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. Lets take you through the advantages, disadvantages, and differences of these two refrigerants a detailed comparison including R12 vs R134a performance. But as there's not a big difference, people say you can suffice with either. Make sure to get the R12 EXP valve if that is the way you go. Skin contact: If the R134a (liquid) comes in contact with your skin, it could cause a burn. Boiling Point: R134a refrigerants boiling point is -26.3C (-15.34F). The problem with these so called drop in replacements is that to properly handle them you may need dedicated equipment to identify the gas and evacuate it for proper disposal. Heres R12 vs. R134a pressure chart. You either get a system that will function well with R1234yf or get any other type. Next I'll jumper the aux fan. Edited: Sat July 14, 2007 at 10:22 PM by fonebone. Different correction factors are applied to other refrigerants. Blows pretty hard on full. How is 1234yf different from . Its chemical symbol is CCl2F2. The general practice of charging the system with 15% less refrigerant adds to the thermal deficiency of R134a. Does it matter - assuming both are new & uncontaminated? Do I leave the orignal condensor in, etc?Thanks. It's not just the poor performance - the cooling just stops working after a while. . You should keep in mind that recharging your air conditioner improperly could result in more serious damage. difference between r12 and r134a expansion valve. James10952001. R12 is simply too expensive for a 25+ year old A/C system. It would make a big difference at idle ,in traffic!! I have one can left, so maybe a plan can be made. In practice this means that the car can overheat and the aux fan will stay off! I'm doing one thing at a time so I know what the cause was. Operating Pressure/Temperature Differences The pressure/temperature curves for R-1234yf and R-134a are very similar. However, you can convert R12 to R134a by yourself, save money and keep all the tools purchased. R404a is a zeotropic blend with a temp glide , because of the mixture of 2 or more refrigerants. The AC usually does not work at all. It has already been clearly stated that R12 is a chemical that damages the earths ozone layer and shouldnt be released into the environment no matter the circumstance. Below are the major differences between R134a and R12: Chemistry The chemical composition of R12 and R134a differ. The expansion valve(Tx) is in the car at the inlet line to the evaporator with compressors you best get advice from an ac specialist shop as the differences could be the gas that it pumps some systems use R12 and others use R134a or later gas yes R1234yf Freon gas can be replaced by R134a; the newer systems were designed with this in mind so no, there will be no damage to the compressor but some time in . On this website we are addressing only R134a and not other suggested drop in replacements. Whether R134a performs as well as R12 in any given a/c system depends upon system components and the amount of R134a used. 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. This is 11F off the FSM performance graph - vent should be around 50F. Note that passwords are case-sensitive. 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. How dumb!I will jumper the aux fan and redo the test. . Rules governing changing from the former to the latter differ between countries. 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. Then I'll put the ball valve in on the coolant and test it and see what we have. After the optimum refrigerant charge is determined the car should be test driven to check for performance of the system. 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. Paul -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. -------------------------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. shown for the parallel flow, aluminum condenser that is listed. Besides, R134a refrigerant was manufactured after R12 was banned to help reduce the harshness of the old chemical (R12) on the ozone layer. If you have 10 ounces of oil in the system, that is contributing to the poor performance as well. You will be fine with a 134a-compatible TXV running R12. What is a T/C?4. of coiled cap tube on VCR system with R134a. However, it was found to be a very bad gas for the environment. Rules governing changing from the former to the latter differ between countries. Below are the major differences between R134a and R12: The chemical composition of R12 and R134a differ. R134a has the chemical formula CF3CH2F and is known as tetrafluoroethane. Thanks for the input. Your average garage that works on a/c on the side probably would not have this. Yes it will work with either Refrigerant! R134a refrigerant fittings are different size. After the system has been tested out it should be checked for leaks. R134a. That's a lot isn't it? 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). difference between r12 and r134a expansion valve. I cleaned the evap as best I could, if that is what you are getting at. It can be used applications like walk-in coolers, food and dairy display cases, domestic refrigerators, and beverage dispensers and vending machines. evarporator, expansion valve plus flushing out the full system and replacing all the o rings. Also the new quick connect fittings for the high & low side. R-134a is widely believed to be the most acceptable R12 substitute. #4. The condensor airflow drops off as the fan clutch dies slowly. In no particular order, here's what I've found out regarding answering the questions posed so far:Fonebone - It is definitely an R4 compressor (they left the c off the front and the p off the end, i.e. 10,000BTU conduction heating? It is mixed with the freon for the most part, and does accumulate in all components in small amounts. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. And, unfortunately a small high side pressure gauge on a short hose. I used a full can of evap cleaner. As for R134a and R1234yf, theres no room for conversion. Nevertheless, if your application is configured only for R12, then you can use it or consider replacing the applications engine. _____ 2012 E350 2006 Callaway SC560 . R12 and R22 are both now banned by the EPA in the United States. 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. According to the thermodynamic characteristics, it is close to the R12 freon, however, it is 10-15% worse in terms of cooling capacity and is more fluid. 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). R134a and R12 are both refrigerants used in vehicle air conditioning systems. It won't be optimal, though. The crossover point is approximately at 64F. -------------------------"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." Looks like a couple of things happening here1) 80's vintage Eurocars were not "meat lockers". system of 0.33 TR and refrigerant used was R12. 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. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. As an example, let's say the R12 charge specification is listed at 2 lbs. Even though their common major function is to cool the system, they have many differences. I'm going to check the condensor is way clean too. -------------------------"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." Ensure you contact a professional mechanic to do the work for you so you dont end up incurring more costs for yourself. It is a haloalkane and hydrofluorocarbon (HFC) refrigerant that has thermodynamic properties, potential global warming for one hundred years, and insignificant ozone depletion. I mean, really a lot. It won't be optimal, though. 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 put in a new (not reman) compressor (R4 I believe it is) in my merc 240D, new drier, new expansion valve, new o-rings, nylog. R-134A has a slightly lower pressure at evaporator temperatures (30-40 degrees), but R-134a also has a much higher pressure at condenser temperatures (120-150 degrees). Components Coils, Heaters, Motors, etc. Use a strong surfactant like Simple Green or Zep Citrus, and soak the fins on the condensor. AFAIK, there is no clutch on the engine fan on the 240D. Is checking the temperature of the in and out of the condensor not the easiest way to tell if it is doing a good job or not? A. Pressure/temperature table for R12, R134a, and R513A is shown in Figure 1. . leading to corrosion of expansion valves, capillary tube plugging, and compressor bearing . We consider the the various types alternative refrigerants that are illegal or not approved to be in two sectors: non-flammables and flammables. They plug all the time. My turn to LOL - greasiesel! I would not do a 134a conversion without a PF condensor. The original CFC expansion valve used for R12 needs to be replaced with an HFC one for 134a to feed the evaporator correctly. I'm putting r12 back in my system, but all of the valves I can for the application (1990 jeep grand wagoneer) say r134a on them. Plus, not releasing the chemical into the air is morally justifiable. 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. 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 . 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. We sometimes use a relay switched from the compressor clutch to run fans. A Lot of the fins are bent, especially at the top. At this point it is time to make an appointment with the a/c shop. Is there a difference between a R134a expansion valve and an R12 TXV? Anyone know what happens when an R12 expansion valve is used in a system charged with R134A? Vent temperatures slowly go down to around 50F with hi speed driving. However, R134a is better than R12. They examined the two configurations of capillary tubes i.e. In cases such as this, the required capacity value of the expansion valve with R134a is reduced by 30% (correction factor 1.42). R134a is the most widely accepted alternative automotive refrigerant used to replace R12. I don't want to be chasing ghosts. This can be very very expensive. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. These two refrigerants are the older types and are not used in newer refrigeration and air conditioning systems. R134a systems operate at higher discharge-side pressures than R12, which can cause compressor seals to leak. Anyone know what happens when an R12 expansion valve is used in a system charged with R134A? Not going to mess up your 'do, but you can feel it. (On firewall where A/C lines go into cab.) -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. Gnats & mosquitos will clog deep. Consider using the newer valve, even with 134a stamped on the valve. Welcome to rxmechanic.com. The pressure at low temperatures is nearly the same between 12 and 134a. Also, they are mostly used in refrigeration and automotive air conditioning systems. 4.R404A R134a increased mass transfer resistance to reduce the transmission chamber heat coefficient, while R507 heat transfer coefficient is higher than R404A. The cure is to use the newer R134a compressors is sealing washers that are different thickness. I'll report back on the aux fan on performance next. Safety: R134a is safe to use as its non-flammable and cant explode. A. Pressure/temperature table for R12, R134a, and R513A is shown in Figure 1. . Recharge the compressor with a/c ester oil and a tracer dye. Then when it is switched off for a few minutes and then back on, the air cools again. But I don't want to waste your time. The approval is very legal one, governed by the U.S. EPA. Answer: OK, I'll bite. I have the original (R12) style expansion valve in the Maverick AC system. Are r12 and r134 fittings different? There is more to check.The evaporator must be clean as well as the condensor - was this a smoker's car?You should check the water control valve for the heater core. 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. Please enter a password for your user account. 4 Stars & Up & Up; 3 Stars & Up & Up; 2 Stars & Up . Any ideas from the info above? R-12 - yellow R-134a - light blue R-22 - green R-402A - light brown (sand) R-402B - olive R-404A - orange R-407C - medium brown R-410A - rose R-507 - teal J Originally Posted by goldNSX. You do not however need to replace all the o-rings or seals for a simple conversion, it is simply a logical thing to do when and if the time comes to work or replace certain components because of age issues. Jun 19, 2007. I've done the FSM test and with 81F ambient, the vent should be 50F. we convert older systems where i work all the time and they work fine. You may have heard of a friend that did the job himself with borrowed equipment and 12 or 16 ounce cans of refrigerant. 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.