As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. Back in that era, my business associates drove those things, brand new, and maybe I should take my Cadillac instead, no they wouldn't be caught dead in a Caddy, people of our esteem should be driving an MB. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. Energy usage: R134a is less efficient in cooling compared to R12. He used thermostatic expansion valve and Capillary tube for analysis with R12. and feeds it through an expansion valve. Make sure to get the R12 EXP valve if that is the way you go. These efforts to balance the system can not be realized if there are problems within the a/c system, such as: poor performing compressor, dirty condenser or poor air flow through the condenser, malfunctioning expansion valve, water or air in the system, improperly operating fresh air or heat input in the climate-air mixing system. The aux fan didn't switch on though and I didn't check the high side temperature. Read on for more information about using automotive r134a in a refrigerator and vice versa. The value of carbon dioxide is 1. Post photos, respond to polls and access other special features. The catalytic converter is an essential component of your car's emission system that helps save the environment from harmful emissions. And yes - expansion valves sometimes need replacing if they are sticky - but a proper AC flush should eliminate the need for a new one if it's already in good condition. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. The typical scenario here is when the car owner buys an inexpensive retro-fit kit from the local auto parts store. You should keep in mind that recharging your air conditioner improperly could result in more serious damage. Related products. Compressor. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. Its chemical symbol is CCl2F2. Right now you know you have a bit too much, but with a CR4P compressor this is an insurance policy. Rules governing changing from the former to the latter differ between countries. Is there more info needed?THanks -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a, Paul:I had to dig a bit deeper - MB made several running changes in the 1983 123'sThere are actually 4 different circuit diagrams for the A/C system that year - just for your 123.123 I found the R4 reference, and it should have 170 Ml of oil in the system.Your aux fan should run at the ambients you listed. R12 and R22 are both now banned by the EPA in the United States. Is the information not applicable to the old Pantera system? Jun 19, 2007. I found that in the..Maxposition on the control it will have the compressor running all the time. Also the new quick connect fittings for the high & low side. I'm just trying to help you avoid headaches in the long run. The non-flammables can have R22 type gas which is not compatible with most rubber hoses or they have gases that contribute to global warming. Lets take you through the advantages, disadvantages, and differences of these two refrigerants a detailed comparison including R12 vs R134a performance. Lasers don't do well on vent temps, a stick thermometer is better in that application. Participate in over 40 different forums and search/browse from nearly 3 million posts. This chart has a column of ambient (outside) air temperatures on one side and a corresponding range of high side pressures on the other side. You will be fine with a 134a-compatible TXV running R12. Or is there always room for improvement, the more the merrier. Recharge the compressor with a/c ester oil and a tracer dye. -------------------------"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." If the system was upgraded by a professional it should have an upgrade sticker. As illustrated in the chart below, the curves below run together nearly throughout the curve, only slightly breaking paths at around 250 psig/150 degrees and above Flammability/Safety R-1234yf has been designated as MILDLY flammable. With tube & fin condensors in MVAC applications there is never "too much" airflow. R12 contains a chemical called chlorine that destroys the ozone layer, thereby causing potential environmental risk. Depending on which circuit diagram fits your car (cough, no vin list exists) you have either one or two switches controlling the aux fan. Flushed, vacuumed etc. You can use the R134a retrofit capacity chart for this purpose. The R134a compressor has a 1/8" step in on the high side port. The car never overheats, if that has any import. So you could likely put off buying those new hoses just a bit longer if you wanted. If ambient is 90 (today) and the output of the condensor is 110, that's pretty good isn't it? Refrigerators generally utilize R22, R32, or 410A-based coolants as their cooling agent. #19. -------------------------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. Accessories Pumps, Cooling Towers, Evap Condensers, etc, Components Valves, Motors, Condensers, Evaporators, etc, Duct Systems Design, Installation & Practice, Piping Systems Design, Installation & Practice, Control System Design, Installation & Practice, Pro's Forum: National Electrical Code (NEC), Pro's Forum: Calculations & Electrical Theory, Pro's Forum: Electrical Business & Marketing. 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. If it splashes inside the eye, it could lead to a serious eye problem. This refers to BTU's (heat) moved per pound of refrigerant moved. There are two hoses listed, R-12 64-53-1-377-821 for $72.50, and R-134a 64-53-8-391-051 fro $262.50. Next I'll jumper the aux fan. However, the supply houses don't indicate a difference. Hot coolant migrates up through the core by convection (is that the word? The Wikipedia explanation for expansions valves cited in Frank's thread says that the gas inside the bulb in the metering valve is the same as the refrigerant in the system. shown for the parallel flow, aluminum condenser that is listed. When I compare parts, 93 uses one part number and 94 has a different part number. and recharged with mineral oil and 2.2 lbs R12. difference between r12 and r134a expansion valvewarning signs for a deteriorating patient with covid 19 infection 2022.07.03 18:36 18:36 Note that passwords are case-sensitive. Spray it deep, and let it sit for a few minutes. Components Coils, Heaters, Motors, etc. If you're getting a R134a compressor, might as well finish the job - replace the receiver/dryer, flush everything else, and convert to R134a anyhow. At least you do not have 16 ounces in there ( yup seen it before).For now, straighten all of the fins that you can, clean the condensor well, and re-test with the aux fan running. 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 . With that said, I would source the TXV from another source such as NAPA just to avoid any problems. Expansion Valve. However, R134a is better than R12. How is 1234yf different from . Also, they are mostly used in refrigeration and automotive air conditioning systems. What was the ambient when you took that reading?Jumpering the aux fan is a common thing here in the desert. If you are replacing other system components, such as condensers, driers or hoses, you may need to add more a/c refrigerant oil to the system. We sometimes use a relay switched from the compressor clutch to run fans. Well, I'm not sure it is 'fine' - it doesn't cool very well in 95F weather. Only show this user. Since 2010, all home AC systems manufactured use a refrigerant like R134a that has zero ozone depletion potential (ODP). It won't be optimal, though.On some/many valves, you can adjust them, but that might make matters worse unless you really know what you're doing (which I don't!).RegardsGeorge. Besides, you have a greaseisel. maintain the A/C of older cars. Interestingly, theres one oil type that works perfectly with both types of refrigerants. This is an electronic tool that sucks in air through a tube and across a sensor. So if you car has a large amount of rubber hose, such as a 40 feet with the 911, then you will be re-charging the system often and that is expensive no matter which refrigerant you use. Safety: R134a is safe to use as its non-flammable and cant explode. Is there a difference in the expansion valve for R12 as opposed to R-134a? One of the differences between auto air conditioners that have been redesigned from R12 to R134a is that the condensers have gone from serpentine to pseudo-parallel. By using a black light the dye will glow in areas where oil leaks are visible. This drop can affect energy consumption since the plant will operate for a longer period or a larger plant will have to be installed. Most importantly, the oil used in the plant must always be compatible with the refrigerant used. 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. 3) A TXV optimized for 134a will be ok with R12. Since then, the industry standard has been R134a, which is an efficient replacement. R404a for freezing of product. Add to cart. The cure is to use the newer R134a compressors is sealing washers that are different thickness. The next piece of equipment to track down leaks is a leak sniffer. It is mixed with the freon for the most part, and does accumulate in all components in small amounts. R134a vs R12 refrigerant? At this time you can still find R12, but, because it is no longer produced, availability is limited to current inventories and the price per pound is greater than R134a. As an example, let's say the R12 charge specification is listed at 2 lbs. It cycles on off in med (or low for that matter)Gotta tell ya. Above this temperature, the saturation pressure of R134a is higher than that of R12; below, it is lower. Welcome to rxmechanic.com. I don't think it has any air dams or seals, I'll check to make sure. This leads me to labor over every small decision. B. 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. The bad thing is I don't know what to do about it. In short, NO! So that indicates it is cooling well there doesn't it? Before R12 was replaced with R134a in 1995, it was mostly used in trucks and cars. The only mechanical differences between an R12 system and an R134a system are that R134a systems typically have larger condensers and more powerful compressors. A York oil capacity is listed as "6.5 to 9.6 ounces". Could that be screwing up the systems performance?Anyway, when I installed the system, the new TXV (is that short for expansion valve?) But some types of PAG do not mix well with the old residual R12 mineral oil left in the system components whereas ester does mix very well. 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. Where would I get some basic info on it, I know nothing about it. The exact amount will vary with each car. In a comparison between R12 vs R134a vs R1234yf, R1234yf will pass as the best refrigerant. But, if your old compressor has lock-up or if your current expansion valve is not functional it would wise to replace the expansion valve with a valve designed for R134a. The global warming potential of R134a is 1430. 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. R134a Refrigerant Recharge Kit with BPV31 Bullet Piercing Valve and R134a Quick Coupler, R134a/R-12/R-22 Freon Refrigerant Hose Can Tap Kit for A/C System - Easy to use. R134a is called tetrafluoroethane (HFC). The compressors used by refrigeration plants to compress gas require oil to help lubricate its moving parts. To bless the system the technician should attach a R134a sticker somewhere in the engine compartment to note the car is using R134a. ing the expansion valve, a maximum opening superheat of 7F, and a standard factory air test superheat setting. #4. 3) A/C Compressor Always On. The #1 question asked by NEW MEMBERS. June 21, 2022 difference between r12 and r134a expansion valve . For instance at 25 F the pressure of R-12 is 24.6 PSI and the pressure of R-134a is 22.1 PSI. . However, you can convert R12 to R134a by yourself, save money and keep all the tools purchased. Don't like the sound of custom parallel condensor. When the sensor detects the refrigerant leak the sniffers lights glow and the sniffer makes a noise. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. Generally this works well for the whole system. look at the difference! R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. You are indeed 20% out of the OEM spec for cooling. -------------------------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. R134a and water have the same abilities to change the state but R134a can do this more rapidly and at a much lower temperature than water. I have just bought gauges. First, differences in physical properties: 1, insoluble R12 compressor oil is used (to reduce the lubricant) 2, dissolved sealing materials are used (resulting in refrigerant leakage) 3, easy to damp (so easy to internal . in /nfs/c05/h04/mnt/113983/domains/toragrafix.com/html/wp-content . If your compressor requires replacement or its seals and o-rings need to be replaced due to leakage, it would be wise at this time to either obtain a compressor that has o-rings and seals that are compatible with R134a or have your unit re-manufactured with compatible components. 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. One thing at a time here, and slowly, the knee is not up to jumping around like I used to at the moment. Later model cars that come with 134A will have 134A only connectors. R-134a XV for R-134a use. 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. 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). Superheat you can consider to be the additional amount of heat. Very interesting! You'll get marginally better performance out of the change as the expansion valve is matches the refrigerant characteristics. I've done the FSM test and with 81F ambient, the vent should be 50F. Should I do the test again with the the aux fan jumpered? Any advice appreciated. evarporator, expansion valve plus flushing out the full system and replacing all the o rings. With R12 you use to check to see if the site glass was full, if it had bubbles it meant you had a low charge. The difference really shows up on the high side. Some say that a chemical reaction can harm the A/C very badly as R134a reacts with mineral oil in some way. Its chemical symbol is CH2FCF3. I've got a ball valve I'm going to put in the coolant line before the coolant goes through the firewall to the core. I think so. difference between r12 and r134a expansion valve. It's not just the poor performance - the cooling just stops working after a while. Performance doesn't seem to have improved. And no, you cannot "drain' excess oil out. is good, then I should be looking elsewhere? But as there's not a big difference, people say you can suffice with either. Helical and Serpentine coils. How about evacing 1 pound of refrig from the system, and then putting 1 lb of pure R12 back in? Yes, this was a smokers car. Why wait for 200f on the engine coolant to start the fan? Then again, there are two different expansion valves. R12 was once used in many air conditioning units as a refrigerant or cooling agent. R12 is used in several applications like low temperature, medium temperature, and high-temperature applications. Vent temperatures slowly go down to around 50F with hi speed driving. R12 systems used mineral oil, but unfortunately mineral oil doesn't dissolve in R134a. Very nice! R134a refrigerant is lighter than R12. I would suggest you do stay away from R-134a since with the hot gas bypass of your system (if it is to be just as the original) extremes of temperature and pressure will be very hard on your compressor and the rest of the system. Consider using the newer valve, even with 134a stamped on the valve. R12 is highly destructive to the earths ozone layer. The crossover point is approximately at 64F. Looks like a couple of things happening here1) 80's vintage Eurocars were not "meat lockers". . AFAIK, there is no clutch on the engine fan on the 240D. What is a good differential? Debug the condensor (I am a computer nerd after all!)3. Bad Car A/C Expansion Valve Symptoms. Paul -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. Besides, R134a refrigerant was manufactured after R12 was banned to help reduce the harshness of the old chemical (R12) on the ozone layer. But I've read that these car's didn't do too well in the a/c stakes, so that might just be as good as it gets. According to Wikipedia, There is such a thing as "r132a" (1,1-Dichloro-2,2-Difluoroethane), however there is no indication of it being a commercially produced refrigerant. leading to corrosion of expansion valves, capillary tube plugging, and compressor bearing . Generally, the new amount is 75-85% of the quantity advised by the manufacturer. Inhalation of vapor: Inhaling a large amount of R134a vapor can lead to drowsiness, temporary nervous system depression, and lethargy. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. To prevent refrigerant loss you should consider replacing your old hose lines with barrier type hose. If 50 degrees across the cond. Hopefully after you have read this entire page you will have enough information to determine which type of refrigerant is best for you. link to How to cut off a Catalytic Converter. It won't be optimal, though. When you add fluorescent tracer dye to with the refrigerant oil it helps to track down leaks that push oil out of the system. 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. of refrigerant insulation tape. It is made up of carbon, hydrogen, and fluorine. The ozone depletion potential of a chemical is a factor that shows the level of degradation itll cause to the ozone layer that surrounds and secures the earth from harmful radiation. Kommentare . Then I'll put the ball valve in on the coolant and test it and see what we have. The expansion valve is designed so that the temperature of the refrigerant at the evaporator outlet must have 8 to 12F (4 to 7C) of superheat before more refrigerant is allowed to enter the evaporator. It's best to determine on a case-by-case basis while monitoring system pressures and output air temperature. Any suggestions, or do you need to know the hi/lo readings? I have one can left, so maybe a plan can be made. Trinary Pressure Switch quantity. sparkee said: Thanks for the Service Bulletin. Edited: Tue July 17, 2007 at 3:25 AM by bohica2xo, I believe there is only one switch - the refrigerant switch. Unfortunately, the oil only mixes with the refrigerant as a liquid. Look at where the lines will end up. By noting the ambient temperature you can look up what the preferred high side pressure should be. (You must log in or sign up to reply here. The condenser water inlet temperature and flow rate are controlled with the use of a . 4.3 out of 5 stars 491. Hence, let us continue to fix it. This would become an expensive investment for a repair or service station to have unique dedicated equipment for every type of alternative refrigerant. Additionally, R134a was introduced as a replacement for R22 and R12 in high and medium-temperature refrigeration systems like domestic and commercial chillers. Do I leave the orignal condensor in, etc?Thanks. The condensor airflow drops off as the fan clutch dies slowly. A vacuum pump, a refrigerant recover system, quality service gauge set with both low and high side gagues, and much more besides the lessons to learn what to do and what not to do. The best oil that runs well with R134a is PAG oil or Polyalkylene Glycol. An extra half ounce? We are an automotive mechanic blog that helps mechanics and car users to find the most recent and accurate technical and repair information for their cars. But, what is considered a good temperature differential across the condensor? July 3, 2022July 3, 2022. We recently created this blog site to enable us to share our knowledge with other automotive mechanics and car owners. As noted, measure up front as best as you can to get as close to the aftermarket dim. There are significant differences between R12, R134a, and R513A, which must be considered when handling, processing, applying, or retrofitting with these refrigerants. (The .133 is the 300D Turbo).So, what does your compressor look like?B. You'll want the expansion valve matched to whatever refrigerant you're using. 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. There are R134a specific valves that operate at a slightly different pressure, but not for any "old" automotive application that I'm aware of. -------------------------"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." On the other hand, R12 has a global warming potential of 10,910. The Wikipedia explanation for expansions valves cited in Frank's thread says that the gas inside the bulb in the metering valve is the same as the refrigerant in the system. So if the TXV is OK, and the too much oil situation is not a big problem, then I wonder why the compressor is switching off after about 15 minutes of cooling? This is due to many facts: R134a refrigerant is about 10% less efficient in moving heat than R12! 4 Stars & Up & Up; 3 Stars & Up & Up; 2 Stars & Up . hardly noticable. Trinary Pressure Switch $ 39.99. R134a requires the use of synthetic oil! 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. 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