10-20, reinstall schrader pins, than continue charging.

  7. #6
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    Thread Starter
    Quote Originally Posted by psehunter View Post
    If your using 2 big hoses, use the core removers from appion, close the balls valves after vacuum attach your manifold, break the vacuum with refrigerant, after you have positive PSI, 10-20, reinstall schrader pins, than continue charging.
    That's pretty much exactly what I wrote. My question isn't how to do it. What I am wondering is if using that method you are adding atmosphere back into the system or if you can successfully purge that small space on your valve core tool.

  8. #7
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    Quote Originally Posted by Steve Max View Post
    That's pretty much exactly what I wrote. My question isn't how to do it. What I am wondering is if using that method you are adding atmosphere back into the system or if you can successfully purge that small space on your valve core tool.
    If the units in a vacuum, and you have the cylinder hooked up and that line is already prepurged with refrigerant, there is no small space with atmospheric pressure.im pretty sure that's what he just said and others said. That's the beauty of the shut off.

    Sent from my XT1710-02 using Tapatalk

  9. #8
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    Quote Originally Posted by Steve Max View Post
    That's pretty much exactly what I wrote. My question isn't how to do it. What I am wondering is if using that method you are adding atmosphere back into the system or if you can successfully purge that small space on your valve core tool.
    my guess is if you slowly screw your refrigerant hose onto the VCR while you are purging the refrigerant hose you would probably push almost all of the air / moisture out of the small space on the VCR with the refrigerant coming from the end of the hose .....

    your concern is valid, you do want to keep air / moisture introduced into the system to a minimum, however, part of the reason a liquid line filter drier is installed is to absorb any incidental moisture that might be introduced into the system, like in that instance .......

    your first method seems like the best approach, unless of course the ball valve at the end of your hose is leaking ..... thats why for my set up I keep a dedicated shut off valve for evacuating only, that way it does not get used as frequently as the other shut off valves because I am guessing over time they leak ..... maybe you could get another hose with a ball valve on the end that is dedicated for this purpose only that is used less frequently .....

    I prefer my method over connecting directly to the VCR ends because it is very quick connection, sometimes you have to wrestle disconnecting those 1/2 " Appion hoses so I eliminate the possibility of accidentally bumping a shut off valve or loosing a seal on one of the VCRs and ruining a few hours worth of work .....
    Last edited by hvacskills; 08-05-2018 at 09:11 AM.

  10. #9
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    Quote Originally Posted by JeffWil View Post
    If the units in a vacuum, and you have the cylinder hooked up and that line is already prepurged with refrigerant, there is no small space with atmospheric pressure.im pretty sure that's what he just said and others said. That's the beauty of the shut off.

    Sent from my XT1710-02 using Tapatalk
    I appreciate the responses. I don't think that is what he was saying but I understand the mechanics of it.

    I have seen videos of guys pulling a vacuum on a system after a compressor repair using 2 core tools and 2 large hoses and nothing else hooked up, i.e no 1/4" pre-purged hose with one end connected to a refer tank and the other to the side port of the core tool. So they have to be connecting a hose after they pull a vacuum but it doesn't show where they hooked the hose use to charge afterwards.

    If you pull a vacuum with no dedicated refrigerant hose connected prior to pulling a vacuum you have 2 ways to add in refrigerant after your vacuum is pulled. One would be to attach a hose to the side port of the core tool, which in my mind would add atmosphere back into the system as your hose depressed the valve core as you were connecting it. Correct me if I'm wrong, even if your hose has a shut off valve at the end of it and it is full of purged refrigerant, as you connect that hose to the valve on the side of your core tool your vacuum will draw atmosphere in as you connect it.

    The other way would be to valve the system off, remove your vac hoses and attach your refrigerant hoses to the ends of the valve core tools and add that way. I can definitely appreciate the aesthetics of a shut valve as much as the next tech, but if you add refrigerant this way there is a space filled with atmosphere between the end of your refrigerant hose (assuming you have a shut off valve at the end of it) and the valve core remover shut off. Maybe an inch, not a huge space but it has atmosphere. My guess is that you can purge this small space after you hook up your hose but I don't know that for sure. Maybe when you purge that space you just force air up against ball valve.

    I am interested in how other people add refrigerant on a manifoldless vacuum set up but my question isn't so much how to do it but more how to do it without compromising a vacuum and maybe more specifically how to not compromise a vacuum when you are connecting a hose(s) after pulling a vacuum, not prior.

    If using valve core removers and big vacuum hoses and measuring vacuum close to the system are proper service techniques to ensure a good vacuum, what is the best way to connect refrigerant hoses to your system after you have pulled a vacuum and not risk adding atmosphere back into the system? I know this question is irrelevant if you connect a hose prior to pulling a vacuum. I have seen videos where guys obviously had to do it after they pulled a vacuum and they seemed like guys who were interested in doing things right but the process of adding refrigerant back in was never discussed or shown. I find connecting a refrigerant tank to my setup as I'm pulling a vacuum leaves a lot going on in a sometimes small space so if I would be interested in connecting them after a vacuum is pulled if I could know I was doing it "right".

    "my guess is if you slowly screw your refrigerant hose onto the VCR while you are purging the refrigerant hose you would probably push almost all of the air / moisture out of the small space on the VCR with the refrigerant coming from the end of the hose ....."


    Thanks, I was wondering if that would be an acceptable way Hvacskills. Using a shut off fitting or hose with one on it for evacuations only is a good suggest. I've just grabbed a hose with one on it off my manifold to use when I've needed it and I can see how that probably isn't the best practice if I want to reduce the chance of it being a leak point.

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  12. #10
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    That little space where the valve core sits before opening the VCRT? Just purge the hose like normal.
    How do you hook up a hose to a system with no core tools? What about that open space around the Schrader pin? Haha.

  13. #11
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    If you want to be super picky about any atmosphere, use a third appion valve core remover like I do. My micron meter is connected to the third tools side port for vacuum, then when I'm finished I valve off the system, remove my hoses and meter, purge my charging hose and then you
    can purge the third appion tool as well.

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  15. #12
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    Good thread. I’ve been wondering the same thing for a little bit now. My plan (when I pony up the money for it) is buy a 1/4” vac rates hose and put a depressor in the end. Then pull the vacuum with that hose connected to the side port of vcrt and refer tank. I use the bluvac so it’s fine if I leave it on the other vcrt until the vacuum is broken. I know this was already mentioned but just my 2 cents

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  17. #13
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    Quote Originally Posted by Steve Max View Post
    Thanks, I was wondering if that would be an acceptable way Hvacskills. Using a shut off fitting or hose with one on it for evacuations only is a good suggest. I've just grabbed a hose with one on it off my manifold to use when I've needed it and I can see how that probably isn't the best practice if I want to reduce the chance of it being a leak point.
    then you might like this idea too .... I have 2 Appion VCRs and 2 Yellow Jacket VCRs ..... I use the Yellow Jacket VCRs strictly for valve core removal / replacement and for recovery, I use the Appion VCRs strictly for evacuating since I dont want to wear out the Appions and I want to be able to rely on them ..... I store everything in these little cloth sack pouches I bought off fleabay so they dont get dirty, I dye colored the sack pouches to make them easier to identify whats inside and so the sack pouches dont look as dirty .....

    also, the reason I have my vacuum gauge on the end of a vacuum rated hose is to help prevent the gauge from becoming contaminated with oil, I special ordered a st st connector hose that is dedicated just for that hook up .....

    in case you are wondering, the sack clothes are ABOUT 3 " x 4 1/2 " ... not sure how much they shrunk ...
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    Last edited by hvacskills; 08-05-2018 at 11:13 AM.

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