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Post by turbokinetic on Sept 14, 2018 22:45:53 GMT
Good Luck David, glad I could help. It is going to good info to know how to recharge one of these, thanks for documenting the work. Thanks, I think the good luck is holding out for me more or less! The bellows is still charged this morning.  Well. I can't express how fortunate I feel for David reaching out to me and helping get my unit back operating. I am optimistic and at the same time flabbergasted by his abilities. I am equally impressed by his taking the time to document and share his work and progress. This knowledge is of great value to me and I hope other forum members appreciate it as well and find it helpful. Thank you thank you thank you. John You're welcome. This is what keeps hobbies interesting and sustainable. If nobody tried then nobody would succeed... and then nobody would be able to replicate the results! So, today I searched for isobutane and found out that it is nearly impossible to get unless you buy it in bulk. I went to a gas supplier and they explained that it's costly and unnecessary to separate n-butane and isobutane for normal uses. They could get me a large canister of refrigerant grade isobutane but it was not a stock item and it was very costly yadda yadda yadda. So, I researched some more of the fuel gas butane products. It turns out that the Bernz-O-Matic butane I have is actually "75 to 80% isobutane, with balance comprised of n-butane." Other fuel gas blends were very much worse; containing propane even. So it looks like this gas is going to be the best choice. I have a plan to charge the bellows tube with just enough material to get some liquid in the sensing line without overcharging the entire bellows. This plan will let the gas do the work, because of its physical properties. In a system with liquid and gas phases, the saturated vapor will condense in the coolest place in the system, filling this area with liquid. I want the lower inch or two of sensing line to have liquid, with the rest having gas. To make the gas do this; the coldest part of the system will be the tip of the sensing line. The second coldest part of the system will be the butane canister. The hottest and least likely place for liquid to condense will be the bellows and remainder of the sensing line. The plan is to place the gas canister in the refrigerator and let it get cool. The tip of the bellows tube will be in ice. The rest of the system will be in a 90 degree workshop. I'll evacuate the system and then introduce butane vapor. Give it a few minutes for it to condense in the tube at the tip, which is colder than the canister. Then cap the system and make another test. It seems feasible for it to work like this since there seems to be plenty of adjustment range to the control. |
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Post by turbokinetic on Sept 15, 2018 2:39:19 GMT
Got progress update on the control repair! It's about finished and just working on the calibration now!
First thing I did was take the bellows back out and clean the control. The whole thing looked like it might have been left outside at some time in its past. There was mud and corrosion on the bottom. I cleaned it up and re-lubricated all the moving parts.
Also, installed a metal cap over the port for the bellows tube, so that it can eventually be installed permanently with Loctite. That will be a hermetic seal so that the charge will stay in there.
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Put some heat shrink tube over the sensing tube as well, to protect it and hide all the battle scars LOL!
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For a test.... I used this rig.... I know it's an awful abomination but it works!
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More details in the video!
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Post by bhammer on Sept 15, 2018 16:32:45 GMT
Good morning David. I was laying in bed this morning thinking about about PV=nRT, Rydberg's constant and Henry's Law. Things they tried to teach me in school over 40 years ago. It's fascinating (and still puzzling) seeing these principals being put to practice. I liken your interest, talent and enthusiasm to my hobbies of ham radio, restoring vacuum tube radios and maintaining my 1969 MGB. I appreciate your good work and hope you are enjoying your time on this endeavor - you seem to be. I hope I get to your part of the country someday so that I can personally thank you. Have a good day. John
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Post by bhammer on Sept 15, 2018 19:22:04 GMT
FYI - The DR unit that David is working on came from the Edmund Meany Hotel in Seattle, WA that was built in 1930-1931. According to the documentation that I have, it was moved to someone's cabin near where I live, about 90 miles north of Seattle, in 1966. It very well may have been left out in the weather and rain as I have found lots of dirt beneath the hinges. It is in pretty good shape however. As David works his magic, I am restoring the DR's cabinet. I will post photos of the completed unit when completed.
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Post by turbokinetic on Sept 15, 2018 19:22:26 GMT
Good morning David. I was laying in bed this morning thinking about about PV=nRT, Rydberg's constant and Henry's Law. Things they tried to teach me in school over 40 years ago. It's fascinating (and still puzzling) seeing these principals being put to practice. I liken your interest, talent and enthusiasm to my hobbies of ham radio, restoring vacuum tube radios and maintaining my 1969 MGB. I appreciate your good work and hope you are enjoying your time on this endeavor - you seem to be. I hope I get to your part of the country someday so that I can personally thank you. Have a good day. John
Yes, I definitely enjoy restoring and fixing things; especially when it seems there are no more good ones to be found as replacements! Again I hope that my effort will not only help you to get your fridge up and running again; but to provide a pattern for others to follow and successfully repair their own controls.
I never got into the ham radio, but I definitely respect that hobby. It must have been amazing back in the day before the Internet to be able to talk across the continent or further. When our family lived in TX many years ago my uncle had a friend who was a ham radio operator. Used to listen in oh his conversations. I remember the large vacuum tube RF amp he had, which was the size of a medium sized suitcase!
You follow Uncle Doug on YouTube? He has some really neat custom tube guitar amp builds and other antique electronics repairs; as well as car show footage. One of my favorites.
I'm tinkering with the temperature range of your control now. It is working with the adjustment screw in a mid position, which is encouraging. The cut-in and cut-out range is what I am trying to get dialed in. The manual states an evaporator temperature range of 15 to 24°F with the knob at midpoint. It seems that the screw which sets the range between cut-in and cut-out was moved quite a lot in the past. The different gas, as well as the contact wear affect this. My problem is, that with poor hearing and other things running, and the fact that I'm using a CK which is almost silent - it's hard to catch it when it just cuts in or cuts out. I'm going to hook up a light on the unit that I can see that will get my attention when it switches.
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Post by turbokinetic on Sept 15, 2018 19:24:30 GMT
FYI - The DR unit that David is working on came from the Edmund Meany Hotel in Seattle, WA that was built in 1930-1931. According to the documentation that I have, it was moved to someone's cabin near where I live, about 90 miles north of Seattle, in 1966. It very well may have been left out in the weather and rain as I have found lots of dirt beneath the hinges. It is in pretty good shape however. As David works his magic, I am restoring the DR's cabinet. I will post photos of the completed unit when completed.
I don't think I got a picture of the control bottom, but that mud under there is what made me think it may have been rained on! Hope you have a chance to inspect the insulation to be sure it hasn't deteriorated. My DR D2 definitely has a problem in the insulation.
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Post by turbokinetic on Sept 16, 2018 22:34:44 GMT
Got an update! This control has been working with the CK test unit since getting it together. It’s functioning well but I am concerned it is allowing the temperature to swing too widely. It will turn off at 10°F and on at 30°F; where the manual states 15°F to 25°F is the normal range.
It seems that in the past the range adjustment was moved all the way to the minimum range already. This makes me believe it’s not the different gas causing this. It’s a problem someone has been fighting for some time. It could be the reason they messed with the control and ended up breaking the bellows tube. You never know!
Will study the control for any possible worn points which could affect the hysteresis between cut-in and cut-out. The cabinet temperature (with Ghetto Edition Door Substitute; and provably horrendous cabinbet insulation) is staying at around 38°F. I honestly feel as if it would be fine like it is; but I would like to see it working at factory specifications, just to be sure it's a good fix. 
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Post by bhammer on Sept 17, 2018 17:58:43 GMT
A man with a plan... thanks David.
When i removed the top unit off of the cabinet I found the upper insulation pieces (four long rectangular pieces wrapped in black material) to be in pretty bad repair. The insulation in the walls and door seemed OK. So to replace the top four pieces I constructed forms of the correct size out of cardboard, filled them with spray/expanding insulation foam and trimmed them to size. I inserted these foam blocks into the original black material and will reinstall them.
I'm currently working on the feet, door cabinet and hardware - removing surface rust and shining the chrome. I'm going to use Rust-Oleum "Biscuit" enamel appliance paint. I'll leave the interior original.
The "monitor top" is going to be tricky with all of those winding tubes, nooks and crannies but I'll get at it.
Looking forward...
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Post by turbokinetic on Sept 18, 2018 14:36:29 GMT
It's good that you are getting the opportunity to refurbish the areas on the cabinet which have suffered throughout the years. I'm sure the expanding foam insulation has a much better insulating value than the original stuff.
As for the painting, I've got to face that on my DR as well. It's a disgusting nicotine-residue-yellow color. Also looks like it was painted with a coarse scrub brush, with latex house paint. Not sure the best way to clean the paint off the condenser either. May just remove all wiring and insulation from the top, and use stripper and pressure washer on it.
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Post by bhammer on Dec 4, 2018 18:51:07 GMT
I'm still alive. I've just been slowed down by winter weather and lack of heated work space. Restoration work is progressing slowly and I hope to get the control unit installed as soon as possible.
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Post by turbokinetic on Dec 4, 2018 19:15:45 GMT
I'm still alive. I've just been slowed down by winter weather and lack of heated work space. Restoration work is progressing slowly and I hope to get the control unit installed as soon as possible.
Glad things are going well for you, other than the cold weather. Hopefully some nicer weather will come through pretty soon. Don't push yourself to do a hasty job when the weather is not conducive to this work. Take time when you can enjoy it and do the best job!
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Post by bhammer on Dec 16, 2018 6:42:28 GMT
The temp reached the lower 60s on Friday - painting weather:-). More progress made today. The DR is looking good. Tomorrow I will start cleaning the chrome hardware.
I posted a thread about line voltage? Id 124 VAC too high. Should a variac be used?
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Post by bhammer on Jun 4, 2019 22:35:35 GMT
I'm just getting around to following up on this - my bad. My monitor top has been working perfectly for the past couple of months thanks to David. The unit cycles on and off as it should, maintains around 35 degrees F at mid-adjustment and sounds wonderful. Its my beer cooler in the garage and all my neighbors think its really cool - as they should. I'm pretty happy with my cosmetic restoration as well. I'll take some photos and try (again) to post them to this forum.
Thanks all for your helpful input along the way and to David I owe a huge THANK YOU.
John
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Post by ckfan on Jun 5, 2019 1:22:12 GMT
I'm very glad that it is working out nicely for you!
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Post by turbokinetic on Jun 5, 2019 10:41:10 GMT
I'm just getting around to following up on this - my bad. My monitor top has been working perfectly for the past couple of months thanks to David. The unit cycles on and off as it should, maintains around 35 degrees F at mid-adjustment and sounds wonderful. Its my beer cooler in the garage and all my neighbors think its really cool - as they should. I'm pretty happy with my cosmetic restoration as well. I'll take some photos and try (again) to post them to this forum. Thanks all for your helpful input along the way and to David I owe a huge THANK YOU. John
That's great that you're getting to put the DR to use and enjoy it! I'm glad to have been able to help with the control repair, as well.
Somehow missed your post about the line voltage. It should be fine with 124V, however it is possible to use a boost/buck transformer to reduce the voltage. A pretty common, standard voltage is 12V, which would result in 112V after a buck arrangement was connected.
At the moment I have to get to work, but if desired I can post a diagram of that.
Sincerely, David
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