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Post by successionalsasha on Aug 25, 2024 1:39:52 GMT
Greetings, everyone! I'm new here and this is my first post. 😊 Little did I know, but as it turned out, life wanted to give no one less but myself the great honor of being in the line of succession to this historical treasure.   An original Frigidaire belt drive refrigerator! If I'm not mistaken it's a model D-4. From...late 1920s, I believe? By a mere coincidence and good circumstances I was allowed access to a big turn of the century house just about to be demolished (this was thanks to a very friendly and helpful supervisor at the site), where I stumbled upon the fridge and managed to pull off an absolute last-minute rescue! (From the UPPER floor, I might add!) The sole reason I found out about it all was simply happening to go by on that particular street just at the right time (a street I only travel once in a while) and noticing the demolition crew and all their equipment already tearing away on some other smaller buildings. I hadn't imagined actually going inside at first, but I ended up having a chat with them and then one thing led to the other. All unplanned for. The kitchen in which the fridge stood was, judging by the style and certain familiar details, constructed sometime around 1950. And the condition of it all said it was hardly even used since then? Overall very little sign of wearage in there. And one strange thing was, even though the fridge was carefully mounted in a built-in enclosed manner, along with the rest of the kitchen kabinets, and earthed by means of a long unisolated solid copperwire, there was no elictricity outlet (or even trace thereof) in the back. The crumbled remains of the fridges cord just lay there loose, without anything to connect it to behind the fridge. Once I got the Frigidaire home and could take a closer look, the old Goodyear drive belt said the same thing. It was solid hard and the shapes of the pulleys would remain on the belt after I removed it. This fridge has not been operated for a VERY LONG TIME. I went and got a new belt and a new cord to it. I also got the electrical motor out and went to a renowned electro mechanical workshop (which has since closed) here in town and had them do some measurement, just to check if it was safe. I have no idea about electrical motors really. I had tried starting it before going there and it worked just fine, but I assumed there would be more to it than that? They hooked it up and measured something and just said the motor is good. Well then, let's get it all together and start this beauty up! Back with the motor, on with the belt and connect the wires. Then time for the *imensely* exciting premiere live Cold Control maneuver! What will happen?! Will this soon-to-be 100 year old refrigerator actually still work? So I gather myself and put my fingers on the Cold Control...take deep breath...and turn knob around. The motor engages and gets going...flywheel rotates and compressor start pumping...evaporator begins hissing...and...then...COOLS DOWN! Well I'll be darned! It IS working! Its spirit is still within! At first, though, it did act up a bit with the crank case also getting all cold and frosty, apart from just the evaporator. (Not so unexpected, I suppose, with some stiff legs after more than half a century of sleep!) But after a couple of cycles it slowly began to get better and after a while more it had sorted itself out and the compressor started running as it should, with the crank case at about room temperature (or slightly over). After that, it refrigerated just fine. And let me tell you, the compressor ran so silent and smoothly that just listening to it was a mere pleasure! And if you opened the door you could hear the special monotonous sound of the strokes from the low-rpm single cylinder compressor echoing inside the evaporator. Made me think of something like a steam locomotive fireing away! Just marvellous! With modern equipment as my only reference I couldn't imagine to hear such a mystifying song from a refrigerator.  Ice trays and drip pan are naturally missing. I searched through every little corner of the whole house (including outside shed) but couldn't find them anywhere. I had it running for about two weeks and it kept the temperature good and cold the whole time. I don't exactly recall the cycling times now, but somewhere around a total of maybe 20 minutes per hour, evenly distributed over three cycles. But then one day the compressor sounded differently. It had started to knock. It still refrigerated, but I could sense something is happening, even though it wasn't a loud, but rather slight knocking noise. IIRC there was also some change in the cycling times as well. I decided to power it down until I could learn how to further examine it. My thought was that maybe it has gotten some air into the system. And not knowing of any technician that would be able and willing to work on a fridge like this, it leaves only the option of myself becoming guerrilla technician to make things happen. I did extensive searching online for documentation on how to work on these systems, but couldn't find it. Overall there didn't seem to be very much info at all available at the time. So it's been sitting there turned off and waiting ever since then. I don't dare touch anything before I know exactly what I'm doing, not wanting to spoil my single chance of getting it in order and keeping the refrigerant at the same time. It was clear to me even without the documentation that these units are built solidly and to be able to be worked on. It would be a shame to not make use of that. Especially since automatic domestic refrigeration in general appear to have been very uncommon up until the mid 20th century here where I live (to the point of fridges from that time period being virtually non-existant today, as it seems to me). For example I didn't even know what a monitor top was and had never seen one, even on picture, until all this happened and I ended up here. So when did all this take place? It was in february and march 2017. Now a friend of mine has been asking occasionally and asked me again earlier this past winter hows it going with the Frigidaire. I assumed theres still nothing to find but did some casual search... Seems things have changed since then! Thanks to someone particular in here I finally found the service manual I was looking for and have carefully been reading up on it, for hours! I'm very grateful for this, thank you so much! Having now gathered this crucial knowledge I'm on to this again. I have started out by getting myself a manifold gauge, which arrived a while ago. First I figured I should start the fridge back up again, to see if it will still be operational, now that it may have gotten air inside and then been sitting like that for seven years. So I hooked up the electric plug and turned it back on, with a thermometer on the evaporator. Sure enough, it immediately started cooling down! And after a moment: all the fins evenly frosted! And no back flooding on the suction line. It also was not knocking any more? However I think there is still some issue with the shaft seal. Because it seems small amounts of oil is making it's way through it somehow, when its in operation. Because before starting it I rotated the flywheel by hand to see that nothing would have gotten stuck-up or anything. When doing so I discovered that there was a fat surface on the inside of the flywheel, on the spot that had been at the bottom when it was sitting still. Anyway, next time around I thought I'd proceed and connect the gauge and do some measuring. I actually wanted to do that before I even started it up again, but I was unsure exactly how the end cap on the service port and the protection caps on the valves are sealed (the service manual was a little ambiguos on that matter), if there may be some packing that have to be replaced when putting the cap back on or something. But now after some consideration I guess I could use, what you call it in english, thread tape? to make it seal if I cant get anything else to work for the moment being. I want to check the different pressures on the low side (I also wouldn't mind checking the head pressure but that will be too complicated right now, because the way it's set up I'd have to first evacuate the compressor and then put special fittings, that I don't have, on the head in order to connect the gauge). And speaking of evacuating, I also want to check if the compressor would hold vacuum overnight. And since I don't own a vacuum pump I thought I could just pump the vacuum down by closing the inlet valve on the compressor (or maybe the low side valve on the evaporator) and keep it running (thus evacuating it at the same time) until the pressure is low enough and then turn it off and close also the discharge valve. And if the vacuum don't hold I could simply just go ahead and disconnect the compressor and unmount it, and take a look at the shaft seal. So that's like my plan of action right now. Could it be a good way to go about it? I'm hoping you guys wouldn't mind educating me, so that I, as successor but also total beginner, may avoid the pitfalls going about this. Please do comment on any of your thoughts. Regards Sasha  Compressor apartment (with secondary Cold Control). Sorry for my horrific wireing! I will make sure to redo it in a neat way, if we get the unit running properly. |
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Post by turbokinetic on Aug 25, 2024 14:00:01 GMT
Hello Sasha. Your condensing unit has manual service valves. You won't need any special fittings to connect manifold gauges to this unit. You will need a valve key and some wrenches. If I remember; the valve key is a 1/4" square drive and the wrenches are 3/4" and 1" or 15/16 depending on the cap style.
The knocking sound you encountered is likely due to air ingress into the system while the machine is running. The low pressure side runs at less than atmospheric pressure and therefore will leak air inwards and build up excess pressure. It stands to reason that it would have leaked back out during the time the fridge was out of service since you first ran it in 2017.
Most likely, the reason your compressor is still viable is because the SO2 has been replaced with either Freon-114 or Freon-12 by a serviceman back in the old days. That would also mean you won't smell any odor if there is slight seeping at the shaft seal area.
Myself and others here can help with lots of info on this. We are having a little trouble with the wording of your post. I understand if you are not from the States and maybe English is not your native language. We would like to know more about where (in general) you are located.
Sincerely,
David
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Post by successionalsasha on Aug 27, 2024 1:29:53 GMT
Hello Sasha. Your condensing unit has manual service valves. You won't need any special fittings to connect manifold gauges to this unit. You will need a valve key and some wrenches. If I remember; the valve key is a 1/4" square drive and the wrenches are 3/4" and 1" or 15/16 depending on the cap style. The knocking sound you encountered is likely due to air ingress into the system while the machine is running. The low pressure side runs at less than atmospheric pressure and therefore will leak air inwards and build up excess pressure. It stands to reason that it would have leaked back out during the time the fridge was out of service since you first ran it in 2017. Most likely, the reason your compressor is still viable is because the SO2 has been replaced with either Freon-114 or Freon-12 by a serviceman back in the old days. That would also mean you won't smell any odor if there is slight seeping at the shaft seal area. Myself and others here can help with lots of info on this. We are having a little trouble with the wording of your post. I understand if you are not from the States and maybe English is not your native language. We would like to know more about where (in general) you are located. Sincerely, David Hi, David! How interesting to be conversating with you myself at last, after having been silently reading your many great and educating posts for some time now. About the valve key, do you think a normal 1/4" socket could fit in there backwards? If so, I could just use an in-6 (or how you call it) wrench inside the socket on the other side. A valve key as described in the service manual is not something I got in my possession. Also, what I was trying to ask about the caps was if there is some sort of seal in the bottom of them? I see that I happened to write "packing", when the word I actually meant was "seal". Sorry about that. The compressor has not been converted. It is still on sulphur dioxide. How I know that? Well, first off there are no signs or anything put up in the compressor room that hints that the system would be charged with anything else than SO2. Secondly, when I was unmounting the old drive belt and then moved the flywheel out of its position where it had been sitting for so long, I could hear how it began to leak at the shaft seal, with the immediately following scent of eau de punch-in-the-face. However, at this point I had a little trumph card in my sleeve. Because of the little info I did manage to come by at the time, (which still didn't say just how the seal works or how it's constructed), someone somewhere had said that sometimes these shaft seals can seal themselves if you just run the compressor. Not being able to run it by the motor I just manually spun the flywheel around, while for the moment having to leave that old habit of breathing aside. And thankfully it did work, the leak stopped. You are correct that I'm not from America and that english not is my native language. It actually takes a while for me to write a post like this, and there will still be some mess-ups here and there. But I have learned to not be ashamed of that (rather on the contrary, I try to laugh about it). I just hope I won't confuse you guys too much. Please give me a notice if there is something hard to understand and I try to rephrase. As to my country of origin, I guess the fridges front emblem is somewhat revealing:  😊 Regards Sasha |
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Post by turbokinetic on Aug 27, 2024 22:48:45 GMT
Hello Sasha. Your condensing unit has manual service valves. You won't need any special fittings to connect manifold gauges to this unit. You will need a valve key and some wrenches. If I remember; the valve key is a 1/4" square drive and the wrenches are 3/4" and 1" or 15/16 depending on the cap style. The knocking sound you encountered is likely due to air ingress into the system while the machine is running. The low pressure side runs at less than atmospheric pressure and therefore will leak air inwards and build up excess pressure. It stands to reason that it would have leaked back out during the time the fridge was out of service since you first ran it in 2017. Most likely, the reason your compressor is still viable is because the SO2 has been replaced with either Freon-114 or Freon-12 by a serviceman back in the old days. That would also mean you won't smell any odor if there is slight seeping at the shaft seal area. Myself and others here can help with lots of info on this. We are having a little trouble with the wording of your post. I understand if you are not from the States and maybe English is not your native language. We would like to know more about where (in general) you are located. Sincerely, David Hi, David! How interesting to be conversating with you myself at last, after having been silently reading your many great and educating posts for some time now. About the valve key, do you think a normal 1/4" socket could fit in there backwards? If so, I could just use an in-6 (or how you call it) wrench inside the socket on the other side. A valve key as described in the service manual is not something I got in my possession. Also, what I was trying to ask about the caps was if there is some sort of seal in the bottom of them? I see that I happened to write "packing", when the word I actually meant was "seal". Sorry about that. The compressor has not been converted. It is still on sulphur dioxide. How I know that? Well, first off there are no signs or anything put up in the compressor room that hints that the system would be charged with anything else than SO2. Secondly, when I was unmounting the old drive belt and then moved the flywheel out of its position where it had been sitting for so long, I could hear how it began to leak at the shaft seal, with the immediately following scent of eau de punch-in-the-face. However, at this point I had a little trumph card in my sleeve. Because of the little info I did manage to come by at the time, (which still didn't say just how the seal works or how it's constructed), someone somewhere had said that sometimes these shaft seals can seal themselves if you just run the compressor. Not being able to run it by the motor I just manually spun the flywheel around, while for the moment having to leave that old habit of breathing aside. And thankfully it did work, the leak stopped. You are correct that I'm not from America and that english not is my native language. It actually takes a while for me to write a post like this, and there will still be some mess-ups here and there. But I have learned to not be ashamed of that (rather on the contrary, I try to laugh about it). I just hope I won't confuse you guys too much. Please give me a notice if there is something hard to understand and I try to rephrase. As to my country of origin, I guess the fridges front emblem is somewhat revealing: 😊 Regards Sasha Thanks for the detail of the Frigidaire logo. Nice to see that some of these machines made it to Sweden back in that era. Sorry you got a face full of sneezing gas LOL! That happens with these, and it is a fact of life for us in the field. As for the valve key, yes you can use a standard 1/4" drive socket, inverted. Maybe use a 6mm socket with a 6mm hex key as a handle, to turn it. The single-cylinder Frigidaire compressor you have there is known for greater seal durability. It has a different design. There is less area for the shaft to corrode and seize to the seal. |
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Post by douro20 on Sept 1, 2024 2:32:46 GMT
It would really be in your best interest to get all of the R-764 (sulphur dioxide) out of there as it is extremely dangerous to your health if a large leak occurs. You can close the outlet valve on the receiver and use the compressor to pump down all of the refrigerant into the receiver. Then the outlet on the valve can be disconnected and a hose attached to the valve and placed in a bucket containing a saturated solution of sodium carbonate (washing soda) in water- this will convert the SO2 to harmless sodium sulphate and carbon dioxide. This must be done outdoors and in a slow and methodical manner. Then you can connect a hose to the high side port on the compressor and use that to pump down the system to remove the rest of the trapped SO2. Converting the system to use R-152a is not too difficult to do if the seal on the compressor is in good shape. The low-side float which is inside of the evaporator will have to be modified for the new refrigerant as it has a different specific gravity- you might want to talk to Dave about it or have him do that part of the job. The pressure control will also have to be modified since the system will now use a refrigerant which has a higher pressure- SO2 systems will actually operate in a significant vacuum on the low side.
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Post by successionalsasha on Sept 3, 2024 1:54:42 GMT
It would really be in your best interest to get all of the R-764 (sulphur dioxide) out of there as it is extremely dangerous to your health if a large leak occurs. You can close the outlet valve on the receiver and use the compressor to pump down all of the refrigerant into the receiver. Then the outlet on the valve can be disconnected and a hose attached to the valve and placed in a bucket containing a saturated solution of sodium carbonate (washing soda) in water- this will convert the SO2 to harmless sodium sulphate and carbon dioxide. This must be done outdoors and in a slow and methodical manner. Then you can connect a hose to the high side port on the compressor and use that to pump down the system to remove the rest of the trapped SO2. Converting the system to use R-152a is not too difficult to do if the seal on the compressor is in good shape. The low-side float which is inside of the evaporator will have to be modified for the new refrigerant as it has a different specific gravity- you might want to talk to Dave about it or have him do that part of the job. The pressure control will also have to be modified since the system will now use a refrigerant which has a higher pressure- SO2 systems will actually operate in a significant vacuum on the low side. Hey you, you're acting all swedish here thinking about risks and safety when I'm trying to ignore them! 😉 For your information, I CUT THE SEATBELTS OF MY VOLVO! Or no, I didn't. But I would have if they were there once I got it! LOL (long story) Jokes aside, I'm not so worried of the sulfur dioxide. I'm quite relaxed about it. It's only under some very specific circumstances it would be, in your words, extremely dangerous. I think it has maybe a little worse reputation than it deserves. I could elaborate on it, but I'm afraid of pulling the thread off topic too much. Though I totally understand there might be questioning of my wish to stick with it as refrigerant. It's allright.
Anyway, a refrigerant rant aside, one of the things I would like to cool with the Frigidaire are my bottles of this wonderful sparkling rosé wine from Italy. And as you all probably already are aware of, almost all wines contain..........SO2! As a preservant. So, some sulfur dioxide in the bottles to keep them fresh, and some more in the refrigeration system to keep them cold. Now that is music of consistency in my ears. 🥂
Cheers Sasha |
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Post by turbokinetic on Sept 3, 2024 1:59:46 GMT
It would really be in your best interest to get all of the R-764 (sulphur dioxide) out of there as it is extremely dangerous to your health if a large leak occurs. You can close the outlet valve on the receiver and use the compressor to pump down all of the refrigerant into the receiver. Then the outlet on the valve can be disconnected and a hose attached to the valve and placed in a bucket containing a saturated solution of sodium carbonate (washing soda) in water- this will convert the SO2 to harmless sodium sulphate and carbon dioxide. This must be done outdoors and in a slow and methodical manner. Then you can connect a hose to the high side port on the compressor and use that to pump down the system to remove the rest of the trapped SO2. Converting the system to use R-152a is not too difficult to do if the seal on the compressor is in good shape. The low-side float which is inside of the evaporator will have to be modified for the new refrigerant as it has a different specific gravity- you might want to talk to Dave about it or have him do that part of the job. The pressure control will also have to be modified since the system will now use a refrigerant which has a higher pressure- SO2 systems will actually operate in a significant vacuum on the low side. Hey you, you're acting all swedish here thinking about risks and safety when I'm trying to ignore them! 😉 For your information, I CUT THE SEATBELTS OF MY VOLVO! Or no, I didn't. But I would have if they were there once I got it! LOL (long story) Jokes aside, I'm not so worried of the sulfur dioxide. I'm quite relaxed about it. It's only under some very specific circumstances it would be, in your words, extremely dangerous. I think it has maybe a little worse reputation than it deserves. I could elaborate on it, but I'm afraid of pulling the thread off topic too much. Though I totally understand there might be questioning of my wish to stick with it as refrigerant. It's allright.
Anyway, a refrigerant rant aside, one of the things I would like to cool with the Frigidaire are my bottles of this wonderful sparkling rosé wine from Italy. And as you all probably already are aware of, almost all wines contain..........SO2! As a preservant. So, some sulfur dioxide in the bottles to keep them fresh, and some more in the refrigeration system to keep them cold. Now that is music of consistency in my ears. 🥂
Cheers Sasha I can tell you from experience, that SO2 is a serious irritant. But, it is not a poison which accumulates in the body. Once it is gone it is gone. As long as you maintain a path to fresh air (in the event of a major release) you can always leave the area until the fumes dissipate. In my years of working with SO2 systems I've had plenty of "bad experiences" and none of them had lasting effects. Worst is a sneezing spell; and having my friends ask why I "smell strange" while we visited later in the day. All I can say is this. Keep it in your mind and always have a way out if things go "south" while working on one of these. |
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Post by successionalsasha on Sept 4, 2024 1:39:21 GMT
I have now made a little more progress. In the form of various measurings, with somewhat interesting results.
During the past weekend I gathered some courage and finally performed my first connection ever of a manifold gauge. Never having done this before, it was quite exciting! I backseated the suction valve all the way to the left, unscrewed the blind flare on the service port and connected the gauge. The valve was not left in a position of one turn to the right from the left, but 1½ turns. I don't know why, or if it matters. It's still a pretty long way to go to close it all the way to the right.
After I connected the gauge and the pressure was still equalized between the high- and low side it read 24 psi at 58°F, which is accordingly to the graph on page 19 in the service manual. However, if I understood the physics right, this will not give an indication of the charge level of the system. As long as there is some amount of liquid SO2 in there, the pressure will still be the same and it won't matter if it's like only ½ lbs or the full 1½ lbs for this particular compressor unit (as specified on page 46 in the service manual). Also, this time the flywheel didn't simply have a small patch of fat surface on the inside, it was downright wet with compressor oil on the inside of the bottom where it had been sitting since the last time.
I started the compressor up and let it run for three cycles (with the Cold Control set at 2, the second warmest setting) and it seemed to do OK at first. However, in the middle of the second cycle something weird happened. I could hear how it suddenly came a rush in the lines, I turned my attention to the gauge and saw how the pressure in an instant jumped from a small vacuum up to about 10 psi and the evaporator right away lost its frosting. But then it came back down in pressure after like a minute and kept on refrigerating?
After those three cycles I went ahead and performed a somewhat petty first time try of a vacuum test. I closed the suction valve all the way to the right and then pumped the pressure down to 15" Hg of vacuum (by simply running the compressor itself). However, the discharge valve stem had, apart from the suction valve, a smaller size on it so the reversed 1/4" drive socket wouldn't fit on it, leaving me with the only option of using a small adjustable wrench instead. Because of this I couldn't close it as fast as I would've liked, leaving me with only 10" Hg of vacuum left once i did get it closed (and at 9" Hg I realised I should put the valve caps back on, but it still kept falling even after I did). The result of the small test was that it kept sinking to about 6" Hg and settled there after like one hour. Then I returned 20 hours later and it was still the same.
I thought, ok it's not too good. What should I do. I soon realised that in the last seven years I still only ran it for a number of cycles I can count on my hands. Maybe the seal need some more time to reseat itself, should there have become slight corrosion on it's surfaces again while it was sitting still. So I opened the valves and started it back up again, but this time with the Cold Control at setting 1 (warmest). And what do I find? At setting 1 the control unit will cut out at just about that value of 6" Hg! (With evaporator temperature at 21°F.) And then kick back in at 5 psi. On setting 2 it cut out at about 8" Hg. To me that settled it. If I just run it at the lowest setting for now, maybe I can avoid most of the suctioning of air inside while running it for a while and then testing to see if it would hold a lower vacuum.
So the fridge is powered up and running now as I type and I'll check back on it tomorrow and see how it's doing.
I also wiped the oil away as good as I could so that I can see if there will have been more coming out of it during this period.
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Post by turbokinetic on Sept 4, 2024 2:05:56 GMT
We will hope to hear good news tomorrow. The fresh oil is a worrisome sign because it means the shaft seal is not working correctly. More than likely you will need to repair the seal. Because the system does work, more than likely the seal can be resurfaced. It can be lapped and returned to like-new condition.
There was a man in France who I helped with a similar Frigidaire. He was able to get SO2 easily because (as you said) it is used in the wine making trades. Not sure how much trouble it would be to bring it to Sweden but that may be an option if you don't want to make modifications to your Frigidaire to adapt a different refrigerant.
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Post by successionalsasha on Sept 5, 2024 3:40:19 GMT
So this is what I found when checking back on the fridge after it had been operating for a day.
As far as I could see, it has not thrown any more oil out. Or at least not any noticeable amount. The cycling times seemed good too, about 20m off and then 4m of running, while maintaning a temperature of 36°F inside (with 58°F in the surrounding) and the Cold Control at setting 1. However the knocking sound has now returned.
Given the cycling times the amount of effective running time on the compressor should be somewhere around 4h during this day, if I counted right. That's maybe still not very much when it comes to the seal having the chance of reseating itself? I performed a vacuum test again anyway, where I pulled it down to 15" Hg. I have only waited for a couple of hours but it seems as it has stabilised at 8" Hg this time. So it is a little bit better. But I take it still not really good?
I'm thinking of trying to vent off the probable air inside by carefully releasing the flare on the discharge valve just a tiny bit to let it seap out, do you think I can dare to do that? I see no other way of getting it out anyway.
Regards
Sasha
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Post by turbokinetic on Sept 5, 2024 13:03:31 GMT
So this is what I found when checking back on the fridge after it had been operating for a day. As far as I could see, it has not thrown any more oil out. Or at least not any noticeable amount. The cycling times seemed good too, about 20m off and then 4m of running, while maintaning a temperature of 36°F inside (with 58°F in the surrounding) and the Cold Control at setting 1. However the knocking sound has now returned. Given the cycling times the amount of effective running time on the compressor should be somewhere around 4h during this day, if I counted right. That's maybe still not very much when it comes to the seal having the chance of reseating itself? I performed a vacuum test again anyway, where I pulled it down to 15" Hg. I have only waited for a couple of hours but it seems as it has stabilised at 8" Hg this time. So it is a little bit better. But I take it still not really good? I'm thinking of trying to vent off the probable air inside by carefully releasing the flare on the discharge valve just a tiny bit to let it seap out, do you think I can dare to do that? I see no other way of getting it out anyway. Regards Sasha I think you are on the right track with purging the air at the discharge; although this may release some SO2 at the same time so be careful. You mentioned something in your previous post: I highlighted the parts which stand out to me. This sounds like explosive boiling in the evaporator. Explosive boiling happens when there is a heavy layer of oil floating on the surface of the SO2. This inhibits the boiling of the SO2, until the pressure has fallen well below the point where it should already be boiling. Eventually, it boils suddenly and with a "thump" resulting in a large volume of vapor and an increase in pressure / temperature. The cause of this is excess oil in the evaporator. This can result from low refrigerant level in the system. It can also happen if the evaporator is not level. If the evaporator is tilted so that the outlet is too high, oil can build up. You may need to see if the evaporator mounting, and the fridge cabinet its self, are level and not tilted down at the rear. If you're planning to continue using SO2 refrigerant, you may want to begin your quest for a supply of this material. I am pretty sure you will end up needing some before your project is complete. |
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Post by successionalsasha on Sept 6, 2024 1:29:26 GMT
We will hope to hear good news tomorrow. The fresh oil is a worrisome sign because it means the shaft seal is not working correctly. More than likely you will need to repair the seal. Because the system does work, more than likely the seal can be resurfaced. It can be lapped and returned to like-new condition. There was a man in France who I helped with a similar Frigidaire. He was able to get SO2 easily because (as you said) it is used in the wine making trades. Not sure how much trouble it would be to bring it to Sweden but that may be an option if you don't want to make modifications to your Frigidaire to adapt a different refrigerant. How does the process of lapping work? Do you add material to get a new surface or do you machine some of it away to accomplish the same result? Or maybe both? I've only heard this term once before. Apparantly it is possible to perform lapping on a cassette players tone head if it has happened to become scratchy and because of that delivers poor sound. Though very few people possess the ability to do it. I read about it briefly on tapeheads forum before. I suppose I could start investigating the possibilitys of getting hold of SO2 around here. However, I do have a box of 750 grams of sulfur powder laying on the shelf. Couldn't I burn it up and then somehow easily condensate its vapors to some container which I in turn may connect to the manifold gauge and charge it to the fridge? 🙂 Regards Sasha |
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Post by turbokinetic on Sept 6, 2024 13:23:04 GMT
We will hope to hear good news tomorrow. The fresh oil is a worrisome sign because it means the shaft seal is not working correctly. More than likely you will need to repair the seal. Because the system does work, more than likely the seal can be resurfaced. It can be lapped and returned to like-new condition. There was a man in France who I helped with a similar Frigidaire. He was able to get SO2 easily because (as you said) it is used in the wine making trades. Not sure how much trouble it would be to bring it to Sweden but that may be an option if you don't want to make modifications to your Frigidaire to adapt a different refrigerant. How does the process of lapping work? Do you add material to get a new surface or do you machine some of it away to accomplish the same result? Or maybe both? I've only heard this term once before. Apparantly it is possible to perform lapping on a cassette players tone head if it has happened to become scratchy and because of that delivers poor sound. Though very few people possess the ability to do it. I read about it briefly on tapeheads forum before. I suppose I could start investigating the possibilitys of getting hold of SO2 around here. However, I do have a box of 750 grams of sulfur powder laying on the shelf. Couldn't I burn it up and then somehow easily condensate its vapors to some container which I in turn may connect to the manifold gauge and charge it to the fridge? 🙂 Regards Sasha Lapping, in this sense means that an uneven surface is sanded down to a very flat, smooth surface. The seals typically need only a small amount of material removal. The proper way is to use a lapping plate and lapping abrasive mixed with oil. The seal faces are moved around on the lapping plate until the uneven surface is corrected. An alternative method is to use flat plate glass as a surface. Then you attach lapping paper to the glass. The seal is moved around on this surface, on a film of oil to recondition the surface. It gets more difficult when the shaft shoulder needs lapping because it is annular to the shaft and a flat lapping surface cannot be used. This will likely need to be ground on a precision lathe with a toolpost grinder of some type. For very small pitting, a lapping plate with a hole bored through can be used, but this is tricky and can result in a tapered surface if not done extremely carefully. As for making SO2, I haven't really studied it. We have seen vintage advertisements before; with description of the process. Apparently they react molten sulfur with purified oxygen in a reactor vessel to get high purity refrigerant grade, anhydrous SO2. I am sure it could be accomplished, but I also expect that the cost outlay to build the equipment and to buy the instruments necessary to test the purity of the resulting product would be worse than the cost of buying SO2. |
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Post by successionalsasha on Sept 7, 2024 21:52:57 GMT
So this is what I found when checking back on the fridge after it had been operating for a day. As far as I could see, it has not thrown any more oil out. Or at least not any noticeable amount. The cycling times seemed good too, about 20m off and then 4m of running, while maintaning a temperature of 36°F inside (with 58°F in the surrounding) and the Cold Control at setting 1. However the knocking sound has now returned. Given the cycling times the amount of effective running time on the compressor should be somewhere around 4h during this day, if I counted right. That's maybe still not very much when it comes to the seal having the chance of reseating itself? I performed a vacuum test again anyway, where I pulled it down to 15" Hg. I have only waited for a couple of hours but it seems as it has stabilised at 8" Hg this time. So it is a little bit better. But I take it still not really good? I'm thinking of trying to vent off the probable air inside by carefully releasing the flare on the discharge valve just a tiny bit to let it seap out, do you think I can dare to do that? I see no other way of getting it out anyway. Regards Sasha I think you are on the right track with purging the air at the discharge; although this may release some SO2 at the same time so be careful. You mentioned something in your previous post: I highlighted the parts which stand out to me. This sounds like explosive boiling in the evaporator. Explosive boiling happens when there is a heavy layer of oil floating on the surface of the SO2. This inhibits the boiling of the SO2, until the pressure has fallen well below the point where it should already be boiling. Eventually, it boils suddenly and with a "thump" resulting in a large volume of vapor and an increase in pressure / temperature. The cause of this is excess oil in the evaporator. This can result from low refrigerant level in the system. It can also happen if the evaporator is not level. If the evaporator is tilted so that the outlet is too high, oil can build up. You may need to see if the evaporator mounting, and the fridge cabinet its self, are level and not tilted down at the rear. If you're planning to continue using SO2 refrigerant, you may want to begin your quest for a supply of this material. I am pretty sure you will end up needing some before your project is complete. I have thought about this and also made some more observations during the past days. I think you may be right about it being low on refrigerant. Because first the fridge is indeed leveled. It sits on a concrete floor. I also made sure the evaporator is firmly bolted in place. Second, back in 2017 I have no memory of issues at the evaporator. As I recall it the surface point inside was clearly visible, in the form of a straight line on the outside where the frost ended. And it was also like that the first time I ran it this year (as stated in the start of the thread). But now that I have had it running for a little bit, it will indeed frost unevenly and all the way to the top of the header. Though the explosive boiling I only observed that one time only. My theory of what happened is that back in 2017 it still wasn't low on refrigerant (the seal faces being simply corroded shut after many decades of inactivity), but now after that there must have been a very small and unnoticeble leak at the shaft seal which after seven long years will leave you with a low level of SO2. So what you say bring be to the conclusion that at first when you power it up everything will seem fine, but eventually after some time of operation, the evaporator will get oil logged and start to behave like that. Could that be it? What I wonder now is if the oil would start making its way back to the crank case on its own if the adequate amount of new SO2 is later added to the system. edit
The evaporator mount was actually a little bit loose at the back, like 3-4 millimeters. I didn't know how to explain it easily. But I tightened it down and let the fridge operate for a day again but the frosting was still in the same way after that. |
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Post by successionalsasha on Sept 8, 2024 2:43:10 GMT
Based on the above and two other reasons I have decided I'm gonna take the compressor out and, for starters, inspect the shaft seal. The other two being that now, after I have performed a third vacuum test, I can say it just isn't holding vacuum. I only got like 3" Hg left after a day this time. It's no use trying anymore. Even though the knocking sound almost disappeared for the moment being (it was back to a wholesome again the next day) after purging the air at the flare at the discharge valve. And also that earlier today I unexpectedly scored a professional vacuum pump in used condition at a large annual fare, primarily aimed at veteran car parts! (This will be needed on the day of reinstatement to get all the air and moisture away, as you understand.)  ITE MK-60-DS vacuum pump (ok I think it's actually an MK-40-DS on the picture because I couldn't find the right one, but they look a same) It was the only thing I bought there. I looked up an electric outlet while still at the fare and tested it and it appears to be working. However the horizontal brass part on top and everything on it is missing. But I'm not sure whether I'll be needing that, whatever it is for? Just if I can get a cap to its connection and use the smaller upper 7/16" inlet on the vertical piece to connect to the manifold gauge. Anyway, this being saturday night and all, couldn't it be time for some stuff a little more intimate now? 😇 Well, here we go:  The control units covering removed so you can see the compressor itself better. All paint is, as far as I know, original. And barely cleaned!  1-cyl crank case. When photographed from the right angle, it looks absolutely massive, yet sleek at the same time. (1920s design, I love you!)  Discharge valve  King valve at suction side of cylinder block The four pictures above are taken this year but before any operation commenced. Regards Sasha |
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