I don't recall all the details, but starts off with the largest parallel flow condenser and improved fans. However, R12 refrigerants are still used as fire retardants in aircraft and submarines. A/C systems designed to use R-12 will cool best when charged with R-12 refrigerant. . Quick View. Hmmmm. Paul -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. Remember, being aluminum, they lower the temps better, and do not pass off as much heat to the radiator, which then makes it's job easier and lowers underhood temps (besides lowering vent temps inside the car). I mean, really a lot. On the other hand, R12 has a global warming potential of 10,910. difference between r12 and r134a expansion valve. Like say half a can or so recharge come springtime warm weather or something. J.Harris said: Or if you want to do it like they do in Mexico you can use propane, it's an excellent refrigerant but highly flammable. These differences in the valve size can be attributed to the correlation of the cooling capacity with the enthalpy difference and the mass flow, which in . Before landing on the debate of R134 vs R12 you should know that both R134a and R12 are AC refrigerants types used in refrigeration and air conditioning systems. Typically 5 to 6 ounces of a/c oil is adequate but this may vary depending upon the car. Replace the drier with a drier that has a desiccant that is R134a compatible, use new R134a o-rings. If you still find it difficult to use R134a in a home AC system, you can check out a comparison of R12 vs R134a fittings to know the refrigerant that best fits the AC system. is good, then I should be looking elsewhere? By noting the ambient temperature you can look up what the preferred high side pressure should be. It is a known suspect that lets heat into the heat exchanger/core even when off because the mono-valve is on the exit side of the heater core. and he synthesized R-134a in 1936, 5 years after R-12 was . If your car does not have a high pressure cut-out switch in the AC system then youll need to have one installed (call us if you need help). Heres R12 vs. R134a pressure chart. Agram a retevis rt22 password i bastrop county district clerk records el material que oferim als nostres webs. R134a refrigerant fittings are different size. Plus, not releasing the chemical into the air is morally justifiable. It cycles on off in med (or low for that matter)Gotta tell ya. 5. Recovery & flushing is the only way out of an oil overcharge in your vehicle.B. Break out the new gauges and measure hi and lo at 1500rpm, and do the Merc FSM test to see how we're doing performance wise. Edited: Sat July 14, 2007 at 10:22 PM by fonebone. What is a good differential? They would then make short "jumper hoses" to connect to the existing stock hoses, refit your old fan if there is a "pusher" fan, and recharge to specs. Next I'll jumper the aux fan. . Does it matter - assuming both are new & uncontaminated? look at the difference! we convert older systems where i work all the time and they work fine. However, take note that R134a refrigerants are manufactured specifically for automotive air conditioners. Post photos, respond to polls and access other special features. What is usually sniffed are all the connections in the system: hoses and compressor, condenser, drier, expansion valve and evaporator fittings. Its chemical symbol is CCl2F2. Als nostres webs oferimOne Piece,Doctor Who,Torchwood, El Detectiu ConaniSlam Dunkdoblats en catal. With that said, I would source the TXV from another source such as NAPA just to avoid any problems. Ensure you contact a professional mechanic to do the work for you so you dont end up incurring more costs for yourself. -------------------------"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest." We sometimes use a relay switched from the compressor clutch to run fans. Just leave it alone for now. Hopefully after you have read this entire page you will have enough information to determine which type of refrigerant is best for you. I had a 1991 BMW switched to 134a by just changing the low pressure charging valve, flushing and refilling with 134 (maybe with 10% . R134a is NOT less efficient than R12 Actually R134a is more efficient. The original CFC expansion valve used for R12 needs to be replaced with an HFC one for 134a to feed the evaporator correctly. Trinary Pressure Switch $ 39.99. Can I just use an adapter and save $200? R-134a is widely believed to be the most acceptable R12 substitute. If 50 degrees across the cond. Gnats & mosquitos will clog deep. You can buy bulk hose, and the proper fittings, then have them crimped off the vehicle.Be sure that no air bypasses the new condensor on the way to the radiator. On this website we are addressing only R134a and not other suggested drop in replacements. There is NO reason to retrofit a vehicle to R-134a as long as the R-12 system is cooling properly and contains a normal charge of refrigerant. Therefore, the higher the factor of the chemical (compound), the greater its effect on global warming. had writing on the side that said R134a. R134a is the most widely accepted alternative automotive refrigerant used to replace R12. Besides, its technology has been tested and trusted. R12 was once used in many air conditioning units as a refrigerant or cooling agent. It is made up of carbon, hydrogen, and fluorine. I think so. Spray it deep, and let it sit for a few minutes. Just because the radiator does not boil people assume that the cooling system is ok. -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a, Bohica, You say the drop in performance is not linear with too much oil. system of 0.33 TR and refrigerant used was R12. Its chemical symbol is CCl2F2. The only difference I can imagine would be the recharge connection. Then at least I'd know really where I am on it. We, the Rxmechanic team, have presented a well-detailed comparison of R134a vs. R12. You do not have to split up the 5-6 oz of oil and add it to each component, just simply put it all in the compressor as it will move throughout the whole system once the system is operational. Until 1995, most cars with air conditioning used R-12 Freon refrigerant which has shown to have an environmental impact. maintain the A/C of older cars. How dumb!I will jumper the aux fan and redo the test. Rxmechanic.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for website owners to earn advertising fees by advertising and linking to Amazon.com. The difference between R12 and R134a TEV (exp valves) is primarily the 'superheat'. Autor de l'entrada Per ; Data de l'entrada calexico west port of entry hours; 12 month libor rate 2021 a difference between r12 and r134a expansion valve a difference between r12 and r134a expansion valve AFAIK, there is no clutch on the engine fan on the 240D. This is the part that controls the system pressures. -------------------------"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest." Temp switch works the aux fan. = R134a Charge Level. don't know enough about the subject to explain the choices.However, a few days ago I called the dealer to see about an OEM TEV and they said something that made me feel a little bit better; the same part number superceded every application back to the '60s, and that they couldn't do that without engineering signing off on it.Still, I would feel a lot better if I could see something written officially that compared the flow characteristics and performance of r12 and 134a TEVs are concluded that they were interchangeable in automotive applications.If someone knows of such a document I would sleep much better!Walt Edited: Mon September 12, 2005 at 8:13 PM by wamcneil. 2) Frost on the Vents. Is there a source of valves by, say, eaton number? I had a pair on my SAAB that seemed ok - but new ones ran 20% faster!Your best clue to airflow issues is a 60 mph test. . R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. Generally this works well for the whole system. Crap! Paul:A 1983 240D should have a York compressor on an OEM system. The current expansion valve is FF - 1/4 - C. Is it neccesary to replace this valve? Once you have replaced the OEM condensor with a PF unit, you will need to make custom hoses to mate with your OEM system. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. There are three different refrigerants officially sanctioned by the EPA for automotive usage: r-12, r-. Theres no doubt that R12 refrigerant is one of the first compounds manufactured for the air conditioning and refrigeration world, but it had to be banned. -------------------------Just another brick in the wallHad a little mule I fed him castor oil and every time he jumped the fence he fertilized the soil, The older expansion valves were filled with the refrigerant they were used with, the replacement valves (today) are filled with a different chemical to work with both refrigerants..Hope this helps-------------------------ChickEmail: Chick---------------------------------------------Freedoms just another word for nothing left to lose, I believe the optimum supercool setting will vary slightly between an expansion valve for an R12, as compared to R134a, system. Interestingly, theres one oil type that works perfectly with both types of refrigerants. Attach the R134a charge port adaptors, there are two types.. one of which you need to remove the old R12 valve cores. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. It's best to determine on a case-by-case basis while monitoring system pressures and output air temperature. 05-25-2017 02:14 AM. What is a T/C?4. James10952001. We suggest dumping the old refrigerant oil in a clean container and inspect the oil for sludge or waxing (old oil that has gelled) and contamination (metal particles). R12 and R22 are both now banned by the EPA in the United States. How an A/C Expansion Valve Works. Very nice! Automotive Replacement Expansion Valves & Parts; Industrial & Scientific; Customer Reviews. The P H and T cond,sat of the HR12 at a T oa of 40 C were higher than that of the R134a, resulting in a higher P e than that for the R134a. Its not that difficult but the procedures of evacuation, charging and testing should be done by a licensed a/c technician that is experienced with R134a and your particular car. R-12 expansion valves can be re-used, but will not be as efficient as R-134a specific ones because of the slightly different pressure specs of R-12 vs. R-134a. 42 (at best) w/ 134A in 2000 isuzu trooper. . They should be able to keep you comfortable on a long trip, but don't expect vent frost in 3 minutes or lesss.2) Too much oil can reduce cooling capacity, and the effect is not linear. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. By using a qualified a/c shop with the proper equipment you odds are in your favor of having the job done correctly the first time. R134a is called tetrafluoroethane (HFC). Do a pre-inspection and then Evacuate (vacuum down) the system, the longer the evacuation the better but there is a point of diminishing return, 2-3 hours is generally very good. I'm just trying to help you avoid headaches in the long run. If the charge is low the compressor will cycle on/off in the max AC position. Well, I'm not sure it is 'fine' - it doesn't cool very well in 95F weather. It won't be optimal, though. The butylcellusolve or the citrus solvent will dissolve the carcass in a few minutes. Differences between R-12 and R-134a systems: 1. If you find any of these conditions you will want to liquid flush (with dedicated AC flush solution) all the lines, condensers, evaporator (remove the expansion valve) before you proceed further. Debug the condensor (I am a computer nerd after all!)3. But, what is considered a good temperature differential across the condensor? Table 1 summarizes the technical characteristics of three potential R134a alternatives. . I'm doing one thing at a time so I know what the cause was. The original rubber a/c hose lines in your car will leak out R12 through the hoses lining. If you have a perfectly operating system using R12 you do not have to drop what you are doing and convert to R134a. R12, on the other hand, has an ozone depletion potential of 1, implying that it can damage the ozone layer. You'll want the expansion valve matched to whatever refrigerant you're using. Inasmuch as R134a has a global warming potential thats over 1000 times more threatening than carbon dioxide, its better than R12. Very interesting! A. Pressure/temperature table for R12, R134a, and R513A is shown in Figure 1. . It does not "pool" to any degree in a large amount anywhere. I remember I had the wrong seals and it leaked some oil, so I put some more in.Bohica - I tested the pressures. R134a vs R12 refrigerant? Took me a while to figure that one out, and how to say that. Therefore, the R12 refrigerant is illegal, and emitting it is illegal. The symbol implies that R12 is a composite of carbon, chlorine, and fluorine. difference between r12 and r134a expansion valvewarning signs for a deteriorating patient with covid 19 infection 2022.07.03 18:36 18:36 R12 can move more heat than r134 so when it isn't very hot and the system isn't maxed out you wont be able to tell the difference but when its 110 out and the inside is 140 R12 will cool the cabin temp faster. Carefully study the chart and compare the following: To a large extent, the choice is up to you. The money you will save by will pay for the R12. The sticker typically has a place to note the amount of refrigerant used, the type of oil and amount of oil, the technicians sign off or name and the date of the conversion. R134a refrigerant is about 10% less efficient in moving heat than R12! Are r12 and r134 fittings different? It was later found that R-134a had a very high Global Warming Potential, or GWP, number. The bad thing is I don't know what to do about it. For those of you who are considering what the cost is for R12 you can think of it this way: Dont go out to dinner this weekend. It is made up of carbon, hydrogen, and fluorine. -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a, Hi pdrayton- If you can remember the oil capacity that you found in all your research and post that, then bohica and others can have a better idea if you have too much; see if you can find that info! evarporator, expansion valve plus flushing out the full system and replacing all the o rings. Make sure to get the R12 EXP valve if that is the way you go. As per their results . If you have the work done, be sure you find a true "A/C" shop that can make up lines. Paul:It is never a waste of my time to chat with someone that understands the problem, and wants to fix it. The evap is hard to get at. Its chemical symbol is CH2FCF3. Bottom line, R134a simply doesn't cool as well as R12. I'm having the same concern. Stay home and grill your own steaks and stir your own martini. Please enter a password for your user account. BTW, I use a stick thermo in the vents and the laser on the condenser. In this study, without the need for major modifications to the bus air conditioner, the variation of the ejector dimensions according to different parameters has been investigated in the case of using the R1234yf, R1234ze(E), or R600a refrigerants, which may be a substitute for R134a as a refrigerant due to . 5) A/C System Failure. Energy usage: R134a is less efficient in cooling compared to R12. R12 contains a chemical called chlorine that destroys the ozone layer, thereby causing potential environmental risk. R 134A is designed for the high demands of an automobile AC and cannot be used on refrigerators due to pressure differences. If ambient is 90 (today) and the output of the condensor is 110, that's pretty good isn't it? That would be the "black death" syndrome. In large application systems, the vapor density of this refrigerant is usually high. Later model cars that come with 134A will have 134A only connectors. I've straightened the fans I can and sprayed simple green on it, let it soak then hosed it down well. difference between r12 and r134a expansion valve . I have some experience with auto a/c but not too much. How is 1234yf different from . Make sure to wear safety gloves, goggles, and shoes when theres a possibility of exposure to the chemical (R134a). Components Coils, Heaters, Motors, etc. Can I use the one for the R-12? R404a is a zeotropic blend with a temp glide , because of the mixture of 2 or more refrigerants. Miscibility with oil: R12 can be mixed with the compressor oil no matter the operating condition. Yes, I don't trust the heater valve either. The general practice of charging the system with 15% less refrigerant adds to the thermal deficiency of R134a. For R12, its mineral oil. I cleaned the evap as best I could, if that is what you are getting at. I've done the FSM test and with 81F ambient, the vent should be 50F. At 40, it is 35psi, which is a difference of 8.9psi. Anyone know what happens when an R12 expansion valve is used in a system charged with R134A? If it splashes inside the eye, it could lead to a serious eye problem. You do not need to replace every o-ring in the system, but if you happen to open a connection that has an o-ring you should replace the old o-ring with one that is compatible with R134a and lubricate the o-ring with ac oil. The cure is to use the newer R134a compressors is sealing washers that are different thickness. The MB chart shows 360 psi with R12 in some conditions. might be due to charge or different compressor and age. That's a lot isn't it? And I lied about the compressor switches on this car - there are 2 switches on the drier - a temp and a pressure switch. ). R134a requires a different oil. Thanks for the input. I'm also thinking maybe I should go to R134 - it might work better with the right amount of oil and the correct expansion valve. Large temperature difference between expansion valve inlet and outlet oReplace expansion valve Air . CONCLUSIONS The differences in the theoretical C.O.P.H calculated for R12 and R134a are consistent with values quoted in the literature. And no, you cannot "drain' excess oil out. You are indeed 20% out of the OEM spec for cooling. The problem with using an approved alternative refrigerants other than R134a is that when the system is serviced it requires certain types of fittings, labels and dedicated equipment. Look at where the lines will end up. I recommend replacing the expansion valve when you do the swap. $21 . Even if the system leaks, repairing the leaks and recharging it with R-12 is usually the best repair alternative. leading to corrosion of expansion valves, capillary tube plugging, and compressor bearing . Trinary Pressure Switch quantity. . You will be fine with a 134a-compatible TXV running R12. Condensers designed to release greater amounts of heat help to expel the greater amount of heat which R134a removes from the cars interior. Get to the point where I can walk without crutches2. Any advice appreciated. After the optimum refrigerant charge is determined the car should be test driven to check for performance of the system. Then again, there are two different expansion valves. But, if your car lacks enough condenser and you have many 100+ degree days then you may want to stick either increase air flow, add another condenser as we mentioned in The Mr. Ice Project or stick with R12. After the initial charge the system is then tweeked : you determine the optimum amount of refrigerant to match your system by monitoring the a/c outlet vent temperature and the high side pressure as you add or remove refrigerant. They might say for instance, add 3-4 oz of oil to the compressor, 1 oz of oil for when you replace a drier, 2 oz oil for the evaporator and so on. Sense ells no existirem. A slow loss of cooling at city speeds is usually related to condensor capacity & airflow issues.You could improve the cooling capacity by replacing the condensor with a high effeciency parallel flow unit. With the oil leaking out and being told all sorts of things about how these compressors don't have a sump etc, I wanted to be on the safe side. These two refrigerants are the older types and are not used in newer refrigeration and air conditioning systems. The pressure/temperature curves for R-1234yf and R-134a are very similar. A/C receiver difference between R12 and R134a? a 50f delta across the condensor is good, but I suspect that is an idle reading. Not going to mess up your 'do, but you can feel it. VerticalScope Inc. All Rights Reserved. The compressors used by refrigeration plants to compress gas require oil to help lubricate its moving parts. Replacement expansion valve for R134a or R12 A/C refrigerants, with O-ring connections. Rules governing changing from the former to the latter differ between countries. The global warming potential measures the amount of heat trapped by any gas compared to the amount of heat trapped by the same amount of carbon dioxide. Lets take you through the advantages, disadvantages, and differences of these two refrigerants a detailed comparison including R12 vs R134a performance. If not, you just don't know unless a test is performed. Some compressor manufacturers or OEMs suggest PAG type oil for R134a. I don't believe it is but I had a service guy tell me it needs to be done. You do not want to exceed the systems high side recommendations. Or is there always room for improvement, the more the merrier. The reason is that the vehicles, for instance, manufactured currently configure the engine for R1234yf refrigerant, making no provision for replacement. Read on for more information about using automotive r134a in a refrigerator and vice versa. Hope this helps. Only show this user. Using R134a requires that Polyolester (POE) lubricant must be used in the compressor.