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  1. #1
    Join Date
    Nov 2011
    Posts
    9

    refrigeration / water to water heat pump

    Sirius model / french product
    The heat pump is a 19KW , water to water

    - on low pressure side we have: inlet water 16C, outlet water 12C, pressure of the refrigerant 4.5 bar

    - on high pressure side: inlet water 30 C, outlet water 35 C, pressure of the refrigerant is 20 bar

    This high pressure is to high for the 35 C water outlet
    The top of the compressor is 70C, too hot

    If the water outlet is set 40 C we have pressure error (compressor stops)

    We recharge the heat pump with R407C, the qty is correct. But the pressures are still to high

    When we open fully the expansion valve the low pressure rich 5.5 bar and high one 18 bar / the top the compressor is still 70C

  2. #2
    Join Date
    Nov 2011
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    USA
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    401
    Who said 70˚C is too hot or 20 bar too high?

  3. #3
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    Nov 2011
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    9
    20bar is to much for 35c water outlet ...

  4. #4
    Join Date
    Nov 2011
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    USA
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    Quote Originally Posted by housed View Post
    20bar is to much for 35c water outlet ...
    I'm not intimately familiar with water source coil applications, but if it's too high, I'd think the problem is over-charge or reduced condensing. Those are usually the causes. Did you measure superheat and subcooling?

    You know what the condensing temp is supposed to be, relative to the water temp?

  5. #5
    Join Date
    Nov 2011
    Posts
    9
    Subcooling is 27 k ...

    Normal condensing presure is around 15




    [
    QUOTE=Saturatedpsi;14617201]I'm not intimately familiar with water source coil applications, but if it's too high, I'd think the problem is over-charge or reduced condensing. Those are usually the causes. Did you measure superheat and subcooling?

    You know what the condensing temp is supposed to be, relative to the water temp?[/QUOTE]

  6. #6
    Join Date
    Nov 2011
    Location
    USA
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    401
    27 k?

    How much in Fahrenheit?

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,596
    20bars=290PSIG, 4.5bars=65PSIG.
    70C=158F.
    27K SC = 48.6F of subcooling.
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  8. #8
    Join Date
    Nov 2011
    Location
    USA
    Posts
    401
    27K SC = 48.6F of subcooling.
    That seems like a lot of excess subcooling to me for a high temp application.

  9. #9
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,596
    Only has a 7F water delta across the evap, and 9F on the condenser.

    R407C at 290PSIG is a sat of 118F, and at 65PSIG is a sat of 42F.

    Chance of a restriction in refrigerant circuit.
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    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  10. #10
    Join Date
    Nov 2011
    Posts
    9
    We made a cleaning with acid solution of the condenser and the situation is back to normal, pressure 16


    Quote Originally Posted by Saturatedpsi View Post
    That seems like a lot of excess subcooling to me for a high temp application.

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