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Thread: Yoshimasa sushi display

  1. #1
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    Yoshimasa sushi display

    Installing a new yoshimasa sushi display setup with remote water cooled condenser. Having issues getting the charge correct ( 404a). System uses an AEV.
    The manufacturer says the charge 404a as a gas ( not a liquid ??? ) only until the suction line freezes back to the compressor. Then adjust AEV. They are advising a head pressure of 125 psi.
    We have been trying to get this thing dialed in but compressor runs way too hot.
    Im used to clearing the site glass and setting the head pressure to 261psi (105 degrees ). Then using superheat to set the TXV.

    Any help is appreciated.

  2. #2
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    I think they are mistaken on charging 404 as a gas....
    You'd probably be just pumping the 134 component into the system that way.
    I've run 404 as low as 150 on headmasters without issue.
    But I really don't know what to say here as I've never dealt with one of these
    You don't squat with your spurs on.
    And you NEVER put the torches away before pressure testing.

  3. #3
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    Unfortunately it says to charge as a gas in the instructions. Doesn’t make sense.
    Thank you for commenting. Anything helps.

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  5. #5
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    I was taught in school to charge everything with gas and spent all my years in the field charging with liquid.
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
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  7. #6
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    It looks like less than 2 degrees of glide so likely not much fractionation would happen but I would use liquid.

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  9. #7
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    After reading this and the rest of the link he posted I would have a hard time listening to anything they said.
    7. Please use the Micron Gauge (up to 1000 or lower) to examine any possible leak before charging a refrigerant.

    8. Please charge the refrigerant as a gas, not as a liquid. Don’t charge refrigerant until sight glass is full or you will have overcharged the unit. Simply charge the refrigerant until at least halfway down the suction line or until the entire suction line is frozen.

    9. Do not charge the refrigerant by having container upside down.

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  10. #8
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    We have tried charging as liquid and a gas. Just can’t get things operating correctly. Their charging procedure is terrible. You pretty much have to guess. Can’t use SH, SC, site glass.
    But we have to make this setup work. Hopefully someone with experience can help.

  11. #9
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    AXV/AEV's are generally used when the load is constant. The instructions you linked to are horrible. Does the unit have a receiver or is it critically charged? Are you using a LPC or a thermostat for temperature control?
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Why is it that those who complain the most contribute the least?
    MONEY CAN'T BUY HAPPINESS. POVERTY CAN'T BUY ANYTHING

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  13. #10
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    It has a receiver. No thermostat. Just an adjustable low pressure switch. Which is supposed to be just to shut the unit down during pump down. The cases are run off a switch with a solenoid.
    It is my understanding the aev will control the case temp. The compressor will run all day until it is shut down at night. At that point the pipes inside the case defrost and start dripping water. Which I can’t have during operating hours with food in the case.

  14. #11
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    Is there a suction accumulator in case it floods back?

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    Quote Originally Posted by smsmechanical View Post
    It has a receiver. No thermostat. Just an adjustable low pressure switch. Which is supposed to be just to shut the unit down during pump down. The cases are run off a switch with a solenoid.
    It is my understanding the aev will control the case temp. The compressor will run all day until it is shut down at night. At that point the pipes inside the case defrost and start dripping water. Which I can’t have during operating hours with food in the case.
    I'm sure that given enough time I could come up with a worse design.
    But right now it's escaping me
    You don't squat with your spurs on.
    And you NEVER put the torches away before pressure testing.

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  17. #13
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    So basically you charge it until there is some liquid in the receiver and set the AEV low enough that you will still have superheat after a long humid day of accumulating ice on the evaporator. I would definitely be looking at superheat and receiver levels and watching the system for a while along with a check at the end of the day before shutting down to make sure there is still 20° of superheat at the compressor.
    It sounds extremely simple. What exactly is the problem you are having?

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  18. #14
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    So basically if its running too hot check the superheat and if its too high you need to raise the evaporator pressure until the superheat is closer to correct and by correct I mean according to standard Refrigeration practice 20° - 40° f superheat and the suction line at the compressor never higher than 65°f since the manufacturer doesn't offer any real information.

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  19. #15
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    Please take everything I posted with a grain of salt because I don't have any experience with these types of systems but that's what I would start with.

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  20. #16
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    Don't listen to R600a on this one, except for the part where he says not to listen to him.

    I've had the fun of installing one of these things a few years ago, so I know the fun you're having. These are strange bastards for sure.

    It sounds like you have a pretty good grasp on things. As you have been told, superheat and subcooling don't really have anything to do with anything on these cases. I'd maybe adjust your water regulator to get a little more head pressure, set your axv to whatever pressure the factory is telling you to set it to, and slowly charge the thing until the frost line reaches the compressor like they say it's supposed to. Then you are done. Not much more you can do.
    If at First You Don't Succeed, Skydiving Is Not for You.

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  22. #17
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    Quote Originally Posted by ammoniadog View Post
    Don't listen to R600a on this one, except for the part where he says not to listen to him.

    I've had the fun of installing one of these things a few years ago, so I know the fun you're having. These are strange bastards for sure.

    It sounds like you have a pretty good grasp on things. As you have been told, superheat and subcooling don't really have anything to do with anything on these cases. I'd maybe adjust your water regulator to get a little more head pressure, set your axv to whatever pressure the factory is telling you to set it to, and slowly charge the thing until the frost line reaches the compressor like they say it's supposed to. Then you are done. Not much more you can do.
    Yeah listen to ammonia dog he has actually seen one. Thanks for keeping me from causing someone problems.

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    https://www.achrnews.com/articles/11...on-valves-work


    When I was in school, the AXV was referred to as the "dumb valve." Unlike a TXV, the dumb valve does not control evaporator superheat.

    It needs constant load environment to work properly. When the evaporator pressure increases, the AXV will close down and allow less refrigerant into the evaporator. When the pressure drops, the AXV will open up. All of this is opposite to a TXV.

    I agree about following the manufacturers suggest about charging with the frost line.

    Then once you have weighed in the charge, write it down somewhere so the next poor bastard can just weigh the charge in.

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  25. #19
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    Id install a TXV but thats me.

    Pull the charge
    Pull a proper vacuum
    Charge LIQUID
    Is there a water regulating valve on this unit? Tower water? Incoming water temperature? Control the head for 225#
    Get a frost line then back it off.

    I hope and pray that valve is adjusted properly!

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  27. #20
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    Did the manufacturer specify the evaporator pressure setting? All I am seeing is that they say to adjust it.

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