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  1. #1
    Join Date
    Sep 2008
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    Western PA
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    25,563

    Help me clean up a hack job.

    Had to deal with a pretty bad hack job today, and am looking for a bit of help cleaning up.

    Walk-in meat cooler. 401a

    2 bohn WKE100BC evaps with EBFFE-A-C txv (R-12)

    Tecumseh Condensing unit
    Model CL312HT
    Serial 6M832629

    Now, here is where it goes bad.

    Somewhere along the lines, someone decided to change out the original compressor with a Copeland CS33K6E-PFV-979.

    Now, the compressor failed overnight and I replaced it, like-for-like today. THEN I find out that the compressor is a 404a pump on a 401a system.

    I talked this over with the boss and we decided on this plan of action. Next time anyone has to touch the refrigeration system, we replace TXVs and change out to either 402a or 404a depending on the oil in the system.

    Thought, suggestions, and input please.

  2. #2
    Join Date
    Nov 2008
    Location
    Sydney, Australia
    Posts
    48
    Not sure about that condensing unit but all evaps will gain capacity on a change to R404a (only need to worry about a new TXV), I am unfamiliar with the condensing unit you have - the only worry i would have is the THR of the condenser coil on R404a, if its OK then first thing monday I would be back with TXV, a tin of POE, driers and a bottle of 404a.

  3. #3
    Join Date
    Jul 2000
    Location
    Guayaquil EC
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    10,326
    After a little digging I found that the original condensing unit model must have been a CL31ZH17 as it's fairly easy to misread some of these older numbers.

    The original compressor then would have been an AGA4534AXN which is in fact a 3 HP HT R12 pump rated at about 20,000 Btuh @ +20F SST. Each evaporator is rated at 10,000 Btuh @ 10F TD so the match was a good one for a 30F (or so) meat box.

    So where did the CS33K6E come from?

    Well, applying a little more refrigeration forensics, I found that a typical 3 HP R12 HT pump would have a displacement of 700-800 CFH. (I couldn't find the displacement of the original Tecumseh.) The CS33K6E has a displacement of 756 CFH, so running it on R12, or in this case R401A, the resulting capacity should be approximately the same as the original.

    As a secondary check, the CS33K6E is rated at about 31,000 Btuh @ +20F SST with R404A. My rule of thumb for R12 performance says that the capacity should be about 2/3 of what it would be running R22 or R404A HT (2/3 x 31,000 Btuh = 20,460 Btuh).

    So in the end, it's really not a bad match. It was likely a necessary and somewhat creative hack to save a boxload of meat...and sounds like something I might do in a pinch.

    I see another possible scenario here too, that being it may have been a totally misinformed selection that turned out roses. It's quite possible that a counter guy at the supply house looked up the Tecumseh number and found it had a HT rating of 33,000 Btuh, so he simply selected a 3 HP HT Copeland without considering the refrigerant difference or the fact that the while CS is a HT compressor the "33" in the model number is taken at +20F and not at +45F as the Tecumseh is. I've seen them do it several times.

    I simply love a good mystery, don't you.

  4. #4
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    Sep 2008
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    Western PA
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    25,563
    SO, despite appearances, this is NOT quite the mis-match that I originally thought?

    Thank you for your input, icemeister.

  5. #5
    Join Date
    Jul 2000
    Location
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    Yep, it looks like a decent matchup to me, however convoluted it may appear.

    I forgot to comment on the last statement you made yesterday:

    Quote Originally Posted by jpsmith1cm View Post
    I talked this over with the boss and we decided on this plan of action. Next time anyone has to touch the refrigeration system, we replace TXVs and change out to either 402a or 404a depending on the oil in the system.
    I'm assuming when you fired up this new CS33 it was with R401A and settled in at around 15-20 psig suction and 150-175 psig discharge...or just as one would expect for R401A on a meat box.

    If this is so, then if you were to retrofit this system to R402A or R404A the compressor would attempt to do about 50% more in capacity than it is right now on R401A. The evaps and the condenser aren't big enough for that.

    The better plan of attack for this system would be to go back and retrofit it to R134A when such an opportunity arises.

    It's funny how some stuff happens....

    A couple of years ago I had a restaurant customer who was setting up a high end Italian bistro style restaurant. The existing place had a 6' x 8' walk-in freezer that he wanted to convert to a cooler, but he didn't want to spend a lot of money if he didn't have to. So I checked the existing R404A condensing unit/evap match and looked into how they would balance out if I converted to R134A. It looked pretty good except for a slightly higher TD on the evap than I'd like but since it was for chilled bottled beer and wine the lower RH wasn't going to be a problem. Other than a little rewiring of the evap, I only had to install a new filter-drier and change the powerhead to a FC charge as the valve port size was OK either way.

    This week I got to change it back to a freezer again because he's going to New Orleans/Cajun family style theme.

  6. #6
    Join Date
    Jun 2005
    Location
    Las Vegas NV
    Posts
    1,152
    Let me add to the mix.

    The Copeland CS33K3E-PFV is rated for R404A and R134a.

    The R134a ratings: 36,500 @ 45/130/65/130
    18,400 @ 20/120/65/120

    The new Copeland replacement for this model is a CS33K6E-PFV.

    The difference between the "3" and "6" is listed as a model variation with no explanation. Copeland shows the "6" replacing the "3" so there should'nt be any problems.

    Copeland also list the CS33 as the replacement for the Tecumseh AGA4534AXN.

    Also, according to Copelands chart, R401A/MP39 is approved for POE use.

    I would suspect that the Copeland failed for the same reasons as the original Tecumseh.
    Last edited by powell; 04-25-2010 at 10:45 AM.

  7. #7
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  8. #8
    Join Date
    May 2009
    Location
    The Pas, Manitoba Canada
    Posts
    212
    Quote Originally Posted by icemeister View Post
    Yep, it looks like a decent matchup to me, however convoluted it may appear.

    I forgot to comment on the last statement you made yesterday:



    I'm assuming when you fired up this new CS33 it was with R401A and settled in at around 15-20 psig suction and 150-175 psig discharge...or just as one would expect for R401A on a meat box.

    If this is so, then if you were to retrofit this system to R402A or R404A the compressor would attempt to do about 50% more in capacity than it is right now on R401A. The evaps and the condenser aren't big enough for that.

    The better plan of attack for this system would be to go back and retrofit it to R134A when such an opportunity arises.

    It's funny how some stuff happens....

    A couple of years ago I had a restaurant customer who was setting up a high end Italian bistro style restaurant. The existing place had a 6' x 8' walk-in freezer that he wanted to convert to a cooler, but he didn't want to spend a lot of money if he didn't have to. So I checked the existing R404A condensing unit/evap match and looked into how they would balance out if I converted to R134A. It looked pretty good except for a slightly higher TD on the evap than I'd like but since it was for chilled bottled beer and wine the lower RH wasn't going to be a problem. Other than a little rewiring of the evap, I only had to install a new filter-drier and change the powerhead to a FC charge as the valve port size was OK either way.

    This week I got to change it back to a freezer again because he's going to New Orleans/Cajun family style theme.
    Cool today freezer tomorrow with an extended forcast of continueing below freezing temperatures. Sorry couldn't resist that one.

  9. #9
    Join Date
    Mar 2007
    Location
    tx
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    1,088
    Quote Originally Posted by jpsmith1cm View Post
    Thanks, guys.

    I should have kept that old pump and cut it open...
    Oh Gosh JP, don't say that, you will have a bunch of guys come tell you how stupid it is for wanting to cut it open and see what killed it. I said on another thread a few days ago that I like to cut them open when I have the time or really want to inspect one. Some had never heard of such a thing, and others said the didn't care what killed it.
    Bad information is worse than no information at all.

    There are three kinds of people in this world. Those who can count and those who can't!

  10. #10
    Join Date
    Jun 2001
    Location
    Michigan
    Posts
    12,077
    Quote Originally Posted by icemeister View Post
    After a little digging I found that the original condensing unit model must have been a CL31ZH17 as it's fairly easy to misread some of these older numbers.

    The original compressor then would have been an AGA4534AXN which is in fact a 3 HP HT R12 pump rated at about 20,000 Btuh @ +20F SST. Each evaporator is rated at 10,000 Btuh @ 10F TD so the match was a good one for a 30F (or so) meat box.

    So where did the CS33K6E come from?

    Well, applying a little more refrigeration forensics, I found that a typical 3 HP R12 HT pump would have a displacement of 700-800 CFH. (I couldn't find the displacement of the original Tecumseh.) The CS33K6E has a displacement of 756 CFH, so running it on R12, or in this case R401A, the resulting capacity should be approximately the same as the original.

    As a secondary check, the CS33K6E is rated at about 31,000 Btuh @ +20F SST with R404A. My rule of thumb for R12 performance says that the capacity should be about 2/3 of what it would be running R22 or R404A HT (2/3 x 31,000 Btuh = 20,460 Btuh).

    So in the end, it's really not a bad match. It was likely a necessary and somewhat creative hack to save a boxload of meat...and sounds like something I might do in a pinch.

    I see another possible scenario here too, that being it may have been a totally misinformed selection that turned out roses. It's quite possible that a counter guy at the supply house looked up the Tecumseh number and found it had a HT rating of 33,000 Btuh, so he simply selected a 3 HP HT Copeland without considering the refrigerant difference or the fact that the while CS is a HT compressor the "33" in the model number is taken at +20F and not at +45F as the Tecumseh is. I've seen them do it several times.

    I simply love a good mystery, don't you.
    Okay. If you would. Explain how you do this. I have never met another refrigeration man do this so methodically. Seriously.

    I wanna know where you got the info. And how were you able to assemble this info so quickly.

  11. #11
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    Jul 2000
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    Guayaquil EC
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    Quote Originally Posted by Dowadudda View Post
    Okay. If you would. Explain how you do this. I have never met another refrigeration man do this so methodically. Seriously.

    I wanna know where you got the info. And how were you able to assemble this info so quickly.
    LOL... I like Powell's method better. It's much easier.

    I found the old Tecumseh compressor info in a United Refrigeration catalog from 1994 that I had on the shelf at the shop. The Tecumseh capacity I got from a Johnstone catalog. The Copeland info was all from their website.

    Comparing compressor displacements and playing around with different refrigerant ratings came from being an applications engineer for Dunham-Bush many years ago. I learned a lot working there.

    Also remember that until the demise of R12 and R502, compressors were typically dual rated for HT12/LT502. The same is true for R134A and R404A...it's just that they don't publish it anymore.

  12. #12
    Join Date
    Jul 2001
    Location
    Gold Coast of Connecticut
    Posts
    4,578
    Quote Originally Posted by icemeister View Post
    LOL... I like Powell's method better. It's much easier.

    I found the old Tecumseh compressor info in a United Refrigeration catalog from 1994 that I had on the shelf at the shop. The Tecumseh capacity I got from a Johnstone catalog. The Copeland info was all from their website.

    Comparing compressor displacements and playing around with different refrigerant ratings came from being an applications engineer for Dunham-Bush many years ago. I learned a lot working there.

    Also remember that until the demise of R12 and R502, compressors were typically dual rated for HT12/LT502. The same is true for R134A and R404A...it's just that they don't publish it anymore.
    Great information to share. I have never had an issue with any R-22 or 404 rated compressor running R-134/ MP-39 refrigerant. I have also questioned replacement compressors selected by United in the past due to the rating on the pump or condenser.
    Aire Serv of SW Connecticut- Gas heat, dual fuel and central a/c systems installed and serviced

  13. #13
    Join Date
    Sep 2005
    Location
    florida
    Posts
    5,505
    Quote Originally Posted by icemeister View Post
    LOL... I like Powell's method better. It's much easier.

    I found the old Tecumseh compressor info in a United Refrigeration catalog from 1994 that I had on the shelf at the shop. The Tecumseh capacity I got from a Johnstone catalog. The Copeland info was all from their website.

    Comparing compressor displacements and playing around with different refrigerant ratings came from being an applications engineer for Dunham-Bush many years ago. I learned a lot working there.

    Also remember that until the demise of R12 and R502, compressors were typically dual rated for HT12/LT502. The same is true for R134A and R404A...it's just that they don't publish it anymore.
    Dunham-Bush Wow that just show's how old you are. 0h that reminds Happy Birthday(Early)
    I love the smell of phosgene first thing in the morning:

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