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Post by turbokinetic on Nov 13, 2018 14:46:20 GMT
Wow. Holy cow ! On the amount of NCGs. I’d say mine usually goes into a vacuum after it’s been off around 15 to 20 min. Maybe a little longer if it’s good and hot. It’s sounds happy ! Now. Kind of like mine on a good day lol. Very happy to see you were able to get it up and running again. 😁 Yeah, I was not expecting the amount of pressure it had, when stopped, considering it was really cold that day, as well! It should have been well into a vacuum at that point. I ran it several hours yesterday and it continued to sound quiet, with stable power draw. I’m glad that it’s behaving now. The only thing that I’m wondering about is the way that you bled off the gasses. In the service manual it says to bleed slowly for 3 minutes and then close it off and wait for 1 minute and then repeat. Otherwise it states that you will run the risk of bleeding off refrigerant. Did you ever get a whiff of methyl formate? To me it seems like the rate you were bleeding at seemed much higher than what I normally do as well. I’ve purposely opened the purge screw wide for a second just to see what it smelled like and it did release MF. I’m just curious if it is possible with a machine with such a buildup as yours had to bleed it faster by skipping the waiting step or if it is truly necessary like GE says it is. I don’t want to cause an argument. Im genuinely curious. I know that when I bled my original CA it took 3 tries and took hours each time. If that time can be cut down with no loss of refrigerant, im all for it. I bet my machine was close to locking up because it sounded absolutely terrible and was drawing close to the same wattage as yours was. Well, I didn't time it with a watch, but for sure went a lot longer during and between purging sessions than the manual recommends. My reasoning for that was because the ambient temperature is so low. They say that methyl formate boils at 85°F, and the room was about 50°F. I don't think it shows well in the video "just how far" the service port was opened at the beginning. I literally just cracked it open to where it wasn't even fully "loose" in the threads, and it was blowing the oil out of the tube; in a cold room. I don't want to guess on the pressure, but expect an R12 system would have about that much pressure in a cold room like this was! I didn't smell methyl formate at any point, believe it or not! Knowing the compressor had been seized up, there was some level of damage or contamination, somewhere, which had been holding it back. My fear was that it seized up again, before the previous damage had time to establish a new, normal wear pattern. If that were to happen, it might be impossible to get it going again. So, I was willing to risk wasting some refrigerant to expedite the process, and minimize running the unit with it operating abnormally. I don't think I got all the NCG's out of it. The float chamber will separate the NCG from refrigerant due to density differences. I'm sure as the unit runs, more of the remaining NCG will build up in the float and additional, slow purging will be necessary. Another thing that could affect it is that I ran it without a control and it was constant running. The off-cycles could affect the way the NCG's collect in the system. However.... as the day warmed up, the float chamber did finally start to warm up and was almost as warm as the condenser after about 4 hours running and the room warming up to about 65°F. |
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Post by Travis on Nov 13, 2018 15:04:37 GMT
My guess is that the GE service manual didn't account for a machine to get this filled with NCG's. I would state a thousand times for a new member that happens to view this, this isn't typical and you should pay close attention to outward pressure and use your nose. A casual member could end up with an empty CA very easily.
I do believe the secondary screw was originally soldered in to avoid having air sucked in.
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Post by turbokinetic on Nov 13, 2018 15:18:13 GMT
My guess is that the GE service manual didn't account for a machine to get this filled with NCG's. I would state a thousand times for a new member that happens to view this, this isn't typical and you should pay close attention to outward pressure and use your nose. A casual member could end up with an empty CA very easily. I do believe the secondary screw was originally soldered in to avoid having air sucked in.
Definitely! Highly doubt the designers of these thought it would develop "that much" NCG; nor did they think it would last 80 years; nor did they think that people would care about them enough 80 years later to try and keep them going! 
I am sure the manual is written to cover all types of people who might be unfamiliar with how things like this work. They would rather error on the side of caution; than have servicemen claim GE told them to do something which ended up causing problems.
And yes, it goes without saying, you would never see this level of NCG in a running CA that was working but sounding poor. This one was a seized-up scrapyard find and no telling how much abuse it saw, and how much time it had been baking in the sun outside forming more NCG's from heat; after it stopped working.
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Post by ckfan on Nov 13, 2018 15:25:32 GMT
That all makes sense. I guess since you had the tube filled with oil on the port it made it look like you had the screw more wide open than it really was. I do like that method. I’ll have to try it! Sounds like I could have done a steady, slow purge on my CA and saved hours. I do agree with it being that sick that the potential loss of refrigerant is outweighed by the risk of the compressor locking up again and doing further damage. Very cool stuff! I plan on doing more purging and work to my CA form B soon. It’s so lonely in the basement!
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Post by turbokinetic on Nov 13, 2018 16:03:07 GMT
That all makes sense. I guess since you had the tube filled with oil on the port it made it look like you had the screw more wide open than it really was. I do like that method. I’ll have to try it! Sounds like I could have done a steady, slow purge on my CA and saved hours. I do agree with it being that sick that the potential loss of refrigerant is outweighed by the risk of the compressor locking up again and doing further damage. Very cool stuff! I plan on doing more purging and work to my CA form B soon. It’s so lonely in the basement!
Yeah, that was my line of thinking. As for the tubing, it was just the cheap vinyl stuff from Lowe's. I heated up the end with a heating gun so it was soft enough to go over the port.
Today I will be making a video (time permitting) on a really sad situation where someone did not follow an informed and methodical troubleshooting process. It's not related to this CA, by the way... thankfully.
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Post by Travis on Nov 13, 2018 16:17:04 GMT
David,
You're correct. The manuals were written in the 1940's for service men that would have been somewhat familiar with repair. They weren't written for the consumer or the hobbyist. They certainly can't cover what may or may not have happened in the past 70 years since they were written.
That CA unit wasn't rusty when I brought it home. It had been sloppily repainted. I quickly gave up on it. It wouldn't start. I couldn't remove the purge screw. I never tried heat or a better tool as I didn't care much. I gently placed the unit on boards in my driveway and let it get rained on. I offered it to David because we would learn from it and it wouldn't have to continue to rot.
Though I am very thrilled that David got it running, I wonder who would be interested in stripping it and repainting it. This isn't the only group that I am in where the number one comment is "what's it worth?". Part of the value in my opinion is that you saved it or were part in saving it.
Nearly all of these units can be saved, but it takes a significant commitment of time and money to do so. A MT will usually run, but the cosmetics and insulation are a bigger issue, the belt-drives need more David.
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Post by ckfan on Nov 13, 2018 18:39:28 GMT
The belt drives need David...and I to fix them. I want to learn and eventually get the tools to do so. That will be much further down the road. I need a shop first. We also need a cheap way to satisfactorily strip and paint units and cabinets. To me this is the missing link. Again, this is where a shop, time, money, and tools come into play. I’m going to get all that eventually. It’s my goal. I, the student, am willing. But my wallet isn’t currently able!
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Post by Travis on Nov 13, 2018 20:43:42 GMT
No one doubts the desire to do all of this. The complexity of the restoration and the shop to do so is the issue. Having a paint shop with a machine shop is an expensive prospect, plus the aptitude to do either and then the market to pay for the finished work.
A missing link is also having enough time to do this work, while being able to support yourself.
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Post by turbokinetic on Nov 14, 2018 5:06:06 GMT
You guys understand..... It's hard to have time / money / abilities / desire all at the same time.
I have a pretty good situation with mechanical repairs and electrical work; but I can't paint to save my life!
One of the neat things is networking. For instance, I can get it working, and someone else has the artistic skills and patience to refurbish the cabinet. Between the two of us, a very nice piece is created.
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Post by ckfan on Nov 14, 2018 13:23:03 GMT
Yes, that’s true. I am thankful for all of the great members on this forum who have helped me out in many ways. No one person can do it all, but I still want to learn more!
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Post by birkie on Nov 15, 2018 4:41:24 GMT
After watching the purging video - yikes, that a lot of NCGs! Does the standard service kit fit that float as well? I'd be curious what sort of pressure it developed on the high side. It almost feels like that thing would have been above a vacuum even just sitting there without turning it on at all.
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Post by solarmike on Nov 15, 2018 4:53:31 GMT
Could it having that much NCGs be the reason that it was locked up in the first place? Or was it several things that happened because of the high gases?
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Post by turbokinetic on Nov 15, 2018 5:09:47 GMT
After watching the purging video - yikes, that a lot of NCGs! Does the standard service kit fit that float as well? I'd be curious what sort of pressure it developed on the high side. It almost feels like that thing would have been above a vacuum even just sitting there without turning it on at all. Hi Aaron. Actually, all that pressure shown at the first cracking of the service valve was without running! It had been sitting for hours without running before that. And it had so much pressure it tried to blow the oil out of the clear tubing! As for the high-side pressures, it must have been ridiculously high. I didn't connect a service kit since this was just a purging operation. Paul is going to give me a couple more seized CA's and I will connect the kit and see what is happening with them. Could it having that much NCGs be the reason that it was locked up in the first place? Or was it several things that happened because of the high gases? Mike, I believe the NCG's caused some minor damage to the compressor by severely overloading it, and causing the refrigerant to dilute the oil. This combination probably lead to some small cored or scuffed areas in the rotary compressor mechanism, which caused the mechanism to be too tight to rotate with normal power levels. After shaking and agitating the oil moving the unit, it got a small taste of oil at the instant it started (with the high powered jolt). That was enough to allow the scuffed area to wear down and establish a new running pattern, so it was no longer stuck. Another issue which happens, is that copper residue from the lines and evaporator and windings can become dissolved in the oil and refrigerant. This will deposit in areas of high temperature and metal-on-metal contact. When the compressor was running under extreme stress due to the NCG's, it may have built up excess copper plating in the rotor chamber. Once the high temperatures and metal-on-metal contact were relieved, the copper plating can wear down; allowing some reasonable running clearances to be established. With either of the above scenarios, the excess pressure, load, heat, and oil dilution caused by the NCG's was a driving factor. It should not reoccur as long as the unit doesn't once again get operated with high NCG buildup. |
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Post by solarmike on Nov 15, 2018 12:28:43 GMT
^^^ That is awesome to know^^^^ Thanks for taking the time to explain it...
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Post by turbokinetic on Nov 15, 2018 17:54:09 GMT
^^^ That is awesome to know^^^^ Thanks for taking the time to explain it...
You're welcome. Remember however I am just posting theories here, so don't quote me on that without qualifying it as theorizing.
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