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  1. #1
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    Old R12 Beverage-Air MT27 with bad compressor

    I'll start by saying great forum. This is my first post but this site has been of great use to me over the years. So much so that I haven't even needed to post... until now. I acquired an older MT27 beverage-air merchandiser. My plan is to make a temperature controlled fermentation chamber out of it. It hasn't worked for quite some time says the guy I got it off of. It hasn't been plugged in so the compressor is completely cold. The compressor windings are open between C-S, and between C-R. I assumed the internal overload was stuck and was gonna try smacking it with a dead-blow hammer but then I checked for a short to ground and have 1Ω to ground between the run winding and the compressor case. I suspect the short may have caused the overload to fry and get stuck open? Either way, looks like I need a new compressor.
    The original is a Tecumseh ae231as717 R12 1/3hp compressor. It appears to be all original, no service taps, factory crimped. Wiring appears all original except for a wire nut that is connecting the condenser fan. The cabinet, evap, cond., and line set all look to be in good shape. The evap is a little dirty in one spot but it's right where the fan is so I suspect it's from the air flow and not a leak.
    I originally thought, until I saw it, that it was R134a and I was going to throw in an Embraco 59-FFI12HBX and Sporlan C-032-CAP-C. Now that I find out it's an older R12 model I'm not sure what to do.
    1.) Will I need to lengthen the cap tube or change it entirely to convert to R134a?
    2.) For the temps that it will be running (40°F to 70°F) should I make any modifications?
    3.) If the compressor burned out, how big of a concern is acid in the evap, cond., and line set? Will a simple flush with some sort of cleaner suffice?
    Here are some pics of the evap manifold, the condensing unit, the dirty spot on the evap., and the cabinet with my fermenter already inside.

    All help appreciated. Thanks in advance!
    Attached Images Attached Images     

  2. #2
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    Oct 2004
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    How about R12? Grab a couple of automotive pounders for $50 on ebay - just make sure it's actual R12.
    Also, Coke might want their machine back...

  3. #3
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    Quote Originally Posted by cjpwalker View Post
    How about R12? Grab a couple of automotive pounders for $50 on ebay - just make sure it's actual R12.
    Also, Coke might want their machine back...
    So just replace the broken compressor with the same model and recharge with R12? Looks like the R12 compressor runs around $ while the similar R134a compressor is only $. At $ for a compressor, I don't think this fridge would be worth it.
    Last edited by beenthere; 01-14-2015 at 05:52 AM. Reason: Prices

  4. #4
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    Dec 2006
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    Quote Originally Posted by n8huntsman View Post
    I don't think this fridge would be worth it.
    I dunno about you just judging the value of this cooler.....
    Isee over head garage doors in the picture..... this makes me lead to this being a cooler at home and maybe the purpose of that cooler may be for holding beers for consumption after a long day fixing other peoples coolers.... not the value to that would be priceless!!!

    *edit* i just read what intended purpose, i assume you'll be adding electric heat to the unit? on a seperate control?
    as for refrig, run a rx11 plush on cut open sys if compressor is bad put in another one and put in what gas you have as long it is similar to R12.... r134a r401a r414b r909a etc what ever you have

    heheheheehe!! lol
    Sig removed by mod. G-Rated site

  5. #5
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    Apr 2003
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    The only difference between a 134a compressor and a R12 compressor would be the oil. Actually, most new compressors are coming with POE in them now no matter what, so the actual difference might just be the cost of the compressor. You could always get the 134a compressor and put mineral oil in it if you wanted to.

    Yes, there probably will be acid and other garbage in the system from the old burn out. I don't think I'd bother with any type of flush on such a small system, but I would blow nitrogen through the evaporator as best as you can. I would also dump a small bottle of Acid Away in the new compressor to neutralize the acid. I would also recommend getting rid of the cap tube and installing a small TXV instead. A TXV won't get plugged up as easily if there is garbage in the system, and it would control superheat alot better. Install the TXV and then slowly charge it up until you get about 8-10º of subcooling. If you do keep the cap tube, you might want to try shortening it a little bit to lower the superheat while running at the temperature that you want to run it at. That poor little compressor probably wouldn't like running at that warmer temperature for an extended period of time, but like I said, a txv would help with that issue. If you do plan to change to a TXV, it might also be a good idea to find a high torque compressor to go with it.

    What's with the oily looking spot on the evap? Do you know if it has any refrigerant in it?

    Also as CJP said, Coke is pretty protective of it's coolers. The one that you have was probably stolen from them at some point, and if they ever found it they might want it back.

  6. #6
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    That box does not have the capacity for fermentation of the two tanks shown.
    Are you a tech, your asking questions that are pretty basic?

  7. #7
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    Quote Originally Posted by pecmsg View Post
    That box does not have the capacity for fermentation of the two tanks shown.
    Are you a tech, your asking questions that are pretty basic?
    The fermenter shown looks bigger than it really is. It's a single conical tank on the top. The bottom one is actually just a stand to hold up the conical so that you have access to the racking valve on the bottom of the cone. I ususally brew 10 gallon batches in it.

    I'm not a tech. I'm an engineer and have had some limited exposure to refrigeration. Plus this is my third commercial type refrigerator if you count my two other True boxes.

  8. #8
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    Quote Originally Posted by MikeySq View Post
    i assume you'll be adding electric heat to the unit?
    Being that I'm in California, it never gets that cold in the garage so I don't think heat will be needed. But I am going to be using a temperature sensor with a data logger so I may find out that I need a source of heat at times and may then add something. Or I can stick to lagers in the winter and everything else in the summer.

  9. #9
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    Quote Originally Posted by ammoniadog View Post
    What's with the oily looking spot on the evap? Do you know if it has any refrigerant in it?
    Also as CJP said, Coke is pretty protective of it's coolers. The one that you have was probably stolen from them at some point, and if they ever found it they might want it back.
    I'll put a tap on it tonight and check if it has any pressure in it tonight. Just picked it up last night and just had time to take some pics. I'm hoping that it's just dirt from where the fan was pulling air through but it does look a little suspect.
    I was hoping that CJP was joking when he mentioned Coke, but apparently not. I really didn't know that. I didn't realize that they were owned by Coke. It was my impression that they were purchased or given to distributors but I guess Coke retains the ownership...

  10. #10
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    From the B/M number posted, the replacement model number should be Tecumseh AEA3440AXA if it didn't have a start capacitor or AEA4440AXA if it did. Both of these come with alkylbenzene AB oil which is good for R12 or its HCFC replacements. The AEA3440ZXA/AEA4440ZXA would have POE oil for R134A.

    That compressor family doesn't use an internal overload. It should have an external Klixon overload protector and a current start relay. I can't see either in the pics you posted.

    That may explain the orange wire nut and the fried compressor motor. ;

    I'd recommend going with an AEA4440AXA, install a Sporlan C032-CAP-T filter-drier and use the same cap tube with some new R12.

  11. #11
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    Oh and good luck brazing that steell line to copper.It takes a little practice.
    if at first you dont succeed,then skydiving is not for you

  12. #12
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    Quote Originally Posted by icemeister View Post
    From the B/M number posted, the replacement model number should be Tecumseh AEA3440AXA if it didn't have a start capacitor or AEA4440AXA if it did. Both of these come with alkylbenzene AB oil which is good for R12 or its HCFC replacements. The AEA3440ZXA/AEA4440ZXA would have POE oil for R134A.

    That compressor family doesn't use an internal overload. It should have an external Klixon overload protector and a current start relay. I can't see either in the pics you posted.

    That may explain the orange wire nut and the fried compressor motor. ;

    I'd recommend going with an AEA4440AXA, install a Sporlan C032-CAP-T filter-drier and use the same cap tube with some new R12.
    The external overload and relay is intact and appears to be all original, just not visible in the pic. There is no start cap but my understanding is that if it did not have one, AEA3440AXA for example, you could substitute the start cap model, AEA4440ZXA, but not visa versa. I also read that the Embraco may be cheaper, quieter, and better quality? This is that thread: http://hvac-talk.com/vbb/showthread....Air-Compressor

    If I stuck with R12, I think the Embraco model would be FFI12BX1.

  13. #13
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    Ice shouldn't it be yxa for 134 i thought zxa was 404
    Honeywell you can buy better but you cant pay more

    I told my wife when i die to sell my fishing stuff for what its worth not what i told her i paid for it

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