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  1. #14
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,847
    Quote Originally Posted by ultitech View Post
    im saying my pressures are in range of where they should be for a 90 deg day. Pressure alone is not a good diagnostic metric. they are not indicating a problem but the line set temp is stuck at 80degs I assume that you mean the suction line temperature.which is not in range and i said the needle goes into retard when charging a r-22 unit with r-22 gauges not pass retard but when you close your valve the needle should quickly go back up not take 3mins to go back up ( i replaced the valve core as well). I think this is a red herring. Forget it for now. the unit is 12 yrs old So what? and is just now having a problem, its not a airflow problem and it doesn't matter how much more freon i put in, the pressures will keep going up like normal but the line set temp will not budge. After i replaced the liquid line dryer and got my head pressure down the compressor doesn't overheat anymore and has been running for 3 days but still the evap only gets cold and sweats on the bottom of the coil, its completely dry on the top half. It doesn't matter what my cfm, wetbulb or temps are, the coil should be saturated top to bottom. for some reason the freon is just not flooding the coil. Im leaning toward a compressor problem.
    I've made some more notes in red. I was in a hurry earlier to go to dinner with my family.

    I also highlighted what I believe to be the error in your logic in blue. Could you please explain to me why you believe that a compressor problem, with what you claim to be "perfect pressures" could be causing your problem?

    The compressor is pumping, you needn't ask more from it at this point in time.

    As requested, please take the requested readings and post back. We'll explain what the problem is and WHY we know it to be the problem from the information that you haven't yet provided.

  2. #15
    Join Date
    Feb 2012
    Location
    Toronto Canada
    Posts
    1,090
    So Blowing a Ton of Hot air across your coil wouldn't cause it not to be wet? I think you better run the unit close the liquid line valve and see if your gauge Retards.
    Or just listen to JP advice cause he knows his Refer
    We need more info to help you

  3. #16
    Join Date
    Dec 2007
    Posts
    4,743
    I will say air flow is MOST DEFINITELY something to check.

    Had an almost same situation today, low TD, low pressures, warm coil, SH & SC off and they wanted on one of our maintenance policies.

    Mind you, this unit was installed as a package with a furnace in 1995 by others. We have serviced the furnace since 2002, but only replace the capacitor in the outdoor unit and nothing else done according to the service sticker.

    Well it was a 75K furnace with a 1.5T a/c with blower tap for cooling on high.

    I found an old invoice with a reading of 11555 CFM, 50/120 PSIG, 74 AMB and a
    16 TD. This was also after he added a LB of refrig because he replaced the core due to a leak( maybe low pressures due to improper, too much, airflow?).

    Duct work is spotty at best.

    Lowered to heat tap, which was 752 CFM, lowest possible, got a 16 TD, but it is, was and will always be WRONG!!!

    So YES airflow matters!!!!!!!
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  4. #17
    Join Date
    Jul 2012
    Location
    Athens, GA.
    Posts
    143
    This is just a wild guess from a new student. I am thinking oversized orifice because of low superheat with high suction side pressures.


    JASON sent this from his DUMB-PHONE

  5. #18
    Join Date
    Nov 2009
    Location
    Kansas City
    Posts
    124
    Definitely need all your data:: return dry bulb, return wetbulb, supply temp, outside ambient, low pressure, high pressure, liquid line temp, suction line temp, condenser saturation temp, and evap saturation temp, with all those numbers you can tell exactly what is wrong, no ifs ands or butts. Science doesn't lie

  6. #19
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,847
    Quote Originally Posted by TriplePoint View Post
    This is just a wild guess from a new student. I am thinking oversized orifice because of low superheat with high suction side pressures.


    JASON sent this from his DUMB-PHONE
    Where did he post about low superheat?

  7. #20
    Join Date
    Apr 2012
    Location
    winnipeg
    Posts
    1,330
    give the guys want they want.... superheat wet bulb dry bulb and you will get help..... no info we cant help.... and 80 suction is not really all that normal
    it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair

  8. #21
    Join Date
    Jul 2012
    Location
    Athens, GA.
    Posts
    143
    Quote Originally Posted by jpsmith1cm View Post
    Where did he post about low superheat?
    I assume the 80 was suction temp then looking at his pressure 225=77 sat. temp.

    JASON sent this from his DUMB-PHONE

  9. #22
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,847
    Quote Originally Posted by TriplePoint View Post
    I assume the 80 was suction temp then looking at his pressure 225=77 sat. temp.

    JASON sent this from his DUMB-PHONE
    I made the same assumption, so he is running an 80 pound suction which is about 48 degrees SST, giving him 32 degrees of superheat.

    225# head is about 109-110 SCT.

    Where the heck did you get 77 degrees from?

  10. #23
    Join Date
    Jul 2012
    Location
    Athens, GA.
    Posts
    143
    Quote Originally Posted by jpsmith1cm View Post
    I made the same assumption, so he is running an 80 pound suction which is about 48 degrees SST, giving him 32 degrees of superheat.

    225# head is about 109-110 SCT.


    Where the heck did you get 77 degrees from?
    Damn I was looking at 410 pt.
    Rookie mistake. Lol

    JASON sent this from his DUMB-PHONE

  11. #24
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,847
    Quote Originally Posted by TriplePoint View Post
    Damn I was looking at 410 pt.
    Rookie mistake. Lol

    JASON sent this from his DUMB-PHONE


    I don't work with 410a enough to know the numbers like I do with 22, otherwise I would have spotted that right away.

  12. #25
    Join Date
    Jul 2012
    Location
    Athens, GA.
    Posts
    143
    One of these days I am going to correctly diagnose one of these internet service calls.

    Jp, is SST suction superheat temp and SCT subcool temp ?

    JASON sent this from his DUMB-PHONE

  13. #26
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,847
    Quote Originally Posted by TriplePoint View Post
    One of these days I am going to correctly diagnose one of these internet service calls.

    Jp, is SST suction superheat temp and SCT subcool temp ?

    JASON sent this from his DUMB-PHONE
    Saturated Suction Temp
    Saturated Condensing Temp

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