R134a refrigerant is about 10% less efficient in moving heat than R12! However, it was found to be a very bad gas for the environment. Therefore, the R12 refrigerant is illegal, and emitting it is illegal. Therefore, the higher the factor of the chemical (compound), the greater its effect on global warming. . Bookmarks: Digg; del . 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. Most vehicles manufactured before 1993 have the R12 A/C system. Please enter the name by which you would like to log-in and be known on this site. The system has been previously converted to R-134a. Its cylinders are colored white. The R134a compressor has a 1/8" step in on the high side port. and feeds it through an expansion valve. R134a is otherwise called 1,1,1,2 Tetrafluoroethane, Florasol 134a, Freon 134a, Norflurane (INN) or HFC 134a. The exact amount will vary with each car. As per their results . Is there a difference between a R134a expansion valve and an R12 TXV? 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. Its chemical symbol is CH2FCF3. There is only a temperature switch on these cars as far as I recall, and it just switches on the aux fan. A good T/C, clamped to the line & insulated gives a repeatable measurement of the tube. But, if your car lacks enough condenser and you have many 100+ degree days then you may want to stick either increase air flow, add another condenser as we mentioned in The Mr. Ice Project or stick with R12. The analysis focuses on Coefficient of Performance for . The substitute that we used for R-12 was the new HFC called R-134a. 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. By: james smith underoath; Comments: 0 . Pray I can let some oil out of the compressor without losing my precious R12. The difference between R12 and r134a is the BTU carrying capability. I don't think it has any air dams or seals, I'll check to make sure. 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. Also, they are mostly used in refrigeration and automotive air conditioning systems. In a comparison between R12 vs R134a vs R1234yf, R1234yf will pass as the best refrigerant. I am ordering new parts, and planning to convert my system to R-134a. A discussion of the relationship between valve capacities and superheat set-tings can be found in Bulletin 10-9. You will be fine with a 134a-compatible TXV running R12. how to get to disney springs from boardwalk / bb dakota plaid jacket canada / difference between r12 and r134a expansion valve. GWP is a measurement of Greenhouse Gases and their effect on Global Warming. I put one in my old daily driver '79 Chevy tank (r-12), and it really made a difference. We ALWAYS want to know the pressure readings! I'm having the same concern. In large application systems, the vapor density of this refrigerant is usually high. Some say that a chemical reaction can harm the A/C very badly as R134a reacts with mineral oil in some way. System has been working fine for a year. Thanks for the input. Some 1993 and older R12 systems aren't as 'compatible' as you'd think to switch over. -The amount of R-134a needed will typically be 80-90% of the R-12 charge. At 40, it is 35psi, which is a difference of 8.9psi. I'm not sure. R1234yf is more environmentally friendly and has a global warming potential of 4. The difference really shows up on the high side. 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. and he synthesized R-134a in 1936, 5 years after R-12 was . Most importantly, the oil used in the plant must always be compatible with the refrigerant used. Talk about what services you provide. The aux fan didn't switch on though and I didn't check the high side temperature. That switch should close @ 52c. 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. That is for the compressor, drier, expansion valve and condenser. In most cases, the systems used have varied components, designs, and service ports. Your old hoses of course will not fit. 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. The common problem when converting from R12 to R134a is lack of knowledge or equipment. At this point it is time to make an appointment with the a/c shop. R134a was selected as a replacement refrigerant for R12 because R12 contains chlorine and has a major effect to ozone layer depletion. |. Put a relay on the compressor clutch to the aux fan (I like that idea - makes a lot of sense)How does that sound? Blows pretty hard on full. What is the refrigerant property involved that has caused this? Below are the major differences between R134a and R12: Chemistry The chemical composition of R12 and R134a differ. If there is no pusher fan, and you have the room, put one in. Interestingly, theres one oil type that works perfectly with both types of refrigerants. Don't like the sound of custom parallel condensor. Depending on which circuit diagram fits your car (cough, no vin list exists) you have either one or two switches controlling the aux fan. Have a look in the FAQ Section, and look for "Fan clutches & testing them". There are significant differences between R12, R134a, and R513A, which must be considered when handling, processing, applying, or retrofitting with these refrigerants. Is there a source of valves by, say, eaton number? 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). 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. R12, on the other hand, is called chlorofluorocarbon (CFC). Miscibility with oil: R12 can be mixed with the compressor oil no matter the operating condition. They might say for instance, add 3-4 oz of oil to the compressor, 1 oz of oil for when you replace a drier, 2 oz oil for the evaporator and so on. Reattach the hose lines using new R134a compatible o-rings, lightly lubricate with compressor oil. The flammables have hydrocarbons. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. This kit comes complete with Expansion valve, o-ring kit, and 1ft. With the A/c off hi and lo were both at 105psi. The first vehicle that used the R1234yf refrigerant was the 2013 Cadillac XTS. Bookmarks: Digg; del . A. Pressure/temperature plot of R134a vs. R12 is shown in figure 1. If you you dont have the free time to play then you are better off to pay a technician. Swapping the components isnt a herculean task, but recharging the AC is a challenge. RULES for AOP - Owner Assistance and Contractors, Energy Efficiency and Building Performance Discussion NEW, Carnak Zone/Locked Areas - For Professional Member Only, How To Become a Pro and Rules For Pro Members, Pro Forum: Refrigerants and EPA regulations **NEW, Pro Forum: Residential Refrigeration and Appliances **NEW, Pro Forum: Equipment Recalls and Bulletins **NEW, Pro's Forum: Building Science Discussions, Educational Forums - Open for all in the industry, Welcome to HVAC-Talk's Educational Forums, How to Submit Links, Articles and Quiz Questions, Frequently Asked Questions About Submissions, Physics, Thermodynamics, Fluid Flow and Combustion, Educational, Training & Reference Information, Manufacturer's Technical Information Links, Electrical Theory, Circuits and Electronics, HVACR Equipment, Components & Accessories, Accessories Humidifiers, Air Cleaners, HRUs, Fans, Filters, etc. had writing on the side that said R134a. In short, NO! As noted, measure up front as best as you can to get as close to the aftermarket dim. The global warming potential of R134a is 1430. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. Flushed, vacuumed etc. A capacity curve is shown in figure 2 for relative capacity of R134a vs. R12 for evaporating temperatures from 0F to 50F. 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. This allows the refrigerant in the condenser to be void of oil particles. However, the supply houses don't indicate a difference. Next I'll jumper the aux fan. Hence, let us continue to fix it. 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. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. About four or five years ago, I guy with an MB came here with the same problem, that tread was over six pages long. 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. Then, subtract that result by 0.25 pounds to get the proper amount of R134a charge. A comparison between R12 vs. R134a temperature will show that R12 has a higher temperature than R134a. 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). These two refrigerants are the older types and are not used in newer refrigeration and air conditioning systems. Why wait for 200f on the engine coolant to start the fan? If the system was upgraded by a professional it should have an upgrade sticker. The cure is to use the newer R134a compressors is sealing washers that are different thickness. This would be a custom install, there is no "drop-in" condensor upgrade for that car.Check for proper fan operation, and clean the air path on both the condensor & radiator. Replace the drier with a drier that has a desiccant that is R134a compatible, use new R134a o-rings. Compared with the cost-performance ratio, R507 is 30-40% . Bad Car A/C Expansion Valve Symptoms. There are other refrigerants: some of which may work, some of which dont work, some of which will destroy your a/c system and some of which are dangerous. Recovery & flushing is the only way out of an oil overcharge in your vehicle.B. Some compressor manufacturers or OEMs suggest PAG type oil for R134a. 3 ounces? The system has been previously converted to R-134a. 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. 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? 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. 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 . When you add fluorescent tracer dye to with the refrigerant oil it helps to track down leaks that push oil out of the system. R12 is used in several applications like low temperature, medium temperature, and high-temperature applications. 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. Then again, there are two different expansion valves. Can I just use an adapter and save $200? 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 . 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. Replied by Rich928 on topic R12 or R134a. 5. We consider the the various types alternative refrigerants that are illegal or not approved to be in two sectors: non-flammables and flammables. 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. The compressors used by refrigeration plants to compress gas require oil to help lubricate its moving parts. It slowly gets warmer and warmer in the car, even at highway speeds. Also, if you want to know what happens if you put R134a in an R12 system, you should first confirm if the R12 system can be replaced or if the refrigerants can be mixed. 4.R404A R134a increased mass transfer resistance to reduce the transmission chamber heat coefficient, while R507 heat transfer coefficient is higher than R404A. It's best to determine on a case-by-case basis while monitoring system pressures and output air temperature. The only difference I can imagine would be the recharge connection. I don't know where it is getting the switch off command, or why the vent temp drops steadily. Can I use the one for the R-12? With that said, I would source the TXV from another source such as NAPA just to avoid any problems. Jun 17, 2011. a 50f delta across the condensor is good, but I suspect that is an idle reading. That is a good thing. This works when the R12 charge specification is listed in pounds. R134a requires a different oil. A/C Expansion Valve Replacement Cost. This is due to many facts: R134a refrigerant is about 10% less efficient in moving heat than R12! Production of R12 ceased in 1996, although it can still be reclaimed, purified, and resold, and small cans of New Old Stock R12 are still widely available on eBay and Craigslist. They examined the two configurations of capillary tubes i.e. Expansion valves are an active device, they regulate the flow of refrigerant to the evaporator depending on evaporator temperature. 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. I'll put the relay on for that. Whether R134a performs as well as R12 in any given a/c system depends upon system components and the amount of R134a used. . 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. 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. Replacement expansion valve for R134a or R12 A/C refrigerants, with O-ring connections. In cases such as this, the required capacity value of the expansion valve with R134a is reduced by 30% (correction factor 1.42). Thomas Jefferson, Thanks,OK, I'm starting to feel a little better about it. Neuro spine Super Speciality Clinic - Above Apollo Pharmacy, Bangarpet Circle, Kolar - Bangarpet Road, Kolar Town. -------------------------"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." 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. How is the vent airflow?I would jumper the aux fan & check the performance. The money you will save by will pay for the R12. 2) Frost on the Vents. I think the way to go here is1. But as there's not a big difference, people say you can suffice with either. Boiling Point: R134a refrigerants boiling point is -26.3C (-15.34F). 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. The pressure/temperature curves for R-1234yf and R-134a are very similar. The difference between the two is about 10,000 btu/h. 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. VerticalScope Inc. All Rights Reserved. Its chemical symbol is CH2FCF3. 2001-2023 Griffiths Technical Inc. All Rights Reserved. After the system has been tested out it should be checked for leaks. Catalog E-1, Thermostatic & Automatic Expansion Valves / Page 1 Table of Contents . 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. R1234yf. Use a drop light in the engine bay, and check the air path from the front of the car at night. 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. 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. Helical and Serpentine coils. I bought a relay to put on it connected to the compressor clutch. 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. Superheat you can consider to be the additional amount of heat. The oil used in R12 systems is not compatible with R134a refrigerant. _____ 2012 E350 2006 Callaway SC560 . R134a is called tetrafluoroethane (HFC). If it splashes inside the eye, it could lead to a serious eye problem. A. Pressure/temperature table for R12, R134a, and R513A is shown in Figure 1. . The major reason for the replacement of R12 with R134a was to curb future greenhouse effects. 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. So I probably put the highest suggested amount in to be safe. If your a/c system is empty/low on refrigerant, if your system has a leak or if you need to open the system, then now is the time to decide which refrigerant you want to use. 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. Can I order a valve based on the original eaton number? 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. And no, you cannot "drain' excess oil out. To prevent refrigerant loss you should consider replacing your old hose lines with barrier type hose. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. In addition, R134a refrigerants are not only used in auto air conditioners, they can be used in freezers, aerosol cans, and refrigerators. 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. Could that be screwing up the systems performance?Anyway, when I installed the system, the new TXV (is that short for expansion valve?) The only mechanical differences between an R12 system and an R134a system are that R134a systems typically have larger condensers and more powerful compressors. Do I leave the orignal condensor in, etc?Thanks. The MB chart shows 360 psi with R12 in some conditions. Paul -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. This means that it has a high potential of causing depletion to the ozone layer. Yes it will work with either Refrigerant! In sum, R12 has done more bad than good. In the automotive world, the replacement for R12 was R134a. As an example, let's say the R12 charge specification is listed at 2 lbs. Then at least I'd know really where I am on it. Thread starter goldNSX; Start date 1 August 2009; Tagged . 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. It is possible I have 10 ounces (250 ml) in the system. Bottom line, R134a simply doesn't cool as well as R12. CR4P). The best replacement for R134a is R1234yf, while R12 refrigerant replacement was R134a. After the initial charge the system is then tweeked : you determine the optimum amount of refrigerant to match your system by monitoring the a/c outlet vent temperature and the high side pressure as you add or remove refrigerant. Energy usage: R134a is less efficient in cooling compared to R12. 3) A/C Compressor Always On. "Howdy, Folks!" 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. In practice this means that the car can overheat and the aux fan will stay off! It is a haloalkane and hydrofluorocarbon (HFC) refrigerant that has thermodynamic properties, potential global warming for one hundred years, and insignificant ozone depletion. 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. You will be fine with a 134a-compatible TXV running R12. Make sure to wear safety gloves, goggles, and shoes when theres a possibility of exposure to the chemical (R134a). 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. (The .133 is the 300D Turbo).So, what does your compressor look like?B. 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!) There is NO reason to retrofit a vehicle to R-134a as long as the R-12 system is cooling properly and contains a normal charge of refrigerant.
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