Results 1 to 10 of 10
  1. #1

    vacuum gauge testing

    heres an odd question. been doing this along time so please understand my problem. I HAD 2 micron gauges ( 3 now ). i decided i should check mine cause there getting old. so i threw them on my pump and pulled a 100+ micron vac and let sit ( only gauges and pump ) and micon climbed. I thought ok there old and maybe not tight.... bought a new one....same thing happend. honestly tried 8 hoses. 3 NEW i just bought with ball valves. So tried just one hose right from gauge to pump..took manifold out. same thing. pull under 100 micons but when valved off, quickly rise to 1200 micons and sit. i know it sounds odd. A friend said lets test with his, cause he never has problems. different pump,hoses,gauges,and his micron gauge. same outcome. we both never checked a micron gauge this way. got to the point it was a 6" hose off pump with a ball valve directly off of micon gauge..... still after isolated from the vacuum it would raise to 1200 to 1400 and sit. now this is 4 micon gauges one is brand new! first time used. can anyone tell me if they have had problems or have info of something i missed.... thank you

  2. #2
    Join Date
    May 2012
    Location
    Asheville, NC
    Posts
    30
    Are the ball valves vac rated ? Try the Appion VCRT as a shutoff valve. Also, could the hose been off gassing ? Do you have a way to connect direct to pump with metal only, no hose at all ? One last idea.... were you using the pump isolation valve to isolate the guage? They are known to be leakers according to other threads I have read here. Chain the three guages up together and compare their readings at the same time.
    Rick

  3. #3
    Join Date
    Jun 2008
    Location
    Rochester, NY
    Posts
    340
    Quote Originally Posted by Checksinmail View Post
    heres an odd question. been doing this along time so please understand my problem. I HAD 2 micron gauges ( 3 now ). i decided i should check mine cause there getting old. so i threw them on my pump and pulled a 100+ micron vac and let sit ( only gauges and pump ) and micon climbed. I thought ok there old and maybe not tight.... bought a new one....same thing happend. honestly tried 8 hoses. 3 NEW i just bought with ball valves. So tried just one hose right from gauge to pump..took manifold out. same thing. pull under 100 micons but when valved off, quickly rise to 1200 micons and sit. i know it sounds odd. A friend said lets test with his, cause he never has problems. different pump,hoses,gauges,and his micron gauge. same outcome. we both never checked a micron gauge this way. got to the point it was a 6" hose off pump with a ball valve directly off of micon gauge..... still after isolated from the vacuum it would raise to 1200 to 1400 and sit. now this is 4 micon gauges one is brand new! first time used. can anyone tell me if they have had problems or have info of something i missed.... thank you
    You will always have that problem pulling on just hoses and a micron gauge. You'll never get it to hold a deep vacuum. The hose is so small that any contamination or anything left in the hose (moisture, etc..) that when breaking free and touching your micron gauge has a big impact on the gauge.
    Plus your using hoses that aren't really supposed to be used for a vacuum. They permeate (air can transfer from outside to inside the hose when in a vacuum.)

    -Mark
    RSES CM Member
    NCI Certified Air Balancer and CO/Combustion Analyst
    NATE Senior technician - Energy efficiency analyst and 7 other NATE Service certifications

    Never stop learning!

  4. #4

    checking micron gauge

    Could you tell me the process you use for checking your micron gauge for leaks? If coming right off pump is a bad idea, what process could be used to check the gauge only for leaks? thank you

  5. #5

    Rick

    Yes Rick i did run three microns together and all read close to eachother with the same rise in microns when left alone. As far as the shut off i used the 6" hose with ball valve, the 5' brand new ball valved hose, and ran straight brass fitting from gauge to pump and tested each alone on pump. the only time i used the vac pump shut off was after i went through all the hosed valves. It didnt matter what way i did it ( gauges alone, series, hoses, ect. ) each time had same outcome. pulled around 150 microns then valve off- meter would quickly climb to 1000-1200 microns and seem to level off 1200 to 1450 microns. If i am checking the wrong way i'd just like to get the correct way of checking. thanks

  6. #6
    Thanks Mark, I didnt know normal hoses did that.

  7. #7
    Join Date
    Jun 2008
    Location
    Rochester, NY
    Posts
    340
    As long as you see that your pulling a low vac and your gauge is reading it that's fine and it means that your pump is also pulling a low vacuum. After you turn your pump off It will rise and eventually level off. If it keeps rising and rising and never levels off you have a leak in your hose.

    I would also apply for pro membership on this site so you can discuss diagnostics in full.

    -Mark
    RSES CM Member
    NCI Certified Air Balancer and CO/Combustion Analyst
    NATE Senior technician - Energy efficiency analyst and 7 other NATE Service certifications

    Never stop learning!

  8. #8
    Join Date
    Sep 2007
    Location
    State College, PA
    Posts
    1,095

    Why not try this ...

    Quote Originally Posted by Checksinmail View Post
    Yes Rick i did run three microns together and all read close to eachother with the same rise in microns when left alone. As far as the shut off i used the 6" hose with ball valve, the 5' brand new ball valved hose, and ran straight brass fitting from gauge to pump and tested each alone on pump. the only time i used the vac pump shut off was after i went through all the hosed valves. It didnt matter what way i did it ( gauges alone, series, hoses, ect. ) each time had same outcome. pulled around 150 microns then valve off- meter would quickly climb to 1000-1200 microns and seem to level off 1200 to 1450 microns. If i am checking the wrong way i'd just like to get the correct way of checking. thanks
    Pull a vacuum on an empty recovery tank. You have 2 connections and you can use the one connection to pull the vacuum and the other one you can connect your micron gauge.

    When you get the vacuum down to where you want to test, close off the 2 valves on the recovery tank. That way you are not testing through your hose. Then you can pull your vacuum again and close off your manifold gauge and see the difference. I am sure you get the picture.

    Please report back to us the results you get.

    Thank You!
    Can someone please explain to me -
    Why is there never enough time to do it right the first time, but plenty of time to do it twice?


    Please view site rules: http://hvac-talk.com/vbb/showthread.php?t=1241

    Apply for Pro Membership: http://hvac-talk.com/vbb/showthread.php?t=116113

    Find your local HVAC-Talk Contractor: http://icemeister.net/aop_map.html

  9. #9
    Just letting you guys know i tried a few things. Found microns do climb a bit when letting sit on a system with some size but will level off if no leaks. if a vaccum is pulled again it seems to level off at a faster rate, and so on. On a smaller size ( reclaim tank ) it will hold micron level very fast. what ive found is an extremely small test area ( like micron gauge right off pump or just manifold and micron gauge ) deep vac will happen very fast but greater micron climb before leveling off. Learned from this, just dont test your micron meter on an extremely small test area. Thanks for your input

  10. #10
    Join Date
    May 2012
    Location
    Asheville, NC
    Posts
    30
    Been seeing the same things you describe......
    Micron climb stops quicker on multiple pull downs.

    Very small spaces are very sensative to any leakage or off gassing.

    I think part of the problem of very small spaces is the lubricant on the shut off device is outgassing. I have found that if I mount the shut off directly to the pump and the guage directly onto the ball valve, it will pump down easily to 15-20 microns. Close the valve and it may shoot back to 1000 microns and drift up from there. Pull it back down to 15-20 microns, and let it run there for 5 minutes and when the valve is closed it might jump to 100 and then drift up.
    Leave it at 15-20 micons for 30 minutes and when the valve is closed it jumps to maybe 50 microns and very slowly drifts up from there.
    Work the valve back and forth a bit while the pump is running and the micron reading jumps up a bit. I have heard folks claim that air is trapped in the valve and moving the valve breaks the air loose. Maybe, but if you leave it under vac with the pump running and then move the valve again, the micron level rises again. Where did it get more air ? I think, it is moving the lubricant and releasing new vapors.

    Hoses kept under deep vac overnight, seem to pump down much quicker next day. Anybody else seeing this ?

    Rick

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event