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Post by don on May 26, 2019 0:09:43 GMT
Thanks Turbokinetic. I will start a new post in the near future about the capillary conversion flattop with the R152a refrigerant.
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Post by don on Jan 8, 2022 15:42:12 GMT
TEMPERATURE GLIDE I believe and see in hindsight that a refrigerant that must be charged as a liquid is a mixture of refrigerants. From what I understand Envirocare is a combination of propane with a boiling point of -43F and butane with a boiling point of 30F. The propane would boil at the start of the evaporator and the butane would continue on to the end of the evaporator. That is the frost pattern I see on the evaporator. I visually saw the oil filled tube at the entrance to the evaporator. I can hear the loud gurgling that confirms the oil is there and need to wait to see if it returns to the compressor. I will observe the machine this summer to see if this compromise works. Maybe the capillary tube would work best with r-152 which is not a mixture of gases. I had a leftover can of ENVIROCARE hydrocarbon refrigerant. It was designed to be a drop in refrigerant for R-12. It is a mixture of propane with a boiling temp of -43F and butane that boils at +30F. Yesterday in Minnesota it was -20F and when I used an access valve to open the -20F cylinder the propane boiled off. Left outside overnight the temperature warmed up here in Minnesota to +16F. This morning the butane liquid was still in the cylinder as a liquid as it will not boil until +30f. I would suggest that this would indicate that refrigerant replacements that are mixtures will not work in refrigerators that have static air flow evaporators. In this case the propane boiled off in the first few inches of the entrance to the evaporator and the +30F butane was left to boil off in the entire rest of the evaporator.
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marko
7 Cubic Foot
Posts: 141
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Post by marko on Jan 9, 2022 7:25:01 GMT
TEMPERATURE GLIDE I believe and see in hindsight that a refrigerant that must be charged as a liquid is a mixture of refrigerants. From what I understand Envirocare is a combination of propane with a boiling point of -43F and butane with a boiling point of 30F. The propane would boil at the start of the evaporator and the butane would continue on to the end of the evaporator. That is the frost pattern I see on the evaporator. I visually saw the oil filled tube at the entrance to the evaporator. I can hear the loud gurgling that confirms the oil is there and need to wait to see if it returns to the compressor. I will observe the machine this summer to see if this compromise works. Maybe the capillary tube would work best with r-152 which is not a mixture of gases. I had a leftover can of ENVIROCARE hydrocarbon refrigerant. It was designed to be a drop in refrigerant for R-12. It is a mixture of propane with a boiling temp of -43F and butane that boils at +30F. Yesterday in Minnesota it was -20F and when I used an access valve to open the -20F cylinder the propane boiled off. Left outside overnight the temperature warmed up here in Minnesota to +16F. This morning the butane liquid was still in the cylinder as a liquid as it will not boil until +30f. I would suggest that this would indicate that refrigerant replacements that are mixtures will not work in refrigerators that have static air flow evaporators. In this case the propane boiled off in the first few inches of the entrance to the evaporator and the +30F butane was left to boil off in the entire rest of the evaporator.I believe that your assessment of the propane/butane refrigerant for use in refrigerators is correct. The butane boils off at too high of a temperature and low to medium temperature refrigerant blends, as a rule, do not contain butane. Perhaps the blend that you had was intended for automotive use and not for medium temperature use.
With this being said, I still prefer the use of "pure" refrigerants, as opposed to blends, and would never consider using highly flammable HC in anything, especially an automobile, where an evaporator leak could potentially pose a very dangerous situation.
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Post by turbokinetic on Jan 9, 2022 14:48:20 GMT
I had a leftover can of ENVIROCARE hydrocarbon refrigerant. It was designed to be a drop in refrigerant for R-12. It is a mixture of propane with a boiling temp of -43F and butane that boils at +30F. Yesterday in Minnesota it was -20F and when I used an access valve to open the -20F cylinder the propane boiled off. Left outside overnight the temperature warmed up here in Minnesota to +16F. This morning the butane liquid was still in the cylinder as a liquid as it will not boil until +30f. I would suggest that this would indicate that refrigerant replacements that are mixtures will not work in refrigerators that have static air flow evaporators. In this case the propane boiled off in the first few inches of the entrance to the evaporator and the +30F butane was left to boil off in the entire rest of the evaporator. I believe that your assessment of the propane/butane refrigerant for use in refrigerators is correct. The butane boils off at too high of a temperature and low to medium temperature refrigerant blends, as a rule, do not contain butane. Perhaps the blend that you had was intended for automotive use and not for medium temperature use.
With this being said, I still prefer the use of "pure" refrigerants, as opposed to blends, and would never consider using highly flammable HC in anything, especially an automobile, where an evaporator leak could potentially pose a very dangerous situation.
Quite a few of us are averse to use of blended refrigerants and HC refrigerants in general, for any conversion. The Monitor Top fridges aren't likely to be damaged; however many other manufacturers from this era used rubber seals in the electrical terminals. The hydrocarbons will swell and soften these seals, resulting in failures. I've had to repair this damage a couple times and it is a very costly repair. The R12 blends were introduced for automotive use, and are bad in that application as well. I learned the hard way back when those were new and R12 was being phased out. They seem to leak more readily than actual fluorinated refrigerants do. I would expect it is due to the same issue with the compressor seals mentioned above - it permeates through the o-rings and other parts of the system.
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