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  1. #1
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    Dec 2011
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    superheat cause increased head pressuse?

    Does evaporator superheat cause a increase in condenser head pressure? Nowhere in my entry level hvac text book have I seen this question being answered outright.

  2. #2
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    Jan 2012
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    more details, low sh, high Sh.

    why did you ask ? real trouble or ...

  3. #3
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    Quote Originally Posted by bluecool View Post
    Does evaporator superheat cause a increase in condenser head pressure? Nowhere in my entry level hvac text book have I seen this question being answered outright.
    Keep in mind that at the point your reading your head pressure your refrigerant is typically subcooled. The superheated gas is actually picking up even more heat passing through the compressor. Both in mechanical heat and the heat of recompression. Making it essential that we have proper air flow through the outdoor coil to change states and subcool the hot gas to a liquid prior to the metering device.
    Ron

  4. #4
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    high evaporator superheat will result in lower head pressures.

    as you add charge to bring down the superheat, you will start absorbing more heat in the evaporator. This increase the temperature of the condenser, which increases the head pressure.

  5. #5
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    pensacola fl.
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    Quote Originally Posted by tibs View Post
    more details, low sh, high Sh.

    why did you ask ? real trouble or ...
    I just thought it was odd that my text book from trade school didn't answer the question. Does superheat at any level from anywhere cause head pressure to increase? I suppose from the lack of responces its a boring question.

  6. #6
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    Quote Originally Posted by craig1 View Post
    high evaporator superheat will result in lower head pressures.

    as you add charge to bring down the superheat, you will start absorbing more heat in the evaporator. This increase the temperature of the condenser, which increases the head pressure.
    system charge is normal. does superheat from anywhere capable of raising head?

  7. #7
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    Quote Originally Posted by bluecool View Post
    system charge is normal. does superheat from anywhere capable of raising head?
    Superheat alone typically shouldn't to significantly but a high load will. Generally speaking SH is just the condition of the refrigerant.
    Ron

  8. #8
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    Dec 2011
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    pensacola fl.
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    Quote Originally Posted by Ron223 View Post
    Superheat alone typically shouldn't to significantly but a high load will. Generally speaking SH is just the condition of the refrigerant.
    Does shouldn't to significantly mean: it doesn't?

  9. #9
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    Sep 2008
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    VA
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    What is your definition of superheat?
    "The only true wisdom is in knowing you know nothing" Socrates

  10. #10
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    Quote Originally Posted by bluecool View Post
    Does shouldn't to significantly mean: it doesn't?
    Your asking for a definitive answer to something with many variables. I'll venture to say that with normal load conditions, proper charge and airflow, no. If it did contribute the pressure increase would be minimal because you have to keep in mind that the purpose of the outdoor unit (in cooling) is to reject heat. Do you have a good understanding of the three states of refrigerant? And the refrigeerant cycle? I'm not making any assumptions as to what you do or don't know but if not this would greatly help you understand what your asking. And is this just a general question or are you actually trying to troubleshoot a job? Of so whats the rest of the conditions?
    Ron

  11. #11
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    NW AR
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    Quote Originally Posted by craig1 View Post
    high evaporator superheat will result in lower head pressures.

    as you add charge to bring down the superheat, you will start absorbing more heat in the evaporator. This increase the temperature of the condenser, which increases the head pressure.
    That is assuming the charge is low.

  12. #12
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    Dec 2011
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    pensacola fl.
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    Quote Originally Posted by Ron223 View Post
    Your asking for a definitive answer to something with many variables. I'll venture to say that with normal load conditions, proper charge and airflow, no. If it did contribute the pressure increase would be minimal because you have to keep in mind that the purpose of the outdoor unit (in cooling) is to reject heat. Do you have a good understanding of the three states of refrigerant? And the refrigeerant cycle? I'm not making any assumptions as to what you do or don't know but if not this would greatly help you understand what your asking. And is this just a general question or are you actually trying to troubleshoot a job? Of so whats the rest of the conditions?
    not troubleshooting, thought I might learn something especially if someone answered yes. Although, didn't know a refrig. could reach a solid

  13. #13
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    Mar 2007
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    NW AR
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    Readings during a hot pull down or heavy load would show high superheat and higher head pressure.

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