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  1. #1
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    Nov 2019
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    Low pressure chillers

    Hello and thank you in advance, I am learning to work on low pressure chillers. How do you determine the amount of r123 in the chiller with no sight glass . I will be recovering a low pressure chiller for the first time on my own and was wondering if you guys had any tips or truck to speed up the recovery. I have recovered several high pressure chillers but struggle on the r123 in the York’s and Tranes. I have trouble getting the push pull started. My foreman is going to bring me the boiler . Why does the liquid not want to come out to warm the evaporator. Does the air need to be removed by the purge before the push pull.
    Also what is the best recovery tank to use with the NRP low pressure recovery machine.I am trying to impress my foreman.
    Thank you

  2. #2
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    Nov 2019
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    Thread Starter
    I should also note the last time I had trouble with the r123 I was told the recovery tank I was using was to small. What tank should I use 125 or 250

  3. #3
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    Nov 2019
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    Thread Starter
    I also drain and dry the barrels

  4. #4
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    Nov 2011
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    there shouldn't be any air in the machine for the purge to remove....if there is, you have leaks that need repaired......you're recovering, so I'm assuming you are fixing leaks.

    heat the condenser water to get the machine up to 3-5psi, that should allow you to start pushing liquid into your drums. usually, you'll be using 100lb. or 250lb. drums....unless you have a tank mounted recovery machine.

    as far as checking charge, you need to have the machine as close to design conditions as possible, and running 100% loaded. then you check approach temps to determine refrigerant charge.

    when the machine is off, and no history, all you can do is assume it contains the factory charge listed on the data tag.


    make sure you get ALL the liquid out before starting on gas!

  5. #5
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    Nov 2019
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    Thread Starter
    Thank you so much sir
    So without heating the chiller I will not be able to do the push pull ? Do I just heat the evaporator.
    I am trying to impress my employer by accepting new challenges

  6. #6
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    Nov 2011
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    pull a slight vacuum on your drums.

    fill them 80% full....NOT to the top.

    how much refrigerant are you recovering?

  7. #7
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    Nov 2019
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    Thread Starter
    800 to 1200pounds sir on a York Chiller , it has leaks
    Do I have to warm the chiller first
    Can I push pull without warming the chiller
    I was going to pick up a lot of 125 pound tanks this morning until the shop can deliver the 500 lb tank that is out on a job my foreman said
    I will be using nrp recovery machine for low pressure
    I just don’t know if I have to warm the chiller first
    My foreman will help me but I want to do it

  8. #8
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    you can recover without warming, but it's gonna take a lot longer.

    just run some hot water from a wash sink through the condenser. don't trust the rupture disk, I don't go above 7 psi.

  9. #9
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    Nov 2019
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    Thread Starter
    We brought out a 500 lb recovery tank and some 250, it went very fast with the hyperwatt

  10. #10
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    so, did you impress them today?

  11. #11
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    Thread Starter
    They said they were impressed with my effort and will be letting me do more chiller work
    Thank you for the information

  12. #12
    Join Date
    Nov 2011
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    Good deal.

    If you really want to do the work, you'll have to put in A LOT of effort. I've tried to help lots of guys, only to realize they really aren't serious about it. Volunteer for everything, especially the crappy jobs....ask questions all the time, make notes of things you're told that you don't understand, and research them on your own.

    the best place to gain knowledge is the equipment manuals, they spell out every detail of the equipment.

    One of the biggest shortcomings of guys I see is that they are in too much of a hurry. when you're working on large, expensive, complex equipment, you have to slow down, and be methodical about what you're doing. one misstep and you could cost your company or your customer tens of thousands of dollars.

    Also, don't be afraid to call for help.....I don't care how long you've been doing chiller work, if someone tells you they never need outside help, they're full of crap. It's better to call someone and ask them a stupid question, rather than destroying a unit.

    Good luck!

  13. #13
    Join Date
    Mar 2015
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    I always evacuate the recovery tanks to make sure they are tight and moisture free. If possible I like to flow cold water through one of the vessels so the liquid collects there. Then push-pull the same as any other chiller.

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