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  1. #1
    Join Date
    Apr 2005
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    where the beer flows like wine
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    2,871

    to flush or no to flush ?

    trying to place back in service an old 50 ton unit, all refrigerant gone, compressor are operable, suction line left open and disconnected from compressor, 4 stages custom made unit, abandoned for over 10 years. I'm leaning towards 2 oil and LL dryer changes and periodical checks after but the boss wants it flush with one of the fake R11 substitutes, I dont believe that's necessary. what do you think?

  2. #2
    Join Date
    Mar 2010
    Location
    Morgan Hill Ca.
    Posts
    1,219
    Quote Originally Posted by hvacpope View Post
    trying to place back in service an old 50 ton unit, all refrigerant gone, compressor are operable, suction line left open and disconnected from compressor, 4 stages custom made unit, abandoned for over 10 years. I'm leaning towards 2 oil and LL dryer changes and periodical checks after but the boss wants it flush with one of the fake R11 substitutes, I dont believe that's necessary. what do you think?
    Is the system dirty, or just wet?

    That would be my criteria for choosing either...If it is just wet, get it closed up and purge a few hundred cubic feet of dry nitrogen through it and a good evac...Let her buck...If dirty (soiled with dust/debris) I would flush just for peace of mind...

    I fired off a large built up system several years ago that sat flat for 18 years...I simply installed three shell driers in parallel and had isolation valves on all of them and just did musical driers for a while.....As far as I know, it is still running...

    GT

    GT
    If a day goes by and you have learned nothing, I hope you got a lot of sleep.

  3. #3
    Join Date
    Mar 2011
    Location
    East Coast FL
    Posts
    1,058
    GT right on the money. I have found that the fake R-11 can be problematic , it requires more time to deal with than most people are willing to give. With its high boiling point , it can lay in low spots or cold spots as a liquid , depending on how much you put in , even after lengthy nitrogen purge I have still smelled that solvent in the system. Better have a micron gauge hooked during evacuation (loooooooong evac) to make sure the non-condensible is removed. I would say it can clean out a pipe , however.

  4. #4
    Join Date
    Feb 2010
    Location
    Ontario Canada
    Posts
    1,341
    I think I would want to find out why it was shut down and left for ten years in the first place. Could be lots of ghosts living in that machine...
    Change oil, run, change oil and liquid line dryer, run, change oil and dryer, run check often.

  5. #5
    Join Date
    Nov 2002
    Location
    NJ - WORK IN NYC AREA
    Posts
    1,457

    Hmm

    HVAC,
    All the guy posted here make some excellent suggestions. This compressor being open for 10 years has trouble written all over it.
    Before you make any repairs please consider some of the following:

    1) Obviously the oil has to drained, but what condition is it in now?
    If the vescosity is thick from laying 10 years you have a problem.

    2) Granted you will install fresh oil but if it's clogged up oil suction
    and oil pump the new oil may not flow on start up.

    3) You say 4 stage. I'm guessing its a receip. Have you opened up valve
    heads? When the oil lays so long it creates a thick film on all internal
    parts. Plugs up everything eventhough motor is operational.

    If I were doing this and I found thick or gooey oil, it should be pulled and rebuild it. Install your driers and monitor system. Don't forget, some of that old oil is laying piping 10 years also.
    "My hands are for sale"

  6. #6
    Join Date
    Aug 2006
    Location
    Wisconsin
    Posts
    1,504
    I would not waste my time with r11 unless there was a good reason to do it. I would do the oil and filter route with an over night evacuation and a micron gage.
    Buy American! The job you save may be your own.

  7. #7
    Join Date
    Mar 2011
    Location
    East Coast FL
    Posts
    1,058
    Good Advice

  8. #8
    Join Date
    Sep 2009
    Location
    Stumptown,USA
    Posts
    1,251
    R22 is an excellent solvent by itself. If you put new driers in and get it flowing, you might be surprised how well the R22 cleans things up. They used to sell R12 in an aerosol can to be used as a television tuner cleaner. (to clean the electrical contacts in the station tuner).
    Challenge yourself, take the CM test --- Certificate Member since 2004 ---Join RSES ---the HVAC/R training authority ---www.rses.org

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