Yoshimasa sushi display

[2sac]

Don't worry he'll find it eventually.

I don't know...I saw a missing compressor ad on the back of a milk carton today. Probably already part of a refrigeration trafficking ring...

[smsmechanical]

Manufacturer didn’t really want to talk about saturation temp , subcooling , or superheat. They were only concerned about frost line and pressures. Which doesn’t make sense

[smsmechanical]

The compressor stopped “running”. So we were able to catch up to it.

[2sac]

Manufacturer didn’t really want to talk about saturation temp , subcooling , or superheat. They were only concerned about frost line and pressures. Which doesn’t make sense

Frost line is an old school rule of thumb way to charge small self contained units. Put enough gas in to get frost to the compressor and then bleed some off until the frost line recedes about 6" from the compressor.

[tt/rich]

hahaha fat fingers must of hit it tumbing throught. I must say it is a fun read!

[smsmechanical]

I’ll update everyone once we get this figured out.

[tt/rich]

I never worked on this type of unit. But in a past life I had the miss pleasure of working on a lot of PTAC unit with AEV.
AEV work by closing the valve the hoter the box and open the colder it gets.

When you go back w/ a compressor and AEV, I would bring Ice bags put them in the case
to bring down the box temp.
After the chang the box temp should be close to 40* start charging vaper slowly
and I do mean slow till you see frost just starting to form @ the end of the coil then mark the top of the AEV in line with a mark on the head you can slowly turn the screw 1/8" turn tracking the unit temp and psi set to temp of box minus evap temp. Well I know it worked for PTAC units haha

[ammoniadog]

I never worked on this type of unit. But in a past life I had the miss pleasure of working on a lot of PTAC unit with AEV.
AEV work by closing the valve the hoter the box and open the colder it gets.

When you go back w/ a compressor and AEV, I would bring Ice bags put them in the case
to bring down the box temp.
After the chang the box temp should be close to 40* start charging vaper slowly
and I do mean slow till you see frost just starting to form @ the end of the coil then mark the top of the AEV in line with a mark on the head you can slowly turn the screw 1/8" turn tracking the unit temp and psi set to temp of box minus evap temp. Well I know it worked for PTAC units haha

What are you talking about with PTAC's and "box temperature"? When I think of of a PTAC, I think of the glorified window air-conditioners that they have at the Motel 6. Are you talking about a walk-in cooler with a self contained package deal that sit on top? Yeah, that sounds like it would suck!

I've worked on a couple of glycol beer chillers that had AXV's. If the glycol (or whatever it is that you are trying to cool) is warm, it can take an excruciatingly long time for it to start coming down to temperature. They sometimes need a full 24 hours to find out if the stupid thing is working or not. It doesn't make a whole lot of sense why any manufacturer would choose one of these.

Luckily from what I remember about these sushi cases, since it's really just copper pipes that we're trying to cool down, with no fan blowing across them or anything, I don't think it takes very long to see if the system is working properly.

[pecmsg]

I never worked on this type of unit. But in a past life I had the miss pleasure of working on a lot of PTAC unit with AEV.
AEV work by closing the valve the hoter the box and open the colder it gets.

When you go back w/ a compressor and AEV, I would bring Ice bags put them in the case
to bring down the box temp.
After the chang the box temp should be close to 40* start charging vaper slowly
and I do mean slow till you see frost just starting to form @ the end of the coil then mark the top of the AEV in line with a mark on the head you can slowly turn the screw 1/8" turn tracking the unit temp and psi set to temp of box minus evap temp. Well I know it worked for PTAC units haha

W T F ?

[ammoniadog]

Actually, I think I get why sushi cases use AXV's. On these things, the copper pipes that run through the cases need to be covered in frost, without being too cold and without the compressor ever shutting off (otherwise the frost would melt and drip all over the sushi). An AXV on a system like this that has a fairly consistent load will allow the refrigerant to run through the pipes at a nice constant pressure, which means it will follow the PT chart relationship to maintain a nice even temperature.

The way in which the AXV works, in that it opens up as the load gets less, means that you can't just maintain a clear sight glass coming out of the receiver. You actually want the thing to start running out of refrigerant as the case gets cold, otherwise you will slug the compressor. That's why you slowly charge it up while watching the frost line, and you stop adding refrigerant as soon as the frost starts getting close to the compressor.

[R600a]

Also no air movement to dehydrate the Sushi.

Sent from the Okie state usin Tapatalk

[BALloyd]

Also no air movement to dehydrate the Sushi.

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You don't like Sushi Jerky?

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[R600a]

You don't like Sushi Jerky?

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I don't like sushi. For that matter I don't like sea food much although shrimp is good.

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[smsmechanical]

Update… we tried piping these 3 cases in series with 3 AXVs. We were able to get 2 cases at perfect temp after adjusting charge ( as a gas ) and setting all axvs to the same pressure 34 psi all day. The third case wouldn’t reach temp. Compressor superheat was around 20 degrees.
We then switched back to piping the three cases in series with a single axv as recommended by the manufacturer. Charged as a gas. Got all cases to reach temp easily but compressor superheat was too high ( 50 ). As we added charge to lower the superheat the site glass cleared. Superheat remained at 50. Added more charge and superheat rose to 70 ! I’m guessing superheat rose due the the axv closing to maintain 25psi as we added charge.

I was happy we were able to make proper case temps but i feel the compressor will not last long at 50 degrees superheat.

I have asked for the manufacturer and job engineers to send out a rep to solve our issue. I will update again after I have answers.

[R600a]

Update… we tried piping these 3 cases in series with 3 AXVs. We were able to get 2 cases at perfect temp after adjusting charge ( as a gas ) and setting all axvs to the same pressure 34 psi all day. The third case wouldn’t reach temp. Compressor superheat was around 20 degrees.
We then switched back to piping the three cases in series with a single axv as recommended by the manufacturer. Charged as a gas. Got all cases to reach temp easily but compressor superheat was too high ( 50 ). As we added charge to lower the superheat the site glass cleared. Superheat remained at 50. Added more charge and superheat rose to 70 ! I’m guessing superheat rose due the the axv closing to maintain 25psi as we added charge.

I was happy we were able to make proper case temps but i feel the compressor will not last long at 50 degrees superheat.

I have asked for the manufacturer and job engineers to send out a rep to solve our issue. I will update again after I have answers.

If you raise the pressure setting the superheat will drop.

Sent from the Okie state usin Tapatalk

[R600a]

If the cases require 25 psi the only way to lower the superheat would be to increase compressor horsepower or decrease the load. Maybe something was overlooked in choosing the condensers because the manufacturer lists a lot of variables that change required horsepower.
The axv feeds exactly the amount of refrigerant that the compressor pumps at that pressure so the only way to lower the superheat is to raise the pressure or increase the horsepower to increase the mass flow and therefore lower the superheat.

Sent from the Okie state usin Tapatalk

[R600a]

If the cases require 25 psi the only way to lower the superheat would be to increase compressor horsepower or decrease the load. Maybe something was overlooked in choosing the condensers because the manufacturer lists a lot of variables that change required horsepower.
The axv feeds exactly the amount of refrigerant that the compressor pumps at that pressure so the only way to lower the superheat is to raise the pressure or increase the horsepower to increase the mass flow and therefore lower the superheat.

Sent from the Okie state usin Tapatalk

Woops I meant 34 psi.

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[BBeerme]

What was the temp of the suction entering the compressor?

Update… we tried piping these 3 cases in series with 3 AXVs. We were able to get 2 cases at perfect temp after adjusting charge ( as a gas ) and setting all axvs to the same pressure 34 psi all day. The third case wouldn’t reach temp. Compressor superheat was around 20 degrees.
We then switched back to piping the three cases in series with a single axv as recommended by the manufacturer. Charged as a gas. Got all cases to reach temp easily but compressor superheat was too high ( 50 ). As we added charge to lower the superheat the site glass cleared. Superheat remained at 50. Added more charge and superheat rose to 70 ! I’m guessing superheat rose due the the axv closing to maintain 25psi as we added charge.

I was happy we were able to make proper case temps but i feel the compressor will not last long at 50 degrees superheat.

I have asked for the manufacturer and job engineers to send out a rep to solve our issue. I will update again after I have answers.

[pecmsg]

Update… we tried piping these 3 cases in series with 3 AXVs. We were able to get 2 cases at perfect temp after adjusting charge ( as a gas ) and setting all axvs to the same pressure 34 psi all day. The third case wouldn’t reach temp. Compressor superheat was around 20 degrees.
We then switched back to piping the three cases in series with a single axv as recommended by the manufacturer. Charged as a gas. Got all cases to reach temp easily but compressor superheat was too high ( 50 ). As we added charge to lower the superheat the site glass cleared. Superheat remained at 50. Added more charge and superheat rose to 70 ! I’m guessing superheat rose due the the axv closing to maintain 25psi as we added charge.

I was happy we were able to make proper case temps but i feel the compressor will not last long at 50 degrees superheat.

I have asked for the manufacturer and job engineers to send out a rep to solve our issue. I will update again after I have answers.

You can’t charge R-404A as a vapor!!!

[VTP99]

You can’t charge R-404A as a vapor!!!

It's definitely not recommend even though the glide is quite low.
I personally have never added R404a as a vapor.
I suppose if you new you were going to empty a complete cylinder it wouldn't matter but who's gonna wait around for that ?

Per Chemours ( DuPont ) check out R407c.