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Thread: How low do you pull vaccum?

  1. #21
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    i agree with some of the other members, i always try to hit 250, i do realize time is money but call backs are not cheap, do it right the first time.

  2. #22
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    Ok. Clear this up for me. Is 500 ok, or not? Yeah or nay. And please don't start a poll. I hate those f'n things.
    "Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler

  3. #23
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    Quote Originally Posted by tostaos View Post
    Show some professionalism and improve your equipment and please do not post in the residential section when you are not willing to work inside of minimum industry standards. It's not good advertisement.
    I must be a hack.

    In 15 years, I have not, to date, EVER used a micron gauge.

    I have seen them, looked at them, learned about them, thought real hard about them, but to date, haven't ever actually used one.

    After learning more on this and other forums, I have decided that the time to buy one is very, very soon.


    Is it correct practice? Yes.

    Is it necessary? No. Not with many, many systems. I have actually made repairs and restarted the system without pulling a vacuum or replacing the drier. It worked and I STILL haven't been back.

    Step down off of your high horse.



  4. #24
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    i know im not a professional but my teacher told and has us in lad pull it down to atleast 500 microns for R-22 and atleast 250 for 410a. He said the reason for goin lower on 410a is because it can attract or absorb unwanted moisture alot easier than R22

  5. #25
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    Quote Originally Posted by jpsmith1cm View Post
    I must be a hack.
    agree

  6. #26
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    This isnt going to end well.
    You sure are cocky for a starving pilgrim.

  7. #27
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    Quote Originally Posted by 2old2rock View Post
    Ok. Clear this up for me. Is 500 ok, or not? Yeah or nay. And please don't start a poll. I hate those f'n things.
    yes, but you posted before, that you shoot for this and that is not good enough. You should shoot for 250, not the minimum.

  8. #28
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    I'll stay out of the name calling, if that's okay. To bad if it isn't okay. Having said that, the trick is to evacuate to a reasonable vacuum as shown on a good micron gauge, which is attached to a good set of hoses and is being drawn down by a good quality, 2-stage, properly maintained vacuum pump. The trick is that once the minimum (deepest) vacuum is recorded, you need to turn off all the valves and then turn off the vacuum pump and wait. It's always going to rise a little. So if you pull it down to "just" 500 microns, what does it hold when the pump is off? Not 500 microns. So if you want to know if the system is dry, you need to evacuate down to something below 300 microns, then turn the pump off and observe. If the vacuum rises above 500 microns, you're not done and need to continue to evacuate, as there's an indication of moisture still boiling away in the system. Now all of this may seem like it's unnecessary but that's what a lot of "technicians" say about charging systems too. But the DOE has done extensive research and guess what they've found? Only 30% of the systems in the USA are properly charged. The rest are either over charged or under charged. So there's "technician education" needed there as well. Likewise on the static pressures in ducts. The average static is over 1.0 inches of WC (total static). Yet installers don't think they need to do a load analysis. Bottom line, it's called being a wannabe or being a technician. Make your bed and lay in it.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  9. #29
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    i must reply one more time to this topic i have seen a 22 unit done by a coworker more than once change a part perge it with freon charge it and years later no problems no this is not CORRECT PROCEDURE !!!! but im sure we all have worked with teh guy that is to fast but that aside our factory area tec rep with american standerd requires us to pull 22units to 500 and 410 to 300 good enough for them good enough for me

  10. #30
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    Skip - I'd say 90% of the systems I see are not charged properly. We've got so many hacks in our area, it's pittiful. Add some gas and it's good to go!!
    Most everything I see is overcharged.
    Call me a wannabe if you like, but I do everything I can to get the system where it should be, and if pulling to 500 microns ain't good enough in your book, I'd hate for you to see what goes on in these parts on a regular basis.
    Not trying to flame here, but I look out for our customers as much as I do the Company. Company has to make money, but system has to be right. 500 microns is right in my book. R22 or 410a. But hey, I didn't write the book, so what do I know.
    "Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler

  11. #31
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    How can some techs not use a micron gauge, how do you know your sytem is sealed and moisture free, the units today have much more advanced technology than what was used in the older days, thats why i tell customers its not the young techs you have to worry about , they are able to keep up with technology and evolve, its the oler techs that are stuck in there old ways and are scared of change.

  12. #32
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    300 at the very minimum on anything I ever work on. If it doesnt get there or it gets there and wont hold I know I have a leak. The system at my house saw a 90 micron vacuum.

    I really really paranoid about a vacuum. I feel that the lower it is the better, and while thats true you cant expect the world in the real world. If the boss said "replace this compressor and you have all day", then a <100 micron vaccum would be pulled on the system and the pump oil would be changed during the process. However its usually "Replace this compressor, then you 5 other calls", so I'll take it too the point where it doesnt rise above 300 once shut off.

    For you professionals that "wing it" or are always in a hurry I would HIGHLY recommend a gauge set with a vacuum line like this...



    Thats a titan manifold gauge set. It ties into the larger line and pulls a vacuum much faster due too this increase from what I've experienced.

    A week ago I was on a job replacing a Copeland compressor and it was cold (very low humidity). Purged with nitrogen before, during and after the compressor install. Replaced the filter drier like your supposed too. Turned on the vacuum pump, waited for the oil to warm up, changed it, then let it run. I returned 20 minutes later with the micron gauge reading 62~ micron. Without the gauge I would have left it on there for another hour an wasted a bunch of time.

    The combination of a quality vacuum pump, quality set of gauges, and micron gauge saved me a ton of time and I KNOW (for a fact) the job is done properly.

  13. #33
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    Yung - You're stepping in a deep hole here. You're also correct that many "seasoned techs" don't always conform to new ways. Just don't lump us all together.
    And really, no one is ever too old to rock! I just can't stay awake till 3am anymore.
    "Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler

  14. #34
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    Cynicx - I'm sending that picture to Boss. Hopefully I'll have it for A/C season. Not holding my breath. That is sweet.
    "Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler

  15. #35
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    Quote Originally Posted by tostaos View Post
    agree
    We will have to agree to disagree.

    If you saw some of the equipment that I work on, you would understand that a micron gauge would really serve me little purpose.

    Rarely do I evacuate an entire unit. Much, much more often, I am evacuating a portion of a larger system that contains thousands of pounds of refrigerant.

    With sometimes shaky valves, I am often lucky to get a vacuum to pull much under 25 inches, much less approaching micron territory.

    Yes, sometimes I work on smaller stuff, but not often.

    Know all the facts before you judge, friend.



  16. #36
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    Quote Originally Posted by 2old2rock View Post
    Cynicx - I'm sending that picture to Boss. Hopefully I'll have it for A/C season. Not holding my breath. That is sweet.
    Go check out the threads on the Tools and Test Equipment Forum. With good equipment you will pull vacuums really fast.

  17. #37
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    Quote Originally Posted by 2old2rock View Post
    Cynicx - I'm sending that picture to Boss. Hopefully I'll have it for A/C season. Not holding my breath. That is sweet.
    Don't waste yours or your boss's money.

    The Titan/Brute manifolds are CRAP! Try turning one of those neat little tapered plastic valve handles with wet, oily or greasy hands. They work great. NOT!!!

    The 4 valve, 4 hose manifolds are nice, but YJ really has a stinker on their hands there.



  18. #38
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    question do you guys use a vac tree im intrerested in one any info? trying to squezze a po # out of the boss different story. hoses have to leak just to get new ones

  19. #39
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    I'm amazed how the seemingly innocent threads can get a little heated. I'm surprised more people don't use micron meters too. Once you start using them, you probably will always use them. This is my 2 cents.

    It depends upon the size of the system, the age of the system and your boss/customer. 500 microns has been around for decades. 500 microns works well on "most" HVAC systems, in my opinion, but there are exceptions. All OEM's have their own evacuation levels and they should be followed. The most common evacuation level that I've seen in OEM literature is 500 micron minimum. The newer POE oils may change this though.

    However, you will probably never see 500 microns on a large circuit or if your 20 year old system has a pinhole, unless your meter is lying. But, you may see 250 microns on a small 5 ton RTU after you leave the vacuum on it all night. It normally takes a long time to get from 500 to 250 microns unless it's just a line-set. There are many other factors that effect evacuation times; such as moisture, refrigerant in the oil, burnouts, etc. I'm talking about when the vacuum sensor that is mounted far away from the vacuum pump port. Your boss/customer may not want to pay you 2 hours OT to go from 750 microns to 500 microns either.

    HVAC vacuum pumps average about 20 microns when clean. The difference between 500 and 750 microns for example is only a few thousandths of a PSI. I'm not saying that 750 microns is good, it's just going to take time to get to 500 microns. I know people say they got down to 50 microns overnight, but I don't believe it. It's taken me 8 days to pull a one HP circuit down to 50 microns. The lower the better but there's a point of diminishing returns too. Personally, I always strive for 500 microns or less on most systems, but I know that I can't obtain that sometimes and "I know why" I can't get it.

    Another point is that many OEM's will also stipulate that you reach 500 microns or less when there's moisture in the system. The 500 microns verifies that there's no moisture/water remaining in the system, unless this is an Ultra Low Temp unit. The Ultra Low systems require 50 microns! They take a LONG time using copper evacuation lines.

    Simple answer, 500 microns or less but there are many variables. Vacuum pump manufactures have printed some good articles too on evacuation procedures. You can search this forum or Google it.

  20. #40
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    any boby tryed thoes digatol gages

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