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  1. #144
    Join Date
    Feb 2010
    Location
    In a boiler room
    Posts
    7,224
    Quote Originally Posted by knave View Post
    I wonder if overtightening a flare nut wouldn't do it as well....

    Evan
    Yes, been there, got ticked off, drilled it out and put new core in.

  2. #145
    Join Date
    Dec 2009
    Location
    maroon lazyboy
    Posts
    1,049
    Quote Originally Posted by chuckcrj View Post
    ....drilled it out
    What did you do with the shavings????? I freak out about shavings!!!!!

  3. #146
    Join Date
    Feb 2010
    Location
    In a boiler room
    Posts
    7,224
    It was on a Mits so the port was facing down on an angle. I just drilled out the part that was coned in preventing removal of the core.

  4. #147
    Join Date
    Apr 2009
    Posts
    70
    I have always used a micron gauge and tried to get as low as possible. I usually get below 500microns. I was told if it holds under 1000microns after 10mins you have no leaks but have a bit of moisture. My question is how long do you do a static test for to test the vacuum. I have been told many different things by different techs.

  5. #148
    Join Date
    Oct 2004
    Location
    Annapolis, MD: ragboat capitol of the world
    Posts
    358
    usually the end of the flare is smashed over into the hole by someone over tightening the cap ...

    If the core turns freely, I file a little off the end of the flare, just the part smashed in to the center ... then I can remove the core. I've been afraid of the filings jamming the core, but with trying to blow and or rinse the filings out before removing the core, I've never had one jam after filing.

    If you are upstream of the drier you are 100% OK ... if you've cut as many OEM compressors as I have, you wouldn't be scared of a little trash in a tin can.

    On commercial AC tin cans, I don't think I've ever seen one that was 100% clean. A lot of little refrigeration stuff does have direct piped suction (and hot shell, that would be the tip off of a direct piped suction), you would need to be extra careful on something like that ... probably worth replacing the whole fitting ... but my general opinion of that stuff is ... the whole thing was junk on the drawing board and its still junk
    Sam

    Know-it-all? Nope, not even half!

  6. #149
    Join Date
    Oct 2004
    Location
    Annapolis, MD: ragboat capitol of the world
    Posts
    358
    Quote Originally Posted by Twigga View Post
    I have always used a micron gauge and tried to get as low as possible. I usually get below 500microns. I was told if it holds under 1000microns after 10mins you have no leaks but have a bit of moisture. My question is how long do you do a static test for to test the vacuum. I have been told many different things by different techs.
    If its under 1,000 I doubt you have moisture. Constant rise indicates a leak. You will have an initial rise after closing off your pump ... after the initial rise stabilizes that's when your blank off test begins. Rise to a high stable reading in the 1,000 range may indicate moisture, but it depends on the unit and how much heat you can apply to all of it.

    Different micron gages have different response times. You need to learn what yours is telling you, it might be different from mine etc.

    My old JB used to tell me I had moisture at a 1,100 - 1,200 reading in about 3 or 4 minutes (if the reading stayed steady) ... someone else's gage may have indicated this at 900 after 10 or 15 minutes.
    Sam

    Know-it-all? Nope, not even half!

  7. #150
    Join Date
    Aug 2008
    Location
    S. Grand Prairie
    Posts
    244
    Quote Originally Posted by itsiceman View Post
    Great idea! I've been using the angled adapter that came with my YJ every time but this would eliminate the need... Thanks!
    Originally Posted by ladyfire3374:

    "I used to wake up excited about the challenges of the day. Now the anticipation level is somewhere between a root canal and a colonoscopy."

  8. #151
    Join Date
    Jul 2011
    Location
    Salt Lake City, Utah
    Posts
    34
    Since I have a sman3 and a VG64, I thought I'd try an experiment. I put the VG64 on the 3/8 liquid line with a short 6" ball valve hose, then to the VG64, then to the sman3 high side with a 3' hose (VG64 has two male connectors). I connected an identical short ball valve hose to the 7/8 suction line, then to a C&D core removal tool with a side port, and then through 12" stainless hose to the vacuum pump JB DV-142n, and connected the side port of the CRT (valve core removed) through a 4" hose to the center tap of the sman3. The low side of the sman3 was capped and valved off. A lot of hoses I know, but I wanted both gauges hooked up.

    I pulled the vacuum and watched the two gauges. I had closed the high side of the sman3 so the VG64 only read from the 3/8 line, sman3 only read from the 7/8 line that had the vacuum pump on it. After a while the sman3 was at 500 microns, but the VG64 was still reading atmosphere, then slowly it started to drop from 9000 microns. I shut off the short hose ball valve on both sides (now the gauges are disconnected from the service lines), opened the sman3 high side, pump is still running and both gauges dropped readily to 150 microns. I know the VG64 tracks pretty close to the sman3, I've tried that before. Put it back like it was and finaly got 3/8 line down to 2750 microns (VG64 changes 250 at a time at that range). Probably a half hour of this and I'm out of patience so I finally opened the high side sman3, closed the C&D, and pulled the vacuum from the 3/8 only for a while to get it down, then both open to 475 microns, then blank off at the vacuum pump and let it sit for 5 minutes and the sman3 eventually rose 5 microns, the VG64 didn't change (changes 5 at a time at that range). I thought all the hoses would have leaked more than that but it didn't read on the gauges.

    This had a 4-ton copeland scroll compressor, and a piston metering device on the coil, and the service line was about 47 feet. It didn't do what I expected it to, I thought the 3/8 would be a little slower dropping when I pulled the vacuum from the 7/8 side, but I didn't expect it to be that slow. I"m thinking that the scroll probably doesn't pass much flow when it is off (just guessing) and the only other way over to the 3/8 line was through the capilary tubes in the coil. Seeing how much a small hose can restrict a vacuum, I figure those 1/8" capilary tubes were not helping much. It convinced me its better to pull a vacuum from both sides, or at least check it a few more times to see if that always happens.

  9. #152
    Join Date
    Oct 2004
    Location
    Annapolis, MD: ragboat capitol of the world
    Posts
    358
    Always pull from both sides
    Sam

    Know-it-all? Nope, not even half!

  10. #153
    Join Date
    Dec 2009
    Location
    maroon lazyboy
    Posts
    1,049
    Quote Originally Posted by kdb4 View Post
    It convinced me its better to pull a vacuum from both sides, or at least check it a few more times to see if that always happens.
    Good experiment. I have been wondering what would happen in that case.

    Just thinking about it though, I had concluded the same as you. You can't pull a vacuum through a metering device.

    The pressure difference is too small. 1000 microns is only 1 mm of mercury.

  11. #154
    Join Date
    Jul 2011
    Location
    Salt Lake City, Utah
    Posts
    34
    A correction to my post #151 experiment, in the second paragraph when I said I closed the C&D to pull a vacuum from the 3/8 line only, that was not the C&D valve that I closed, it was the ball valve on the short hose to the 7/8 line. Closing the C&D would have isolated everything (both gauges and the service lines) from the vacuum pump. I did it right, just described it incorrectly, and I can't edit the post now. If you were trying to follow what I did, it would have been confusing.

  12. #155
    Join Date
    Aug 2007
    Location
    Dallas Area
    Posts
    20
    micron gauges are like leak detectors, the are only good if you have one you trust. also the prob i have had in past cones from over tightening the flare cap that has copper washer instead of rubber seal, it smashes the top of the flare in.

  13. #156
    Join Date
    Aug 2007
    Location
    Dallas Area
    Posts
    20
    i let it stand as long as i can, 24 hrs is a good rule, but if you have longer itll make you feel better. 1500 ton trane B left at 300 microns for 1 month while waiting on starter work, left me real confident. on an emergency you wont have as long.

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