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  1. #1
    Join Date
    Aug 2017
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    Glycol system question

    Hi guys, i have a heat reclaim station with glycol 35%. The pump is 92 feet head for 400 gpm.
    I have 40 feet between the top of the loop and the floor where the pump is.
    If i put the rule feet/2.31+5psig i need to have approximately 22 psig on the suction and my expansion tank too.
    My questions are:

    -do i need this setting when the pump is on or off?

    - i have a balance valve between discharge and suction for my differential pressure to the pump. It is 92 feet (45 psig)

    - what will happen if i have less glycol in the system. Can i run glycol in the vacuum upthere?

    -what will happen if i put too much glycol? My head never changes but global pressure does. Is it bad for the pump?

    - if my head drops, my discharge pressure rises, but will the gpm drop too?


    Thank you very much
    Last edited by frigoriste; 10-12-2017 at 10:40 AM. Reason: Correction

  2. #2
    Join Date
    Aug 2002
    Location
    Southold, NY
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    2.31 is the pressure of 1' of water
    Glycol changes that #.

    What are you trying to do? where are you taking your measurements? What type of pump, system,

  3. Likes djennings91 liked this post
  4. #3
    Join Date
    Aug 2017
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    Thread Starter
    I have a loop for heating with glycol.
    I heat the glycol at 85f by passing in a exchanger plate . We take
    The heat from parrallel pack compressor refrigeration.
    I have 5 airhandler with a glycol coil at the top of the bulding.
    My pump is on the first floor.
    My pump is armstrong 4380 Vertical In-Line Pumps 92 feet head


    What happen if i have to much glycol in the system. You can see on my first post all my question

    Thanks

  5. #4
    Join Date
    Jan 2004
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    PA
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    Glycol is a poor conductor of heat compared to water. So the more glycol you have in the system, the less heat transfer you have.

    Along with your head pressure for altitude, you also need enough to over come the PD of the coils, pipe, and all fittings and hydronic valves. Do you know the CV of your coils and valves.
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  6. #5
    Join Date
    Aug 2017
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    Thread Starter
    Ok, but if i put to much fluid ( mix : glycol+ethyl) in the system what problem there will be? High pressure? The performance of the pump will drop?
    does the fluid contract in the loop if there is too much?
    Thanks

  7. #6
    Join Date
    Jan 2004
    Location
    PA
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    Too much, and your GPM will drop, along with the amount of heat you transfer. Glycol is much heavier than water. So hat is why your GPM rate will drop.
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