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  1. #66
    Join Date
    May 2000
    Location
    Monmouth Junction-NJ-USA
    Posts
    6,011
    Quote Originally Posted by ZeroTolerance View Post
    Ya, some have them. I know the lennox's do and so does the kairak refer system I service
    If they come with the refrigerant in them, that is not a field charged unit. That is a precharged unit that needs to be field adjusted. Or if charge is lost then weigh in according to name plate. Again never on a 50 ton or completely field charged. Wayyyyyyyyyy to many variables in line size or line length. Talking here about a 7/8 liquid line and maybe a 2-5/8 or larger suction line. hmmmmmmmmmm
    If you really know how it works, you have an execellent chance of fixin' er up!

    Tomorrow is promised to no one...

  2. #67
    Join Date
    Jul 2002
    Location
    Yuma, AZ
    Posts
    2,361
    Quote Originally Posted by dijit View Post
    what did you do in lieu of vacuum pumps?
    • The HVAC compressors were all semihermetic with suction and discharge service valves. (No cans.)
    • With the system at atomspheric pressure, and the dicharge service access port on the compressor side of the valve open to the atmosphere
      and the discharge valve nearly closed
    • then we would bump the compressor a couple of times and finish closing the dicharge SOV.
    • Finally, we would run the compressor for a minute or so to get 28" of vacuum on a compound low pressure gauge. (Microns were unknown at the time.)
    • Later when we got canned compressors we used a funcitoning 1/2 hp Copelemetic medium temp compressor for years and years. Change the oil? Never.


    System cleanup after a burnout.
    • Unknown. We would dump the gas if it smelled nasty, install a new compressor and go.
    • We used to blow nasty systems using R-12 as a flush gas. ($0.39 per pound)
    • Then we used R-11 for years to flush out systems.
    • Suction line driers for system cleanup came along in 1970's. Novel idea.
    • Not much change since then except that the arrival of internal compressor motor protection greatly reduced burnouts and nearly eliminated nasty burnouts.
    "I have never let my schooling interfere with my education."
    Mark Twain
    More at: http://www.quotationspage.com/subjects/education/

  3. #68
    Join Date
    May 2000
    Location
    Monmouth Junction-NJ-USA
    Posts
    6,011
    Quote Originally Posted by lynn comstock View Post
    • The HVAC compressors were all semihermetic with suction and discharge service valves. (No cans.)
    • With the system at atomspheric pressure, and the dicharge service access port on the compressor side of the valve open to the atmosphere
      and the discharge valve nearly closed
    • then we would bump the compressor a couple of times and finish closing the dicharge SOV.
    • Finally, we would run the compressor for a minute or so to get 28" of vacuum on a compound low pressure gauge. (Microns were unknown at the time.)

    • Later when we got canned compressors we used a funcitoning 1/2 hp Copelemetic medium temp compressor for years and years. Change the oil? Never.


    System cleanup after a burnout.
    • Unknown. We would dump the gas if it smelled nasty, install a new compressor and go.
    • We used to blow nasty systems using R-12 as a flush gas. ($0.39 per pound)
    • Then we used R-11 for years to flush out systems.
    • Suction line driers for system cleanup came along in 1970's. Novel idea.
    • Not much change since then except that the arrival of internal compressor motor protection greatly reduced burnouts and nearly eliminated nasty burnouts.
    Yep, that was back in the day for sure.
    If you really know how it works, you have an execellent chance of fixin' er up!

    Tomorrow is promised to no one...

  4. #69
    Join Date
    May 2010
    Posts
    1,295
    The lennox 60-ton packaged dehumidifier unit has the lbs of refrigerant per circuit on it for charging. 35lbs a circuit. 2 1/2" suction.

    Maybe I am misunderstanding what you are saying

  5. #70
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,758
    Quote Originally Posted by ZeroTolerance View Post
    The lennox 60-ton packaged dehumidifier unit has the lbs of refrigerant per circuit on it for charging. 35lbs a circuit. 2 1/2" suction.

    Maybe I am misunderstanding what you are saying
    Typically, larger systems like that are built up like a residential split system, just BiGGER.

  6. #71
    Join Date
    May 2000
    Location
    Monmouth Junction-NJ-USA
    Posts
    6,011
    Quote Originally Posted by ZeroTolerance View Post
    The lennox 60-ton packaged dehumidifier unit has the lbs of refrigerant per circuit on it for charging. 35lbs a circuit. 2 1/2" suction.

    Maybe I am misunderstanding what you are saying
    We are on 2 different pages here. What you are talking about is a packaged unit. Our 20 ton package units have the charge on a name plate on them also. That is a close coupled unit. What I am referring to is a 50 or 60 ton split system with maybe one or more evaporator coils (or fan coils) for the system
    If you really know how it works, you have an execellent chance of fixin' er up!

    Tomorrow is promised to no one...

  7. #72
    Join Date
    May 2010
    Posts
    1,295
    Ya, split systems never have charge written on them for the obvious fact. I knew I was misunderstanding you. Sorry

  8. #73
    Join Date
    Oct 2009
    Location
    new jersey
    Posts
    246
    The 50 ton carrier split system book w condenser listed system charge plus a certain Amt. Per foot of piping. Weighed it in subcooling was pretty close. Alittle more it is good.

  9. #74
    Join Date
    Apr 2010
    Location
    Minnesota
    Posts
    517
    Found a leaky receiver on a 75 ton 2 circuit Seresco unit the other day. It says 100 lbs factory , 100 lbs field charge, per circuit, add more if over 50 foot lineset. R407c

    At least I think it was 75 ton, it was rated at 30,000 cfm

  10. #75
    Join Date
    Oct 2003
    Location
    las vegas
    Posts
    1,505
    before the old b & g we had kinney cam action & seargant welch.
    i have 1 of each both belt drive & on 4 wheel dollys to move around.
    took 3 good guys to get them loaded on the truck.both about 20 cfm
    230 volt. my 1 cfm welch scientific weighs around 65 #.

  11. #76
    Join Date
    May 2000
    Location
    Monmouth Junction-NJ-USA
    Posts
    6,011
    Quote Originally Posted by marvin View Post
    before the old b & g we had kinney cam action & seargant welch.
    i have 1 of each both belt drive & on 4 wheel dollys to move around.
    took 3 good guys to get them loaded on the truck.both about 20 cfm
    230 volt. my 1 cfm welch scientific weighs around 65 #.

    WOW. What era was that?? Not big enouh for wheels. I had a belt drive Welch. Really was a super pump. Not fun getting it to the roof.
    If you really know how it works, you have an execellent chance of fixin' er up!

    Tomorrow is promised to no one...

  12. #77
    Join Date
    Oct 2003
    Location
    las vegas
    Posts
    1,505
    dad bought those pumps in the earli 50's...
    they botg will still pull below 200 microns but in those days we
    used merc. manometers.

  13. #78
    Join Date
    Aug 2010
    Location
    Florida
    Posts
    246
    FYI, at AccuTools, we have a nice scale for charging, the DS-220R. With 220 lb. capacity and 0.1 oz. resolution, it is ideal for large systems and critically charging small ones. It'll measure in Lbs., Lbs & oz., oz., and kg. MITTS made a nice video of the DS-220 (the high end version, same specs additional features):

    http://www.youtube.com/watch?v=Tby5PhIg5DU

    Specs and manual are here:

    http://accutools.com/index.php?page=...subpage=ds220r

    We are give 15% off list price ($199.95 for DS-220R, $229.95 for DS-220) till the end of March.

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