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Thread: 19XR Float Woes

  1. #1
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    19XR Float Woes

    Hi To All

    Over the last few years we’ve encountered “sticking” floats on 19XL’s w/ R-22, 19XR’s w/ R-134a and 23XL’s w/ R-22. Most of the cases involve 19XR’s but we also have more 19XR’s under our care than the other models mentioned previously. I myself have contemplated whether it had anything to do specifically with the 134a but I find little or no evidence (other than coincidence) to support that idea.

    In each case we’ve pulled the float, found nothing broken or obviously worn, cleaned all moving parts (using a scotch pad & degreaser) while completely disassembling & reassembling the component & each time the cleaning seemed helpful because it would move easier although it wasn’t very difficult to move in the beginning.

    • Has anyone else ran into this?
    • Does anyone know of any bulletins related to this problem??

    One more thing: The most common alarms we see that tell us it is occasionally sticking are unexplained low refrigerant (cooler) temp trips accompanied by excessive surge trips. When this activity starts, we start looking for the wide cooler approach & sometimes we are able to see it on the frozen screen prior to resetting.
    All my leon freaked out!

  2. #2
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    the problem in the lack of a mesh in the suction of the compressor, as used in centrifuges to r-11

  3. #3
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    Other Conditions

    I hate to say this, but I think if you looked at all the other operational characteristics of how the chiller is running you would find out the low temp and surge are caused by something else. My first hunch on this particular machine is to always investigate the possibility of a rapid change in water flows (has or can) occur during normal operation.

  4. #4
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    Bulletin #CO120 (on paper) states that Carrier does not want refrigerant charging thru the valve on the bottom of the float. Reason as given:
    (Quote) The potential exists to introduce particles or TRASH into the chiller when adding refrigerant that could cause the float to stick or bind. Refrigerant should be added thru the valve on the relief valve tree on the CONDENSER. (unquote)
    I can't find the bulletin, but somewheres I have one that state charging thru the float cover may cause mis alignment on the float, causing binding or sticking. That bulletin states to charge into valve on relief valve tree on COOLER.
    \m/
    original member of the racoon brotherhood

  5. #5
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    I have run into this a few times working for Carrier and since then as well. There is no strainer, but also check the bubbler tube is in the correct position, but the vast number of cases have been caused by leaking ( the relief manifold always seemed to be a weak spot). There is a service bulletin relating to disassembly of the float, but nothing highlighting a problem. Your approach alert should be set at 2.8 dC (can't do that in dF) and should be under 1dC normally. If you are short the chiller will not properly load either.
    A problem shared is a problem halved

  6. #6
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    I've had the same prob. with 19XL's. I have found that it has never the float causing the low evap. temp but usually fouled enhanced evap. tubes, or oil, just a small amount, in in evap. Just enough to drop site glass level about a 1/4 glass. But with the latter, I usually see a big drop in discharge temp. when machine loads, due to carry over. Oh and yes you could be under charged.

  7. #7
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    Quote Originally Posted by cperk View Post
    I've had the same prob. with 19XL's. I have found that it has never the float causing the low evap. temp but usually fouled enhanced evap. tubes, or oil, just a small amount, in in evap. Just enough to drop site glass level about a 1/4 glass. But with the latter, I usually see a big drop in discharge temp. when machine loads, due to carry over. Oh and yes you could be under charged.
    Low discharge superhat will give oil issues away. We normally current limit to get the discharge superheat up and run the machine to return the oil. In extreme cases we have had to link the sensor
    A problem shared is a problem halved

  8. #8
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    Quote Originally Posted by retube View Post
    I hate to say this, but I think if you looked at all the other operational characteristics of how the chiller is running you would find out the low temp and surge are caused by something else. My first hunch on this particular machine is to always investigate the possibility of a rapid change in water flows (has or can) occur during normal operation.
    I agree

  9. #9
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    Quote Originally Posted by bunglebear View Post
    Low discharge superhat will give oil issues away. We normally current limit to get the discharge superheat up and run the machine to return the oil. In extreme cases we have had to link the sensor
    Yes I agree, all except the sensor, never had to do that.

  10. #10
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    Quote Originally Posted by heavymetaldad View Post
    Bulletin #CO120 (on paper) states that Carrier does not want refrigerant charging thru the valve on the bottom of the float. Reason as given:
    (Quote) The potential exists to introduce particles or TRASH into the chiller when adding refrigerant that could cause the float to stick or bind. Refrigerant should be added thru the valve on the relief valve tree on the CONDENSER. (unquote)
    I can't find the bulletin, but somewheres I have one that state charging thru the float cover may cause mis alignment on the float, causing binding or sticking. That bulletin states to charge into valve on relief valve tree on COOLER.
    I think the refrigerant charging valve is the one you're talking about.

    Here is another one I've got on the linear floats. Maybe they'll help.
    Attachment 111032

    Attachment 111062
    Sic Semper Tyrannis.

  11. #11
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    Quote Originally Posted by cperk View Post
    Yes I agree, all except the sensor, never had to do that.
    We only ever had to do it if the machine keeps going out on low discharge superheat. That being said, it's only ever happened during the winter with machines short cycling. Only happened a handful of times.
    A problem shared is a problem halved

  12. #12
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    Abnormal running conditions

    Quote Originally Posted by bunglebear View Post
    We only ever had to do it if the machine keeps going out on low discharge superheat. That being said, it's only ever happened during the winter with machines short cycling. Only happened a handful of times.
    For the XR's and XRV's, contrary to popular belief these units will run flawless without the enhanced oil eductors and will continue to run flawless with the charge well under the skimmer line. For this to happen the cycles need to be rated in cycles per day and the chiller needs to maintain the true minimum capacity as these machines were intended to run. No chiller should be rated in cycles per hour. All the conditions mentioned in the prior posts (IMHO) fall into the abnormal running conditions category. Change the XR to XRV and there is no finer chiller on the market hands down.

  13. #13
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    Quote Originally Posted by txhvac View Post
    I think the refrigerant charging valve is the one you're talking about.

    Here is another one I've got on the linear floats. Maybe they'll help.
    Attachment 111032

    Attachment 111062
    I stand corrected, Tex. Much better copy than my paper...... Thank you
    \m/
    original member of the racoon brotherhood

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