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  1. #1
    Join Date
    Feb 2007
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    Ohio
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    Low glycol flow?

    50 ton chiller, opening dialog on start up sheet from installer = 17 f superheat, replaced #2 compressor in a tandem set-up. superheat = 8-9 with subcoooling at 11. No maintenance program, they have no idea what hey have there. My chiller days were long ago... 25 and 15 on the water pump, thought it should be 30 and 15....?

  2. #2
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    Feb 2017
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    It all depends on the chiller. Do you know what the ∆T is supposed to be across the evap?
    If I have no design data, I shoot for 10° across the evap at full load no matter what the pressures are. Then I look at approach (saturated evap refrigerant temp vs leaving glycol temp).
    Another thing is I have seen many chillers big and small with glycol that were not designed for glycol. They will run, but numbers are a bit off and capacity is reduced.
    -----Stop, step back, relax and have another go at it.-----

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  4. #3
    Join Date
    Aug 2006
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    Mixing oil and fire with a big spoon.
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    got a model?
    Don't step on my favorite part of the Constitution just to point out your favorite part.

    Political Correctness is forced on you because you have forgotten decency.

  5. #4
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    Feb 2007
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    Ohio
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    Thread Starter
    McQuay AGZ050DHSNN-ER10

    Quote Originally Posted by jayguy View Post
    got a model?

  6. #5
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    Thread Starter
    I'm going to have to get that info from McQuay, unfortunately there tech support is hard to get in contact with.

    Quote Originally Posted by BennyD View Post
    It all depends on the chiller. Do you know what the ∆T is supposed to be across the evap?
    If I have no design data, I shoot for 10° across the evap at full load no matter what the pressures are. Then I look at approach (saturated evap refrigerant temp vs leaving glycol temp).
    Another thing is I have seen many chillers big and small with glycol that were not designed for glycol. They will run, but numbers are a bit off and capacity is reduced.

  7. #6
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    Feb 2005
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    Central Florida
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    Glycol percentage is ?

  8. #7
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    Quote Originally Posted by jimp View Post
    Glycol percentage is ?
    And is it ethylene or propylene?
    -----Stop, step back, relax and have another go at it.-----

  9. #8
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    Feb 2007
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    Ohio
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    Thread Starter
    Like I said, my chiller days are way back but did have USAF training 30 yrs. ago. I think there's air in the system just by listening to the video I took, and my water system training is like I forgot everything... how do it post the vid... its a welded plate evap. I'm Going to go to the church Sunday morning while the chiller is loaded and take all the operational specifics..ie water delta T across the evap, compressor sump temp, superheat, amp draw and so on... If worse comes to worse I'll close down the TXV's but they should not be the problem. I have a feeling its neglect of the water side...

  10. #9
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    Feb 2007
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    Ohio
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    Thread Starter
    From the documentation left on site your guess is as good as mine..will investigate. Its my understanding of course one has a better transfer of heat and enthalpy They left the maintenance man with maintaining the system and he of course has no clue, couldn't expect him to ...to tell truth. They left a barrel of it on site and told him to give the system a "squirt" now and then . I didn't get to see the water side of it until after I did the tandem replace. Thats when I started to question the water side....running 9-11 degree's of superheat but that seems low when start up said 17 on install. Also did a sump temp on each compressor and it shows boarder line refrigerant mixed with the oil return which will wash the bearings in a hurry. Spoke to my distributor about that and he said " i'll get back with you" Noticed on my fist call there that on a real hot day all 4 compressors had sweat on them to beat hell, running cold.
    Quote Originally Posted by BennyD View Post
    And is it ethylene or propylene?

  11. #10
    Join Date
    Apr 2013
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    The IOMM will give you min and max flows and info for the % glycol.McQuay used to write some good manuals they ship with the unit or you can get it on line.

  12. #11
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    Feb 2007
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    Ohio
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    Thread Starter
    Thanks got it from there website and downloaded the IOMM.

    Quote Originally Posted by summerhelp View Post
    The IOMM will give you min and max flows and info for the % glycol.McQuay used to write some good manuals they ship with the unit or you can get it on line.

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