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  1. #1
    Join Date
    Aug 2011
    Location
    NYC
    Posts
    6

    Liquid Line Pressure ZERO But Suction Fine?

    Hello,

    This is an AC R22 Unit for my home. Specifically, the second floor split system. It's a Goodman 2 1/2 ton (Wish I had a 3 ton Now that it was 115 In NYC) and the AC just barely handle this.

    Anyway, when the weather cooled off I tested my system to see why it could barely handle this while the exact same system downstairs kicked ass during that time.

    I have superheat at 4f or around outside on the blue dial with 55f wet bulb temp. I had to run this higher due to the suction length being over 50' to my attic. I'm using a 3/4 line set but I thinking about getting bigger to reduce the pressure.

    Problem:

    My Line Pressure (Red Dial) is zero.nada zilch. I cleaned the entire system and flushed the condenser in the attic out with a garden house for an hour after spraying it with mold spray first. There was little black mold spots in the condenser not allot but it was enough to make me clean it good. The air filter however was so clogged from 5 cats that I don't know how it even worked. It's all cleaned now and almost new again... 5 years old.

    When my AC guy put these in they came with a little bag that had a fixed orifice valve. I'm thinking its probably DOA now. I read about TXV are better for my system than fixed valve.

    I'm hoping that its only a clog in the line from the fixed orifice valve but I can't see it being anything else since I'm able to get pressure from the suction line with no problem.

    Ideas: Suggestion?

  2. #2
    Join Date
    Feb 2011
    Location
    North East Ohio
    Posts
    786
    how do you have pressure in the return(suctiuon) line if you don't have pressure in the supply(liquid) line?

  3. #3
    Join Date
    Jan 2009
    Location
    South Georgia
    Posts
    53
    valve core in unit damaged or valve core depressor in hose missing or damaged.

  4. #4
    Join Date
    Aug 2011
    Location
    NYC
    Posts
    6
    I have no idea. I tried to open and close the valve on the outside condenser several times to try to free up whatever is blocking the pressure. Im thinking of replacing the valve orfice?

    Any Ideas?

    Thanks

  5. #5
    Join Date
    Mar 2011
    Posts
    13
    My opinion would be the valve core depressor in the gauges. I have been called out before , when this happened and twisted the gauges down a little bit more and it was fine.

  6. #6
    Join Date
    Aug 2011
    Posts
    568

    Cool

    Quote Originally Posted by mikeinnyc View Post
    I have no idea. I tried to open and close the valve on the outside condenser several times to try to free up whatever is blocking the pressure. Im thinking of replacing the valve orfice?

    Any Ideas?

    Thanks
    call a hvac tech, and have him ck. the unit!

  7. #7
    Join Date
    Aug 2011
    Location
    NYC
    Posts
    6
    I didn't think of that. I will try the gauges on my other system to see if the red dial works properly. If not I will call a tech Again but this time I want a filter and a sight glass and a TMV instead of a fixed one.

    When you say valve you mean on the condenser in my attic or the compressor outside?

  8. #8
    Join Date
    Aug 2011
    Posts
    568

    Confused

    Quote Originally Posted by mikeinnyc View Post
    I didn't think of that. I will try the gauges on my other system to see if the red dial works properly. If not I will call a tech Again but this time I want a filter and a sight glass and a TMV instead of a fixed one.

    When you say valve you mean on the condenser in my attic or the compressor outside?
    just wondering what is a TMV?

  9. #9
    Join Date
    Mar 2009
    Location
    Triad - North Carolina
    Posts
    439
    I like Ebay, where anyone can buy tools he does not know how to use.
    Yes, I've seen that before and it doesn't mean I like it.

  10. #10
    Join Date
    Aug 2011
    Location
    NYC
    Posts
    6
    txv my bad expansion valve.

    Hopefully I wont have to bother. I think maybe my gauges maybe the problem. Otherwise I would not have cold air right? It appears to be working fine yet my tool maybe missing a part from hanging on my garage wall for a few years.

  11. #11
    Join Date
    Feb 2011
    Location
    North East Ohio
    Posts
    786
    Quote Originally Posted by mikeinnyc View Post
    I didn't think of that. I will try the gauges on my other system to see if the red dial works properly. If not I will call a tech Again but this time I want a filter and a sight glass and a TMV instead of a fixed one.

    When you say valve you mean on the condenser in my attic or the compressor outside?
    OK it's a TXV or a TEV (thermal expansion valve) The condenser coil is outside in the compressor unit. The indoor coil is the evaporator. How long is the line set and how high does it go? A filter drier should be installed anytime you open a system to ambient conditions. A sight glass is probably not needed. But if you want to pay for it, it won't hurt.

  12. #12
    Join Date
    Aug 2011
    Location
    NYC
    Posts
    6
    My Attic is way high, Its a victorian house about 25-28' straight up with 20' run from driveway and attic. The pressure was much higher from day one 85lbs my other is around 75 but my ac guy said its under 90lbs don't worry be happy.

  13. #13
    Join Date
    Feb 2006
    Location
    Phoenix,AZ
    Posts
    2,895
    Don't feed the clueless!

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