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  1. #1
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    Need help answering test question. Hot gas bypass or Guide Vanes?

    These are potential test questions I may have for my license HVAC test and I forgot to get them answered in todays class and have my New York City test on Monday.

    This is for a centrifugal steam/turbine chiller.

    Here are four separate questions. They can have the same answer for multiple questions, but I can only choose 1 component for each question.

    1) Find the component used during extreme low load conditions?

    2) Find the component which maintains evaporator pressure during low loads.

    3) What controls the capacity of the centrifugal compressor located on the compressor.

    4) Find the component that regulates chiller capacity.

    I don't know if the answer would be hot gas bypass or guide vanes? Would any of you happen to have an idea about how you would answer each question?

    Since each question may have the same answer or not, I'm leaning on hot gas bypass for #1, hot gas bypass for #2, and Guide vanes for question #3, and guide vanes for question #4. Thanks in advance for any advice about answering these.

  2. #2
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    So you got a copy of the test and you want us to help you cheat? Honestly, if you don’t know these answers then you don’t know anything about centrifugals so you shouldn’t be getting your license and shouldn’t be working on them. And steam turbine centrifugal chillers are very specialized chillers and only a handful of techs with many years of experience even work on them. You just took your EPA test a couple months ago.

  3. #3
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    These are multiple choose questions.........

    We need too see all the answers

  4. #4
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    Thread Starter
    Quote Originally Posted by R123 View Post
    So you got a copy of the test and you want us to help you cheat? Honestly, if you don’t know these answers then you don’t know anything about centrifugals so you shouldn’t be getting your license and shouldn’t be working on them. And steam turbine centrifugal chillers are very specialized chillers and only a handful of techs with many years of experience even work on them. You just took your EPA test a couple months ago.
    This is just so wrong accusing someone of cheating without knowing and just assuming. These were from a study guide which was given to us all and would be answered during class. I didn't to get a few questions answered during the class because the instructor rushed out to a meeting and only gave us time to get a few of the questions answered and I have my test this Monday. I've seen many other posts when people ask for help with questions from their classes and were helped on this forum without being accused of cheating. Thanks again for calling me a cheater, a liar, and feeling unwelcome and probably making most everyone else scared now to help me out.

    I'm not taking any specialized test just a general hvac test with different machines and it is a test on operating them not repairing them.


    These are not multiple choice questions but I would have to click on the component on a computer out of a whole steam chiller setup with hundreds of different parts. So based on the question I would click on the guide vanes or the hot gas bypass valve to answer the question, or really another of the hundreds of other parts highlighted on the computer but they would be wrong.

    I just don't know if Guide Vanes would be used for low evaporator pressures and Hot gas bypass would only be used for extremely low evaporator pressures. Or is this questions hard to determine as guide vanes can or hot bypass can be used for low evaporator pressures.

    The guide vanes control capacity so I'm sure they must control the pressure somewhat at low evaporator pressures.

  5. #5
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    Guide vanes limit refrigerant flow. Water temperatures determine pressures.

  6. #6
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    Quote Originally Posted by iDred View Post
    This is just so wrong accusing someone of cheating without knowing and just assuming. These were from a study guide which was given to us all and would be answered during class. I didn't to get a few questions answered during the class because the instructor rushed out to a meeting and only gave us time to get a few of the questions answered and I have my test this Monday. I've seen many other posts when people ask for help with questions from their classes and were helped on this forum without being accused of cheating. Thanks again for calling me a cheater, a liar, and feeling unwelcome and probably making most everyone else scared now to help me out.

    I'm not taking any specialized test just a general hvac test with different machines and it is a test on operating them not repairing them.


    These are not multiple choice questions but I would have to click on the component on a computer out of a whole steam chiller setup with hundreds of different parts. So based on the question I would click on the guide vanes or the hot gas bypass valve to answer the question, or really another of the hundreds of other parts highlighted on the computer but they would be wrong.

    I just don't know if Guide Vanes would be used for low evaporator pressures and Hot gas bypass would only be used for extremely low evaporator pressures. Or is this questions hard to determine as guide vanes can or hot bypass can be used for low evaporator pressures.

    The guide vanes control capacity so I'm sure they must control the pressure somewhat at low evaporator pressures.
    1&2 is hot gas bypass.
    3&4 is inlet guide vanes.

    I gave you the answer I did because in almost 4 months being on this forum the only posts you posted were 3 posts asking test questions and when given the answers, you never responded, thanked for the help, or anything. My suggestion to you is participate in this forum and converse with people after they help you instead of just posting a question and disappearing until you need help again.

  7. #7
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    Quote Originally Posted by R123 View Post
    1&2 is hot gas bypass.
    3&4 is inlet guide vanes.

    I gave you the answer I did because in almost 4 months being on this forum the only posts you posted were 3 posts asking test questions and when given the answers, you never responded, thanked for the help, or anything. My suggestion to you is participate in this forum and converse with people after they help you instead of just posting a question and disappearing until you need help again.
    His questions are for the FDNY "Operators" certificate of fitness. Required in NYC and the 5 boroughs to "Operate" any refrigeration equipment over 100-Tons.

    Like 608 its a formality and really doesn't mean squat outside of NYC

  8. #8
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    @iDred

    How was the test?

  9. #9
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    We'll see if he shows back up to say thanks....

  10. #10
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    Quote Originally Posted by timmy2734 View Post
    We'll see if he shows back up to say thanks....
    Don’t hold your breath. We probably won’t see him again until he has another test question.

  11. #11
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    Quote Originally Posted by R123 View Post
    Don’t hold your breath. We probably won’t see him again until he has another test question.
    Then hell be back shortly. I believe theres several hundred C of F's for FDNY

    Torch use
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