Are new compressors built worse or is it the gas??
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  1. #1
    Join Date
    Aug 2003
    Posts
    26

    Confused

    I got a job at a big resturant doing mantinance. Things mostly for the building but just recently there has been several small coolers down and owner asked me if I can fix them. He has a refrigration company do repairs and maintaince but they are not cheap. I looked at coolers and all of them have dead compressors. One of them is locked up another shorted start winding and thrid one a grounded run winding. All of these coolers where r12 and one time and now where converted to either r134a or mp39. These comprssors are 1/3hp.

    The owner is upset because most compressors are 2-3 years old and the orginal ones lasted longer than that he said. Also just before these compressors died the refrigration company replaced the compressor in a big preptable. A month ago the thing stoped working. I looked at it also and found a leak where the low cutout switch is piped. I told the owner what it was and he called the company up because its under warrenty. They came and said the compressor was bad and its under warrenty. But he had to pay the labor to change it because the compressor is only under warrenty. I told the company that the compressor went bad because there was a leak and the thing was sortcycling. They denied everything and charged 580dollars. Boss was pissed because the labor was more than first bill. They worked on a Sunday. This is a big sore spot for the boss.

    I told my boss just get new coolers but he dosent want too. He says it would screw up the kitchen because of how everthing is custom built. Also these coolers are stainless and used as a tables. He is willing to pay me extra but I dont want to do the job if I am going to do it wrong.

    I have changed compressors in my own stuff and never seem to have problem. It seems the most of these compressor died because of dirty condensors. Here are my questions.

    Would it be better to covert them back to 12? Reason is the compressors lasted a lot longer and the mineral is more forgiving when the temps are high and everything was sized for 12.

    Should I stick to 134a and put expansion valves in and figure some saftey device to kill the compressor if an overheating is present?

    Is this just totaly bad idea??

  2. #2
    Join Date
    Feb 2004
    Location
    Maine
    Posts
    483
    Lack of maintenance and improper service techniques are what kills compressors. True some of the newer refrigerants that require POE oil will sludge and plug up cap tubes if overheated by a dirty condenser, actually it is the oil that breaks down and sludges up. I retrofitted an R-12 walkin cooler about 10 years ago to run on MP39, still running today without a single problem, have never had to add gas either as I made sure this system was tight before the retrofit. Good service practices means a long life for compressors. I am assuming these were burnouts? Did they clean the whole system out and replace filter driers? Did they add a suction dryer temporarily to help clean up the system?

    [Edited by jdenyer on 12-28-2004 at 09:09 AM]

  3. #3
    JD is right on the money, Joe.

    How far you are comfortable going with this is up to you. To a degree.

    Do you have experience with someone teaching you the proper proceedures in this trade?

    Do you have an EPA lic?

    Do you have the tools? Torch, vacum pump, gages, micron meter, etc.?


    I know what your boss means about not wishing to replace that stainless prep table. I have rebuilt several of those. When someting in the kitchen fits, they just keep on repairing them. It is very cost evfective.

    If you choose to embark upon this journey, Mr. Phelps, you should be advised that if anything bad comes of this ... we will disavow any knowledge of you or your team!



    Tell me about your knowledge/ understanding of system cleanup in a case like yours.


  4. #4
    Join Date
    Apr 2004
    Posts
    395

    Thumbs down

    Maintenance-Maintenance-Maintenance-Maintenance and poor and sloppy service techniques. But the hacks keep us working.
    Tin Knockers BANG for a living

  5. #5
    Join Date
    Aug 2003
    Posts
    26
    This is what I am thinking now. I think I am going to get everything new. Just get new condesing units and put in new captubes. Just one unit looks to tight fit an entire condesing unit. This will only get a comprssor with newcap. I always put in a new drier filter. On these small systems I dont put in a filter on the suction side. Just hit the evap with nitrogen and try to blow everything out. When I charge the system I do it by weight let it run for a hour check superheat and adjust charge. This is with capsystem. I have all the tools except the micron gauge and i have the epa card. It just seems these old small systems converted to newer gases are not as durable. I just wanted to know if you guys think the samething.

  6. #6
    Join Date
    Feb 2004
    Location
    Maine
    Posts
    483
    jokey,

    Get a micron gauge, it's a must. If you don't get one we will call you a hack I have evacuated systems that I thought should take about an hour to hit 500 microns and it ended up taking 6 hours, because there was a lot of moisture in it. There is no way to tell what vacuum you have in the system without a good micron gauge. Pay special attention to the evaps on these small cap tube systems, alot of acid and crap can get in there. I usually blow a solvent thru with nitrogen at the design pressure. Then I blow it out with just nitrogen really well. I then evacuate it to 2500 microns and break the vacuum with nitrogen, evacuate to 1000 microns and break vacuum again with nitrogen, then I do the final evacuation down to 500 microns. Time consuming? You bet, but I don't get called back to replace that compressor again. By taking my time and doing it right the first time I save money by not having to go back, and I don't have to advertise, I get more work by word of mouth than I know what to do with.

    The newer refrigerants and oils are not as tolerant to sloppy service practices as the older ones were.

  7. #7
    Join Date
    Sep 2001
    Location
    East Stroudsburg, PA
    Posts
    13,215
    The compressors and the gases are extremely dangerous in the hands of hacks.

    They always WERE, and always WILL BE.

    You can't idiot-proof chemicals or machinery. It's been tried.

  8. #8
    Join Date
    May 2004
    Posts
    13
    Agree... the new refrigerants and POE oil do not tolerate poor workmanship (Actually it's really just the oil). However I will say that compressors (and everything else) are not manufactured the same anymore. The manufactures will use anything to save on costs, and we are the only ones to blame for this... cheap, cheap, cheap.

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