pulling a vacuum
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  1. #1
    Join Date
    Apr 2006
    Posts
    7
    How many of you technicians use a micron gage when pulling a vacuum on a residential units? I'm a student taking air-conditioning technology at WCTC, and they teach that you need to use a micron gage. I would like to know whether the technicians out in the field actually use micron gages or whether they just leave the vacuum pump running for so long. Any comments about this matter would be appreciated.

  2. #2
    Join Date
    Jun 2004
    Location
    Howell, Michigan
    Posts
    16,168
    Everyone that works for me uses a micron guage.

  3. #3
    Join Date
    May 2004
    Location
    Rapid City, SD
    Posts
    7,414
    Every good tech uses one, no matter what. That said I know there are likely more tech's not using them than are, but it's small steps like using one that will seperate you from the rest of the crowd.

    So many guys I know say "if the gauge goes down to -29 it's good enough)... heck the micron gauge would just be thinking about taking over at that reading.

    In short, a micron gauge may take an extra couple seconds to hook up, but in the long run it will always save you time and money.
    "If you call that hard work, a koala’s life would look heroic."

  4. #4
    Join Date
    Oct 2004
    Location
    PDX
    Posts
    4,917
    I alway use one, Now having said that, I'll second what Amick said. There are probably more techs and installers out there that do not use one. Some guys (and gals) will say stuff like, "I let it run for 45 min, and thats good enough!".. But take a look around, these are the same guys that charge units by "the split" or "beer can cold"...

    I can summise it up pretty good; Not using a Micron gauge is like driving your car at night with out the lights on. You just can't see where you are driving. Same goes for inside the system. Without the gauge, you have no idea what is happening inside the system under vacuum. You don't know if you have removed all the moisture or if there is a leak, just to mention a few things, and not to mention providing an inferior install or repair for your customer.

  5. #5
    Join Date
    Apr 2006
    Posts
    7
    Thanks guys for the information on that.

  6. #6
    Join Date
    Nov 2000
    Location
    Upstate, SC
    Posts
    2,919
    I tell the guys that question me about my micron gauge that you will never understand how important it is until you use one. For years, I didn't know any better and just watched my gauges like I had seen everyone else doing, until I had some extra money in my pocket one day and seen a shiny new micron gauge right there in the display case. I bought it and tried it out the next day. I couldn't get that thing to pull down at all, but yet, my gauge was dead on 30 inches of vacuum. I worked and worked to get my gauges and hoses leaktight and then realized my pump wasn't working correctly. I sent it in for repairs and things went much better after that, but I often wondered how long I had been hooking it up and doing nothing. That was probably 12 or so years ago and I have used a micron gauge since. Just two weeks ago, I had a system that wouldn't pull below 100,000 on my micron gauge. I kept at it until I found a tiny leak in the unit that I would have never even known was there without the micron gauge.

    Bobby

  7. #7
    Join Date
    Sep 2005
    Location
    maui
    Posts
    389
    Quote Originally Posted by BobbyBJr View Post
    I tell the guys that question me about my micron gauge that you will never understand how important it is until you use one. For years, I didn't know any better and just watched my gauges like I had seen everyone else doing, until I had some extra money in my pocket one day and seen a shiny new micron gauge right there in the display case. I bought it and tried it out the next day. I couldn't get that thing to pull down at all, but yet, my gauge was dead on 30 inches of vacuum. I worked and worked to get my gauges and hoses leaktight and then realized my pump wasn't working correctly. I sent it in for repairs and things went much better after that, but I often wondered how long I had been hooking it up and doing nothing. That was probably 12 or so years ago and I have used a micron gauge since. Just two weeks ago, I had a system that wouldn't pull below 100,000 on my micron gauge. I kept at it until I found a tiny leak in the unit that I would have never even known was there without the micron gauge.

    Bobby
    what sucks for home owners is barely any installers use one so from day one the systems going down hill
    Last edited by ryand; 09-21-2007 at 10:44 PM.

  8. #8
    Join Date
    Sep 2005
    Location
    maui
    Posts
    389
    I have always used a micron gauge but just recently bought a Y.J. two valve manifold with the 3/8th to 1/4 hoses and schrader core removers and it is one of the best investments i have made! not only did it pump down fast i pulled a residential 4 ton system down to 140 microns and held it at 168. I dont know about you guys but i have never gotten lower than 400 microns. the Y.J. part number for the kit is 93865 and its worth its weight in gold

  9. #9
    Join Date
    Jun 2005
    Location
    Near Chicago, IL
    Posts
    3,317
    I have also had difficulty getting and maintaining 500 microns and below.

    That started to change once I ditched the standard 3/8 charging/vacuum hose for one of those Goodyear Galaxy barrier hoses.

    I also noticed a change when I switched to Refco charging hoses with the quick connects on them. The new Refco manifold may have helped, too.

    I suspect that the only way to go is the stainless hoses.... or, all barrier style hoses.

    Then I tried the triple evacuation method. There was plenty of time to let 10 psig of nitrogen sit in the system for 20 minutes a cycle, and that really helped to bring the micron levels down quickly.

    *That* did the trick.

    After actually doing it and watching the micron gauge, I don't believe there is a way to achieve and maintain low micron levels unless the triple evacuation method is used.

    On the opposite end of the spectrum, I am aware of several big name outfits that don't even use a vacuum pump. Purge and go- only 2 hours per install...
    Proper Prior Planning Prevents Piss Poor Performance

    "There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man's lawful prey. It's unwise to pay too little.
    When you pay too much, you lose a little money -- that is all. When you pay too little, you may lose everything, because the thing you bought was incapable of doing the thing it was bought to do.

    The common law of business balance prohibits paying a little and getting a lot -- it can't be done. If you deal with the lowest bidder, it is well to add something for the risk you run. And if you do that, you will have enough to pay for something better."

    John Ruskin


  10. #10
    Join Date
    Jul 2000
    Location
    NW IL.
    Posts
    3,935
    To purge aircraft liquid oxygen systems we would run nitrogen through a 120 vac operated heater. One of those being used to sweep a wet system could have possibilities.

  11. #11
    Join Date
    Apr 2006
    Posts
    7
    Does anybody know whether yellow jacket makes a good micron gage?

  12. #12
    Join Date
    Dec 2003
    Location
    Citrus County, Florida
    Posts
    1,485
    yes they do. I have the 69075 thgat I just bought. I've been using an old Robinair that used 6 D cell batteries. That worked great IF the barteries were kept up. I modified it to use rechargable batteries. Decided to step up to the digital world.
    Doug

  13. #13
    Join Date
    Feb 2005
    Location
    Alabama
    Posts
    534
    Since we're on the topic of vacuum, I have a question. First off I pull a vacuum whenever I have to open a system, I also use a micron guage. I've been getting conflicting statements on "how" to pull the vacuum. Some say pull from one side only i.e the vapor line, others say pull from both sides at the same time. Which is correct, or does it matter? I take pride in my work and always want to learn more. Thanks, Bill
    "If you can't fix it, don't break it."

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