Air in the line
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Thread: Air in the line

  1. #1
    How do you get the air out the system with out recovering everything? I open system without a vacum. System works good, but you can hear air at liquid line near a-coil.

    I hate to remove all freon, but I think that all I can do..

    regards,
    Kelvin

  2. #2
    Join Date
    Nov 2004
    Posts
    2,927
    What type system?

    Since air is considered non-condensable it should pass into condenser and stay there.It also finds the highest point(or rather,since the liquid weighs more it finds the lower places.)Anyway,the only method I know of is to vent off a high point in condenser.I know that is not always possible...

    Is your name really Kelvin?I use to know a Kelvin.We called him the Kelvinator.Are you from Texas?

  3. #3
    Join Date
    Oct 2001
    Location
    Waterford Michigan
    Posts
    2,668
    You can tell its air by the sound? Wow; I always thought the sound was the Freezon.

  4. #4

    yelp

    Yelp, I am from texas..

    I heard the girgaling at the liquid line near the evaparator..

  5. #5
    Join Date
    Sep 2002
    Posts
    532
    I have the same sound at the same place... I always thought it was air, my contractor says it's "normal" freon sound. Still sounds like trapped air to me. Unfortunately my line goes up 7 feet across and down 10 feet... no easy way to bleed anything off.

  6. #6
    Join Date
    Sep 2001
    Location
    Vancouver Canada
    Posts
    996
    What do you mean " I open system without vacuum"? Did you install this unit and then not evac. the system? I would be concerned not so much with dry air in the system but certainly with the moisture contained in the air. Creates a nice little acid cocktail for your compressor. I would say have a tech pull the charge, evac. and recharge with virgin freon.
    "Go big or Go Home"

  7. #7

    ok

    I did this job for my cousin... I replaced furnace and ac system.. In a hurry came back next day and open up the lines..I went to the furnice..I could here the freon girgaling at the evaporator... I thought it was low on freon added a little, but preasure show it to be ok.. After I got to work and thought about it.. I remembered not vacuming the system down.. That where the girgaling came from air in the place of the freon.

    He say it works fine, but I will get over and recover and recharge system..

    regards,
    kelvin

  8. #8
    Join Date
    Apr 2003
    Location
    the Great Pacific Northwest
    Posts
    607
    Non condensable = elevated to high head. What's your S.C.

  9. #9
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,271
    If the system uses a piston for a metering device at the evaporator coil, there can be a "gurgling" sound if the piston is not receiving a full column of liquid in the liquid line from the condenser. Usual causes are undercharge or filthy condensing coils which leads to little to no subcooling before liquid leaves condenser, which may lead to liquid flashing into vapor in liquid line, especially if liquid line runs through very hot attic.

    On a normally operating system with a piston, there can be "gurgling" at the piston when the system first starts up until everything smooths out as head pressure builds and the system balances out.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


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  10. #10
    Join Date
    May 2005
    Location
    Calgary, Alberta, Canada
    Posts
    92
    Klyons,

    So in a hurry you opened condenser valves and forgot to pull a vacuum on the system, is that correct??

    -websy
    Yes we have air conditioning in our igloos.

  11. #11

    yes, yes, yes

    yes, that is what happen...

  12. #12
    Join Date
    Apr 2004
    Location
    Midwest
    Posts
    2,682
    There are many issues to talk about in this thread…

    I am guessing pressure testing with Nitrogen and utilizing a good micron gauge is out of the question?

    I doubt very seriously you are hearing air gurgling. What you are hearing is the fact that the liquid line is not a full column of liquid refrigerant.

    This is probably due to air that is being trapped in the condenser/moisture freezing at the metering device. Easy to tell, fluctuating pressures, high head, high sub-cooling...

    Typically head is high because you are reading more than one compound, instead of reading just the refrigerant pressure you are reading refrigerant + air + moisture…it’s a false reading.

    This in turns jacks up your sub cooling number to some ridiculous levels, like 30/40 degree’s.

    Although I am assuming this is a side job you still should be practicing proper refrigeration techniques.

    Get rid of the refrigerant, add liquid line dryer, pressure test with Nitrogen, evacuate with a Micron gauge, confirm airflow, set charge accordingly (by superheat with a piston, by sub cooling with TXV)

    Slow down, do it right and stop doing side work…especially for family!
    Live each day like it is your last, for one day you will be right!

  13. #13
    Join Date
    May 2005
    Location
    Calgary, Alberta, Canada
    Posts
    92
    Yes unfortunatley Klyons you are going to have to pull the gas and air from unit. I know what its like to be in a hurry, especially on a side job that you prob. aren't making any money on anyways.Life sucks.

    -websy
    Yes we have air conditioning in our igloos.

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