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Post by birkie on Jan 12, 2014 17:11:49 GMT
Hello, this is my first post
My wife and I found a monitor-top refrigerator for sale, with a stated model number of CK-2-E16. The service manual seems to imply that this is a replacement top from 1942. So I'd guess that the unit for sale is probably an older unit whose top failed and was replaced with the CK-2-E16. Does that sound about right?
It also appears that the CK-2-E16 differs from other CK models in that it uses a porcelain-coated evaporator (not stainless steel), and that the evaporator sits to the right rather than in the center of the space inside the cabinet. It also appears that it has a higher minimum temperature (10°F) vs comparable first-run CK-2 units (5°F), even though it uses the same refrigerant SO2. Do any of these changes negatively impact the practical use and durability of the refrigerator? Would the porcelain-coated evaporator be more fragile or prone to leaks/corrosion than the stainless steel models, or would, say, chips or cracks in the porcelain simply be cosmetic?
Thanks!
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Post by allan on Jan 12, 2014 17:48:45 GMT
Performance difference in my opinion would not be an issue. To me the porcelain coated evaps are much more attractive and vintage looking if in good condition. If they are chipped that reduces the look somewhat but they can be repaired. The main concern you should have is with the connections to the evap. Where the 2 copper tubes are brazed to the steel evap you need to closely inspect for corrosion and deep pitting. Light corrosion can be treated and arrested but deep pitting of the steel at this connection can be bad news for future reliability.
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Post by birkie on Jan 21, 2014 3:45:10 GMT
Thanks Allan, I went ahead and took a look at the evaporator, and this is what I found: The corrosion at the inlet to the evaporator was much more than I expected. There was much less corrosion at the outlet, but the picture also reveals a series of slightly rusty chips in the porcelain, and a larger rusty spot. We turned on the unit - it was very quiet. The condenser tubing got slightly warm, and the evaporator started to chill. The rate of cooling of the evaporator seemed slow to me, but I'm not very familiar with the operating characteristics of the monitor top. After about a minute, I could feel the evaporator starting to get cold. After about 4-5 minutes, it was clear that water from the air was condensing on the evaporator in a thin layer, but it wasn't getting visibly frosty - how long should it take before a distinct layer of frost is formed? Anyway, my feelings are distinctly mixed about pursuing this particular machine. Given the photos, does it seem that the corrosion has reached the level of requiring extraordinary measures to keep the machine reliably running?
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Post by coldspaces on Jan 21, 2014 4:32:01 GMT
Not that I have done one but it does look like the evp is gonna need a restore before too long. The stainless steel ones are hard to beat.
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Post by cablehack on Jan 21, 2014 8:02:44 GMT
You can always install a stainless steel evaporator if necessary. The top would need to opened up to rewire it anyway.
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Post by allan on Jan 21, 2014 11:59:02 GMT
Good pictures! The inlet tube does look bad, but it would take a detailed clean up with a Dremel tool to see just how deep the corrosion has gone. My guess is that it has gone too far and you will not enjoy long term reliability. The other picture however shows corrosion that is completely treatable with Supco epoxy. It will take care of the evaporator chips and the tubing. May I suggest you take a remote sensing thermometer and attach the sensor to the evaporator along with the thermostat sensor. Evaluate the actual evap temps with the top on the cabinet. Give it adequate time to stabilize and get all the SO2 pulled out of the sump. I have a CK1 that will only pull the evap down to about 22 degrees and with the help of jhigdon we have determined it has a restriction in the float seat, which will require opening the system just below the seat and cleaning it out. I am eager to try this but as of yet cannot find affordable replacement SO2. My best price yet, delivered is about $70 a pound.
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Post by birkie on Jan 21, 2014 21:23:43 GMT
Hm, It looks like no matter what, it is going to be necessary (or wise, at least) to purge the system of SO2 in order to to properly repair or replace the evaporator (as well as make it easier to do rewiring, and potentially address any other issues it may have).
If I try to save the porcelain-coated evaporator, I don't think I'd be confident enough in its durability to trust it to safely hold a charge of SO2 without spring a leak some day. If that is the case, absent a stainless steel evaporator coming my way from some poor donor unit, I'm wondering if that makes this machine a perfect candidate for conversion to a modern fluorocarbon refrigerant. From reading around postings from the flickr group, it looks like the compressor will be nearly as happy and run with nearly the same overall efficiency with R134a and a restricted suction tube compared to the original refrigerant. Does that sound about right?
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Post by allan on Jan 21, 2014 22:19:10 GMT
Hm, It looks like no matter what, it is going to be necessary (or wise, at least) to purge the system of SO 2 in order to to properly repair or replace the evaporator (as well as make it easier to do rewiring, and potentially address any other issues it may have). If I try to save the porcelain-coated evaporator, I don't think I'd be confident enough in its durability to trust it to safely hold a charge of SO 2 without spring a leak some day. If that is the case, absent a stainless steel evaporator coming my way from some poor donor unit, I'm wondering if that makes this machine a perfect candidate for conversion to a modern fluorocarbon refrigerant. From reading around postings from the flickr group, it looks like the compressor will be nearly as happy and run with nearly the same overall efficiency with R134a and a restricted suction tube compared to the original refrigerant. Does that sound about right? Yes and I believe we have some members that have converted to 134a. I would like to know what is the longest record of a unit reliabilby running on 134a in full every day use with tolerable noise levels. If you want to stay original I think it would be fairly easy to come by a stainless evap and you may want to start by contacting Rusty Metal Rescue.com.
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Post by coldspaces on Jan 21, 2014 23:06:58 GMT
My 32 has worked great so far on 134a,little louder than the so2 flat top but not to noisy at all compared to when I had it full of R12. jhodon2 also converted one of his to 134a about the same time as me.
Mine has not always been turned on since the conversion to 134a last year, but it has been on non stop since the contacts were replaced on 1-17-2013
Coldspaces
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Post by allan on Jan 22, 2014 1:05:21 GMT
My 32 has worked great so far on 134a,little louder than the so2 flat top but not to noisy at all compared to when I had it full of R12. jhodon2 also converted one of his to 134a about the same time as me. Mine has not always been turned on since the conversion to 134a last year, but it has been on non stop since the contacts were replaced on 1-17-2013 Coldspaces That means that your 32 is a DR correct? If so that is a high side dome and this machine is a low side dome that may be very different in operation and sound levels. Do you think we have a member with a converted CK?
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Post by coldspaces on Jan 22, 2014 2:23:49 GMT
My 32 has worked great so far on 134a,little louder than the so2 flat top but not to noisy at all compared to when I had it full of R12. jhodon2 also converted one of his to 134a about the same time as me. Mine has not always been turned on since the conversion to 134a last year, but it has been on non stop since the contacts were replaced on 1-17-2013 Coldspaces That means that your 32 is a DR correct? If so that is a high side dome and this machine is a low side dome that may be very different in operation and sound levels. Do you think we have a member with a converted CK? As far as I know no one has done a 134a conversion on a CK. I would think it would work better than the DR as the refrigerant would not have a chance to stay in the dome. As for sound,not sure but with the restrictor its should be about the same. If the CK pump it stronger length of the restrictor may need to be different.
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Post by birkie on Jan 22, 2014 2:47:44 GMT
As far as I know no one has done a 134a conversion on a CK. I would think it would work better than the DR as the refrigerant would not have a chance to stay in the dome. As for sound,not sure but with the restrictor its should be about the same. If the CK pump it stronger length of the restrictor may need to be different. This thread mentions a converted CK, at least on an experimental basis: www.flickr.com/groups/monitortops/discuss/72157633145716724/I wonder this 'guinea pig' unit was the one he converted. Interestingly enough, it too is a 1942 replacement top with a porcelain-coated carbon steel evaporator! www.flickr.com/photos/66756696@N07/8092609245/
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Post by coldspaces on Jan 22, 2014 3:25:52 GMT
You are right jhigdon2 did say his guinea pig is a CK.
jhigdon2 said in the Flickr thread "I got my gunea pig CK2 out and tried that restriction trick in the low side line.... I used 6" of 3/16" tubing in the low side(1/8" id) line to detune compressor and charged the unit with 134A,"
As I recall his guinea pig and my DR had surprisingly similar run times and watt draws after the conversions were done.
Coldspaces
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Post by cablehack on Jan 22, 2014 6:00:19 GMT
Hydrocarbon refrigerants have been used in CK's and also don't forget the guy who used Hot Shot with a restrictor.
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Post by jhigdon2 on Jan 22, 2014 7:53:21 GMT
My 42 CK unit that I converted to 134 with a restrictor is still working fine. Admittedly though It is a little louder at times than with S02. I haven't ran it for more than a few months at a time so I can't say for sure what long term reliability is going to be, but I think it will be ok. Run Amps are a little higher, at startup but duty cycle is very good. The unit has a cap tube system instead of the float chamber (I cannibalized it during one of my experiments) I am a little off with the cap tube length, so performance could be better, if I could spend more time with cap tube calibration I think.
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