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Post by turbokinetic on Jan 8, 2020 5:52:25 GMT
Here is a series on troubleshooting a D2 which looks a whole lot better than it cools!
The backstory is, it was restored about 10 years ago and has worked until recently. One day it was found to be rattling and not cooling; and was taken out of service.
The repairs aren't done yet; this will be an ongoing video series until it's fixed.
Sincerely, David
https://youtu.be/Dj7dxAf8Deg
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Post by elec573 on Jan 9, 2020 5:29:33 GMT
Nice job on how to replace the heater and the video makes it very understandable. It would be great to just put that under a heading of how to check and replace a heater in a dr or a ca . Hopefully people would check it out . The only other thing would be where to buy a replacement heater .
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Post by turbokinetic on Jan 9, 2020 14:21:05 GMT
Nice job on how to replace the heater and the video makes it very understandable. It would be great to just put that under a heading of how to check and replace a heater in a dr or a ca . Hopefully people would check it out . The only other thing would be where to buy a replacement heater . Thanks! I appreciate the feedback on the video. Once it's completed and the repairs done, maybe I can edit the first post and add some "index" times to the videos for the different repairs such as the heater, charge checking etc. I've got a guest over for a few days so this one will be shelved for a while. But expect more videos to be forthcoming. The heater I used was the last one from the group-buy we had last year. It seems there is an active heater thread now which has a lot of good info in it as well. Sincerely, David
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Post by turbokinetic on Jan 11, 2020 6:01:41 GMT
Made some more diagnostic work today. Video tells all...
https://youtu.be/wFefE2QQVR0
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Post by elec573 on Jan 12, 2020 2:41:00 GMT
That’s too bad it didn’t come to life ,very nice looking fridge. Thanks very much for the float information it really made it clear how it works to me hopefully others also . Very nice video and very informative thanks again !
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Post by turbokinetic on Jan 12, 2020 2:51:09 GMT
That’s too bad it didn’t come to life ,very nice looking fridge. Thanks very much for the float information it really made it clear how it works to me hopefully others also . Very nice video and very informative thanks again ! Thanks.. Yeah I really hate it that it failed. I plan to make a separate video with just the float information, soon and share it.
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Post by turbokinetic on Jan 12, 2020 17:35:09 GMT
I had shared this elsewhere, but want to post it here as well for thoughts. The wording was for another group who are not as far along experts as we are. Therefore some of this may seem like stating the obvious to us. Just warning you that the writing style is different for that reason.
The DR models (those with the open coil condenser) were the first and were a bit of a learning curve for GE it seems. I've done a lot of reading on them and talking with other collectors and enthusiasts. It seems that GE learned about the shortcomings early-on and made a lot of improvements during production. A combination of two design elements together in the system makes the DR machines very finicky. They have a metering device which is normally closed, until refrigerant liquid is present; combined with the large volume of the compressor housing being on the high side of the system. This makes the system incredibly sensitive to any sort of noncondensible gases or air in the system. There is a trap in the line between the condenser and float, so unless the system is completely free of noncondensibles, they will collect in the float chamber, and with the uphill trap in the lines, this will prevent liquid from filling the float chamber. Since the float is normally closed in the absence of liquid, this results in a no-circulation (blockage) situation. The large volume of the high-side compressor housing will accommodate the entire refrigerant charge when this happens, leading to the rattling noise when the refrigerant is at a high level in the sump.
The manuals explain that SO2 systems normally never develop noncondensible gases except if the low side has a leak (it operates in a slight vacuum) or if the motor has been severely overheated.
This one seemed to sound OK initially, but I noticed some ominous signs. First, the bad contact between the control and the baseplate was the main winding circuit. If this circuit were intermittent or had a high resistance, it would provide low voltage to the motor all the time it was running. Another ominous sign was the amount of time it took for the compressor to build up to speed during a start. I have another working D2, and the startup takes a lot less time. It seems that with the DR Monitor Tops, this slow spin-up has preceeded winding failures in more than one case with other enthusiasts on the forum. There was a Kill-A-Watt meter in the circuit during startup, which was beeping indicating 15 amps or more current draw during the startup. That's also not expected. And finally, the ground resistance. I saw about 200KΩ if I remember, when making the first video. On the day of the second video before startup, this resistance was much less. So as much as I hate to say it, I wasn't really expecting it to live but wanted to remain hopeful.
Cotton wrapped windings fail in an entirely different manner than modern enamel magnet wire windings. Whereas enamel magnet wire windings fail suddenly as soon as the coating melts and the winding turns short - cotton never melts. The cotton will char and become hard and brittle, with carbonized oil and charred cotton remaining in position. The damaged insulation will still remain in place, keeping the winding from making a dead-short, but it has become partially conductive and leads to resistive shorts which cause ground leakage high current draw.
The SO2 interacts with the "vapors" from the chemical breakdown of the cotton, resulting in formation of noncondensible gases. This is by way of the cotton cellulose releasing water vapor as it degrades. The SO2 mixes with the water vapor and forms an acid solution. This immediately breaks down into hydrogen gas and some solid residues; in contact with metals.
From what I have found, cotton is considered a "Class "0" insulation system. It begins slowly deteriorating above 90°C (194°F). This would be the maximum hotspot temperature of the winding, inside the coils. So the overall temperature of the motor would not have to be 90°C to have hotspots above the winding insulation limit.
So, one theoretical sequence of events leading to the failure would be:
1 - Poor contact developed between base and control, causing motor to have intermittent voltage and reduced voltage. 2A - Over time, the motor winding operated consistently at or above its temperature limit, leading to slow deterioration and release of NCG. 2B - Or, alternatively, the motor was overheated severely, once; by a control malfunction or improper repair / testing methods. This could have been decades ago. 3 - The NCG built up to a level requiring excess pressure to obtain flow through the high-side float metering valve. 4 - The compressor pulled into a vacuum or near vacuum, resulting in excessive hot-gas discharge temperature on the high side. 5 - The motor is cooled by high-side hot gas, which was entering the housing at an abnormally high temperature and low flow volume. 6 - The overheating continued for a period of time (years?), exacerbating the deterioration of the motor winding and creating enough NCG to stop the refrigeration cycle. At this point, the unit was taken out of service. 7 - The refrigerator was transported across country, with vibration and position changes causing the charred winding insulation to mechanically break apart. 8 - The lost insulation allowed the motor to developed multiple turn-to-turn, and winding-to-ground shorts. 9 - Attempting to run the motor in such damaged condition led to a complete failure of the winding.
I think that the reason the DR machines are so hit-or-miss is because you never know how far along the path to failure they really are when you acquire them.
The CK models were the final revision of the Monitor Top. They did away with the high-side compressor housing and went with a forced-oil cooled winding. There is an oil pump which forces oil through the winding and then sprays it against the inside of the compressor housing as a heat exchanger. These are the most reliable, with winding failures being nearly unheard of. They also have a better control and protection system, with many having dual overload breakers.
The CK also has a direct connection from the compressor discharge, through the condenser, to the high-side float chamber. This ensures that a modest amount of NCG can be in the system and still allow the unit to function.
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Post by coldspaces on Jan 12, 2020 21:58:20 GMT
That is a nice write up!!
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Post by elec573 on Jan 13, 2020 2:29:17 GMT
Very nice right up and hopefully people will read it !
But unfortunately people don’t seem to want to do that.
Just my opinion but , a lot of people aren’t willing to look for an answer but want in instant answer! . Just my opinion !
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Post by turbokinetic on Jan 13, 2020 2:33:46 GMT
Thanks y'all. It is sad that people are too lazy to read. They will seemingly watch videos and then forget what they saw in 5 minutes, though!
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Post by davido on Feb 13, 2020 18:37:50 GMT
Good information. I'm learning more and more about these Antique refrigerators Everytime I sign in to this forum. I only have 7 refrigerators spanning 1927(Frigidaire) to a 1948 GE. All but the '27 Frigidaire are in working order. Somebody had already removed the belt driven system from it by the time I got it.
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Post by turbokinetic on Feb 14, 2020 11:41:01 GMT
Good information. I'm learning more and more about these Antique refrigerators Everytime I sign in to this forum. I only have 7 refrigerators spanning 1927(Frigidaire) to a 1948 GE. All but the '27 Frigidaire are in working order. Somebody had already removed the belt driven system from it by the time I got it. Hi David. That's a good collection, at 7. I never intended to become a collector, but have amassed quite a few. I love the unique stuff more than having duplicates and a massive number of units.
I'm still disappointed about the damage to the DR in the videos here. I am reasonably sure that the poor connection at the control mounting caused extra stress on the motor, and played a large part in the failure of the winding.
I got started with the belt drive Frigidaires; actually. My first one was a 1931 WM-5 model. It's too bad that the condensing unit was missing from your cabinet. Depending on the condition of the cabinet, it might be worth searching for a unit. They can be found, but often have been altered or damaged by use as an air compressor. Other than that, the compressors are very durable and about the only failure is the shaft seal needing replacement. Does yours have the evaporator still in place? All the trim around the evaporator as well?
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Post by davido on Feb 14, 2020 12:50:11 GMT
I will post pictures of the '27 Frigidaire today. It's actually very nice condition inside and out. Complete with 3 ice trays, crisper drawers and all shelves. I use it for parts storage.
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Post by davido on Feb 14, 2020 15:59:50 GMT
Turbo....here's a link with pics of the '27 Frigidaire....hope you like! Link-1927 Frigidaire
David O.
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Post by gman1969 on Feb 14, 2020 21:37:29 GMT
David, thanks for posting those pics. That's a nice refrigerator you've got there. I hope you find a compressor and get it running. Gary
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