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CO2 in the fridge - are readings accurate?

Discussion in 'Bottling/Kegging' started by wantonsoup, Nov 15, 2016.

 

  1. #1
    wantonsoup

    Well-Known Member

    Posted Nov 15, 2016
    So I found quickly not to panic when checking on the CO2 tank the next day after a refill - the temperature made the regulator think it was much less full than it was. That makes sense to me.

    My question is - does the PSI gauge on the outlet also need to be adjusted for temperature? Here's what mines looks like with a full tank:

    [​IMG]

    I'm trying to do a normal serving pressure of around 12-13 psi. Am I there? Or do I need to adjust because the tank and regulator are at 38F ? Thanks!
     
  2. #2
    day_trippr

    We live in interesting times...

    Posted Nov 15, 2016
    The low pressure gauge will be accurate in spite of being chilled in the fridge.
    So, right now the CO2 pressure is set to ~11.5 psi. If you're going for 12, you need to nudge it up.

    As you surmised, the high pressure gauge reflects the cylinder pressure as a function of fill and temperature...
    [​IMG]

    Cheers!

    [edit] "upon further review" ;) I agree, you're already at 13 psi.
     
  3. #3
    Yooper

    Ale's What Cures You! Staff Member  

    Posted Nov 16, 2016
    It's at 13 psi right now (each like is 2), so it's fine.

    The high pressure regulator is pretty useless- it'll stay where it is until the gas is almost completely gone and then it'll drop to 0 in a few minutes. The way to see how much gas you have is to weigh the tank. Co2 is a liquid, dispensed as a gas, so the psi on your regulator to your tank is correct (reading the psi of the gas).
     
    Gravity likes this.
  4. #4
    Jaybird

    Sponsor  

    Posted Nov 16, 2016
    Absolutely! Each tank has a tare weight stamped on the tank. just weigh the tank (WITHOUT THE REGULATOR) and you can see EXACTLY how much liquid you have left.

    Cheers
    Jay
     
  5. #5
    wantonsoup

    Well-Known Member

    Posted Nov 16, 2016
    Thanks guys. I have a small 50lb scale I don't use so maybe i'll just leave it under the tank 24/7 :)
     
  6. #6
    LearningBeer

    New Member

    Posted Jul 5, 2017
    I'm new on the board and wanted to try and contribute something. In the op it was asked about checking the psi the day after a refill. This may or may not apply but if the c02 is filled into the bottle quickly it will heat up and show a higher psi. Once it cools the psi will drop to the actual psi. At least that is what happens when a breathing air bottle is filled. But may not apply at all with co2 if someone would like to correct me fyi.
     
  7. #7
    day_trippr

    We live in interesting times...

    Posted Jul 5, 2017
    No, that's not how things work.
    A CO2 tank is filled with liquid CO2 and will be incredibly cold for hours after a fill...

    Cheers!
     
  8. #8
    LearningBeer

    New Member

    Posted Jul 5, 2017
    Great thank you I was not sure how it worked.
     
  9. #9
    day_trippr

    We live in interesting times...

    Posted Jul 5, 2017
    Don't want to leave a false impression, but the actual reason why a freshly filled CO2 cylinder will be frosty is to fill the tank completely it has to be repeatedly bled. It's the bleeding that creates the cold, not the actual liquid CO2 going into the cylinder.

    Air tanks filled directly from a compressor will indeed go the other direction due to the heat of compression...

    Cheers!
     
  10. #10
    LearningBeer

    New Member

    Posted Jul 6, 2017
    Makes sense thank you
     
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