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  1. #14
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    Apr 2019
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    it was 59F. Sorry my meter was metric ,didnt convert right

  2. #15
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    Apr 2019
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    Quote Originally Posted by doc havoc View Post
    Are you sure there's not a filter/drier inside the condensing unit that's restricted? That could explain the cool liquid line temp.
    there is no dryer on this system, only thing on line might be a piston hiding in line at evap

  3. #16
    Join Date
    Jan 2015
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    Iowa
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    I think BNME8EZ hit the nail on the head. While a better job of troubleshooting may have been done it was not documented in the OP or follow on comments. Take a full set of readings and give the unit a good inspection before you do anything else

    Good Luck

  4. #17
    Join Date
    Jul 2018
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    NW Louisiana aka Hell Pit of Louisiana
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    This may very well be a system that was installed and never vacuumed properly, if at all. the fact that you found the pistons near the outdoor units, that tells me they also left the piston in the 'A' coil that came in it and it is probably mis-matched. At the very least, I would recover the existing charge, nitrogen purge and check the indoor piston against the outdoor unit and replace if necessary, replace or install a drier after making sure the system holds pressure and vacuum according to epa regulations, purge with nitrogen once more and vacuum to 500 microns and recharge and set according to superheat/ subcool.

    If it is going up and down like you stated, it is more than likely, non-condensibles in the system and if it was never vacuumed from initial install, it could be a clog from waxing or other debris in the system from moisture. I had one just today, it was a new install by a retired contractor, that did the job for a little extra money, he didn't vacuum the system, it was doing the same thing as you described, high on subcool and superheat but fluctuating up and down. recovered, flush with nitrogen and verify it held pressure and vacuum, replaced drier and recharge to correct superheat and I like to check subcool as well and the unit was steady and working properly at that point. R22 is way more forgiving than R410-A, it has been my experience, R410-A will not cool correctly or you run into compressor shut down from over temp if you don't set the subcool or superheat correctly.

  5. #18
    Join Date
    Jul 2018
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    NW Louisiana aka Hell Pit of Louisiana
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    Quote Originally Posted by zebra1 View Post
    That's what I figured too. Now have to suck r22 to recovery, replace piston, purge, vaucum and refill. Somewhere on youtube, two dudes said no need to vacuum if only replace piston, any idea?
    You should always pull a vacuum

  6. #19
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    Jul 2018
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    NW Louisiana aka Hell Pit of Louisiana
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    Quote Originally Posted by zebra1 View Post
    Now I am wondering if someone either half or total close the service valves on suction or liquid lines would cause this problem, because the owner told me the tech before me tried very hard to persuade him to replace the whole system and very rarely I saw two systems have piston failed at same time. I outside now, and wont go there until next tuesday, waiting for pistons.. But meantime, anyone can tell me if the block of service valves can cause the same restriction problem as i first mentioned?
    I have came across this as well. The guy before me was telling the home owner their system wouldn't last to the end of the summer and he had partially closed off the valves. What happened on this instance, The compressor wasn't getting enough refrigerant back and it was shutting off on over temp. I shut it off and iced it down and left it over night. what I observed on the gauges, it would pull down on the low side and had a low pressure on the high side but keep running and made a weird noise, like the compressor was loading up, but it wasn't showing high pressure on the gauge, then after the compressor shut off, both the high side and low side pressure would start to rise. This threw me for a loop, so I decided I was going to valve off the compressor and go inside and see if the piston was clogged and that's when I found the valves partially closed and decided to ice down the compressor and leave it off over night to cool. The next morning, it started up and worked, that was 5 years ago, we now clean and service that ac and it hasn't been replaced yet. Oh, the condenser was really dirty, that was the only thing I found wrong with it, besides the partially closed valves. The worst thing about it is, I helped the other contractor get started and he is dishonest, I can tell you this, honesty will take you a long way and you can feel good about yourself when your head hits the pillow at night.

  7. #20
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    Apr 2019
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    I am back.Thanks for all posting here. Really appreciate it.
    After reading all your comments, I came to the site, parts still not here yet. But I checked the valves, all full back seated open, so restriction must came from elsewhere, most likely metering device. I recheck the whole system, inside out condenser, no filter/dryer, upstair attic, only two lines directly to evap box. And I am afraid of compressor burnt out, and did acid test of the R22 in sys, negative. Now I am planning to do the following while waiting for parts

    1. recover all r22 in sys and weigh
    2. take out piston and close without new piston to prevent clog again.
    3. purge the whole system (this one I am not sure to purge section by section, like full front seated both service valves to purge line set with evap coils first then the whole sys or just purge the whole altogether)
    4. install the new piston
    5. vacuum the whole system to 500 micro manufacturer said to 23,000 micro absolute pressure. Whathack atmos pressure minus vac pressure? hold to check leak
    6. purge once more. vacuum once more
    7. weigh in R22 to manufacturer nameplate 4 lb 13oz. line is abt 35ftx2
    8. start the sys check super heat add more R22 if necessary.

    Pls comment if anything I missed or make suggestions

  8. #21
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    Apr 2019
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    also, I will use dryer to do the recovery. Is that I can still use the old R22 to refill back or better use virgin R22? I inclined the latter. And I am not planning to install dryer in the system which involve brazing. And basically Las Vegas is pretty dry all year round

  9. #22
    Join Date
    Apr 2004
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    MN
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    Quote Originally Posted by zebra1 View Post
    also, I will use dryer to do the recovery. Is that I can still use the old R22 to refill back or better use virgin R22? I inclined the latter. And I am not planning to install dryer in the system which involve brazing. And basically Las Vegas is pretty dry all year round
    Refill with virgin R-22. If a vacuum was never pulled, the stuff you recover will be contaminated and unuseable. Why no drier? The weather in Nevada has no bearing on the function of the filter/drier.
    A Veteran is a person, who at some point in their life, wrote a blank check payable to the United States of America for payment up to and including their life.
    Gene Castagnetti-Director of the National Memorial Cemetery of the Pacific in Hawaii

  10. #23
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    Apr 2019
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    Quote Originally Posted by doc havoc View Post
    Refill with virgin R-22. If a vacuum was never pulled, the stuff you recover will be contaminated and unuseable. Why no drier? The weather in Nevada has no bearing on the function of the filter/drier.
    Good question. Originally, this Lennox 13ACD-230-30 manufacturer set up has no dryer configuration. So I leave it alone.

    seehttps://www.hvacpartsshop.com/conten...ACD_Series.pdf

  11. #24
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    Dec 2009
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    maroon lazyboy
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    Edited post: wrong info taken from ACX manual instead of ACD

  12. #25
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    Apr 2006
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    Tyler, Tx
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    You need a drier installed on the liquid line, it has the job of protecting the metering device. And it should be the brazed in kind, the flare could be a future leak if lines vibrate any.
    Philippians 4:13
    I can do all things in him that strengthen me.
    Apostle Paul inspired by GOD.

  13. #26
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    Aug 2002
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    Southold, NY
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    Quote Originally Posted by Artietech View Post
    You need a drier installed on the liquid line, it has the job of protecting the metering device. And it should be the brazed in kind, the flare could be a future leak if lines vibrate any.
    Nothing wrong with a properly flared drier install!

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