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Post by allan on Jun 30, 2014 1:47:30 GMT
The CA is definitely an interesting machine, form A and B. I love mine but find the form A to look more Antique and rugged. In my experience the form A's I own produce more sound and it seems strong and deep where my Form B's are almost silent except for an original tinny sounding rattle!
I often wonder how our converted machines will hold up over the next 10-20 years. I strongly believe that the cap tube will help self correct most minor NCG issues and maybe with the performance of the capillary NCG won't be an issue. Running these refrigerators in conditioned spaces also has to help long term performance and reliability
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Post by allan on Jun 30, 2014 1:54:14 GMT
And thanks to the father of CA capillary's, jhigdon, my CA's maintain consistent temperature and cycle times with half full evaporator tanks! I spent too much time setting charge on run times and starting setting charge very slowly, a bit at a time over a few days to set frost line on right evap tank. Now I have my best run times and a stable frost line- which insures the best oil return to that little rotary.
Thanks jhigdon and all you other forum members!!
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Post by ChrisJ on Jun 30, 2014 1:56:37 GMT
And thanks to the father of CA capillary's, jhigdon, my CA's maintain consistent temperature and cycle times with half full evaporator tanks! I spent too much time setting charge on run times and starting setting charge very slowly, a bit at a time over a few days to set frost line on right evap tank. Now I have my best run times and a stable frost line- which insures the best oil return to that little rotary. Thanks jhigdon and all you other forum members!! How much refrigerant did you find you usually need on a size 2 machine? |
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Post by allan on Jun 30, 2014 2:00:36 GMT
As well as I can remember it varied slightly. This year I have converted 5 and all were slightly less than nameplate by an ounce or so. I learned early on that slow adjustments spread out 6-12 hours apart work best.
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Post by allan on Jun 30, 2014 2:02:10 GMT
I am still working on a new float valve assembly though that I hope will be testing this year.
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Post by cablehack on Jun 30, 2014 2:35:29 GMT
The reason GE terminated the CA was because of non condensable gas build up. This has been documented by a couple of retired GE employees at least. Patents also show they knew of the problem and tried to solve it; additives to the methyl formate and a bypassing system are two attempts I know of.
Evidently, they had enough troubles with the 1933 model to create the form B with its NCG bypass tube and larger float chamber. In fact, the form A never even made it to Australia so its reputation may have been tainted fairly early on.
The eroded needle and seat is permanently fixed with the capillary conversion - there's no moving parts or finely machined surfaces to wear.
So, that only leaves the NCG problem, but I get the impression that varies amongst individual fridges, some not needing a purge for many years. I guess I see the purge procedure as something quickly and easily done so I don't think much about it, but a non technical person would find it a huge inconvenience in the modern day. What I'm saying is that for someone who understands it, a CA works very well. Others need to choose a Scotch Yoke model if they need 'plug in and forget/know nothing about it' kind of performance. One reason I hinted to my CA-1 previous owners that it would be better with me than them.
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Post by cablehack on Jun 30, 2014 2:50:14 GMT
I learned early on that slow adjustments spread out 6-12 hours apart work best. Indeed, that is one of the most important things to know when working on a CA. The golden rule is to wait to see the effect of anything you do to it. Now, as to other kinds of fridge, I wouldn't have a clue how they react. |
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Post by ChrisJ on Jun 30, 2014 3:29:02 GMT
The reason GE terminated the CA was because of non condensable gas build up. This has been documented by a couple of retired GE employees at least. Patents also show they knew of the problem and tried to solve it; additives to the methyl formate and a bypassing system are two attempts I know of. Evidently, they had enough troubles with the 1933 model to create the form B with its NCG bypass tube and larger float chamber. In fact, the form A never even made it to Australia so its reputation may have been tainted fairly early on. The eroded needle and seat is permanently fixed with the capillary conversion - there's no moving parts or finely machined surfaces to wear. So, that only leaves the NCG problem, but I get the impression that varies amongst individual fridges, some not needing a purge for many years. I guess I see the purge procedure as something quickly and easily done so I don't think much about it, but a non technical person would find it a huge inconvenience in the modern day. What I'm saying is that for someone who understands it, a CA works very well. Others need to choose a Scotch Yoke model if they need 'plug in and forget/know nothing about it' kind of performance. One reason I hinted to my CA-1 previous owners that it would be better with me than them. True, Assuming the methyl formate breaking down and causing corrosion isn't a huge problem. So far your CA-2 machine has me concerned. |
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Post by ChrisJ on Jun 30, 2014 3:29:20 GMT
The reason GE terminated the CA was because of non condensable gas build up. This has been documented by a couple of retired GE employees at least. Patents also show they knew of the problem and tried to solve it; additives to the methyl formate and a bypassing system are two attempts I know of. Evidently, they had enough troubles with the 1933 model to create the form B with its NCG bypass tube and larger float chamber. In fact, the form A never even made it to Australia so its reputation may have been tainted fairly early on. The eroded needle and seat is permanently fixed with the capillary conversion - there's no moving parts or finely machined surfaces to wear. So, that only leaves the NCG problem, but I get the impression that varies amongst individual fridges, some not needing a purge for many years. I guess I see the purge procedure as something quickly and easily done so I don't think much about it, but a non technical person would find it a huge inconvenience in the modern day. What I'm saying is that for someone who understands it, a CA works very well. Others need to choose a Scotch Yoke model if they need 'plug in and forget/know nothing about it' kind of performance. One reason I hinted to my CA-1 previous owners that it would be better with me than them. True, Assuming the methyl formate breaking down and causing corrosion isn't a huge problem. So far your CA-2 machine has me concerned.  |
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Post by cablehack on Jun 30, 2014 5:42:39 GMT
True, Assuming the methyl formate breaking down and causing corrosion isn't a huge problem. So far your CA-2 machine has me concerned. Time will tell on that one, but the CA-1 was all clean because I don't think it had been open very long. Also, from the CA's that everyone has worked on here they look clean inside, so corrosion must only be a problem when exposed to the atmosphere, and not something that occurs when the unit stays sealed. This brings up a question for Coldspaces: Since the dismantled evaporator has been exposed to the atmosphere for a long time, is there any kind of blockage or sediment build up in the high side tube? Are all the holes clear? It may just give some clues as to my evaporator blockage. |
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Post by coldspaces on Jun 30, 2014 12:54:10 GMT
I will take a better look at the hi side tube tonight.
My thoughts are that the green tint to the oil did not just happen from sitting open. I am thinking this one got a little moisture in it that over time caused the oil to take on the green from the copper in the system. Could be the compressor on this one was locked up? Might have died from copper plating of the hot compressor parts.
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Post by allan on Jul 1, 2014 4:29:11 GMT
The really interesting thing to me is the fact that the last 5 machines I worked on have all gave instant MF odor instantly after opening the charge valves. I know you guys have purged out NCG but to date I have not observed any. The manual talks about the sweet smell which I always get instantly on a purge. I am going to pay special attention to this form b I got today and get it real hot for a couple of days on the condenser side with a really cold evap and see if I can retrieve some NCG. Any ideas on how to definitely discern between NCG and sweet smelling NCG during the purges??
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Post by cablehack on Jul 1, 2014 6:17:02 GMT
The really interesting thing to me is the fact that the last 5 machines I worked on have all gave instant MF odor instantly after opening the charge valves. I know you guys have purged out NCG but to date I have not observed any. The manual talks about the sweet smell which I always get instantly on a purge. I am going to pay special attention to this form b I got today and get it real hot for a couple of days on the condenser side with a really cold evap and see if I can retrieve some NCG. Any ideas on how to definitely discern between NCG and sweet smelling NCG during the purges?? The NCG's will only exist if the methyl formate is reacting with contaminants or otherwise breaking down, there's air, or as in the case with my cap tube work, another gas like nitrogen introduced into the system. The one and only time I attempted to purge my CA-1 when I first filled it, there was MF straight away. If you get MF soon as you open the charge valve it's a good sign. It means no leaks or contaminants in the system. However, I would expect all original condition CA's to have NCG's by now. I can hardly detect MF by odour unless it is quite concentrated, so I use condenser and float chamber temperature to indicate the presence of NCG's. Sometimes I have seen droplets at the charge valve - they're obvious because of the way they react with the oil. The other way I know when the MF is coming through is when it gets on my fingers and feels cool as it evaporates. |
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Post by coldspaces on Jul 1, 2014 23:26:00 GMT
Well I cut the tube open last night and then we had over an 8 hour power outage that kept me from posting. The tube looked pretty clear other that a little dark residue you can see in the pics. Only a little signs of any green corrosion inside or out. Notice the first hole in the tube is cleaner around the hole than the rest for what ever reason.   Split it with a hacksaw and then spread it open.  |
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Post by ChrisJ on Jul 2, 2014 1:21:52 GMT
Any ideas on what size those holes are?
I have to assume they are mighty small for the little amount of refrigerant that is expected to "spray" out of them, so to speak?
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