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Dauphin Manitoba | Thanks for the response from the other post. That got me to the next question. Will it work to take that nice white bottle from the BBQ and flip it upside down and charge the system with (R290)? Just wondering if it will work and how well? |
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| Yep. But the refrigerant is a little more pure. I would use vapor though |
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Dauphin Manitoba | So its better to leave the bottle the right side up? |
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| Yes or add very slow so that it vaporizes in the hose. |
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Wisconsin | I agree, I don't want the gunk that is in the liquid. Use a half tank to reduce the less condensable impurities. |
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| How does one figure how much r290 to use vs R12 or R134a? Same amount or do you need to adjust one way or another? Local AC parts place was telling me this new R1234abcdlgbtq+ bull crap they've forced on us is basically just propane anyway with a billion percent markup.
The flammability doesn't worry me since I've used that Duracool stuff you get at Napa that's just butane and when I blew a hose it sprayed in the precleaner of a tractor and the engine revved right up so if they can sell that why not just use propane anyway. |
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Mid-Missouri | I often use r-152 instead of R134 lately. It is cheap, easy to find, and requires less product.
https://www.youtube.com/watch?v=6VVSfx9UN78
Edited by seedcleaner 8/1/2024 16:05
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SW Ontario | R290 works for me. And the cook never notices a little missing.
Definitely want to charge with vapour, do not flip tank. |
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| Look up the pressure temperature chart for r290 and proceed. Each system might be a bit different. In my old r12 sytem the bottom reads about 25 psi and the high 175 when the outside temp is 100 F. The evap puts out white foggy cold air.
Edited by phatcow 8/1/2024 16:37
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Dauphin Manitoba | So i got it working now. But after a while of running it isn't blowing nearly as much air and it's much warmer. Also the suction lines are all white from frost. What am I missing. Pressures seemed decent. High pressure seemed on the high side but also wasn't sure what it should be with r290. Didn't have much time. Had to go get supper. |
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| Probably your evap coil iced up. |
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Dauphin Manitoba | What should I do about that? |
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| Probably undercharged but it's hard to tell without knowing your system. You can find a PT chart for r290 online that has temp readings for your ambient temps and some will have suggestions about the inlet outlet temps across the condensor coil. |
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Faunsdale, AL | I haven’t tried the R290 ………yet! Have used some propane blend years ago that was supposed to be a R12 drop in replacement.
I expect your expansion valve or orifice tube tends to result in the evaporator too cold and or it may be partially plugged with dust and debris. Anytime it frosts the coil, it soon stops air flow completely.
I always heard the most appropriate fuel gas to use was high altitude stove fuel which was isopropane. I actually bought a can that I saw on a clearance rack a while back but haven’t tried it in anything yet. I expect you’re undercharged and by the time you get enough in it, the head pressure will be very high. But I have no experience, so that’s a guess. Try more or less charge and report back your results.
Maybe you need to raise the temp setting so the compressor cuts out when the evaporator gets too cold and starts frosting. Have had that when the evaporator was partially plugged with dust. Better to have some cooling long term than lots and then none!
Edited by ccjersey 8/2/2024 06:27
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SW Ontario | R290 seems to run colder in the evaporator. So the evaporator needs to be really clean and the blower needs to be moving lots of air. If your system has a TX valve that is not working properly that can also cause evap freeze ups. |
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NW KS | I have never been able to get straight propane to work. I have tried it in systems with orifice tubes and ones with expansion valves. Every time I have tried it it lacks cooling capacity. You might be able to get some cold air on low fan speed but never on high. This was with bulk propane from a 20lb bottle. The compressor and expansion valve just aren't designed to use propane. Propane matches r22 very well but not r12. R290 and R600A blends are supposed to solve these issue(redtech, Envirosafe, etc). I haven't tried any of the blends but I want to. |
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| My experience has been with r290 only and the system is and was made for r12. The r290 has out performed the r12 in this system but i filled the system according to the pt chart. At 100 degrees my pressures are 25 low and 175 high. The system cycles as it should no freezing |
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| I will add that my coils are clean and i have good to excellent airflow across both coils. The temp across the coils and back to the compressor all show good to excellent differentials. |
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Dauphin Manitoba | So this morning I took a closer looks at the system and the evaporator was completely plugged. (surprised that it cooled at all) so i took it out and washed it off. Also inspected the expansion valve that I just put in. And it was plugged up with some nasty black powder that smelled kinda like propane. Maybe because I charged it with the propane bottle upside down? Now that you guys say to do it right side up I'll maybe try that. Just pulling a vacuum on it again and will charge it up right away. |
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Dauphin Manitoba | Also me and BIL were looking at the black powder in the system and he started wondering if there would be a 1 micron filter that would work to filter the propane. Has anyone heard of something like this? |
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| Your tank could have any kind of rust or other contamination in it that is now in your ac system. The accumulator on your system should have a dessicant and a filter in it to help. You might need to flush your system? |
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Faunsdale, AL | I have a propane conversion on a 350 Chevrolet with the now old TBI fuel system. In my book these were the last simple pickups conversions. The multi-port fuel injection systems and their enhanced computer controls vastly complicated the traditional bolt-on conversions that had been done since the 1940’s.
Anyway there were usually filters from the component manufactures like IMPCO and CENTURY, usually with replaceable elements. While these might still be available, my supplier sells a disposable filter that looks very like a 033 commercial refrigeration component with 3/8 male flare connections on each end. Not sure that it has any desiccant in it, I doubt it since it has never stopped up in the decade or more that it’s been in use. In the case of the use in refrigeration, desiccant would be highly desirable, so I think any receiver-drier you could plumb into the propane supply would do the job. I assume that the XH-7 desiccant that is in use would work just fine. |
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| I’ve used the natural gas replacement for R134a from Envirosafe. I got it to work good in a few systems that have a condenser fan that runs full blast all the time. I’ve never been able to get it to work as good as standard refrigerant in vehicles. The cooling seems to go up and down while you are driving. You also never know how much to put in. The conversion charts never seem to be accurate. |
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Charging AC system with R290
