Low refrigerating effect per pound: In comparison to other refrigerants, the refrigerating effect of R12 per pound is low. The ozone depletion potential of a chemical is a factor that shows the level of degradation itll cause to the ozone layer that surrounds and secures the earth from harmful radiation. 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. This allows the refrigerant in the condenser to be void of oil particles. Some 1993 and older R12 systems aren't as 'compatible' as you'd think to switch over. The condensor airflow drops off as the fan clutch dies slowly. If the charge is low the compressor will cycle on/off in the max AC position. With R134a you do not rely on the site glass. I used a full can of evap cleaner. The money you will save by will pay for the R12. R12 is simply too expensive for a 25+ year old A/C system. Since the hose is the stock hose, you cannot tell what refrigerant is inside. Instead, top off R12 with R134a refrigerant. Above this temperature, the saturation pressure of R134a is higher than that of R12; below, it is lower. ESP when a compressor has frozen. With that said, I would source the TXV from another source such as NAPA just to avoid any problems. Yes, I don't trust the heater valve either. R134a was selected as a replacement refrigerant for R12 because R12 contains chlorine and has a major effect to ozone layer depletion. 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. Gain access to our free AOP (Ask a Professional) Section to get real answers for your questions. A/C systems designed to use R-12 will cool best when charged with R-12 refrigerant. Most vehicles manufactured before 1993 have the R12 A/C system. The adjusted tension of this spring is the determining factor in the opening and closing of the expansion valve. 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. Could that be screwing up the systems performance?Anyway, when I installed the system, the new TXV (is that short for expansion valve?) Edited: Tue July 17, 2007 at 3:25 AM by bohica2xo, I believe there is only one switch - the refrigerant switch. 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. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. 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. Some cars have both an engine coolant temp switch & a refrigerant temp switch, others only the refrigerant switch. 5. The cure is to use the newer R134a compressors is sealing washers that are different thickness. Debug the condensor (I am a computer nerd after all!)3. If you have the work done, be sure you find a true "A/C" shop that can make up lines. 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. Instead of using R12, its preferable to use R134a because it is very easy to find in the market, its sold at an affordable price, and is environmentally friendly. Its chemical symbol is CH2FCF3. Expansion Valve. CONCLUSIONS The differences in the theoretical C.O.P.H calculated for R12 and R134a are consistent with values quoted in the literature. A discussion of the relationship between valve capacities and superheat set-tings can be found in Bulletin 10-9. and an evaporator core and expansion valve that are optimized for R134a . R12 was once used in many air conditioning units as a refrigerant or cooling agent. _____ 2012 E350 2006 Callaway SC560 . R-134a XV for R-134a use. Discussion in 'Technical' started by Jsarnold, May 25, 2012. 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. If there is no pusher fan, and you have the room, put one in. Until 1995, most cars with air conditioning used R-12 Freon refrigerant which has shown to have an environmental impact. Stability: RR12 doesnt disintegrate even under extreme operating conditions. 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. But as there's not a big difference, people say you can suffice with either. Hopefully after you have read this entire page you will have enough information to determine which type of refrigerant is best for you. According to the thermodynamic characteristics, it is close to the R12 freon, however, it is 10-15% worse in terms of cooling capacity and is more fluid. Even with proper fan operation, missing seals & air dams can effect condensor effeciency. You can also check the Aux fan in your case. 05-25-2017 02:14 AM. R12 Expansion Valve = 201 830 06 84 R134A Expansion Valve = 201 830 04 84 Is there a difference after all? -------------------------"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." Gnats & mosquitos will clog deep. The only difference I can imagine would be the recharge connection. Is there a source of valves by, say, eaton number? The Main change in the system is the expansion valve. Yes, this was a smokers car. link to How to cut off a Catalytic Converter. The primary function of the design engineer is to make things difficult for the fabricator and impossible for the serviceman. The compressors used by refrigeration plants to compress gas require oil to help lubricate its moving parts. -------------------------"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." The exact amount will vary with each car. Compressor. Your average garage that works on a/c on the side probably would not have this. difference between r12 and r134a expansion valvewarning signs for a deteriorating patient with covid 19 infection 2022.07.03 18:36 18:36 B. Use a drop light in the engine bay, and check the air path from the front of the car at night. 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. ). You are indeed 20% out of the OEM spec for cooling. |. 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. R12 systems used mineral oil, but unfortunately mineral oil doesn't dissolve in R134a. "Howdy, Folks!" The value of carbon dioxide is 1. Trinary Pressure Switch quantity. 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. Temp switch works the aux fan. gital control scheme. But R22 is almost equally damaging. of refrigerant insulation tape. Pray I can let some oil out of the compressor without losing my precious R12. system of 0.33 TR and refrigerant used was R12. All pre-97 XJs use systems with the same basic operating principle, although the parts do change a bit. This would become an expensive investment for a repair or service station to have unique dedicated equipment for every type of alternative refrigerant. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. The oil used in R12 systems is not compatible with R134a refrigerant. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. 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. You may need to adjust the valve in a bit to get desired superheat. Is that reasonable?Vent airflow is good, I think. In a car ac, using this type of freon 20 years ago was difficult. Read on for more information about using automotive r134a in a refrigerator and vice versa. CLUTCH CYCLING SWITCH. As noted, measure up front as best as you can to get as close to the aftermarket dim. Environmental Impact: When R134a escapes into the atmosphere, it contributes to global warming. 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. With the A/c off hi and lo were both at 105psi. Questions About Becoming A Professional Member? 1) Look Here at the available sizes of PF condensors.2) Go look at your vehicle's condensor & mounting. Formula: (R12 Charge Specification x 0.9) - 0.25 lbs. 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. R134a refrigerant is about 10% less efficient in moving heat than R12! The major reason for the replacement of R12 with R134a was to curb future greenhouse effects. Table 1 summarizes the technical characteristics of three potential R134a alternatives. Even if the system leaks, repairing the leaks and recharging it with R-12 is usually the best repair alternative. What is a good differential? We mention using ester type refrigerant oil. R134a is NOT less efficient than R12 Actually R134a is more efficient. Differences between R-12 and R-134a systems: 1. Is it exponential, squared? 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. Performance doesn't seem to have improved. 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. At the time I thought nothing of it, but now I am thinking maybe that is contributing to the system not working as well as it could. At this point it is time to make an appointment with the a/c shop. Is there a difference in the expansion valve for R12 as opposed to R-134a? . 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. Its cylinders are colored white. This is due to many facts: R134a refrigerant is about 10% less efficient in moving heat than R12! -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. R134a and R12 are both refrigerants used in vehicle air conditioning systems. might be due to charge or different compressor and age. compressor, condenser, evaporator and expansion valve are specifically designed for use with R134a. Next I'll jumper the aux fan. Hence, let us continue to fix it. 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. Expansion Valves Catalog E-1, July 2012. difference between r12 and r134a expansion valve . R134a has an ozone depletion potential of 0, implying that it has a slight effect on the ozone layer. Where would I get some basic info on it, I know nothing about it. A capacity curve is shown in figure 2 for relative capacity of R134a vs. R12 for evaporating temperatures from 0F to 50F. R12, on the other hand, is called chlorofluorocarbon (CFC). The old compressor used R12 and the new unit will be R134a. Different correction factors are applied to other refrigerants. Boiling Point: R134a refrigerants boiling point is -26.3C (-15.34F). When the sensor detects the refrigerant leak the sniffers lights glow and the sniffer makes a noise. However, R134a is better than R12. Best for varieties of operating conditions: Its boiling point is -21.6 Celsius. It is mixed with the freon for the most part, and does accumulate in all components in small amounts. 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 . It didn't seem too dirty though - I don't think it is the problem, but I could be wrong. To ensure the right charge, you must fill the new system with between 75 and 85% of the factory-set capacity for optimal cooling. 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. That is a good thing. However, it was found to be a very bad gas for the environment. The system will be checked for gross leaks while under vacuum. You either get a system that will function well with R1234yf or get any other type. ing the expansion valve, a maximum opening superheat of 7F, and a standard factory air test superheat setting. R12 is heavier than R134a and has smaller molecules. You will be fine with a 134a-compatible TXV running R12. Can I just use an adapter and save $200? Its chemical symbol is CH2FCF3. The system has been previously converted to R-134a. The chemical composition of R12 and R134a differ. There is only a temperature switch on these cars as far as I recall, and it just switches on the aux fan. SO here's my question. -------------------------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. I had a pair on my SAAB that seemed ok - but new ones ran 20% faster!Your best clue to airflow issues is a 60 mph test. 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. This means that it has a high potential of causing depletion to the ozone layer. So that indicates it is cooling well there doesn't it? I found that in the..Maxposition on the control it will have the compressor running all the time. 5) A/C System Failure. 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. So you could likely put off buying those new hoses just a bit longer if you wanted. You do not want to exceed the systems high side recommendations. Then, subtract that result by 0.25 pounds to get the proper amount of R134a charge. That is for the compressor, drier, expansion valve and condenser. Paul:It is never a waste of my time to chat with someone that understands the problem, and wants to fix it. This drop can affect energy consumption since the plant will operate for a longer period or a larger plant will have to be installed. You can use this space to go into a little more detail about your company. Generally this works well for the whole system. R134a and R12 are among the most popular types of refrigerants. 1.5 ounces - hmmm. difference between r12 and r134a expansion valve. In sum, R12 has done more bad than good. Generally the system will be initially charged with approximately 80% to 85% of the original amount of R12, using R134a. In addition, R134a refrigerants are not only used in auto air conditioners, they can be used in freezers, aerosol cans, and refrigerators. Have a look in the FAQ Section, and look for "Fan clutches & testing them". It is usually sold under the brand name, Freon 12. Do I leave the orignal condensor in, etc?Thanks. 3) A TXV optimized for 134a will be ok with R12. It is common for eurocar threads to go multiple pages, and as Nick points out - sometimes cool is all you will ever get. Recharge the compressor with a/c ester oil and a tracer dye. The MB chart shows 360 psi with R12 in some conditions. 5. 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. It cycles on off in med (or low for that matter)Gotta tell ya. So I probably put the highest suggested amount in to be safe. I think the way to go here is1. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. The name of the oil is Polyol Ester (POE). Sense ells no existirem. (You must log in or sign up to reply here. There are R134a specific valves that operate at a slightly different pressure, but not for any "old" automotive application that I'm aware of. Look deep into the fins. 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. However, theyre still used in older plants, systems, and the automotive industry. We sometimes use a relay switched from the compressor clutch to run fans. What is the refrigerant property involved that has caused this? The higher the ambient temperature the higher the high side pressure. #19. Safety: R134a is safe to use as its non-flammable and cant explode. $21 . Thus, when the system is running, condensing the CO2 is not a problem. R404a is a zeotropic blend with a temp glide , because of the mixture of 2 or more refrigerants. Replied by Rich928 on topic R12 or R134a. Moreso, it had been banned. Are r12 and r134 fittings different? Rules governing changing from the former to the latter differ between countries. GWP is a measurement of Greenhouse Gases and their effect on Global Warming. The larger fitting goes on the discharge port and the smaller fitting goes on the suction line or compressor inlet / suction port. difference between r12 and r134a expansion valve. The problem with not being an expert is that you don't know what is important and what's not. Above this temperature, the saturation pressure of R134a is higher than that of R12; below, it is lower. Generally, the new amount is 75-85% of the quantity advised by the manufacturer. 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. Please enter a password for your user account. 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. In most cases, the systems used have varied components, designs, and service ports. 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. Superheat you can consider to be the additional amount of heat. Refrigerators generally utilize R22, R32, or 410A-based coolants as their cooling agent. The aux fan seems to be working fine - it switches on occassionally. Replacement expansion valve for R134a or R12 A/C refrigerants, with O-ring connections. He used thermostatic expansion valve and Capillary tube for analysis with R12. Since then, the industry standard has been R134a, which is an efficient replacement. Still, I have some simple green, so may as well give it a go. B. 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. By: james smith underoath; Comments: 0 . The common problem when converting from R12 to R134a is lack of knowledge or equipment. we convert older systems where i work all the time and they work fine. Failure to abide by the EPA regulations can result in expensive fines for either you or your service technician. I have one can left, so maybe a plan can be made. R12 and R134 are of different chemistry. I'm just trying to help you avoid headaches in the long run. Most of all the differences gravitate to longevity, functionality, and safety. In practice this means that the car can overheat and the aux fan will stay off! Besides, you have a greaseisel. If you have a perfectly operating system using R12 you do not have to drop what you are doing and convert to R134a. Agram a retevis rt22 password i bastrop county district clerk records el material que oferim als nostres webs. 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. It can be used applications like walk-in coolers, food and dairy display cases, domestic refrigerators, and beverage dispensers and vending machines. I could easily be over at least 2 - 3 ounces over on the oil. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. To bless the system the technician should attach a R134a sticker somewhere in the engine compartment to note the car is using R134a. I know this is bad, etc, and deposits on the metal can act as insulators. Bohica, I appreciate your help with this. So, instead of using R12, other better options include R401b, R134a, R401a, etc. Crap! The oil is spread all over your system when it is at rest. You'll want the expansion valve matched to whatever refrigerant you're using. Consider using the newer valve, even with 134a stamped on the valve. This is a great space to write long text about your company and your services. However, R12 refrigerants are still used as fire retardants in aircraft and submarines. Edited: Sat July 14, 2007 at 10:22 PM by fonebone. Thanks so much Bohica - you've save me many more hours of fruitless speculation. It won't be optimal, though. Therefore, the higher the factor of the chemical (compound), the greater its effect on global warming. You do not need to replace the expansion valve in most cases. 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. What effect would it have on performance, if any?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. Make sure visiually that no large gaps exist that would allow the air to bypass the condensor on the way to the radiator.B. Thread starter goldNSX; Start date 1 August 2009; Tagged . A. Pressure/temperature table for R12, R134a, and R513A is shown in Figure 1. . The good thing is that after you convert to R134 you can top off the system easily and cheaply. 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. This is 11F off the FSM performance graph - vent should be around 50F. Unfortunately, the R12 refrigerant doesnt always blow cold air. Your old hoses of course will not fit. If you you dont have the free time to play then you are better off to pay a technician. In more serious, it could result in cardiac irregularities or death. R134a refrigerant fittings are different size. At 2000rpm, windows open, highest fan, hi pressure stabilized at 225 psi, low 25psi.Ambient 81F, vent 61F. So to keep things simple and to avoid controversy and politics we have R134a. Only show this user. 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. R12 is used in several applications like low temperature, medium temperature, and high-temperature applications. Even though their common major function is to cool the system, they have many differences. video clubhouse baseball; nick fairley draft profile; ben davis work pants July 3, 2022July 3, 2022. a 50f delta across the condensor is good, but I suspect that is an idle reading. I remember I had the wrong seals and it leaked some oil, so I put some more in.Bohica - I tested the pressures.
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