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Thread: New compressor not working properly

  1. #1
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    New compressor not working properly

    I have a Goodman CLT 36B air conditioner that just had the compressor replaced. A friend of mine (HVAC tech) did the replacement. However, when he charged the unit to the recommended lbs. and started it up, it made a very loud noise (at start-up and about every 30 seconds or so). I'd describe the noise as a very loud vibrating or humming.

    He took out the refrigerant and purged the lines from both the inside and outside and re-charged. Same result, loud noise.

    He took out a few lbs. of refrigerant and the loud noise stopped, but the lines iced up. Unfortunately, he had to leave before he could troubleshoot more.

    Also, the capacitor was replaced, the fan motor replaced and he added a hard start capacitor as well.

    Any ideas as to what the issue(s) might be would be greatly appreciated.

    Thanks!

  2. #2
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    What we're all the readings and measurements? SH? SC? What killed the previous compressor? Refrigerant being used? Was the unit flushed? Micron level achieved? Piston or TXV? Conditions during startup? Is this the correct compressor?
    I havent failed. Ive just found 10,000 ways that wont work. - Thomas Edison

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  3. #3
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    Thread Starter
    Sorry, I don't have readings (SH, SC). I'm not quite sure what those are?

    What killed the previous compressor? Age I suppose. It was about 10-11 years old.

    R-22 refrigerant.

    It was flushed.

    Not sure of micron level.

    Piston (he removed the piston, cleaned it and put it back).

    Conditions at start-up, about 80-85 degrees, somewhat humid.

    It's the same compressor that came with the original unit.

    Hope this helps.

  4. #4
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    Compressors don't really just "go bad", especially after 10-11 years. They are usually killed via other issues. You may be finding out what did the old compressor in, which will require further troubleshooting.
    Superheat and subcooling readings are what I was asking, your friend should have been using those to charge the unit properly.
    Is this new refrigerant? If the old refrigerant was being reused has it been tested for acid?
    I havent failed. Ive just found 10,000 ways that wont work. - Thomas Edison

    Its not whether you get knocked down, its whether you get up. - Vince Lombardi

    "In this house we obey the laws of thermodynamics" - Homer Simpson

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  5. #5
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    It sounds to me like he slugged the new compressor with liquid when he weighed in the refrigerant the after he took so me out he didn't get it added back in properly so it started to frost up.

  6. #6
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    Thread Starter
    Thank for the SH/SC explanations. I'll ask him what they were.

    As far as I know it was new refrigerant. I'll ask him that as well.

  7. #7
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    This is why residential customers are warned about replacing expensive components outside of warranty. You likely had something happen, to kill the previous compressor. Now that there's a new compressor installed the original problem remains. Your friend will have to sit with it and pick through the system to figure out what's happening. If it's not fully diagnosed, and properly charged, you'll be changing the compressor again shortly
    Last edited by rider77; 06-07-2016 at 09:26 AM.
    I havent failed. Ive just found 10,000 ways that wont work. - Thomas Edison

    Its not whether you get knocked down, its whether you get up. - Vince Lombardi

    "In this house we obey the laws of thermodynamics" - Homer Simpson

    Local 486 Instructor & Service Technician

  8. #8
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    Thread Starter
    Thanks again.

    I've shut it down for now. I'll call a local service tech.

  9. #9
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    I am pulling out 6 40 Year old units tomorrow that work just fine.
    We are replacing them as part of a budget upgrade.

    My point is that compressors don't wear out easily after 10 years.
    Find out what took out the first one and fix it on this one....
    "The value of quality is long rembered after the thrill of low price is forgotten."

  10. #10
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    Thread Starter
    Makes sense. My original reason for reaching out on this forum was that a service tech came out last fall and only said to replace the compressor. He never mentioned that it should not have failed after only 10 years or addressing any reason(s) that it would need to be replaced that caused it to fail to begin with. If you have any thoughts as to what the main culprits are to ask a tech to look for, please let me know.

    Thanks again!

  11. #11
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    There's a million and one things that can cause the compressor to fail, everything from restrictions, incorrect charges, incorrect sizing, lineset issues, oil issues, refrigerant issues, contamination issues. Readings and measurements must be taken to determine what the cause is.
    I havent failed. Ive just found 10,000 ways that wont work. - Thomas Edison

    Its not whether you get knocked down, its whether you get up. - Vince Lombardi

    "In this house we obey the laws of thermodynamics" - Homer Simpson

    Local 486 Instructor & Service Technician

  12. #12
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    From my own experience....10 years ago we just started paying attention to how much refrigerant we put in r-22 systems. My training 25 years ago on installing ac units was to dump refrigerant in until the big line got cold and water came out of the drain. not sure about the guy that installed yours but not too many people told me I was wrong for a lot of years.....

    10 Years agoish R-22 starting moving out and R-410a started moving in...with 410a came training that told me how many systems I had put in unknowingly wrong....like so may others I imagine...we now have better ways to diagnose and charge units.

    Whoever is filling the unit should use superheat and subcooling as a charging method. This will tell that person if your system is operating the way it should and how to fix it....In short...we did things different back then and only some people caught up. Make sure your tech is caught up....if he can't tell you what the SH and SC is send him here...we will shame him enough to learn....
    "The value of quality is long rembered after the thrill of low price is forgotten."

  13. #13
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    don't worry. a competent tech will know what to look for.

    a parts changer will not.

    ability to change a compressor, and the knowledge how to diagnose a problem with a compressor installation are different skills entirely.

    most likely there is an orange or yellow card that came with the compressor with blanks to fill in several parameters after the install is complete...

    google compressor change card...
    The TRUE highest cost system is the system not installed properly...

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  14. #14
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    YOU NEED a new tech

  15. #15
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    I know what the issue is.
    You had a guy "come over and change a compressor" without a complete diagnostic inspection.
    And now you have the same problem.
    "Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler

  16. #16
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    Goodman = plugged pickle drier in the condensing unit that should have been removed but is still there...Everton a tech comes out they add refrigerant because it looks low as the are check8ng downstream LL pressure, not discharge....in the end, these units are grossly overcharged and the compressors overworked

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