Boiling Point: R134a refrigerants boiling point is -26.3C (-15.34F). When I compare parts, 93 uses one part number and 94 has a different part number. 34 in 70 series w/ R12 in 100+ Tucson, AZ summer heat w/ hd-t, w/ 13B-T is was unbearable about 31 at vent w/ R12. Unfortunately, the R12 refrigerant doesnt always blow cold air. Inasmuch as R134a has a global warming potential thats over 1000 times more threatening than carbon dioxide, its better than R12. Heres R12 vs. R134a pressure chart. Its among the greenhouse gases and will keep adding the current problem of heat not leaving the earths atmosphere. All fans must work at 100% of the OEM rating. If it splashes inside the eye, it could lead to a serious eye problem. 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. This refers to BTU's (heat) moved per pound of refrigerant moved. Yep, definately not a meat locker. The symbol implies that R12 is a composite of carbon, chlorine, and fluorine. Bookmarks: Digg; del . R-12 vs R-134a Hose - Pelican Parts Forums Generally the system will be initially charged with approximately 80% to 85% of the original amount of R12, using R134a. I'm not sure. The R134a compressor has a 1/8" step in on the high side port. The flammables have hydrocarbons. With the knowledge of the differences, youll be able to draw a comparison between R12 vs R134a efficiency. Components Coils, Heaters, Motors, etc. The Main change in the system is the expansion valve. 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. R12 is highly destructive to the earths ozone layer. There is only a temperature switch on these cars as far as I recall, and it just switches on the aux fan. That is a good thing. Amazon.com: 134a Valve R134a has an ozone depletion potential of 0, implying that it has a slight effect on the ozone layer. This is 11F off the FSM performance graph - vent should be around 50F. difference between r12 and r134a expansion valve Compatible with multiple applications: The major reason for the introduction of R134a was to replace R12, so it functions perfectly in the same range of applications like rotary, screw, and centrifugal compressors for air conditioning and refrigeration. With R134a you do not rely on the site glass. The general practice of charging the system with 15% less refrigerant adds to the thermal deficiency of R134a. and feeds it through an expansion valve. Maybe a jerky locker.I cleaned the condensor with the off the shelf ac cleaner stuff from Home Depot that I used on my home evaporator. R12 or R134a - 928 Owners Club Forum Concentration level: The R134a vapor dilutes the oxygen concentration in the air to a low level, thereby causing harm. 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. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. The difference between R12 and R134a TEV (exp valves) is primarily the 'superheat'. Should I do the test again with the the aux fan jumpered? How dumb!I will jumper the aux fan and redo the test. Its chemical symbol is CH2FCF3. 37 in 2005 tacoma, R134A. You can also check the Aux fan in your case. Below are the major differences between R134a and R12: Chemistry The chemical composition of R12 and R134a differ. Compared with the cost-performance ratio, R507 is 30-40% . 30 deg is pretty coldSystems generally run between 40 and 43 deg. They examined the two configurations of capillary tubes i.e. You can use the R134a retrofit capacity chart for this purpose. Replacement expansion valve for R134a or R12 A/C refrigerants, with O-ring connections. Note that passwords are case-sensitive. With that said, I would source the TXV from another source such as NAPA just to avoid any problems. Hopefully after you have read this entire page you will have enough information to determine which type of refrigerant is best for you. Yes, the 50F diff (160-110F) on the condenser was at idle, and ambient was about 90F. Some 1993 and older R12 systems aren't as 'compatible' as you'd think to switch over. Stability: RR12 doesnt disintegrate even under extreme operating conditions. How an A/C Expansion Valve Works. With R-12, 30 is 28.4psi and 40 is 36.9psi, for a difference of 8.5psi. 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). R12 was once used in many air conditioning units as a refrigerant or cooling agent. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyers guides, and car and tools comparisons. Thread starter goldNSX; Start date 1 August 2009; Tagged . It is made up of carbon, hydrogen, and fluorine. (You must log in or sign up to reply here. Recovery & flushing is the only way out of an oil overcharge in your vehicle.B. VerticalScope Inc. All Rights Reserved. You do not want to exceed the systems high side recommendations. Nice to use new gadgets! The difference between R12 and r134a is the BTU carrying capability. Could that be screwing up the systems performance?Anyway, when I installed the system, the new TXV (is that short for expansion valve?) The approval is very legal one, governed by the U.S. EPA. If you have a perfectly operating system using R12 you do not have to drop what you are doing and convert to R134a. Also, would a genuine R12 TXV be better, or is it too marginal to worry about?I think I should do the FSM test for performance - they have a graph with ambient temp and a/c temp. Safe but sorry! 5. Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. In a car ac, using this type of freon 20 years ago was difficult. Also, it can be used with all types of compressors. -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. Big . By using a black light the dye will glow in areas where oil leaks are visible. I don't want to be chasing ghosts. An orifice tube is just a fixed nozzle that pisses refrigerant into the evaporator without any sort of feedback. I'm going to check the condensor is way clean too. That's a lot isn't it? An extra half ounce? The pressure/temperature curves for R-1234yf and R-134a are very similar. Even though their common major function is to cool the system, they have many differences. I think the way to go here is1. Use a drop light in the engine bay, and check the air path from the front of the car at night. 1) Warm Air From Vents. The difference really shows up on the high side. The OEM spec is 2300 rpm @ 12.6v (engine stopped fully charged battery). 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. Mark Baker R-401b is the mixture by weight of 61% R22, 11% R-152a and 28% of R-124. Gnats & mosquitos will clog deep. I know this is bad, etc, and deposits on the metal can act as insulators. Theres no problem with using R134a in a home air conditioning system because it is a hydrofluorocarbon that doesnt cause environmental harm. I don't believe it is but I had a service guy tell me it needs to be done. What effect would it have on performance, if any? Consider using the newer valve, even with 134a stamped on the valve. They plug all the time. Using R134a requires that Polyolester (POE) lubricant must be used in the compressor. I used a full can of evap cleaner. I don't have the FSM matrix handy for that 123.123, but a 123.133 shows a test rpm of 2,000 - and vent temps between 54f & 66f at 91f to 95f ambient. |. Bottom line, R134a simply doesn't cool as well as R12. Thanks again. Here are the basics for converting a system that does not have a charge of R12, its empty. MB has specfic test parameters for performance, but you can always test at max load - doors open fan on highest speed.The oil overcharge looks like a parabolic curve. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. 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 . Replace the drier with a drier that has a desiccant that is R134a compatible, use new R134a o-rings. However, R134a is better than R12. ). A. Pressure/temperature plot of R134a vs. R12 is shown in figure 1. It didn't seem too dirty though - I don't think it is the problem, but I could be wrong. 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? The catalytic converter is an essential component of your car's emission system that helps save the environment from harmful emissions. B. Talk about what services you provide. 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. How is the vent airflow?I would jumper the aux fan & check the performance. Differences between R-12 and R-134a systems: 1. 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. Any advice appreciated. Miscibility with oil: R12 can be mixed with the compressor oil no matter the operating condition. What was the ambient when you took that reading?Jumpering the aux fan is a common thing here in the desert. We say generally because the vehicle manufacturer may have a formula already worked out for the R134a conversion process. A thermostatic expansion valve (TXV) (see Figure 1) is a refrigeration and air conditioning throttling device that controls the amount of refrigerant liquid injected into a system's evaporatorbased on the evaporator outlet temperature and pressurecalled the superheat. R-134a XV for R-134a use. Any ideas from the info above? 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. ThanksPaul -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. On the other hand, R12 has a global warming potential of 10,910. There is a lot of differences between the R12 and the R134a fittings, you can't mistake them. The crossover point is approximately at 64F. Then again, there are two different expansion valves. -------------------------"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." Putting R12 into a R134 vehicle | AnandTech Forums: Technology Also, since R134a uses synthetic oil, it has a low global warming potential, unlike R12 which uses mineral oil which poses a negative environmental impact. 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. If your cars system has a sufficient condenser design and air flow to expel the greater amount of heat extracted by R134a, then by all means you should convert over when the time comes. Nevertheless, if your application is configured only for R12, then you can use it or consider replacing the applications engine. Effects of alternative refrigerants on the ejector dimensions for A/C Expansion Valve Replacement Cost. Air Conditioning Expansion Valve R134a - R12 replacement kit compressor, condenser, evaporator and expansion valve are specifically designed for use with R134a. Paul:A 1983 240D should have a York compressor on an OEM system. How about evacing 1 pound of refrig from the system, and then putting 1 lb of pure R12 back in? Just had knee surgery yesterday, so I"M not exactly hopping around too well. I remember I had the wrong seals and it leaked some oil, so I put some more in.Bohica - I tested the pressures. 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. R134a refrigerant fittings are different size. This may be the source of your oil confusion. 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. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. _____ 2012 E350 2006 Callaway SC560 . I have some experience with auto a/c but not too much. -------------------------"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." About four or five years ago, I guy with an MB came here with the same problem, that tread was over six pages long. Is there a difference between a R134a expansion valve and an R12 TXV? With tube & fin condensors in MVAC applications there is never "too much" airflow. Edited: Tue July 17, 2007 at 3:25 AM by bohica2xo, I believe there is only one switch - the refrigerant switch. . and he synthesized R-134a in 1936, 5 years after R-12 was . What is the refrigerant property involved that has caused this? There are significant differences between R12, R134a, and R513A, which must be considered when handling, processing, applying, or retrofitting with these refrigerants. I found that in the..Maxposition on the control it will have the compressor running all the time. However, if it is taken close to a fire flame or any electrical heating element, it disintegrates into toxic products. But as there's not a big difference, people say you can suffice with either. El maig de 2016, un grup damics van crear un lloc web deOne Piece amb lobjectiu doferir la srie doblada en catal de forma gratuta i crear una comunitat que inclogus informaci, notcies i ms. Sense ells no existirem. The larger fitting goes on the discharge port and the smaller fitting goes on the suction line or compressor inlet / suction port. R134a refrigerant is about 10% less efficient in moving heat than R12! 10,000BTU conduction heating? I'm just trying to help you avoid headaches in the long run. . 2001-2023 Griffiths Technical Inc. All Rights Reserved. This is the part that controls the system pressures. The general practice of charging the system with 15% less refrigerant adds to the thermal deficiency of R134a. You either get a system that will function well with R1234yf or get any other type. Low refrigerating effect per pound: In comparison to other refrigerants, the refrigerating effect of R12 per pound is low. Make sure visiually that no large gaps exist that would allow the air to bypass the condensor on the way to the radiator.B. In short, NO! R12, on the other hand, is called chlorofluorocarbon (CFC). R-134a can actually cool better than R-12 in a well designed R-134a system as it has better thermoconductive properties, but all the high pressure issues have to be addressed.But even when these cars were brand new, didn't cool worth a damned, recall almost dying in one in Las Vegas at the time, but a good way to lose weight with gallons of perspiration pouring out, just don't let that drip on the seats, that is inappropriate. 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. 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. 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 car never overheats, if that has any import. of coiled cap tube on VCR system with R134a. You can use this space to go into a little more detail about your company. difference between r12 and r134a expansion valve The exact amount will vary with each car. 3) A/C Compressor Always On. Best for varieties of operating conditions: Its boiling point is -21.6 Celsius. american sniper longest shot; how to adjust sunsetter awning arms; pastor jeremy roberts texas. . difference between r12 and r134a expansion valve The MB chart shows 360 psi with R12 in some conditions. 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. So, instead of using R12, other better options include R401b, R134a, R401a, etc.
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