Page 1 of 4 1234 LastLast
Results 1 to 20 of 62

Thread: FIGURE OUT the Microns

  1. #1
    Join Date
    May 2021
    Posts
    24
    Post Likes

    Hmm FIGURE OUT the Microns

    I am trying to grasp how much moisture is in the system so I can determine where I think its coming from either Materials or oil or water Basically so i can convince myself that its OK to stop pulling the vacuum.

    "When they say"... 1 micron is 25,400 of an inch in the water column is that a literate measurement
    of what is in the system??? ( no clue)

    Hypothetically, If I am pulling 1100 mics for days and I know that when I reach 1000 basically all moisture is gone, I would be safe to assume that 100 mics of moisture is in material, right?
    Sooo, how much is 100 mics of moisture 1 teaspoon, 1 spec of water/oil?

  2. Likes millerpl liked this post.
  3. #2
    Join Date
    Jul 2019
    Location
    Oklahoma home its in the name
    Posts
    7,679
    Post Likes
    I don't know the answer to your question although I'm pretty sure there isn't really an answer.
    If it's taking that long to pull down I can only think of three reasons. Either it's seriously wet and you're removing a lot of water and in that case you should know because you're changing your vacuum pump oil over and over and over and it's milky or your vacuum pump and/or micron gauge is shot or maybe you've got a leak.

    Sent from the Okie state usin Tapatalk

  4. Likes ksefan liked this post.
  5. #3
    Join Date
    Jul 2013
    Location
    Richmond, VA
    Posts
    5,795
    Post Likes
    A micron is a measurement of air pressure (very, very, very tiny amount of air pressure). It's not a measurement of moisture.

    If you stop pulling a vacuum at say 1,000 microns and it starts rising and stalls, there's a good chance there's still moisture in the system. If it rises and keeps rising to atmospheric pressure, there's a leak.
    Everything Im going to say today are my conclusions and my opinions, my opinions are based on my education, my training, my experience. Different people have different experiences, so they have different opinions and I make no claim that my opinion has its origin in the mind greatness. - Paul Harrell

  6. Likes R600a, dieseldude, Zamoramax, artisancorp liked this post.
  7. #4
    Join Date
    Oct 2011
    Location
    Harrisburg, NC
    Posts
    1,534
    Post Likes
    I was in the middle of a conversation about microns a while back.

    If you cannot pull under 1000:

    1. You are pulling through your manifold and it leaks.

    2. There is a leak in the system

    3. There is moisture in the system.

    That being said. Let's start with the "inches of water column".

    Imagine a 1/4" clear glass tube with a bend, like a "J". The bottom of the "J" is full of water. If you apply a bit of pressure to the short part of the "J", the water will rise up the long side. When you apply enough pressure to raise the water in the long side 1 inch, that's 1"wc.

    It's a tiny measurement of pressure.

    Microns, if I remember correctly is basically a measurement of pressure between 29 and 30"hg (mercury)

    Made me realize... Inches WC is for pressure, has nothing to do with vacuum. Sure you didn't mean inch mercury?

    Now. As far as the micron issue, did you have moisture in the system prior or think you do?



    Sent from my remote link to R2D2 using Tapatalk

    I can't fix it if it won't stay broke..

  8. Likes R600a liked this post.
  9. #5
    Join Date
    Jul 2019
    Location
    Oklahoma home its in the name
    Posts
    7,679
    Post Likes
    OP I thought I should let you know to expect some ribbing over your screen name because usually when we refer to a hack we are referring to someone who installs things incorrectly or does sloppy work.
    Welcome to the forum. There is a ton of information here to help you on your way to becoming a better tech and it's a really great bunch of guys once you get to know them and probably the largest group of collective knowledge in the industry.

    Sent from the Okie state usin Tapatalk

  10. #6
    Join Date
    May 2021
    Posts
    24
    Post Likes
    Thread Starter
    Quote Originally Posted by BadDaddy420 View Post
    As far as the micron issue, did you have moisture in the system prior or think you do?



    Sent from my remote link to R2D2 using Tapatalk
    Yes definitely, Installed this unit last year, discovered a bad braze that had the dried sooty residue,95% r410a was gone. My understanding is...If it leaks out, moisture comes in.

  11. #7
    Join Date
    Jan 2012
    Location
    Missouri, USA
    Posts
    2,204
    Post Likes
    If it is still under any pressure above atmospheric, moisture should not get in. Unless the leak is in the section of the system running in a vacuum.

  12. Likes R600a liked this post.
  13. #8
    Join Date
    Oct 2011
    Location
    Harrisburg, NC
    Posts
    1,534
    Post Likes
    Quote Originally Posted by AC Hacker View Post
    Yes definitely, Installed this unit last year, discovered a bad braze that had the dried sooty residue,95% r410a was gone. My understanding is...If it leaks out, moisture comes in.
    A note about 410a I read.

    You are not completely moisture free until you are under 500microns. The moisture and refrigerant will create an acid. I'll have to look later and find it.

    So, this was on the suction line I am assuming? I don't know why mfr's, excuse me manufacturers, don't put LP controls on all units. I feel like the cost of the switch would be cheaper than all the warranty.

    Anyway. First things first.

    Did you do a standing nitrogen pressure test after fixing the leak?

    Have you tried a triple evac? (Vac/break with nitrogen/vac/break/vac).

    The tiny bits of moisture can freeze in a vacuum. Part of the triple evac process is to thaw that bit of ice so you can pull again.



    Sent from my remote link to R2D2 using Tapatalk

    I can't fix it if it won't stay broke..

  14. Likes R600a liked this post.
  15. #9
    Join Date
    Oct 2011
    Location
    Harrisburg, NC
    Posts
    1,534
    Post Likes
    Inch of mercury (inHg and ″Hg) is a unit of measurement for pressure. It is used for barometric pressure in weather reports, refrigeration and aviation in the United States.
    It is the pressure exerted by a column of mercury 1 inch (25.4 mm) in height at the standard acceleration of gravity.

    In
    air conditioning and refrigeration, inHg is often used to describe "inches of mercury vacuum", or pressures below ambient atmospheric pressure, for recovery of refrigerants from air conditioning and refrigeration systems, as well as for leak testing of systems while under a vacuum, and for dehydration of refrigeration systems. The low-side gauge in a refrigeration gauge manifold indicates pressures below ambient in "inches of mercury vacuum" (inHg), down to a 30 inHg vacuum.

    Micron is a unit of measurement starting from a perfect vacuum (no pressure) that is expressed in linear increments. One inch= 25,4000 microns thus one micron= 1/25,400 of an inch. When discussing vacuum in terms of microns, this refers to total ABSOLUTE pressure as opposed to GAUGE pressure.

    So, for every micron above absolute zero is 1/25,400ths of an inch, which is a unit of length, in this case a 1/25,400ths Inches Mercury.

    And lookie what I found!

    If you look at the patterns, you can see why you cannot tell microns of a system by a manifold guage.

    Name:  Micron Chart.png
Views: 321
Size:  31.1 KB

    I can't fix it if it won't stay broke..

  16. #10
    Join Date
    Oct 2011
    Location
    Harrisburg, NC
    Posts
    1,534
    Post Likes
    Nice article by AccuTools on evacuations.

    https://accutools.com/how-long-shoul...cuate-a-system

    I can't fix it if it won't stay broke..

  17. #11
    Join Date
    Oct 2011
    Location
    Harrisburg, NC
    Posts
    1,534
    Post Likes
    Also, I keep seeing questions on the forum about the gas ballast on a pump.

    https://www.vacuumscienceworld.com/b...mp-gas-ballast

    Sent from my remote link to R2D2 using Tapatalk

    I can't fix it if it won't stay broke..

  18. #12
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
    32,932
    Post Likes
    Test your pump.
    Take a recovery tank and hook up your vacuum rig and pump. Should hit500 within 15 minutes

  19. Likes R600a liked this post.
  20. #13
    Join Date
    Oct 2011
    Location
    Harrisburg, NC
    Posts
    1,534
    Post Likes
    Quote Originally Posted by pecmsg View Post
    Test your pump.
    Take a recovery tank and hook up your vacuum rig and pump. Should hit500 within 15 minutes
    Oh yeah, and #4, your vacuum pump isn't performing (old oil, worn pump)



    Sent from my remote link to R2D2 using Tapatalk

    I can't fix it if it won't stay broke..

  21. Likes R600a liked this post.
  22. #14
    Join Date
    Sep 2016
    Posts
    42
    Post Likes
    Changing oil in your vacuum pump frequently is important. I've suspected leaks before, and it was just old oil. If that doesn't help you have a leak in your gauges, or in your system. Or you need a new pump.

  23. Likes R600a liked this post.
  24. #15
    Join Date
    Jan 2020
    Location
    Winnipeg Canada
    Posts
    1,169
    Post Likes
    I'll chime in a bit here. Holding below 500 means the system is absolutely dry.
    Getting to an ACTUAL 500 on a system that's been in service is very difficult.
    Refrigerant mixes with oil. And the Refrigerant will also be UNDER the oil in a system that's been used.
    Hitting the system a bunch of times with nitro when you stall on microns from THE OPPOSITE side you are vacuuming from can get you there.
    However, with a used system I'm generally happy with 1500 microns and a new dryer.
    At 1500 it's basically a system with zero leaks.
    Now the above only applies to a system that hasn't been running in a vacuum.
    If it's been running in a vacuum then a full compressor oil change and 500 microns hold is required
    You don't squat with your spurs on.
    And you NEVER put the torches away before pressure testing.

  25. #16
    Join Date
    Oct 2011
    Location
    Harrisburg, NC
    Posts
    1,534
    Post Likes
    Quote Originally Posted by Restaurant mech View Post
    I'll chime in a bit here. Holding below 500 means the system is absolutely dry.
    Getting to an ACTUAL 500 on a system that's been in service is very difficult.
    Refrigerant mixes with oil. And the Refrigerant will also be UNDER the oil in a system that's been used.
    Hitting the system a bunch of times with nitro when you stall on microns from THE OPPOSITE side you are vacuuming from can get you there.
    However, with a used system I'm generally happy with 1500 microns and a new dryer.
    At 1500 it's basically a system with zero leaks.
    Now the above only applies to a system that hasn't been running in a vacuum.
    If it's been running in a vacuum then a full compressor oil change and 500 microns hold is required

    I've had leaks on a 1500 micron pull.

    Never under 1000.

    Sent from my remote link to R2D2 using Tapatalk

    I can't fix it if it won't stay broke..

  26. #17
    Join Date
    Jan 2020
    Location
    Winnipeg Canada
    Posts
    1,169
    Post Likes
    Quote Originally Posted by BadDaddy420 View Post
    I've had leaks on a 1500 micron pull.

    Never under 1000.

    Sent from my remote link to R2D2 using Tapatalk
    Where were you measuring the microns? If you're measuring on the same side you're pulling then it's NOT 1500 microns
    You don't squat with your spurs on.
    And you NEVER put the torches away before pressure testing.

  27. Likes R600a liked this post.
  28. #18
    Join Date
    Jul 2019
    Location
    Oklahoma home its in the name
    Posts
    7,679
    Post Likes
    Quote Originally Posted by Restaurant mech View Post
    Where were you measuring the microns? If you're measuring on the same side you're pulling then it's NOT 1500 microns
    My boss used my blu vac kit one time and he couldn't get the valve core out but he still used the valve core remover and he was just amazed at how fast it got down to 100 microns.

    Sent from the Okie state usin Tapatalk

  29. Likes Lahrs liked this post.
  30. #19
    Join Date
    Jan 2020
    Location
    Winnipeg Canada
    Posts
    1,169
    Post Likes
    So measuring from the same side as pulling?
    If you're measuring from the opposite side you'll actually have a true micron reading. Then no need to wait for decay
    You don't squat with your spurs on.
    And you NEVER put the torches away before pressure testing.

  31. Likes R600a liked this post.
  32. #20
    Join Date
    Oct 2011
    Location
    Harrisburg, NC
    Posts
    1,534
    Post Likes
    Quote Originally Posted by Restaurant mech View Post
    Where were you measuring the microns? If you're measuring on the same side you're pulling then it's NOT 1500 microns
    I always have a micron in the middle of th pull.

    Eg. Pulling from suction and discharge headers and my micron guage is on the liquid header.

    A 17cfm duoseal on a 100+ hp rack with (3) 1/2"

    Couldn't get below 1500 microns after a conversion and had to get it going. Get some pressure in it and there's going to be a leak. Somewhere.

    And there was.

    1000 is leak free

    500 is moisture free

    Anything else below 500 is a bonus to be proud of.



    Sent from my remote link to R2D2 using Tapatalk

    I can't fix it if it won't stay broke..

Page 1 of 4 1234 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •