Yep, definately not a meat locker. We ALWAYS want to know the pressure readings! Just leave it alone for now. Add to cart. That way I will have reduced the oil by about 1/3 (assuming the oil is mixed evenly through the system). To prevent refrigerant loss you should consider replacing your old hose lines with barrier type hose. Nice to use new gadgets! . Most importantly, the oil used in the plant must always be compatible with the refrigerant used. Yes, the 50F diff (160-110F) on the condenser was at idle, and ambient was about 90F. . The difference between R12 and r134a is the BTU carrying capability. 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). Participate in over 40 different forums and search/browse from nearly 3 million posts. Since there is only about a 10% difference between R-12 and R-134a, the expansion valve being self-compensating really doesn't make that much difference. This is a great space to write long text about your company and your services. 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). The crossover point is approximately at 64F. Then again, there are two different expansion valves. Generally, the new amount is 75-85% of the quantity advised by the manufacturer. It's best to determine on a case-by-case basis while monitoring system pressures and output air temperature. Whether R134a performs as well as R12 in any given a/c system depends upon system components and the amount of R134a used. As an example, let's say the R12 charge specification is listed at 2 lbs. Ask Our Pros-Owner Assistance - NO DIY advice will be given. At least you do not have 16 ounces in there ( yup seen it before).For now, straighten all of the fins that you can, clean the condensor well, and re-test with the aux fan running. Not osmosis, but you know what I mean). R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. The most common influences which effect the capability of R134a to perform well are the condenser, in some cases the the superheat setting of the expansion valve or the amount of R134a. 4.R404A R134a increased mass transfer resistance to reduce the transmission chamber heat coefficient, while R507 heat transfer coefficient is higher than R404A. We recently created this blog site to enable us to share our knowledge with other automotive mechanics and car owners. An orifice tube is just a fixed nozzle that pisses refrigerant into the evaporator without any sort of feedback. Not going to mess up your 'do, but you can feel it. R404a is a zeotropic blend with a temp glide , because of the mixture of 2 or more refrigerants. The #1 question asked by NEW MEMBERS. Even if the system leaks, repairing the leaks and recharging it with R-12 is usually the best repair alternative. 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 . It's not just the poor performance - the cooling just stops working after a while. Blows pretty hard on full. It's actually a reaction with chlorine in the mineral oil that may have been absorbed and leftover from the old R-12. In large application systems, the vapor density of this refrigerant is usually high. shown for the parallel flow, aluminum condenser that is listed. I've done the FSM test and with 81F ambient, the vent should be 50F. I had a 1991 BMW switched to 134a by just changing the low pressure charging valve, flushing and refilling with 134 (maybe with 10% . 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. If the system was upgraded by a professional it should have an upgrade sticker. Post photos, respond to polls and access other special features. The mechanical fan & clutch should be checked as well. Then again, there are two different expansion valves. This can be very very expensive. 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. Bottom line, R134a simply doesn't cool as well as R12. Flushed, vacuumed etc. R12 was once used in many air conditioning units as a refrigerant or cooling agent. ESP when a compressor has frozen. #4. R 134A is designed for the high demands of an automobile AC and cannot be used on refrigerators due to pressure differences. A Lot of the fins are bent, especially at the top. Comparatively, larger R134a molecules should take more space, and a smaller amount might be required. 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. 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. 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. However, the supply houses don't indicate a difference. Rules governing changing from the former to the latter differ between countries. 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. The symbol implies that R12 is a composite of carbon, chlorine, and fluorine. Can I just use an adapter and save $200? The original CFC expansion valve used for R12 needs to be replaced with an HFC one for 134a to feed the evaporator correctly. This works when the R12 charge specification is listed in pounds. Performance doesn't seem to have improved. I'm just trying to help you avoid headaches in the long run. It is made up of carbon, hydrogen, and fluorine. A York oil capacity is listed as "6.5 to 9.6 ounces". 4) Repeat step 2, making sure it will fit. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. GWP is a measurement of Greenhouse Gases and their effect on Global Warming. A capacity curve is shown in figure 2 for relative capacity of R134a vs. R12 for evaporating temperatures from 0F to 50F. 3) A TXV optimized for 134a will be ok with R12. system of 0.33 TR and refrigerant used was R12. 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. It won't be optimal, though. This is not to say that one of these small retro-fit kits cant be used, however to be used wisely. 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. At this point it is time to make an appointment with the a/c shop. Like say half a can or so recharge come springtime warm weather or something. What is usually sniffed are all the connections in the system: hoses and compressor, condenser, drier, expansion valve and evaporator fittings. 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. Until 1995, most cars with air conditioning used R-12 Freon refrigerant which has shown to have an environmental impact. Energy usage: R134a is less efficient in cooling compared to R12. R-134a XV for R-134a use. Does it matter - assuming both are new & uncontaminated? Using R134a requires that Polyolester (POE) lubricant must be used in the compressor. 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. You can use this space to go into a little more detail about your company. I'll put the relay on for that. Fitting a PF condensor is not rocket science, but it requires some planning. Stability: RR12 doesnt disintegrate even under extreme operating conditions. Before R12 was replaced with R134a in 1995, it was mostly used in trucks and cars. Below are the major differences between R134a and R12: The chemical composition of R12 and R134a differ. Biggest you can fit in there is best. Please enter a valid email address for yourself. 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. Skin contact: If the R134a (liquid) comes in contact with your skin, it could cause a burn. Instead, top off R12 with R134a refrigerant. How dumb!I will jumper the aux fan and redo the test. Figure 2 shows the different phases and pressures the refrigerant . is good, then I should be looking elsewhere? How an A/C Expansion Valve Works. Also, R134a cylinders are light-blue in color. 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. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. a 50f delta across the condensor is good, but I suspect that is an idle reading. Is that why expansion valves are specific to R12 or R134A? One of the differences between auto air conditioners that have been redesigned from R12 to R134a is that the condensers have gone from serpentine to pseudo-parallel. ThanksPaul -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. Spray it deep, and let it sit for a few minutes. To ensure the right charge, you must fill the new system with between 75 and 85% of the factory-set capacity for optimal cooling. In more serious, it could result in cardiac irregularities or death. Its chemical symbol is CH2FCF3. Further production of R12 was banned in some developed countries by the Montreal Protocol because of its harsh effect on the ozone layer. About four or five years ago, I guy with an MB came here with the same problem, that tread was over six pages long. With R134a you do not rely on the site glass. We've updated our forums!Click here to visit the new forum, Year: 1983Make: MercedesModel: 240DEngine Size: 2.4Refrigerant Type: R12Ambient Temp: 90Pressure Low: 35Pressure High: ?Country of Origin: United States, Hi, this is my first post, so please take it easy on the noob. 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. Its cylinders are colored white. I don't want to be chasing ghosts. 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. -------------------------"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." Bohica, I appreciate your help with this. Is there a graph? R134a is called tetrafluoroethane (HFC). A/C receiver difference between R12 and R134a? A. Pressure/temperature plot of R134a vs. R12 is shown in figure 1. 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. Quick View. 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. Should I do the test again with the the aux fan jumpered? 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? 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. The higher the ambient temperature the higher the high side pressure. Disconnect the two hose lines to the compressor, protect the ends from getting dirty. VerticalScope Inc. All Rights Reserved. Its chemical symbol is CH2FCF3. Replacement expansion valve for R134a or R12 A/C refrigerants, with O-ring connections. Usually, mechanics charge around $200 for conversion. Its chemical symbol is CCl2F2. absorb by the evaporator to insure all liquid refrigerant entering the evaporator. 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. If the water valve is not closing all the way you will have re-heating of the cabin air.The cabin blower was not exactly a powerhouse - it was rated at 200w. When you add fluorescent tracer dye to with the refrigerant oil it helps to track down leaks that push oil out of the system. You will be fine with a 134a-compatible TXV running R12. The experimental values of C.O.P.H obtained with the R134a/ester charge were 20.2% 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. This would become an expensive investment for a repair or service station to have unique dedicated equipment for every type of alternative refrigerant. When the temperature is reduced to-7C or below, the plants ability to cool the airdrops significantly. Ensure you contact a professional mechanic to do the work for you so you dont end up incurring more costs for yourself. |. 2001-2023 Griffiths Technical Inc. All Rights Reserved. compressor, condenser, evaporator and expansion valve are specifically designed for use with R134a. There are three different refrigerants officially sanctioned by the EPA for automotive usage: r-12, r-. I would not do a 134a conversion without a PF condensor. 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. 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. It is made up of carbon, hydrogen, and fluorine. Thomas Jefferson, Thanks,OK, I'm starting to feel a little better about it. (The .133 is the 300D Turbo).So, what does your compressor look like?B. . Is it exponential, squared? Moreso, it had been banned. He used thermostatic expansion valve and Capillary tube for analysis with R12. If there is no pusher fan, and you have the room, put one in. The only mechanical differences between an R12 system and an R134a system are that R134a systems typically have larger condensers and more powerful compressors. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. The first vehicle that used the R1234yf refrigerant was the 2013 Cadillac XTS. Agram a retevis rt22 password i bastrop county district clerk records el material que oferim als nostres webs. Boiling Point: R134a refrigerants boiling point is -26.3C (-15.34F). The typical scenario here is when the car owner buys an inexpensive retro-fit kit from the local auto parts store. This refers to BTU's (heat) moved per pound of refrigerant moved. 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. I don't believe it is but I had a service guy tell me it needs to be done. Are r12 and r134 fittings different? A comparison between R12 vs. R134a temperature will show that R12 has a higher temperature than R134a. Have a look in the FAQ Section, and look for "Fan clutches & testing them". That is for the compressor, drier, expansion valve and condenser. Expansion Valves Catalog E-1, July 2012. The difference between the two is about 10,000 btu/h. Next I'll jumper the aux fan. Be sure to test @ 1500 to 2000 engine rpm, and record the ambient temp as well. leading to corrosion of expansion valves, capillary tube plugging, and compressor bearing . 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. Pound for pound R134a is a more efficient refrigerant than R12, however it runs at higher pressures in some aspects and therefore requires more effective condensing. 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. 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. R134a requires the use of synthetic oil! "Howdy, Folks!" Hope this helps. Operating Pressure/Temperature Differences The pressure/temperature curves for R-1234yf and R-134a are very similar. It will work and there will be very little, in any difference in performance.As Chick stated, the difference is only the gas used in the sensor tube. I dont know why the cost difference between compressors is so huge, though. I just got some hi/lo side gauges so I'm going to take readings, if they are needed. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. Edited: Sat July 14, 2007 at 10:22 PM by fonebone. Note that passwords are case-sensitive. asia pacific stevie awards 2021. gin, amaretto cocktail. So, instead of using R12, other better options include R401b, R134a, R401a, etc. 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. The newer valves and switches will work with both refrigerants. We sometimes use a relay switched from the compressor clutch to run fans. Even with proper fan operation, missing seals & air dams can effect condensor effeciency. As noted, measure up front as best as you can to get as close to the aftermarket dim. R1234yf is more environmentally friendly and has a global warming potential of 4. Unfortunately, the oil only mixes with the refrigerant as a liquid. hardly noticable. R134a vs R12 refrigerant? The primary function of the design engineer is to make things difficult for the fabricator and impossible for the serviceman. Remove the old mineral oil from the compressor by turning it upside down, side to side, and turn the front hub on the clutch assembly. $21 . If not, you just don't know unless a test is performed. If the system was upgraded by a professional it should have an upgrade sticker. In this study, without the need for major modifications to the bus air conditioner, the variation of the ejector dimensions according to different parameters has been investigated in the case of using the R1234yf, R1234ze(E), or R600a refrigerants, which may be a substitute for R134a as a refrigerant due to . R134a refrigerant fittings are different size. There is only a temperature switch on these cars as far as I recall, and it just switches on the aux fan. Don't like the sound of custom parallel condensor. R12, on the other hand, has an ozone depletion potential of 1, implying that it can damage the ozone layer. Also, it can be used with all types of compressors. Attach the R134a charge port adaptors, there are two types.. one of which you need to remove the old R12 valve cores. It is mixed with the freon for the most part, and does accumulate in all components in small amounts. If you find any of these conditions you will want to liquid flush (with dedicated AC flush solution) all the lines, condensers, evaporator (remove the expansion valve) before you proceed further. These efforts to balance the system can not be realized if there are problems within the a/c system, such as: poor performing compressor, dirty condenser or poor air flow through the condenser, malfunctioning expansion valve, water or air in the system, improperly operating fresh air or heat input in the climate-air mixing system. Rxmechanic.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for website owners to earn advertising fees by advertising and linking to Amazon.com. Thus, when the system is running, condensing the CO2 is not a problem. video clubhouse baseball; nick fairley draft profile; ben davis work pants I am ordering new parts, and planning to convert my system to R-134a. I could easily be over at least 2 - 3 ounces over on the oil. Bookmarks: Digg; del . Hence, the effect of R12 on global warming is up to 10,000 times higher than carbon dioxide. 3) A/C Compressor Always On. link to How to cut off a Catalytic Converter. Make sure to wear safety gloves, goggles, and shoes when theres a possibility of exposure to the chemical (R134a). R-12 to R-134a Conversion. 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). _____ 2012 E350 2006 Callaway SC560 . -------------------------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. In short, NO! The R134a compressor has a 1/8" step in on the high side port. The system will be checked for gross leaks while under vacuum. 1.5 ounces - hmmm. 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. Consider using the newer valve, even with 134a stamped on the valve. Rules governing changing from the former to the latter differ between countries. If you have a perfectly operating system using R12 you do not have to drop what you are doing and convert to R134a. The oil used in R12 and R134a are different and not compatible. Also the new quick connect fittings for the high & low side. They have no moving parts. 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. By using a black light the dye will glow in areas where oil leaks are visible. 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. Use strips of foam to couple the two heat exchangers if necessary.B. Yes, this was a smokers car. R134a has the chemical formula CF3CH2F and is known as tetrafluoroethane. The name of the oil is Polyol Ester (POE). What is a good differential? A capacity curve is shown in figure 2 for relative capacity of R134a vs. R12 for evaporating temperatures from 0F to 50F. Its duty is to convert toxic gasses produced by the engine into A brake cleaner is a powerful solvent for cleaning dirt from the brakes and other car components. It didn't seem too dirty though - I don't think it is the problem, but I could be wrong. Make sure to get the R12 EXP valve if that is the way you go. But R22 is almost equally damaging. Some cars have both an engine coolant temp switch & a refrigerant temp switch, others only the refrigerant switch. Jun 17, 2011. Most of all the differences gravitate to longevity, functionality, and safety. The smoking question & vent airflow indicate that the evaporator is fairly clean - and you are aware of the importance of that.The heater valve stops the flow, but there is always some conduction heating. #19. Generally this works well for the whole system. Just had knee surgery yesterday, so I"M not exactly hopping around too well. R12 and R22 are both now banned by the EPA in the United States. Interestingly, theres one oil type that works perfectly with both types of refrigerants. difference between r12 and r134a expansion valve why is miles raney not on homestead rescue June 21, 2022. manila mayor candidates 2022 When the ambient air temps get above 80F the gauge readings can run a bit higher on the high side and lower on the low side when using R134a. -The amount of R-134a needed will typically be 80-90% of the R-12 charge. 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. R134a is called tetrafluoroethane (HFC). Plus, not releasing the chemical into the air is morally justifiable. Talk about what services you provide. 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. -------------------------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. For example, if your system originally had 36 ounces of R12 then you multiply that by .80 and you have 29 ounce of R134a. R12 systems used mineral oil, but unfortunately mineral oil doesn't dissolve in R134a. 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. 5. If the charge is low the compressor will cycle on/off in the max AC position. Environmental Impact: When R134a escapes into the atmosphere, it contributes to global warming. difference between r12 and r134a expansion valve. They plug all the time. 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. Gain access to our free AOP (Ask a Professional) Section to get real answers for your questions. You do not need to replace the expansion valve in most cases. I put one in my old daily driver '79 Chevy tank (r-12), and it really made a difference. The best oil that runs well with R134a is PAG oil or Polyalkylene Glycol. It is a haloalkane and hydrofluorocarbon (HFC) refrigerant that has thermodynamic properties, potential global warming for one hundred years, and insignificant ozone depletion. 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. Hopefully after you have read this entire page you will have enough information to determine which type of refrigerant is best for you. R134a is NOT less efficient than R12 Actually R134a is more efficient. and an evaporator core and expansion valve that are optimized for R134a . The oil is spread all over your system when it is at rest. The condenser water inlet temperature and flow rate are controlled with the use of a . and he synthesized R-134a in 1936, 5 years after R-12 was . R-401b is the mixture by weight of 61% R22, 11% R-152a and 28% of R-124. Recharge the compressor with a/c ester oil and a tracer dye. In sum, R12 has done more bad than good. 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.

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