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Post by Dave on Mar 11, 2018 17:33:53 GMT
I recently found a Frigidaire 5400426 last week. It was being sold by a guy in New Orleans who had it in his vintage décor historic home. Unfortunately, the evaporator got punctured during an ill advised defrosting procedure.
The fridge had been sitting for a certain amount of time with the punctured coil open, so it was no sure thing that it would survive. When I got it home, I found the Meter-Miser compressor was stuck. Fearing the worst, and having nothing to lose, I planned to try my arsenal of stuck compressor wakeup tricks. The first was a large motor start capacitor in the start circuit. It hummed. I let it cool and hit it again.... and it started!
The evaporator is soft copper, so it was very trivial to clean up the injury and solder a plug of copper wire into the hole. Since it had been open the air for a long time, I placed a heater on the compressor / condenser area and let the vacuum pump run overnight to help remove any moisture that had seeped into the compressor.
I have been wanting to try some alternative refrigerants, and this gave me the chance. First I tried R600 (butane) because it is cheap and disposable. If the compressor didn't live, nothing lost. With R600, the compressor ran fine, and the current draw was low. After about 30 minutes of running, the evaporator was frosty. I never intended to use R600 permanently, mainly due to the flammability. But aside from that, the pressure seemed too low. It didn't seem to put much load on the compressor, and didn't reject much heat from the condenser.
After evacuating the R600, I evacuated it again. Next test was R152A. This is something I have used in automotive applications for years. It has several good points about it that far outweigh its downsides. It's more efficient than R12, not ozone depleting, and not a global warming gas. So the tree huggers get all warm and fuzzy about it. Engineers get happy because it has a high refrigerant COP rating. (That means it uses less energy.) And finally, I am comfortable with it because it has a low flammability rating (compared to R600).
So in went the R152A and the old fridge got COLD. It cools off at least as quickly as my other vintage Frigidaire with its original R12 charge.
My goal with this experiment is to see how well the compressor is compatible with the R152A. The only concern is oil logging in the evaporator since this refrigerant isn't miscible in mineral oil.
Time will tell, but for two days now it has been working very well. If it lives it's a great WIN for me. If it fails, I will call it inconclusive because the compressor had been exposed to air and was stuck for a while - so there could be internal damage already.
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Post by Dave on Mar 11, 2018 17:35:23 GMT
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Post by ckfan on Mar 12, 2018 10:39:30 GMT
Very interesting. Was that unit an R114 unit at first?
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Post by birkie on Mar 12, 2018 11:55:12 GMT
Fantastic post and video series, thanks for sharing, I really appreciate the detail in the videos In case people didn't notice, there are three videos on this refrigerator - checkout and initial repairs- service port, wiring, and test charge- Relay, reassembly, and test runGood to hear it run, and see inside the relay. I'd guess it originally ran R12, especially if it is from 1959. n-butane is a lot more like R114 than R12. In a compressor designed for R12, n-butane (or R114, for that matter) would have noticeably less capacity, which is consistent with Dave's observations. R152a looks like it could have a slight (7% or so) decrease in capacity compared to R12, but as Dave mentioned a slight increase in theoretical COP. As far as oil return, the monitor tops all had flooded evaporators as well. SO2 is not miscible with mineral oil, so their mechanism of oil return presumes that the oil will float on top ov the evaporator and eventually be skimmed off and make its way through the suction line. A few of the models were R-12 as well. I'd suspect the Frigidaire would be fine with R152a as long as it is charged enough to bring the oil to the suction line.
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Post by turbokinetic on Mar 12, 2018 20:42:37 GMT
Very interesting. Was that unit an R114 unit at first? Thanks, I'm happy you found it interesting. It is still running like a top today. It was R12. Fantastic post and video series, thanks for sharing, I really appreciate the detail in the videos...... Thanks! I really appreciate the positive feedback, and also your including all 3 video links. It was originally an R12 unit. The nameplate shows "dichlorodifluoromethane" 23 ounces charge information. I scaled the amount by the difference in liquid density between R12 and R152A to get the charge amount. This is how we do it for the GM car A/C conversions so I figured it was a good starting point for this. If I remember it came out to about 15 ounces by mass. As for the oil, that's good info that the SO2 is also nonmiscible. It seems that the densities of mineral oil (quick Google search shows .85 g/CC) and that of R152A liquid (0.9g/cc) are very close, but the refrigerant is still a little heavier than the oil. That should help the oil float up to the top of the evaporator and make its way into the suction line. One thing I noticed between this one and my AS76 (same compressor and evaporator but with R12) is the sound of the boiling refrigerant in the evaporator has a different pitch to it between the two units. The difference is slight but with the two side by side you can hear it when both doors are open. I forgot I had already got a login for this site for a car repair forum on here. Sorry about the 'guest' post earlier! Sincerely, David
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Post by jake on Mar 13, 2018 1:34:14 GMT
Yes, fantastic videos! Thanks for sharing! NICE fridge!! Looks like a 1948 or '49 model. Very glad you're saving it!! I have an owners booklet with a picture of that exact refrigerator on the cover. It's dated 1949. It states that the normal position of the temperature control is #1. Keep us posted on your progress!! Good luck with it!!
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Post by turbokinetic on Mar 13, 2018 2:14:02 GMT
Yes, fantastic videos! Thanks for sharing! NICE fridge!! Looks like a 1948 or '49 model. Very glad you're saving it!! I have an owners booklet with a picture of that exact refrigerator on the cover. It's dated 1949. It states that the normal position of the temperature control is #1. Keep us posted on your progress!! Good luck with it!! Hi Jake, thanks for the reply! I'm delighted with the porcelain finish of this fridge. It looks almost brand new on the white surface. The trim on it has a few dings and nicks, however. Today I tried to order a door gasket, but they were out of stock. Hope to get some confirmation of when that will be in stock again. Very nice that you have the owners booklet for it. Interesting about the recommended setting #1 but that makes sense! I think I had it colder than that and it was showing 25°F on my thermometer on the second shelf. That was with only a few water bottles in there and they were frozen. As for the compressor, it sounds exactly the same as it did when first started. Still cycling well and not seeming to have any problems in spite of the poor door gasket condition.
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Post by coldspaces on Mar 13, 2018 2:25:06 GMT
I have this same frig in my garage right now. The control in mine had a date from 1948 on it.
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Post by elec573 on Mar 13, 2018 2:41:45 GMT
Thanks for posting Dave very informative. Have an old fridge dare my self it’s on the list to work on also it runs and starts to get cold but then seems to stop . Ray gave me a good tip but on it but waiting for warmer weather. Good luck!
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Post by turbokinetic on Mar 13, 2018 3:40:51 GMT
I have this same frig in my garage right now. The control in mine had a date from 1948 on it. Wow. I have a feeling my 1959 date is from a relay replacement that happened after the fridge was in use for a few years. I didn't look closely at the control its self because I didn't want to stress the capillary tube to the sensing bulb, and ruin it. I just moved it out enough to terminate the new wires on it. Thanks for posting Dave very informative. Have an old fridge dare my self it’s on the list to work on also it runs and starts to get cold but then seems to stop . Ray gave me a good tip but on it but waiting for warmer weather. Good luck! You're welcome! I looked at your recent threads and couldn't locate your Frigidaire posted. I'm not a forum guru so probably didn't search correctly. Could you point me to that thread? I am curious what was suggested. I've seen a window A/C that would get cold and then randomly stop working, then stall out. It was some trash in the system that may or may not block the orifice tube. After the pressures equalized, the trash would fall back down and it would work again until that particle found its way against the capillary tube again. It looked like a large steel chip, sort of a section of a spiral chip as from a drill bit. After blowing that out, and re-assembling the unit, it never has done it again.
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Post by jake on Mar 13, 2018 5:23:34 GMT
You're welcome. Glad to be of some help. I agree, the porcelain finish is excellent. I have a '50 Frigidaire model DM-90P. The "P" in the model number is for the porcelain finish. From what I've seen the model number of the fridge was spray painted on the back during this time period and consisted of the two letters, dash,and the two numbers followed by the "P" for the porcelain finish. I'm pretty sure my model number, to give you an example, decodes as follows D=Deluxe, M=1950, 90=9 cubic feet capacity, P=Porcelain Finish. I'll dig out that owner's booklet tomorrow and see what it says would likely be your model number. I'm very glad to hear that the compressor is running well!! Did you try antiqueappliances.com for the door gasket?
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Post by birkie on Mar 13, 2018 11:21:19 GMT
One thing I noticed between this one and my AS76 (same compressor and evaporator but with R12) is the sound of the boiling refrigerant in the evaporator has a different pitch to it between the two units. The difference is slight but with the two side by side you can hear it when both doors are open. I really like little details like this, thanks for pointing it out. Does the R152a sound higher-piched/tinny than the R12? The speed of sound is about 26% greater for R152a compared to R12 in the gas phase at 0°F, and 38% greater at the liquid phase.
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Post by turbokinetic on Mar 13, 2018 13:21:06 GMT
One thing I noticed between this one and my AS76 (same compressor and evaporator but with R12) is the sound of the boiling refrigerant in the evaporator has a different pitch to it between the two units. The difference is slight but with the two side by side you can hear it when both doors are open. I really like little details like this, thanks for pointing it out. Does the R152a sound higher-piched/tinny than the R12? The speed of sound is about 26% greater for R152a compared to R12 in the gas phase at 0°F, and 38% greater at the liquid phase.
Interesting facts! I must preface this by saying that I have abnormal hearing capacity due to a birth defect. So anything I say about "sounds" is going to be relative. To me; the R152A has a slower, lower burbling sound. The R12 seems higher pitched but quieter; slightly.
Currently I don't have the AS76 running since I don't need two fridges in my workshop and want to give the repaired one a run-in. When I have both running and stabilized, I'll do a side by side video of them both; focusing on the evaporator sound.
Since I know you're a seasoned vintage fridge veteran; I have a question. Been reading about the Annie compressor tester on here. I understand what it does and what it uses to do that. Is the Annie a design which people build themselves, or is it a commercial product? Sounds very useful to me.
Sincerely, David
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Post by birkie on Mar 13, 2018 14:03:10 GMT
To me; the R152A has a slower, lower burbling sound. The R12 seems higher pitched but quieter; slightly. When I have both running and stabilized, I'll do a side by side video of them both; focusing on the evaporator sound. Fascinating, thanks! I love the way these flooded evaporator fridges sound, and like to understand what makes them tick. The methyl formate machines (which operate at very low pressures - both high and low sides are typically in vacuum) make a neat crackling sound. I hope to own one some day Since I know you're a seasoned vintage fridge veteran; I have a question. Been reading about the Annie compressor tester on here. I understand what it does and what it uses to do that. Is the Annie a design which people build themselves, or is it a commercial product? Sounds very useful to me. I'm not really a seasoned veteran - just a nerd But yes, an annie was a commercial product. They appear on ebay semi-regularly. Here's a thread on another forum that talks a little bit about them, and how to use them. The neat thing is that it makes it easy to try different capacitance values, and try starting the compressors in reverse.
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Post by turbokinetic on Mar 13, 2018 23:25:46 GMT
...... But yes, an annie was a commercial product. They appear on ebay semi-regularly. Here's a thread on another forum that talks a little bit about them, and how to use them. The neat thing is that it makes it easy to try different capacitance values, and try starting the compressors in reverse. Thanks for the links to the info on this. Will have to get one or build something similar.
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