Pump Down Procedures
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  1. #1
    Join Date
    Sep 2005
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    46
    I am a student in HVAC/R and we are starting A/C Refrigeration Tomorrow and our teacher asked us to list the steps for Pumping Down???

    All Help Is Greatly Appreciated!

  2. #2
    Join Date
    Oct 2003
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    Washington
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    Originally posted by azikas86
    I am a student in HVAC/R and we are starting A/C Refrigeration Tomorrow and our teacher asked us to list the steps for Pumping Down???

    All Help Is Greatly Appreciated!
    First thing you should do is perform a search on this site: vacuum, pump, ac charging.

    I can tell you that the first step in pumping down is pressurizing with nitrogen. Good luck

  3. #3
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    May 2001
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    Bennington, Vermont U.S.A.
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    13,864
    Originally posted by seatonheating
    Originally posted by azikas86
    I am a student in HVAC/R and we are starting A/C Refrigeration Tomorrow and our teacher asked us to list the steps for Pumping Down???

    All Help Is Greatly Appreciated!
    First thing you should do is perform a search on this site: vacuum, pump, ac charging.

    I can tell you that the first step in pumping down is pressurizing with nitrogen. Good luck
    My impression of the question, seaton, is that he is asking how to isolate the refrigerant charge into the reciever or condenser.

    You have to give us more to go on 86.

  4. #4
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    Sep 2004
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    Memphis
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    Here's how we do it. We let the a/c run for a few minutes. Put your gauges on (of course). Then close the liquid line valve with a valve wrench. You'll see the pressures start to go down. We usually wait til the suction pressure gets to about 15-20 & pull the disconnect. The valve in the compressor will shut off the other side. After this, close the suction line valve & recover the rest. There will be very little to recover.

    You can let your suction pressure go all the way down to zero, but its not real good for the compressor.

    Life is like a jar of jalapenos. What you do today might burn your ass tomorrow.

  5. #5
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    Oct 2003
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    Washington
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    Originally posted by hvac hero
    Here's how we do it. We let the a/c run for a few minutes. Put your gauges on (of course). Then close the liquid line valve with a valve wrench. You'll see the pressures start to go down. We usually wait til the suction pressure gets to about 15-20 & pull the disconnect. The valve in the compressor will shut off the other side. After this, close the suction line valve & recover the rest. There will be very little to recover.

    You can let your suction pressure go all the way down to zero, but its not real good for the compressor.

    Is that something they teach in classes though? I always figured that was just something we do in the field to conserve refrigerant. I highly doubt they would teach that in school considering the strain it puts on the compressor. I believe he is asking about evacuating. Like bennie said, more info please.

  6. #6
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    Nov 2005
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    netherlands\europe
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    Could it be that you mean, a pump down after a cooling cycle?
    This is how it goes at the end of a cooling cycle:
    The unit drops the liquid valve, the liquid gets stored in the liq, tank, the unit pulls a low pressure becouse there is no more gas to move[ the liq, valve holds the liq,], the pump-down-pressostat stops the compressor.
    The next time the unit has to cool again, it can start with less starting amps.That is a plus!!and much easyer for the compressor.
    .................................................. ......................
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  7. #7
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    May 2001
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    Bennington, Vermont U.S.A.
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    13,864
    Originally posted by dutchcool
    Could it be that you mean, a pump down after a cooling cycle?
    This is how it goes at the end of a cooling cycle:
    The unit drops the liquid valve, the liquid gets stored in the liq, tank, the unit pulls a low pressure becouse there is no more gas to move[ the liq, valve holds the liq,], the pump-down-pressostat stops the compressor.
    The next time the unit has to cool again, it can start with less starting amps.That is a plus!!and much easyer for the compressor.
    Yes, exactly. This (what dutchcool just described) is a "pump down system". It is common to see this type of system on walk-in coolers.

  8. #8
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    Jun 2003
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    Florida
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    Originally posted by azikas86
    I am a student in HVAC/R and we are starting A/C Refrigeration Tomorrow and our teacher asked us to list the steps for Pumping Down???

    All Help Is Greatly Appreciated!


    So the first thing your teacher asked you to learn/list is pumping down a system? Sorry, I don't believe you. Register as a pro if you're really a student.

    You're a DIY IMO.

    [Edited by smokin68 on 04-11-2006 at 05:39 PM]
    If everything was always done "by the book"....the book would never change.

  9. #9
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    Nov 2000
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    Coastal Georgia
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    Register as a pro if you're really a student.

    eh?

  10. #10
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    Jun 2003
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    Florida
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    How about semi-pro James? There's already some in there.
    If everything was always done "by the book"....the book would never change.

  11. #11
    Join Date
    Nov 2000
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    Coastal Georgia
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    You do know that once upon a time there was a student. Maybe we need a student section or wait a while before he rip their heads off. I would rather piss on a electric fence than to cut a young kid up trying to learn this trade but just the same I don't think the pro area should be a open to students. That is why it is called the "Pro" area.

  12. #12
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    Jun 2003
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    Florida
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    I wouldn't purposely rip any student/person trying to learn the trade.I love learning myself. However,due to the Forum in which this was posted, I couldn't answer him/her even if their legit. I looked up their past posts, and just doesn't look right....sort of DIY topics. A student section would be DIY in no time IMO.
    If everything was always done "by the book"....the book would never change.

  13. #13
    Join Date
    Feb 2005
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    GEORGIA
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    Originally posted by James 3528
    You do know that once upon a time there was a student. Maybe we need a student section or wait a while before he rip their heads off. I would rather piss on a electric fence than to cut a young kid up trying to learn this trade but just the same I don't think the pro area should be a open to students. That is why it is called the "Pro" area.
    AMEN..
    "Value our Differences"

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