Some compressors are designed for a variety of refrigerants just different capacities for those refrigerants. So that one there may be fine with 404a you'll have to dig deeper
Whats the compressor model number?

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Compressor is an Embraco FF 7.5HBK. All the data online specifically says its for 134A.

Thank you for responding

 

Compressor # ? I’m guessing this is an environmental chamber ie cascade my guess is 404. But that’s it a guess

 

It is an environmental chamber but not a cascade. Both systems chill a different part in the chamber. Both use 404A. One has an evaporator coil and the other chills an evaporator plate.

Thanks for your response.

 

If very low temperatures 404A

 

Yes its very low temperature. -20C. Thanks

 

 

Ugh!!! upside down. Why?

 

Seen oem use a r12 compressor for r508 at least they marked it

 

Hi there!
First post.
I went through this yesterday with Copeland, r22 draught line condensing unit (labeled), compressor said R404a on the side. After a bit of chatting with the engineer at Copeland the oil in the compressor is POE. That compressor will work with what ever compatible refrigerant. The bugaboo is its capacity and in my case the condensing unit it was built into.

They don't publish the performance for all compatible refrigerants.

Great site!
Good luck and stay safe.

 

Thank you!

 

The equipment manufacturer has it tagged for 404a, so put 404a in it

 

I agree

 

Can it be that is a cascade with the high temperature system running R-134 and the low temperature side running R-404? That would seem odd as R-404 won't make better than -45º F. and remain positive.

Has the compressor ever been replaced before? Does the compressor serial number date to about the same time as the condensing unit serial number?

You have to pump a much larger amount of R-134 to move the same amount of BTU's as R-404. And the compression ratio would be about 300% higher - so off the top of my head: I would think that an R-134 compressor cannot successfully pump R-404.

Is there a condenser and an evaporator ganged together? What is the configuration of the unit? What do the two condensing units do?

PHM
-------

 

This chamber actually has two evaporators. One is a standard coil and the other is cold plate. I can say now with certainty that its all 404A. But honestly, Im still a bit confused on the piping configuration. I see 3 solenoids that are tying both systems together. The manufacturer, Leica, refuses to provide any information like a schematic, wiring diagram, theory of operation etc. Very frustrating to say the least. I did find a compressor on Ebay for only about $100 so I think its worth replacing the bad compressor and see what happens.

Thanks for your input.
Semper Gumby

 

The OEM usually gets approval from the compressor manufacturer to use the compressor with a different refrigerant. As has been said, it happens all the time. I recall some slide-top ice cream cases used LT R12 Copelametics with R502. You're quite lucky to have the R404A stickers on there.

 

That was a little different, wasn't it? The R-502 / R-12 thing I mean.

Weren't they running about the same head and suction pressures? So the compression ratio was the same - just the suction temperature ranges were different?

How are they doing that with R-404 / R-134 ? Hmmm . . . .the same way? The R-134 is medium temp and the R-404 is low temp? Are the condenser coils different?

And what is the advantage? When R-502 was first introduced there were no R-502 compressors - but there certainly are R-404 compressors. Why use an R-134 compressor in that case?

PHM
---------

 

If you look up a Copeland compressor quite often they will list alternative refrigerants.
Here's an example at the bottom

 

Yes; I laugh to think that I have been doing it for years and now suddenly it's all Their Idea. <g>

But more: I wonder if it has become cheaper to just install a large HP motor in All compressors and then just let the RLA drift with the loading?

Oh; that reminds me - I was given a 5HP R-410 condensing unit and while thanking the guy I mentioned that it was perfect for what I was doing - because I needed 2.5 HP. So I would be charging the system with R-134.

His argument was that I was stupid to do that - because I would be running a 5 HP motor to get only 2.5 HP worth or work done.

I don't believe that - but am I wrong to picture that if operating a 5 HP compressor with a 2.5 HP load it will draw 2.5 HP worth of amps? And also have the benefit of the 5 ton condenser coil only rejecting 2.5 tons of heat.

PHM
-------------

If you look up a Copeland compressor quite often they will list alternative refrigerants.

 

What's the btu/h per pound difference between R410a & R134a ?
50 ℅ ?

 

Lol, gotta keep a watch out for Poodle's posts, might miss a good story if you don't.

I didn't know compressors could run different refrigerants, but wouldn't it be impractical to run 1 kind in 1 side and another in another section?

I guess if they need one lower than the other, but still, would seem easier to me to have them both the same.

 

If it has 2 evaporators, 2 condensers and 2 compressors, it's 2 entirely different systems it sounds like.

The 3rd solenoid could be a hot gas bypass valve or a headmaster to maintain head pressure.

I hate manufacturers like that, they are such a PIA.

 

double post

 

Maybe lead lag or 2 stage?

 

Yes, thanks. I had forgotten his name. Mike was younger than the most of them. I didn't know him as well as I did Ted Kuklis in NJ (?) and Aaron Kaminsky in NYC. The guy I started out with in the Boston office, Bob Thorpe, was a Marine fighter pilot in WWII and Korea, joining D/B at it start soon after that with Cecil Boling and Red Mulcahey. Many of the old crowd came over from Carrier and Worthington. The corporate offices were all closed around 1980, so the ones who stayed on as reps started their own offices.

 

If you're sure that the 2 refrigeration circuits are tied together, it's a no brainer that you can't have 2 different refrigerants. It could be that the 3 solenoids are one for each evaporator, and one that controls capacity and probably energizes with the second compressor. I saw an arrangement like that on a medical refrigerator. It would use both compressors to quick-cool, and just one if it was refrigerating. If it needed to freeze, it would run both on starting, then cut to one to get to the final set point. (-15°F)
• The ff series of Embraco's are usually not expensive. I hope you got a brand new one at least! The temperature range is -10 to 45° so they can do a lot of different applications. I see in one of the pics that it's clearly marked R134a on the OEM MN tag. However, I have seen them in other applications running R404a. They seem to be a pretty resilient compressor!

 

Yeah it’s pretty obvious about it all being 404a. The system is still confusing though. Everything seems back back asswards. Even the solenoids all operate on DC voltage. I’m an hvac contractor and feel I’m good at it but this new job has me only working on commercial, industrial refrigeration systems. Definitely a change for me. Changing out a compressor on the high side of a -80 freezer cascade system doesn’t scare me. Changing out the compressor on the low side scares the crap outta me.

 

Randell is wacky with this sort of stuff and you just gotta look at an LG household refrigerator to see what craziness goes on. They use 2 evaporators with cap tubes that come from a 3 way valve. Either one or both evaporators can be fed, or none, in which they actually pump down!! A fully variable linear compressor drives it. (Nothing turns in the compressor, it works more like a bicycle pump with a DC coil taking the place of 'you'. Power on, piston pulls up. Power off, big springs pull it back. By varying the voltage, you get a different stroke, and varying the 'frequency', how many pumps per second. The cap tubes have an intentional crimp right as it enters the evaps, supposedly to quiet them down. They plug up at that pinch point. What you have there is nothing comparatively. But still can throw you if you don't see it often enough.

 

Oh yeah and there's also a check valve for the freezer evaporator so refrigerant doesn't flow from the common suction back into that freezer coil while the refrigerator coil is calling only.

 

...and of course, there is the whole idea of using the condenser as a receiver... Don't get me started....ROFL

 

Dont know how the hell we're suppose to keep up with all of this new technology. I cant attend enough training classes to stay on top of it.
Thanks for your input.

 

Keep up? GFL. Much of this is the school of 'figure it out for yourself'!! (or come to places like this and hope that someone else has!)

 

I went on a w/I and it had. R12 exp valves and someone changed it over to r 408 I always heard and read that r 409 was the freon of choice when dealing with r12 it’s been running like that for 4 years now I believe some of these old semis with the suction line. on the end going through the windings will pump any thing you put in it.its only about 30 years old and went under water in Katrina tiff stuff back in the day

 

R408a was a replacement for R502 and yes R409a was for R12 as well as R401a (MP39) , R414b (HotShot) and others.

 

and the a c guys have issues with
410A
NU-23
407A, B , C