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  1. #1
    Join Date
    Oct 2009
    Location
    Lewisburg, TN
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    43

    Question about Reach-In Cooler Compressor Replacement

    I am an HVAC guy slowly crossing over into refrigeration as called. I live in a small town in Middle Tn. and some of the locals don't want to call the big city refrigeration companies. I really want to learn the refrigeration side of this business, and this site has helped me greatly.

    I was asked the other day by a local store owner to give him a price on replacing a compressor on a reach-in cooler. The cooler used R-12. He already has a replacement compressor. I have worked with R-12 once in an industrial setting working on a cascade system when I first got started in this business, (I did not work for myself back then). But we had enough R-12 on site to do the job.
    My question is: What replacement refrigerant should I use for this reach-in and will I need to flush the old oil out of system?

    Thanks,
    Travis
    "Dedicated to providing the highest quality and customer satisfaction"

  2. #2
    Join Date
    Jan 2010
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    5,812

    Smile

    Travis
    There are different refrigerant choices to replace that R12 each having different pressures. I found Hot Shot to be very close to R12 pressures but most compressor manufactures don't accept it. Other choices could be MP39 or R409 both accepted. Also if your store owner has his own compressor make sure its the right one.

  3. #3
    Join Date
    Oct 2009
    Location
    Lewisburg, TN
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    43
    Quote Originally Posted by VTP99 View Post
    Travis
    There are different refrigerant choices to replace that R12 each having different pressures. I found Hot Shot to be very close to R12 pressures but most compressor manufactures don't accept it. Other choices could be MP39 or R409 both accepted. Also if your store owner has his own compressor make sure its the right one.
    The company that furnished the cooler to the owner also gave him the compressor. I'm guessing because it is an R-12 unit. If I use Hot Shot, will I have to change the oil?
    "Dedicated to providing the highest quality and customer satisfaction"

  4. #4
    Join Date
    Jan 2010
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    5,812
    No oil change will be necessary but filter change is standard practice. Make sure your cap tube is clear if it has one or maybe two. Weigh in your charge to the right percentage for hot shot. And trust no one on that compressor run model # and check specs with original if original is present. Otherwise check unit model # and call manufacture to confirm.: patriot:

  5. #5
    Join Date
    Feb 2009
    Location
    Texas
    Posts
    43

    Thumbs up

    Quote Originally Posted by tholder1 View Post
    The company that furnished the cooler to the owner also gave him the compressor. I'm guessing because it is an R-12 unit. If I use Hot Shot, will I have to change the oil?
    I would recommend checking the oil type in the replacement compressor to verify that it is indeed Mineral Oil. The compresssor they supplied could very well have been sent with POE or AB in it for a replacement gas for 12. Never take the customers word in a situation like this. I would recommed verifying everything thru the compressor manufacture of the box manufacture.

  6. #6
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,078
    Today, most service replacement compressors designed for R12 are shipped with alkylbenzene (AB) oil, which is the recommended oil for the interim R12 replacement refrigerants.

    Here's a link to DuPont's retrofit guidelines:
    http://www2.dupont.com/Refrigerants/...ofit_guide.pdf

  7. #7
    Join Date
    Oct 2009
    Location
    Lewisburg, TN
    Posts
    43
    I went by the store today and looked at the replacement compressor. It is a 134A compressor.
    What do I need to do to convert this system over to 134A? Or is it even possible?
    Thanks,
    Travis
    "Dedicated to providing the highest quality and customer satisfaction"

  8. #8
    Join Date
    Jul 2000
    Location
    Guayaquil EC
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    10,078
    It's really not a big deal...at least not as big a deal as we once thought it to be.

    You'll need to replace the capillary tube. Typically it's the same bore but about 10% longer. (I use the Supco cap tube sizing charts.)

    A lot of guys will say you need to flush the system. I have found that is not necessary. With the old compressor and cap tube removed, just blow out the condenser and evaporator with N2 and that'll get rid of any large amounts of pooled oil.

    Use a good filter-drier...not the spun copper or pencil type. I recommend a Sporlan C032-CAP-T because it's designed for cap tubes, has a high side shrader valve and it works. If the old compressor failed due to burnout, install a suction filter as well.

    A proper vacuum is essential. You need to use a good micron gauge and get at least a 500 micron pull that holds. Charge by weight to the original data plate and adjust by compressor suction superheat accordingly...no less than 20F and no more than 40F when the box is at design temperature.

    Be aware though, POE oil is an excellent solvent and will scrub the system clean in no time. It's not unlikely you may need to go back and change the cap tube and filter-drier one more time when one, the other or both plug up. I've only had that happen a couple of times, but I tell the customer if it does occur it's not an in-warranty job.

  9. #9
    Join Date
    Jan 2010
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    5,812
    HSC
    Get us the compressor model #s for the new and old compressors. Why not a R12 compressor ? What you see is what you get or can you still get a R12 compressor from whoever is supplying it ? Could be a lot less hassle then changing out a cap tube. Unless its easy access & not attached to the suction line. Reason for model #s is to check the btu rating. I would check with the manufacture for proper btu requirement. Assume nothing !

  10. #10
    Join Date
    Oct 2009
    Location
    Lewisburg, TN
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    43
    Quote Originally Posted by VTP99 View Post
    HSC
    Get us the compressor model #s for the new and old compressors. Why not a R12 compressor ? What you see is what you get or can you still get a R12 compressor from whoever is supplying it ? Could be a lot less hassle then changing out a cap tube. Unless its easy access & not attached to the suction line. Reason for model #s is to check the btu rating. I would check with the manufacture for proper btu requirement. Assume nothing !
    I will try to do that one day next week. The owner is not in any big hurry and I definitely don't want to do this the wrong way.

    And I just want to take the time to tell you guys how much I appreciate your help when I ask for advice. I still consider myself a rookie in this profession after working in the automotive manufacting business for 18 years. I study this stuff on my not so busy days trying to absorb as much in as I can.

    This same man asked me to install a new condensing unit at his store last year, and when I gave him my bid, he asked if I could do it any cheaper. I told him I couldn't do it cheaper AND do it right. And I also went on to tell him that if the new unit failed because of a shortcut I would have to take to do it cheaper, he wouldn't remember to tell people that he told me to take the shortcut, he would just tell them what a sorry A/C man I was, and with me just starting my own business in Jan. 09, I was not going to start out with that type of reputation. Well, I eventually got the job.

    Thanks again,
    Travis

    P.S. Learning the refrigeration side is almost like starting all over, but I really like the challenge.
    "Dedicated to providing the highest quality and customer satisfaction"

  11. #11
    Join Date
    Oct 2009
    Location
    Lewisburg, TN
    Posts
    43
    Here is an update on the compressor. Let me know what ya'll think about this.
    Went back to the store today to get info on unit. The owner said he got it changed out about two weeks ago by a local that used to work for International Comfort Products here in Lewisburg. No certifications or license of any kind, just a guy that knew how to solder ref. lines. Everyone that got laid off there a few years back think they are ref. experts because they worked on an assy. line for years. The guy put the new compressor in for 50 bucks and according to the store owner was done in 45 min. I asked if he flushed the old R12 oil out and changed capillary tubes for the 134A and the owner said, quoting here "the oil is sealed in the bottom of the new compressor, there ain't no need to flush anything out, it's running fine." All I could say was that I could also do a half-@ss job for fifty dollars, but I wasn't going to ruin my reputation just to get the job.
    "Dedicated to providing the highest quality and customer satisfaction"

  12. #12
    Join Date
    Mar 2009
    Location
    Indianapolis, IN
    Posts
    80
    Isn't it great to have such a knowledgeable customer that knows all about oil and cap tubes?

    I have worked for folks like this a few times. You just have to balance the need of the job vs the need of the headache that these people cause. Usually my price to do it right is more than they are willing to pay. (at least until they are willing to get the job done right)

    Hang in there and keep learning. Sound like you have the skills and the heart.

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