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  1. #1

    How to fill my dial a charge cylinder?

    I saw a guy using a dial a charge, charging cylinder. I do alot of critically charged stuff, so I bought one. How do I fill this thing, the instructions tell how, but it leaves a few open questions like do I need to pull a vacuum on it first or no. I bought it used, but it still appears new. I called Robinair who makes it, and they told me if I can, to do it, well im thinkin why couldnt I? And also if I dont pull a vacuum on it, wont that put air in my system upon charging it, or am I missing something in the way it works. Then after I empty the cylinder of its refrigerant, will I have to pull a vacuum on it again to use it a second time? Im a little confused on it, as I have only ever used my digital scale, but am sorta eager to use this device I now have. And one last question hypathetically, if I fill it to like say 8 oz, and then I turn on the heater in it, it expands to 10oz now, would I put the full amount in the my system if I needed 8oz of refrigerant even though it now says ten, or would I put still only 8 in and stop the filling with two left in the cylinder. This is sorta confusing me. Im guessing all of the charge in the cylinder because even though the volume increased it was still only 8 from the start RIGHT?

  2. #2
    Join Date
    Jan 2004
    Location
    Location: Tulsa Oklahoma
    Posts
    222
    That is a perfect museum piece. Best put it up and go purchase a high quality
    digital scale for that critical charging.
    Whoa Maynard - that's not how it works.

  3. #3
    Join Date
    Jul 2008
    Location
    Southern California
    Posts
    138
    Yes, you should pull a vacuum on it whenever there is a chance that non-condensibles contaminated the cylinder. Eight ounces is eight ounces, by heating it you just increased the volume by changing some of the liquid molecules to vapor. We converted over to digital scales, there easier and not as bulky.

  4. #4
    Join Date
    Mar 2006
    Location
    New Zealand
    Posts
    300
    Don't think it will be much use to you as I imagine the graduations will be for R12, R22 and R502. You would need to have a formula to calculate the volume variation for other refrigerants.

    Pull a vacuum on the cylinder, charge by liquid form from your tank.
    Depress the shrader valve on top to let vapour out and liquid in to the desired level.
    Note the pressure on the top mounted gauge and turn the outer shield to match that reading. This caters for the volume change at various pressures.

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,741
    Haven't used one of them since the 80s.

    They aren't as easy or nice for charging as you may think.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  6. #6
    Join Date
    Aug 2002
    Location
    Louisville
    Posts
    283
    I use one at the school to demonstrate to students just how little space 8 oz of refrigerant occupies and also how much 8 oz can change system performance. After the once a year demonstration it goes back into the vault.

  7. #7
    Join Date
    Mar 2006
    Location
    OK
    Posts
    2,144
    EPA rules against venting refrigerant apply to those also. You have to recover any left in it.
    Never knock on Death's door. Ring the bell and run, he hates that.

    Views expressed here are my own and not neccessarily those of any company I am affiliated with.

  8. #8

    Thanks

    You guys are killing me, museum piece LOL. I really liked the idea of having this thing, looks very chemistry class like, I think mainly because you can see the refrigerant. The one I have has the shroud that dials the volume so its easy to use, I just had a few questions about it, we didnt even discuss this tool much in HVAC school. I was collecting muscle cars for a little while, should I put this dial a charge with my meter that I use to set the "ignition detent" LOL. Whens the last time you heard that term LOL. Thanks alot for your help guys.

  9. #9
    Join Date
    Nov 2004
    Location
    Skokie , IL near chicago
    Posts
    1,126

    Talking measuring charges

    Quote Originally Posted by amanda11270 View Post
    You guys are killing me, museum piece LOL. I really liked the idea of having this thing, looks very chemistry class like, I think mainly because you can see the refrigerant. The one I have has the shroud that dials the volume so its easy to use, I just had a few questions about it, we didnt even discuss this tool much in HVAC school. I was collecting muscle cars for a little while, should I put this dial a charge with my meter that I use to set the "ignition detent" LOL. Whens the last time you heard that term LOL. Thanks alot for your help guys.
    Love your name as it's my great little grandaughters name (little? she's 13 & taller than me) , anyway if you start using a digital scale you'll just love it. you'll get done in 1/2 the time & no venting. haven't used mine in 20 years. Regards.........Jack

  10. #10
    Join Date
    Jun 2005
    Posts
    14
    I show the dial a charge in school. I used one all the time before digital scales. Most important that you have metal case to store unit in or you will destroy it in the truck. Also if venting refrigerant vapor from top of cylinder in order to fill, EPA regulations say you must recover and not vent to atmosphere

  11. #11
    Join Date
    Jul 2005
    Location
    Tulsa
    Posts
    281
    got one too... sitting un-used in it's metal box.

  12. #12
    Join Date
    Mar 2007
    Location
    A Lan Far, Far Away in Podunk, Georgia
    Posts
    234
    the "ignition detent" LOL
    I STILL have one of those vehicles you have to (gasp) set the DWELL on the POINTS. Yes, it has an "Antique Vehicle" tag on it, LOL.
    Those old Kettering ignition systems have went the way of the dinosaur, thank God.

    Digital scale... the only way to fly these days for measured refrigerant charge.

  13. #13
    Sorry for the late addition to this thread, just had to mention...

    I was wandering through the dark hallways of youtube and came across a video that showed one of these things being used. I'd never seen one before. I thought it looked interesting. I couldn't find much info online, not even a user manual from Robinair (Yeah, bad sign). I found a few places still selling them for, wait for it, $450.00(!!!!!) However, I found a guy selling one on ebay with a starting bid of $30, that no one had bid on yet. Sure, what the heck, I thought.

    Did some more research and found that the one on ebay must be an older one since it a.) doesn't have a case, b.) doesn't have a heater, and c.) is only calibrated for R22.

    And then I found this thread. Thanks guys!!! I'm off to cancel my bid.

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