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GWP is a measurement of Greenhouse Gases and their effect on Global Warming. The substitute that we used for R-12 was the new HFC called R-134a. Operating Pressure/Temperature Differences The pressure/temperature curves for R-1234yf and R-134a are very similar. R134a requires the use of synthetic oil! I had a 1991 BMW switched to 134a by just changing the low pressure charging valve, flushing and refilling with 134 (maybe with 10% . Flush with a garden hose - do not use a high pressure washer - you can bend the fins flat & damage the condensor.B. This means that it has a high potential of causing depletion to the ozone layer. Safe but sorry! Best for varieties of operating conditions: Its boiling point is -21.6 Celsius. I'm thinking of jumping the temp switch and leaving the fan on to see how it does. We mention using ester type refrigerant oil. You do not need to replace the expansion valve in most cases. George Bray on Wed August 31, 2005 5:03 PM I believe the optimum supercool setting will vary slightly between an expansion valve for an R12, as compared to R134a, system. Since the hose is the stock hose, you cannot tell what refrigerant is inside. They plug all the time. Ask Our Pros-Owner Assistance - NO DIY advice will be given. Trinary Pressure Switch $ 39.99. This leads me to labor over every small decision. Poc temps desprs van decidir unir els dos webs sota el nom de Xarxa Catal, el conjunt de pgines que oferirien de franc sries doblades i/o subtitulades en catal. BTW, I use a stick thermo in the vents and the laser on the condenser. What effect would it have on performance, if any? B. Trinary Pressure Switch quantity. For example, at an evap temp of 30 (your daughter's system is probably running around 25-28 saturated in order to give a 32 duct temp), the pressure of R-134a is 26.1psi. Therefore, its most suitable for both commercial and domestic environments. The general practice of charging the system with 15% less refrigerant adds to the thermal deficiency of R134a. 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. Paul:It is never a waste of my time to chat with someone that understands the problem, and wants to fix it. 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 . Welcome to rxmechanic.com. Most importantly, the oil used in the plant must always be compatible with the refrigerant used. R1234yf. Questions About Becoming A Professional Member? difference between r12 and r134a expansion valvewarning signs for a deteriorating patient with covid 19 infection 2022.07.03 18:36 18:36 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. And no, you cannot "drain' excess oil out. Rules governing changing from the former to the latter differ between countries. and recharged with mineral oil and 2.2 lbs R12. I'm thinking I might have put too much oil in the system - everywhere i read had a different amount - the manufacturer of the compressor, the MB factory service manual, online forums. R134a was selected as a replacement refrigerant for R12 because R12 contains chlorine and has a major effect to ozone layer depletion. Low refrigerating effect per pound: In comparison to other refrigerants, the refrigerating effect of R12 per pound is low. leading to corrosion of expansion valves, capillary tube plugging, and compressor bearing . At this point it is time to make an appointment with the a/c shop. Then again, there are two different expansion valves. A slow loss of cooling at city speeds is usually related to condensor capacity & airflow issues. Stopleak is also risky. Paul:A 1983 240D should have a York compressor on an OEM system. Debug the condensor (I am a computer nerd after all!)3. The compressors used by refrigeration plants to compress gas require oil to help lubricate its moving parts. R134a is called tetrafluoroethane (HFC). Compared with the cost-performance ratio, R507 is 30-40% . It can be used applications like walk-in coolers, food and dairy display cases, domestic refrigerators, and beverage dispensers and vending machines. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. The newer valves and switches will work with both refrigerants. a 50f delta across the condensor is good, but I suspect that is an idle reading. Generally you follow the refrigerant flow moving from connection to connection, component to component, and you sniff the a/c vents to check for evaporator leaks as well. This drop can affect energy consumption since the plant will operate for a longer period or a larger plant will have to be installed. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. With the A/c off hi and lo were both at 105psi. 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. Its chemical symbol is CCl2F2. Don't like the sound of custom parallel condensor. An extra half ounce? If you have 10 ounces of oil in the system, that is contributing to the poor performance as well. A. Pressure/temperature table for R12, R134a, and R513A is shown in Figure 1. . If the charge is low the compressor will cycle on/off in the max AC position. I recommend replacing the expansion valve when you do the swap. The typical scenario here is when the car owner buys an inexpensive retro-fit kit from the local auto parts store. Thanks so much Bohica - you've save me many more hours of fruitless speculation. Or is there always room for improvement, the more the merrier. With new R12 no longer being manufactured, the market price soared to $100/pound. Yep, definately not a meat locker. Recovery & flushing is the only way out of an oil overcharge in your vehicle.B. maintain the A/C of older cars. Rich Membership Chairman Using R134a in an R12 system will cause the oil not to move with the refrigerant, causing a system failure and probably won't even cool the system well, if at all. 10,000BTU conduction heating? At the moment, the ac is acting up - will work fine for about 15 minutes and then slowly the vent temperatures rise until the compressor switches off. In a car ac, using this type of freon 20 years ago was difficult. Generally, the new amount is 75-85% of the quantity advised by the manufacturer. Since then, the industry standard has been R134a, which is an efficient replacement. Could that be screwing up the systems performance?Anyway, when I installed the system, the new TXV (is that short for expansion valve?) Can I just use an adapter and save $200? The system has been previously converted to R-134a. So that indicates it is cooling well there doesn't it? I put one in my old daily driver '79 Chevy tank (r-12), and it really made a difference. This is the part that controls the system pressures. 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. 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. and an evaporator core and expansion valve that are optimized for R134a . There are R134a specific valves that operate at a slightly different pressure, but not for any "old" automotive application that I'm aware of. Quick View. A comparison between R12 vs. R134a temperature will show that R12 has a higher temperature than R134a. 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. You will be fine with a 134a-compatible TXV running R12. -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. R12 and R134 are of different chemistry. I have some experience with auto a/c but not too much. Rules governing changing from the former to the latter differ between countries. That is for the compressor, drier, expansion valve and condenser. Sense ells no existirem. But with an R4, better too much than too little.3) A TXV optimized for 134a will be ok with R12.4) The airflow across the condensor is crucial to good performance. What is usually sniffed are all the connections in the system: hoses and compressor, condenser, drier, expansion valve and evaporator fittings. . Flushed, vacuumed etc. Some 1993 and older R12 systems aren't as 'compatible' as you'd think to switch over. As for R134a and R1234yf, theres no room for conversion. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. So the steps involved are cleaning out the old oil, replacing all the O-rings, replacing the dryer, replacing the expansion valve, and converting the high and low side connectors from Schrader to quick connect valves. 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. R-12 is no longer used or produced in many countries and remaining quantities have skyrocketed in price. Differences between R-12 and R-134a systems: 1. ESP when a compressor has frozen. The analysis focuses on Coefficient of Performance for . It is also used in automotive car conditioning and the plastic industry. When I compare parts, 93 uses one part number and 94 has a different part number. Measure what you have now.3) Go back to the page in step one, and find the largest condensor you can put in your vehicle. Please enter the name by which you would like to log-in and be known on this site. R-134a is widely believed to be the most acceptable R12 substitute. A discussion of the relationship between valve capacities and superheat set-tings can be found in Bulletin 10-9. 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. We, the Rxmechanic team, have presented a well-detailed comparison of R134a vs. R12. 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. 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. The original rubber a/c hose lines in your car will leak out R12 through the hoses lining. The oil used in R12 and R134a are different and not compatible. 3 ounces? Existing technology: R134a has been in use in the refrigeration industry for very many years, and theres so much information about the safe use of the product. R12, on the other hand, has an ozone depletion potential of 1, implying that it can damage the ozone layer. The old compressor used R12 and the new unit will be R134a. Depending on which circuit diagram fits your car (cough, no vin list exists) you have either one or two switches controlling the aux fan. Given two identical vehicles, each with the same weighted amount of refrigerant, the vehicle with the R134a has the capability to remove more heat (measured in btus) from the vehicle than the same type of vehicle using the same amount of R12.