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Post by flyspray on Oct 11, 2023 18:21:54 GMT
I can't tell about pressure in bellows. I took the temp. knob off and turned the stem toward cold and the points closed. I connected back and it is running. Of course I don't have any idea where I am at with temperature or where it will cut off when it gets cold enough. I'll just play with it and see. If the thermostat has gone bad is there a replacement available?
s.
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Post by turbokinetic on Oct 11, 2023 18:59:58 GMT
I can't tell about pressure in bellows. I took the temp. knob off and turned the stem toward cold and the points closed. I connected back and it is running. Of course I don't have any idea where I am at with temperature or where it will cut off when it gets cold enough. I'll just play with it and see. If the thermostat has gone bad is there a replacement available? Unfortunately, there are no more like-for-like replacements. Many times they can be repaired. If you do decide to adapt a different thermostat it is extremely critical that you install an overload breaker if the original thermostat had one inside it.
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Post by flyspray on Oct 11, 2023 22:00:10 GMT
Update: Inside temp went down to 5 to 10* inside and it never cut off. I turned knob toward warmer until it cut off. It never started again and frost melted off evaporator. I turned knob toward cold until it started, now waiting to see what happens.
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Post by ckfan on Oct 12, 2023 11:50:05 GMT
Just a thought, have you actually opened up the thermostat and lubricated (very lightly) all of the moving parts inside? It almost seems like something is sticking. You can kind of confirm this by tapping on the thermostat when you think it should be turning off or on. If it clicks when you tap it, something is most likely holding it up.
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Post by flyspray on Oct 12, 2023 17:50:01 GMT
Took thermostat out again, checked and don't think it is sticking. It was real clean inside but I lubed it all anyway and just now started it up. I'll see but I'm not crossing my fingers. Hope someone is following this thread that has used another thermostat and will share what it is.
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Post by flyspray on Oct 12, 2023 21:47:10 GMT
UPDATE: Must be something wrong with the bellows. I let it run until down to 20* inside and it wouldn't cut off. I turn knob down almost to 1 and it cut off. I put hair drier where bellows connects to evaporator and it won't start. I have another CK for about 25 years. When I got it the line was broke right at the float. A ac man I knew bypassed the float with I think a cat tube and charged with propane. It runs like a champ
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Post by turbokinetic on Oct 13, 2023 13:14:18 GMT
UPDATE: Must be something wrong with the bellows. I let it run until down to 20* inside and it wouldn't cut off. I turn knob down almost to 1 and it cut off. I put hair drier where bellows connects to evaporator and it won't start. I have another CK for about 25 years. When I got it the line was broke right at the float. A ac man I knew bypassed the float with I think a cat tube and charged with propane. It runs like a champ That does sound like the bellows has lost its charge. I sent you a message about it; don't know if you saw it. Sincerely, David
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Post by turbokinetic on Oct 13, 2023 14:44:15 GMT
UPDATE: Must be something wrong with the bellows. I let it run until down to 20* inside and it wouldn't cut off. I turn knob down almost to 1 and it cut off. I put hair drier where bellows connects to evaporator and it won't start. I have another CK for about 25 years. When I got it the line was broke right at the float. A ac man I knew bypassed the float with I think a cat tube and charged with propane. It runs like a champ I just wanted to comment on your other CK. I'm delighted that it's working for you and expect it will continue to work for many more decades! When that repair was made, there was scarcely little info available about these refrigerators. We are in so much better of a place now that the Internet has allowed for so much social networking to be done. Alternative refrigerants are always an important topic, especially with the repeating "invent, use a few years, then ban" cycle which the government has fallen into. There are two main characteristics a refrigerant must have; plus several other minor ones. The main ones are its temperature/pressure relationship (basically, the boiling point and vapor pressure); and the oil solubility. Just a few of the more minor ones are the density of the liquid and vapor phases; and heat of vaporization. Back in the day, when SO2 was king, most refrigeration systems were engineered around it. Different manufacturers had greater or less engineering margin (safety factor) built into their design. We are fortunate that GE was very conservative and put a large margin into the CK machines. Due to their higher margin of motor horsepower and oil volume, they can work with propane (R290); in spite of it being a terrible match for the properties of SO2. The first official replacement for SO2 was Freon-114, which was phased out decades ago, replaced by R-124. That has also been phased out. The worst concern with R290 is the standing pressure of the charge when the unit is stopped. The test pressure (a theoretical maximum for the system) for the low-side is 150 PSI. The evaporator is not engineered for high pressures. If the unit is turned off and stored in a high temperature area, such as a garage, the refrigerant pressure will rise. For SO2 it would take over 130°F to reach test pressure during standby due to high ambient. For R152A (a proven replacement in these units) it would take over 120°F to reach test pressure. For propane, the test pressure is reached at about 90°F. Any storage above that temperature is exceeding test pressure. With the high level of flammability and large charge volume, exceeding the test pressure for prolonged periods of time seems like a high risk situation. For most other non-GE SO2 machines, the compressor motor would not be able to work with the higher pressures at all. Again, 25 years ago none of this info was readily available and nobody had any proven replacements so I am not trying to talk negatively about your CK nor the guy who repaired it. I am saying that now, things have changed and more research has been done leading to better alternatives. As a technician and engineer and a forum admin, I have to remind readers that it is not OK to use propane in these machines nor any others not engineered for it. The safety risks are too high, and there are more suitable alternatives. Respectfully, David
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