Expansion valves are an active device, they regulate the flow of refrigerant to the evaporator depending on evaporator temperature. 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. By: james smith underoath; Comments: 0 . Have a look in the FAQ Section, and look for "Fan clutches & testing them". This refers to BTU's (heat) moved per pound of refrigerant moved. 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. -The amount of R-134a needed will typically be 80-90% of the R-12 charge. A lower GWP alternative to R-134a had to be found and thus we have the new 1234yf. Before R12 was replaced with R134a in 1995, it was mostly used in trucks and cars. We've updated our forums!Click here to visit the new forum, Year: 1991Make: Jaguar Model: XJ6Engine Size: 4.0. Before we mentioned that you can add approximately 5-6 ounces of ester oil to the compressor. This would become an expensive investment for a repair or service station to have unique dedicated equipment for every type of alternative refrigerant. -------------------------"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." a 50f delta across the condensor is good, but I suspect that is an idle reading. The pressure at low temperatures is nearly the same between 12 and 134a. 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. A. Pressure/temperature plot of R134a vs. R12 is shown in figure 1. Well, I'm not sure it is 'fine' - it doesn't cool very well in 95F weather. The primary function of the design engineer is to make things difficult for the fabricator and impossible for the serviceman. Kommentare . Then, subtract that result by 0.25 pounds to get the proper amount of R134a charge. A slow loss of cooling at city speeds is usually related to condensor capacity & airflow issues. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. Note that passwords are case-sensitive. But R22 is almost equally damaging. Are r12 and r134 fittings different? 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. Stopleak is also risky. Your average garage that works on a/c on the side probably would not have this. R12 and R22 are both now banned by the EPA in the United States. How about evacing 1 pound of refrig from the system, and then putting 1 lb of pure R12 back in? Miscibility with oil: R12 can be mixed with the compressor oil no matter the operating condition. Then at least I'd know really where I am on it. It is mixed with the freon for the most part, and does accumulate in all components in small amounts. R134a is the most widely accepted alternative automotive refrigerant used to replace R12. Vent temperatures slowly go down to around 50F with hi speed driving. R12 is highly destructive to the earths ozone layer. You do not want to exceed the systems high side recommendations. They plug all the time. 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. -------------------------"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." I'm not sure. I put one in my old daily driver '79 Chevy tank (r-12), and it really made a difference. El juny de 2017, el mateix grup va decidir crear un web deDoctor Who amb el mateix objectiu. The only difference I can imagine would be the recharge connection. The best oil that runs well with R134a is PAG oil or Polyalkylene Glycol. R134a is called tetrafluoroethane (HFC). 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. With the A/c off hi and lo were both at 105psi. 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. Any suggestions, or do you need to know the hi/lo readings? BTW, I use a stick thermo in the vents and the laser on the condenser. in /nfs/c05/h04/mnt/113983/domains/toragrafix.com/html/wp-content . R134a systems operate at higher discharge-side pressures than R12, which can cause compressor seals to leak. So to keep things simple and to avoid controversy and politics we have R134a. I could easily be over at least 2 - 3 ounces over on the oil. The common problem when converting from R12 to R134a is lack of knowledge or equipment. and recharged with mineral oil and 2.2 lbs R12. R 134A is designed for the high demands of an automobile AC and cannot be used on refrigerators due to pressure differences. leading to corrosion of expansion valves, capillary tube plugging, and compressor bearing . Please enter a password for your user account. It's actually a reaction with chlorine in the mineral oil that may have been absorbed and leftover from the old R-12. We recently created this blog site to enable us to share our knowledge with other automotive mechanics and car owners. Anyone know what happens when an R12 expansion valve is used in a system charged with R134A? Energy usage: R134a is less efficient in cooling compared to R12. 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. Edited: Sat July 14, 2007 at 10:22 PM by fonebone. Bookmarks: Digg; del . "Howdy, Folks!" Temp switch works the aux fan. I think the way to go here is1. This leads me to labor over every small decision. difference between r12 and r134a expansion valve. A/C Expansion Valve Replacement Cost. Is it exponential, squared? I'll put the relay on for that. Using R134a requires that Polyolester (POE) lubricant must be used in the compressor. One thing at a time here, and slowly, the knee is not up to jumping around like I used to at the moment. difference between r12 and r134a expansion valve. 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. This kit comes complete with Expansion valve, o-ring kit, and 1ft. Safe but sorry! However, R134a is better than R12. Even with proper fan operation, missing seals & air dams can effect condensor effeciency. To ensure the right charge, you must fill the new system with between 75 and 85% of the factory-set capacity for optimal cooling. bokoen1 hoi4 the great purge / meryl and maks dancing with the stars / difference between r12 and r134a expansion valve. 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. 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. 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. The R134a compressor has a 1/8" step in on the high side port. The evap is hard to get at. What effect would it have on performance, if any? R12 was once used in many air conditioning units as a refrigerant or cooling agent. Related products. Recovery & flushing is the only way out of an oil overcharge in your vehicle.B. 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. (You must log in or sign up to reply here. Rules governing changing from the former to the latter differ between countries. But R22 is almost equally damaging. and an evaporator core and expansion valve that are optimized for R134a . 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. A capacity curve is shown in figure 2 for relative capacity of R134a vs. R12 for evaporating temperatures from 0F to 50F. Thanks so much Bohica - you've save me many more hours of fruitless speculation. This is due to many facts: R134a refrigerant is about 10% less efficient in moving heat than R12! Thomas Jefferson, Thanks,OK, I'm starting to feel a little better about it. Only show this user. I recommend replacing the expansion valve when you do the swap. 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. 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. 3) A TXV optimized for 134a will be ok with R12. R-12 is no longer used or produced in many countries and remaining quantities have skyrocketed in price. 5) A/C System Failure. Agram a retevis rt22 password i bastrop county district clerk records el material que oferim als nostres webs. These cheap kits usually have a few cans of R134a (either 12 ounce or 16 ounce), maybe an extra can of refrigerant oil, a few generic R134a charge port adapters and maybe some o-rings. The general practice of charging the system with 15% less refrigerant adds to the thermal deficiency of 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. R12 systems used mineral oil, but unfortunately mineral oil doesn't dissolve in R134a. difference between r12 and r134a expansion valve. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. . Blows pretty hard on full. 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. This implies that the discharge pressure of the compressor should be moderate so it can produce the refrigerants condensation in the condenser at the atmospheric temperature. Though I have seen em run as cold as 12 deg F. If the thermo switch is malfunctioning. Disconnect the two hose lines to the compressor, protect the ends from getting dirty. If 50 degrees across the cond. It is a haloalkane and hydrofluorocarbon (HFC) refrigerant that has thermodynamic properties, potential global warming for one hundred years, and insignificant ozone depletion. The flammables have hydrocarbons. Jun 17, 2011. Comparatively, larger R134a molecules should take more space, and a smaller amount might be required. What is a good differential? An orifice tube is just a fixed nozzle that pisses refrigerant into the evaporator without any sort of feedback. VerticalScope Inc. All Rights Reserved. The major reason for the replacement of R12 with R134a was to curb future greenhouse effects. -------------------------"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." ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. 3) A/C Compressor Always On. A discussion of the relationship between valve capacities and superheat set-tings can be found in Bulletin 10-9. If ambient is 90 (today) and the output of the condensor is 110, that's pretty good isn't it? What is needed? With that said, I would source the TXV from another source such as NAPA just to avoid any problems. look at the difference! Concentration level: The R134a vapor dilutes the oxygen concentration in the air to a low level, thereby causing harm. 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. R134a requires a different oil. Any advice appreciated. 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. You may be just fine on oil - it depends on what compressor you have & how much oil you put in.A T/C is short for Thermocouple. The Main change in the system is the expansion valve. -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. If you have a perfectly operating system using R12 you do not have to drop what you are doing and convert to R134a. In a car ac, using this type of freon 20 years ago was difficult. In sum, R12 has done more bad than good. R12 is CFC: Even though R12 is one of the most commonly used refrigerants, it is CFC. ESP when a compressor has frozen. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. On this website we are addressing only R134a and not other suggested drop in replacements. Spray it deep, and let it sit for a few minutes. Depending on which circuit diagram fits your car (cough, no vin list exists) you have either one or two switches controlling the aux fan. A final difference is that most (though not all) R-1234yf cars will have a Suction Line Heat Exchanger. The problem with not being an expert is that you don't know what is important and what's not. The aux fan seems to be working fine - it switches on occassionally. The oil used in R12 systems is not compatible with R134a refrigerant. R134a vs R12 refrigerant? The adjusted tension of this spring is the determining factor in the opening and closing of the expansion valve. Swapping the components isnt a herculean task, but recharging the AC is a challenge. The bad thing is I don't know what to do about it. I cleaned the evap as best I could, if that is what you are getting at. This is 11F off the FSM performance graph - vent should be around 50F. All fans must work at 100% of the OEM rating. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. For instance you can evacuate FRIGC FR-12 into a refrigerant recovery bottle that has R134a in it or visa versa. You can use this space to go into a little more detail about your company. The difference between R12 and r134a is the BTU carrying capability. 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. Biggest you can fit in there is best. This is not to say that one of these small retro-fit kits cant be used, however to be used wisely. We chose to use 5-6 ounces of oil to be on the safe side: 3-4 ounces for the compressor, 1 oz of oil for the drier and another ounce of oil for system losses. However, if it is taken close to a fire flame or any electrical heating element, it disintegrates into toxic products. The crossover point is approximately at 64F. A York oil capacity is listed as "6.5 to 9.6 ounces". 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. 1) Look Here at the available sizes of PF condensors.2) Go look at your vehicle's condensor & mounting. The cost of recharging the air conditioner is between $150 to $500. At this point it is time to make an appointment with the a/c shop. However, take note that R134a refrigerants are manufactured specifically for automotive air conditioners. Since you will be using less R134a than R12 you do not want to rely on the driers site glass to determine if the system is full. And by matching the correct amount of R134a to use in a given vehicle, correcting the superheat of the expansion valve (if necessary), you can in some manner nearly balance or match the amount of heat drawn out by the evaporator and released by the condenser. It would make a big difference at idle ,in traffic!! Is that why expansion valves are specific to R12 or R134A? and he synthesized R-134a in 1936, 5 years after R-12 was . You will be fine with a 134a-compatible TXV running R12. Thus, when the system is running, condensing the CO2 is not a problem. The OEM spec is 2300 rpm @ 12.6v (engine stopped fully charged battery). 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 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. Later model cars that come with 134A will have 134A only connectors. The condenser water inlet temperature and flow rate are controlled with the use of a . ambulance tailgate conversion If it splashes inside the eye, it could lead to a serious eye problem. Whenever its exposed to the environment, it changes to a gas. In addition, R134a refrigerants are not only used in auto air conditioners, they can be used in freezers, aerosol cans, and refrigerators. evarporator, expansion valve plus flushing out the full system and replacing all the o rings. At 40, it is 35psi, which is a difference of 8.9psi. Minor adjustments to the expansion valve and other controls may be necessary for some plans. And I already have so much time and money in this a/c project that I REFUSE to cut any corners as small as a TEV.It doesn't help that most people in the business (at least that I come in contact with, present company excluded, of course!) You will be fine with a 134a-compatible TXV running R12. 5. The name of the oil is Polyol Ester (POE). (On firewall where A/C lines go into cab.) Paul:It is never a waste of my time to chat with someone that understands the problem, and wants to fix it. 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. When ever possible you should ask the technician to note the same information on your repair bill and keep a copy in your glove box for future reference. 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). R12 was once used in many air conditioning units as a refrigerant or cooling agent. Yes, the 50F diff (160-110F) on the condenser was at idle, and ambient was about 90F. So you could likely put off buying those new hoses just a bit longer if you wanted. In the automotive world, the replacement for R12 was R134a. 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. Lets take you through the advantages, disadvantages, and differences of these two refrigerants a detailed comparison including R12 vs R134a performance. In a comparison between R12 vs R134a vs R1234yf, R1234yf will pass as the best refrigerant. -------------------------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. The current expansion valve is FF - 1/4 - C. Is it neccesary to replace this valve? B. Its chemical symbol is CCl2F2. To bless the system the technician should attach a R134a sticker somewhere in the engine compartment to note the car is using R134a. You may have heard of a friend that did the job himself with borrowed equipment and 12 or 16 ounce cans of refrigerant. 10,000BTU conduction heating? Use a drop light in the engine bay, and check the air path from the front of the car at night. Make sure visiually that no large gaps exist that would allow the air to bypass the condensor on the way to the radiator.B. Is there a difference in the expansion valve for R12 as opposed to R-134a? The cure is to use the newer R134a compressors is sealing washers that are different thickness. R404a is a zeotropic blend with a temp glide , because of the mixture of 2 or more refrigerants. Safety: R134a is safe to use as its non-flammable and cant explode. 2) Frost on the Vents. The only material difference between automotive A/C and a window A/C unit or refrigerator is that in the home application, the components are all inside the same rectangular box, but in the automotive application, the components are distributed throughout the car. Is that reasonable?Vent airflow is good, I think. 2022 nba 2k22 starting a fashion label signing the designer, a difference between r12 and r134a expansion valve, 2020 white paper of the church of pentecost, Chime Mobile Check Deposit Funds Availability, Why Does James Kill Donald In The Vanishing, nba 2k22 starting a fashion label signing the designer. Therefore, its most suitable for both commercial and domestic environments. 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.
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