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  1. #27
    Join Date
    Feb 2004
    Location
    New Mexico
    Posts
    5,542
    I'd listen to NormChris on this. All compressors that fail too soon or any if you have the time and the techsshould be torn down. I remember one I tore down and it reveiled a phase failure. All looked ok until I followed the supply to another subpanel and found a failled buss bar. Beleive the evidence. Bleading phase protectors??? Give me a break.
    Tracers work both ways.

  2. #28
    Join Date
    Sep 2002
    Location
    South Dakota
    Posts
    6,579
    Originally posted by penny lane
    I appreciate all the feedback surrounding the failed compressors at my building. The service company I have tried to leave out for reasons of decorum is Trane. The compressors that are installed here (regularly it seems) are refurbished. Which makes me wonder if the problem is in the compressor, not the phase monitor or some phantom electrical charge. The other possibly that Shophound mentioned is airflow. This building is in the heart of New York City and the unit was built with noise control in mind so it is possible that there is some interference to the airflow. I’d be shocked if we were loosing so many compressors to airflow, but it is a possibility.
    Rebuilt compressors are often of as high a quality as new. If the compressors were rebuilt at a rebuilding facility I would generally discount the compressor as the problem.

    Low airflow could be the problem but that is only one of a number of possibilities. If low airflow is the problem that too can be detected as resulting in liquid floodback causing bearing failure and and an electrical failure as one possibility.

    The local Trane dealer is not the same as Trane factory service. Just because their name is Trane does not mean they are actually Trane factory personnel.

    Unless you specifically locate a technician trained in "compressor failure analysis" you will just be guessing when you change to another service company. You need a verified "expert" in compressor failures.

    Norm

  3. #29
    Join Date
    Sep 2002
    Location
    South Dakota
    Posts
    6,579
    Originally posted by hvacbear
    Norm are'nt you in Arizona?

    Also we need to educate the customers to demand quality service. The major manufactureers are a good start ,but when it comes to the people writing the checks then the industry will listen. No one would dream of going to an improperly trained doctor for a 100$ physical but they fork over 5000$ to a hack to make them uncomfortable in thier own home. I don't understand:[
    No, I work out of the York UPG factory in Oklahoma.

  4. #30
    Join Date
    Jan 2004
    Posts
    144
    The one thing that jumped into my mind as I read the original post was acid test and clean up if a burnout was the oiginal problem. Just my dos pesos.
    Licensing laws are tough, and it's about time.

  5. #31
    Join Date
    Dec 2003
    Location
    Nevada
    Posts
    1,815
    Sorry I got the wrong Norm
    Quote
    “Engineers like to solve problems. If there are no problems handily available, they will create their own." Scott Adams

    "We can't solve problems by using the same kind of thinking we used when we created them."
    Albert Einstein

  6. #32
    Join Date
    Jun 2004
    Location
    Richmond Virginia
    Posts
    1,078
    Never replace a semi-hermetic compressor without pulling the heads and sometimes hand hole covers to inspect the defective compressor and try to determine the cause of the failure. Norm Chris is dead on; many electrical failures root cause are actually mechanical in nature.

    As for the phase monitor, I have found many that are incorrectly wired in the control circuit to break the compressor through the normal "hot" wire. If the system has a pump down circuit, that will not catch the compressor and cut it off. It's usually better to break the common wire to all the loads (and make sure you are also killing the liquid line solenoid also).

    When dealing with multiple compressor failures, question everything. Don't assume that even the safeties are the correct type for the system. Use an adjustable oil pressure switch that is set to the actual minimum oil pressure you are looking for on the compressor you're working on. I've lost count of how many 9 psi oil pressure switches I've seen on Trane or Copeland compressors that need a minimum of 40 psi net oil pressure. Check every pressure switch and timer for proper operation, and check all solenoids for migration. Also check the system under different load conditions whenever possible. That TXV with great superheat during a heavy load; is it throttling back when the load is lighter.

    Norm Chris, I'll be contacting Virginia Air Distributors regarding the possibility of training classes.

  7. #33
    Join Date
    Sep 2002
    Location
    South Dakota
    Posts
    6,579
    Seaboard:

    They may still be working with our old course schedule and list of classes. Just today I have been generating our new course list and it is much more extensive than last years. So Virginia Air will not be aware of our 2004-2005 offerings yet. You could always have them call me.

    Norm

  8. #34

    Talking

    Wow!What did they forget to do three times?

    Such as a acid test, system flush (nu calgon rx11 flush), extra clean filter driers installed on the suction and discharge line. New start components are also needed for the compressor.. contactors, capicitors, pontential relays..

    I'm just curious what did the contractor and or factory tech put on the invoice as materials other than the compressor and labor.

    Three phase protector gives low/high voltage protection, phase loss, short cycling, momentary power interruptions.
    Its designed to save the units life,not kill it.

  9. #35
    Join Date
    Feb 2004
    Location
    New Mexico
    Posts
    5,542
    I was lucky enough to take a three day Carrier compressor failure seminar in Phoenix about 12 years ago and it changed the way I look at failures completly. If any of you get a chance to take the classes I'd say do it.
    Tracers work both ways.

  10. #36
    Join Date
    Mar 2003
    Location
    NY
    Posts
    2,146
    Wow!!! This one sounds like a major blunder on the part of the service contractor. These replacements should all be under warranty. Makes you wonder where they are getting the compressors from. You would think that the supplier would send a rep. to check this out.

    Just my W.A.G. on this. My bet is it has nothing to do with clean-up, acid etc. too quick, three days or so. Definitely not the phase monitor. (This says a lot about the service tech that is there.) My guess is it has something to do with single phasing, flooding back, or a VERY dirty condenser. Just my 2 cents.

  11. #37
    Join Date
    Feb 2002
    Location
    Oregon
    Posts
    292
    I think that I would be looking at floodback.
    Do it right the first time.

  12. #38
    Join Date
    Oct 2002
    Posts
    970
    Originally posted by hvacbear
    Had one that blew out a compressor because our controls contractr wired it into the compressor contactor. The unit has a liquid line solinoid valve controled by a seperate t-stat and a time delay wire in series with the time delay in the phase monitor eventually wired into the low press control for the compressor. When the compressor came on 20 min after the solinoid valve opened dumping liquid into the suction it blew it's valves. There were 5 compressors previously and since we rewired it there have been none for over 2 years.

    I don't understand how you smacked that compressor, bear.

    Liquid injection solenoid right into suction?
    I work with the Chiller Whisperer...

  13. #39
    Join Date
    Dec 2003
    Location
    Nevada
    Posts
    1,815
    No, liquid would build up in the evaporator which is fed by two expansion valves that were usually fully open. Twenty min. later when the compressor finally came on a large “slug” of liquid would be pooled up in the evaporator and in an improperly constructed trap. The compressor would get a double whammy from the two slugs in a row pushed by the head pressure 110 degree ambient blows through two wide open txv’s along with help from the suction.
    Quote
    “Engineers like to solve problems. If there are no problems handily available, they will create their own." Scott Adams

    "We can't solve problems by using the same kind of thinking we used when we created them."
    Albert Einstein

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