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Thread: 19XR Float Woes

  1. #14
    Join Date
    Aug 2008
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    Parts Unknown
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    I had one in a 19XL with a small hole develop in the float it filled with liquid refrigerant and made the chiller tripp on low evap.

  2. #15
    Join Date
    Nov 2004
    Location
    North Florida/South Georgia
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    Thread Starter

    My Latest Theory

    I've got approval to perform the inspection of the float. But, before I do I was contemplating the following:

    What if it is slightly overcharged? Surely we all agree that no two compressors pump the same & no two heat exchangers give up or absorb heat the same. As far as I know, the charge was weighed into this machine according to the name plate. Additionally, the cooler approach is 1.2* @ FLA (when the float isn't stuck) & the DSH is around 20*.

    I've always thought 20* could be a little tight although I've seen many a machine run @ 15 on the low end 25 on the high end.

    What if I pull out refrigerant in 50# increments til I see the cooler approach start to widen. Then, put back that little bit to maintain the official "minimum" & as long as my DSH is <25* I should be "trimmed".

    My thinking is that if the charge is all wrong & there is too much liquid in that area or maybe there is liquid making it's way into the bubbler, who knows.? I guess what I'm trying to consider is the possibility that there isn't enough buoyancy there (due to a lack of vapor) to allow the float to work correctly. I know it sound like a stretch but, maybe it's worth a try because something has got to give. Otherwise the big oval needs to step up & admit there is a problem with these floats & do something about it.

    Any thoughts???
    All my leon freaked out!

  3. #16
    Join Date
    May 2001
    Location
    Western Wa
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    Out here in part load country we sometimes see stacking in the condenser at low loads and the low end of the condenser temp range (on 19XRVs), and the expected lack of oil return from the skimmer. One of my OEM buddies came up with a scheme of resetting, inversely, the condenser water temp at low loads, which did seem to help with oil return. Like about 5 degrees higher at the low end, using the head reference as a variable. And you can screw with the range of the head reference, providing of course that you're not already using it for something else. You may have to go away from the sticker values on the T1 and P1 settings if you try this.

    My wild country boy theory is that the bubbles collapse at the low end of the load range and just can't lift the coffee can to float the boat.

    It also helps to get the DDC people on the same sheet of music and not be running the chiller when they really should be still economizing over on the air side. Bringing up the gross waste of energy helps with this one, well, sometimes.

    More often than not, the DDC crowd tends to slam open and shut the coil valves, which is yet another issue. Have also seen them slam off multiple buildings on a central loop, and surge the machine. I'm an old process control guy so it really drives me nuts, and ain't too good on the chiller, either.

    The fun never ends...
    God Bless our Veterans

    God Bless the USA

  4. #17
    Join Date
    Jan 2008
    Location
    windy city
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    4,575
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    Quote Originally Posted by chiller mekanik View Post
    I've got approval to perform the inspection of the float. But, before I do I was contemplating the following:

    What if it is slightly overcharged? Surely we all agree that no two compressors pump the same & no two heat exchangers give up or absorb heat the same. As far as I know, the charge was weighed into this machine according to the name plate. Additionally, the cooler approach is 1.2* @ FLA (when the float isn't stuck) & the DSH is around 20*.

    I've always thought 20* could be a little tight although I've seen many a machine run @ 15 on the low end 25 on the high end.

    What if I pull out refrigerant in 50# increments til I see the cooler approach start to widen. Then, put back that little bit to maintain the official "minimum" & as long as my DSH is <25* I should be "trimmed".

    My thinking is that if the charge is all wrong & there is too much liquid in that area or maybe there is liquid making it's way into the bubbler, who knows.? I guess what I'm trying to consider is the possibility that there isn't enough buoyancy there (due to a lack of vapor) to allow the float to work correctly. I know it sound like a stretch but, maybe it's worth a try because something has got to give. Otherwise the big oval needs to step up & admit there is a problem with these floats & do something about it.

    Any thoughts???
    If you have the time, by all means, play with it. And of course, weigh the charge coming out, And please post your findings.
    \m/
    original member of the racoon brotherhood

  5. #18
    Join Date
    Jan 2008
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    windy city
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    Quote Originally Posted by Randy S. View Post
    Out here in part load country we sometimes see stacking in the condenser at low loads and the low end of the condenser temp range (on 19XRVs), and the expected lack of oil return from the skimmer. One of my OEM buddies came up with a scheme of resetting, inversely, the condenser water temp at low loads, which did seem to help with oil return. Like about 5 degrees higher at the low end, using the head reference as a variable. And you can screw with the range of the head reference, providing of course that you're not already using it for something else. You may have to go away from the sticker values on the T1 and P1 settings if you try this.

    My wild country boy theory is that the bubbles collapse at the low end of the load range and just can't lift the coffee can to float the boat.

    It also helps to get the DDC people on the same sheet of music and not be running the chiller when they really should be still economizing over on the air side. Bringing up the gross waste of energy helps with this one, well, sometimes.

    More often than not, the DDC crowd tends to slam open and shut the coil valves, which is yet another issue. Have also seen them slam off multiple buildings on a central loop, and surge the machine. I'm an old process control guy so it really drives me nuts, and ain't too good on the chiller, either.

    The fun never ends...
    !
    \m/
    original member of the racoon brotherhood

  6. #19
    Join Date
    Jan 2008
    Location
    windy city
    Posts
    4,575
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    Quote Originally Posted by Randy S. View Post
    Out here in part load country we sometimes see stacking in the condenser at low loads and the low end of the condenser temp range (on 19XRVs), and the expected lack of oil return from the skimmer. One of my OEM buddies came up with a scheme of resetting, inversely, the condenser water temp at low loads, which did seem to help with oil return. Like about 5 degrees higher at the low end, using the head reference as a variable. And you can screw with the range of the head reference, providing of course that you're not already using it for something else. You may have to go away from the sticker values on the T1 and P1 settings if you try this.

    My wild country boy theory is that the bubbles collapse at the low end of the load range and just can't lift the coffee can to float the boat.

    It also helps to get the DDC people on the same sheet of music and not be running the chiller when they really should be still economizing over on the air side. Bringing up the gross waste of energy helps with this one, well, sometimes.

    More often than not, the DDC crowd tends to slam open and shut the coil valves, which is yet another issue. Have also seen them slam off multiple buildings on a central loop, and surge the machine. I'm an old process control guy so it really drives me nuts, and ain't too good on the chiller, either.

    The fun never ends...
    DDC guys here slammed a 16'' cdw valve so hard, a 1200T absorber literally jumped on it's pad. Sheared bolts on butterfly lug valves also.
    \m/
    original member of the racoon brotherhood

  7. #20
    Join Date
    Mar 2008
    Location
    Central,IL
    Posts
    25
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    Had two 19xrs that were thought to have float issues. The first one ended up having a divider plate put back wrong in the head after brushing tubes and dead heading the cond. The other was low on charge and had low water flow issues. PITA.

  8. #21
    Join Date
    Feb 2009
    Location
    USA
    Posts
    27
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    Something that gets overlooked is confirming that your evap. transducer is calibrated? Just a few F/ PSI out of calibration will give a false evap. reading.

    I've replaced floats many a times after I've confirmed;

    1-Transducer calibrated
    2-Correct CHW flow
    3-Clean tubes
    4-Division plate is 100%
    5-Correct charge

    Generally the float mushrooms (so to speak) in a semi closed position which in turn starves the evap.

  9. #22
    Join Date
    Apr 2019
    Posts
    1
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    Confused 19 XR low refrigeratnt temperature and pressure

    Dear All,
    I am looking after three 19 XR centrifugal machines. Refrigerant temperature and pressure of one of those machines has dropped to nearly 5 degree celcuis. The evaporator approach which remains 0.1 - 0.5 degrees has increased to 4 degrees and the color of oil in the sight glass is reddish. I have checked the temperature sensors and also replaced them but the issue is still there. Someone please suggest the way forward.
    Regards,
    Salman

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