Operating Pressure/Temperature Differences The pressure/temperature curves for R-1234yf and R-134a are very similar. Questions About Becoming A Professional Member? R-12 to R-134a Conversion. Anyone know what happens when an R12 expansion valve is used in a system charged with R134A? June 21, 2022 difference between r12 and r134a expansion valve . Above this temperature, the saturation pressure of R134a is higher than that of R12; below, it is lower. With tube & fin condensors in MVAC applications there is never "too much" airflow. Just leave it alone for now. Heres some important advice Whenever you notice your R12 refrigerant is leaking, turn off all flames and open the doors so it can escape to the open atmosphere. Below are the major differences between R134a and R12: Chemistry The chemical composition of R12 and R134a differ. shown for the parallel flow, aluminum condenser that is listed. 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. difference between r12 and r134a expansion valve why is miles raney not on homestead rescue June 21, 2022. manila mayor candidates 2022 The compressors used by refrigeration plants to compress gas require oil to help lubricate its moving parts. R404a is a zeotropic blend with a temp glide , because of the mixture of 2 or more refrigerants. By using a qualified a/c shop with the proper equipment you odds are in your favor of having the job done correctly the first time. These two refrigerants are the older types and are not used in newer refrigeration and air conditioning systems. I recommend replacing the expansion valve when you do the swap. The system has been previously converted to R-134a. R134a vs R12 refrigerant? It is made up of carbon, hydrogen, and fluorine. I put in a new (not reman) compressor (R4 I believe it is) in my merc 240D, new drier, new expansion valve, new o-rings, nylog. There is only a temperature switch on these cars as far as I recall, and it just switches on the aux fan. Though you can purchase 12 or 16 ounce cans of R134a from local retailers it is very difficult to measure out the correct amount into your system. Is there more info needed?THanks -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a, Paul:I had to dig a bit deeper - MB made several running changes in the 1983 123'sThere are actually 4 different circuit diagrams for the A/C system that year - just for your 123.123 I found the R4 reference, and it should have 170 Ml of oil in the system.Your aux fan should run at the ambients you listed. R12 was once used in many air conditioning units as a refrigerant or cooling agent. 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. Is the information not applicable to the old Pantera system? If you have the work done, be sure you find a true "A/C" shop that can make up lines. Differences between R-12 and R-134a systems: 1. Make sure visiually that no large gaps exist that would allow the air to bypass the condensor on the way to the radiator.B. The aux fan seems to be working fine - it switches on occassionally. With R-12, 30 is 28.4psi and 40 is 36.9psi, for a difference of 8.5psi. Some compressor manufacturers or OEMs suggest PAG type oil for R134a. Even though their common major function is to cool the system, they have many differences. 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. Spray it deep, and let it sit for a few minutes. 1) Look Here at the available sizes of PF condensors.2) Go look at your vehicle's condensor & mounting. It may take a couple of tries to get things really clean.The laser is usually close on clean surfaces, but I prefer a T/C. Answer: OK, I'll bite. 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. R134a has an ozone depletion potential of 0, implying that it has a slight effect on the ozone layer. We consider the the various types alternative refrigerants that are illegal or not approved to be in two sectors: non-flammables and flammables. R12, on the other hand, is called chlorofluorocarbon (CFC). Some say that a chemical reaction can harm the A/C very badly as R134a reacts with mineral oil in some way. . R1234yf is more environmentally friendly and has a global warming potential of 4. So if you car has a large amount of rubber hose, such as a 40 feet with the 911, then you will be re-charging the system often and that is expensive no matter which refrigerant you use. Can I just use an adapter and save $200? 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. The oil used in R12 and R134a are different and not compatible. 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. Recomanem consultar les pgines web de Xarxa Catal per veure tota la nostra oferta. Also the new quick connect fittings for the high & low side. 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. Heres R12 vs. R134a pressure chart. . To ensure the right charge, you must fill the new system with between 75 and 85% of the factory-set capacity for optimal cooling. I have a laser temp reader, and it says the temps going into the condensor are up to 160F - coming out it is always around 110 or so. system of 0.33 TR and refrigerant used was R12. This works when the R12 charge specification is listed in pounds. Very nice! The difference between R12 and R134a TEV (exp valves) is primarily the 'superheat'. sparkee said: Thanks for the Service Bulletin. You do not want to exceed the systems high side recommendations. Boiling Point: R134a refrigerants boiling point is -26.3C (-15.34F). 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 . There are three different refrigerants officially sanctioned by the EPA for automotive usage: r-12, r-. Talk about what services you provide. The name of the oil is Polyol Ester (POE). The chemical composition of R12 and R134a differ. This leads me to labor over every small decision. R12 is CFC: Even though R12 is one of the most commonly used refrigerants, it is CFC. Helical and Serpentine coils. If you have 10 ounces of oil in the system, that is contributing to the poor performance as well. Besides, its technology has been tested and trusted. The higher the ambient temperature the higher the high side pressure. With the A/c off hi and lo were both at 105psi. Therefore, its most suitable for both commercial and domestic environments. Vent temperatures slowly go down to around 50F with hi speed driving. I dont know why the cost difference between compressors is so huge, though. Just because the radiator does not boil people assume that the cooling system is ok. But R22 is almost equally damaging. Gain access to our free AOP (Ask a Professional) Section to get real answers for your questions. What is a good differential? However, R134a is better than R12. A. Pressure/temperature table for R12, R134a, and R513A is shown in Figure 1. . The global warming potential of R134a is 1430. Also, R134a cylinders are light-blue in color. In practice this means that the car can overheat and the aux fan will stay off! For R12, its mineral oil. They examined the two configurations of capillary tubes i.e. That way I will have reduced the oil by about 1/3 (assuming the oil is mixed evenly through the system). 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 that said, I would source the TXV from another source such as NAPA just to avoid any problems. The current expansion valve is FF - 1/4 - C. Is it neccesary to replace this valve? 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. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. Thomas Jefferson, Thanks,OK, I'm starting to feel a little better about it. The ARPA Zone/Open Membership Discussion Forums. Then at least I'd know really where I am on it. Rich Membership Chairman Using R134a in an R12 system will cause the oil not to move with the refrigerant, causing a system failure and probably won't even cool the system well, if at all. Look deep into the fins. It is made up of carbon, hydrogen, and fluorine. The experimental values of C.O.P.H obtained with the R134a/ester charge were 20.2% asia pacific stevie awards 2021. gin, amaretto cocktail. I used a full can of evap cleaner. 3) A TXV optimized for 134a will be ok with R12. The money you will save by will pay for the R12. -------------------------"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 cycles on off in med (or low for that matter)Gotta tell ya. 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. Therefore, the R12 refrigerant is illegal, and emitting it is illegal. The symbol implies that R12 is a composite of carbon, chlorine, and fluorine. The R134a compressor has a 1/8" step in on the high side port. If the system was upgraded by a professional it should have an upgrade sticker. 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. Big . That is for the compressor, drier, expansion valve and condenser. -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. -------------------------"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." (You must log in or sign up to reply here. So you could likely put off buying those new hoses just a bit longer if you wanted. R12 is highly destructive to the earths ozone layer. Performance doesn't seem to have improved. If ambient is 90 (today) and the output of the condensor is 110, that's pretty good isn't it? On this website we are addressing only R134a and not other suggested drop in replacements. If the charge is low the compressor will cycle on/off in the max AC position. hardly noticable. Lets take you through the advantages, disadvantages, and differences of these two refrigerants a detailed comparison including R12 vs R134a performance. . 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. 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. If you you dont have the free time to play then you are better off to pay a technician. 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. It would make a big difference at idle ,in traffic!! Well, I'm not sure it is 'fine' - it doesn't cool very well in 95F weather. We ALWAYS want to know the pressure readings! You can use this space to go into a little more detail about your company. Paul -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. When you add fluorescent tracer dye to with the refrigerant oil it helps to track down leaks that push oil out of the system. "Howdy, Folks!" 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. Bookmarks: Digg; del . However, R12 refrigerants are still used as fire retardants in aircraft and submarines. 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? An extra half ounce? I have the original (R12) style expansion valve in the Maverick AC system. The AC usually does not work at all. And I lied about the compressor switches on this car - there are 2 switches on the drier - a temp and a pressure switch. might be due to charge or different compressor and age. is good, then I should be looking elsewhere? 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 . 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. With the knowledge of the differences, youll be able to draw a comparison between R12 vs R134a efficiency. It runs between the condenser outlet, receiver/drier unit and expansion valve at the firewall. The only difference I can imagine would be the recharge connection. It won't be optimal, though. A final difference is that most (though not all) R-1234yf cars will have a Suction Line Heat Exchanger. But as there's not a big difference, people say you can suffice with either. The problem with these so called drop in replacements is that to properly handle them you may need dedicated equipment to identify the gas and evacuate it for proper disposal. BTW, I use a stick thermo in the vents and the laser on the condenser. I'm doing one thing at a time so I know what the cause was. 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. Thanks so much Bohica - you've save me many more hours of fruitless speculation. But I don't want to waste your time. . difference between r12 and r134a expansion valvewarning signs for a deteriorating patient with covid 19 infection 2022.07.03 18:36 18:36 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. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. I have some experience with auto a/c but not too much. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. This is due to many facts: R134a refrigerant is about 10% less efficient in moving heat than R12! Could that be screwing up the systems performance?Anyway, when I installed the system, the new TXV (is that short for expansion valve?) Comparatively, larger R134a molecules should take more space, and a smaller amount might be required. This means that it has a high potential of causing depletion to the ozone layer. A lower GWP alternative to R-134a had to be found and thus we have the new 1234yf. Quick View. (On firewall where A/C lines go into cab.) Large temperature difference between expansion valve inlet and outlet oReplace expansion valve Air . Is that reasonable?Vent airflow is good, I think. Generally this works well for the whole system. GWP is a measurement of Greenhouse Gases and their effect on Global Warming. 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. The adjusted tension of this spring is the determining factor in the opening and closing of the expansion valve. Additionally, R134a was introduced as a replacement for R22 and R12 in high and medium-temperature refrigeration systems like domestic and commercial chillers. As an example, let's say the R12 charge specification is listed at 2 lbs. Looks like a couple of things happening here1) 80's vintage Eurocars were not "meat lockers". With the oil leaking out and being told all sorts of things about how these compressors don't have a sump etc, I wanted to be on the safe side. 5) A/C System Failure. 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. When the temperature is reduced to-7C or below, the plants ability to cool the airdrops significantly. Pray I can let some oil out of the compressor without losing my precious R12. This allows the refrigerant in the condenser to be void of oil particles. Inasmuch as R134a has a global warming potential thats over 1000 times more threatening than carbon dioxide, its better than R12. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. He used thermostatic expansion valve and Capillary tube for analysis with R12. 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. Use a drop light in the engine bay, and check the air path from the front of the car at night. . Not going to mess up your 'do, but you can feel it. 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. 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. Where would I get some basic info on it, I know nothing about it. 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. Its chemical symbol is CCl2F2. I'm thinking I might have put too much oil in the system - everywhere i read had a different amount - the manufacturer of the compressor, the MB factory service manual, online forums. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. Besides R134a there are some other refrigerants that are approved to replace R12 and there is a long list of refrigerants that are not approved. -------------------------"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." link to How to cut off a Catalytic Converter. 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. I've done the FSM test and with 81F ambient, the vent should be 50F. You either get a system that will function well with R1234yf or get any other type. R12 is heavier than R134a and has smaller molecules. The cable is adjustable at the valve arm. Rules governing changing from the former to the latter differ between countries. Different correction factors are applied to other refrigerants. Unfortunately, the oil only mixes with the refrigerant as a liquid. Also called the orifice tube. I'm not sure. With R134a you do not rely on the site glass. Also, it can be used with all types of compressors. For instance at 25 F the pressure of R-12 is 24.6 PSI and the pressure of R-134a is 22.1 PSI. R404a for freezing of product. In 1994 they switched from R-12 to R-134a. The difference really shows up on the high side. 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. But, what is considered a good temperature differential across the condensor? Its among the greenhouse gases and will keep adding the current problem of heat not leaving the earths atmosphere. 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. _____ 2012 E350 2006 Callaway SC560 . I've got a ball valve I'm going to put in the coolant line before the coolant goes through the firewall to the core. The oil is spread all over your system when it is at rest. A/C Expansion Valve Replacement Cost. ). In cases such as this, the required capacity value of the expansion valve with R134a is reduced by 30% (correction factor 1.42). In addition, R134a refrigerants are not only used in auto air conditioners, they can be used in freezers, aerosol cans, and refrigerators. In sum, R12 has done more bad than good. The cost of recharging the air conditioner is between $150 to $500. Add to cart. I had to vaccum the system for 2 hours and recharge 4 oz of PAG oil plus 36 oz of 134A freon (3 cans). And no, you cannot "drain' excess oil out. I remember I had the wrong seals and it leaked some oil, so I put some more in.Bohica - I tested the pressures. Flushed, vacuumed etc. 2) Frost on the Vents. This drop can affect energy consumption since the plant will operate for a longer period or a larger plant will have to be installed. A slow loss of cooling at city speeds is usually related to condensor capacity & airflow issues. Nevertheless, if your application is configured only for R12, then you can use it or consider replacing the applications engine. The mechanical fan & clutch should be checked as well. Further production of R12 was banned in some developed countries by the Montreal Protocol because of its harsh effect on the ozone layer. It is made up of carbon, hydrogen, and fluorine. However, theyre still used in older plants, systems, and the automotive industry. I'm just trying to help you avoid headaches in the long run. 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. Also, they are mostly used in refrigeration and automotive air conditioning systems. The newer valves and switches will work with both refrigerants. Is there a difference between a R134a expansion valve and an R12 TXV? The aux fan didn't switch on though and I didn't check the high side temperature. How is the vent airflow?I would jumper the aux fan & check the performance. 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. In large application systems, the vapor density of this refrigerant is usually high. The evap is hard to get at. The whole trick is to sit there in those steam boxes and not perspire, it's vulgar to perspire when driving on public roads.If you want esteem, drive an MB, if you want comfort with 60*F interiors in a 125*F environment, get a Caddy. difference between r12 and r134a expansion valve. If it splashes inside the eye, it could lead to a serious eye problem. Some 1993 and older R12 systems aren't as 'compatible' as you'd think to switch over. 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 best oil that runs well with R134a is PAG oil or Polyalkylene Glycol. The condensor airflow drops off as the fan clutch dies slowly. in /nfs/c05/h04/mnt/113983/domains/toragrafix.com/html/wp-content . How is 1234yf different from . About four or five years ago, I guy with an MB came here with the same problem, that tread was over six pages long.
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