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  1. #1
    Join Date
    Jan 2008
    Location
    East berlin, PA
    Posts
    287

    Upgrading walk in coolers- reasonable alternatives-questions

    I have a customer with 2 30k walk in coolers, one was r12 converted to 409a and the other is R22. Both are at least 20 years old. Both have been experiencing problems due to age. I would like to upgrade his equipment to something more up to date and reliable and get away from 409a and r22 since the refrigerant prices are ridiculous. I was told by the local supply house I could replace the condensing units and replace the txv's with 404a stuff, flush the systems and I would not have to replace the evaps. Then a few days later the supply house calls and says the distributor orifices would have to be removed in the current evaporators and replaced, and if the TXVs were sweated in that would be next to impossible to do so then I got them to requote the jobs with new evaps as well. This seems awful expensive at a time when lots of places are just struggling to get by.


    Are there any alternatives to this scenario?
    For the R22 unit can I just get another R22 unit and switch the refrigerant to MO99? Although MO99 isn't much cheaper.

    I'd like to avoid having to replace the evaps, but there doesn't seem to be much of a choice....
    "Delay is preferable to error"- Thomas Jefferson

  2. #2
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,392
    The distributor nozzles for R12/R409A usually will be the same size as the ones needed for R404A. In my experience, the original R12 expansion valve body will also be OK for R404A, so only the powerhead needs to be changed.

    R22 distributor nozzles are smaller, so it's necessary to replace that one. It can indeed be a pain to get the old one out, but if a regular nozzle removal pin doesn't cut it I've had some luck using a small self tapping or sheet metal screw to get them out. Short of that, replacing the distributor nozzle would still be a lot cheaper than replacing the evaporator.

  3. #3
    Join Date
    Oct 2008
    Location
    Cleveland, Ohio
    Posts
    27
    The answer to that question is replace the equipment 100%. If the equipment was a little newer maybe retrofit. Sounds old and its gonna be something you're married to.

  4. #4
    Join Date
    Dec 2000
    Location
    Auburn, New York
    Posts
    241
    I agree. Replace everything and go with 404A. Best choice.
    once you think you know everything, you'll never learn another thing!

  5. #5
    Join Date
    Nov 2011
    Location
    New Hampshire
    Posts
    14
    Yes it might cost some money to update the equipment but the customer will get another 20years out of it. If you just start changing things here and there then it sounds like it will become a nightmare sooner than later.

  6. #6
    Join Date
    Jul 2011
    Location
    Lehigh Valley, PA
    Posts
    454
    I have successfully converted two walk in recently from R22 to R404. Well, I did one, a hired contractor crew did one. The local contractor had two call backs so far, my unit has been steady & stable, no issues.
    ( I am an in-house tech for a restaurant chain ). just install the new TXV's. Yea, some are difficult to sweat but you can work some new tubing in to solve this issue or maybe install SAE TXV's. . The old evaps have more space. The new evaps are the ones that scare me. They bury those Emerson TXV's behind tubing where it would be very difficult to sweat in/out. Run new line sets if you can.

    In regards to installing new equipment...I am more concerned with the actual box & door more than I am with an old evaporator & fan motor.

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