difference between r12 and r134a expansion valvemouse trap game with toilet instructions
The difference between R12 and R134a TEV (exp valves) is primarily the 'superheat'. 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 The difference between R12 and R134A systems compared with the R12 R134a have different physical and chemical properties. Differences between R-12 and R-134a systems: 1. CLUTCH CYCLING SWITCH. 12-06-2006, 10:55 PM #4 Andy Schoen Professional Member Join Date Apr 2002 Location Dallas, TX Posts 2,566 Post Likes 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. 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. absorb by the evaporator to insure all liquid refrigerant entering the evaporator. GWP is a measurement of Greenhouse Gases and their effect on Global Warming. An orifice tube is just a fixed nozzle that pisses refrigerant into the evaporator without any sort of feedback. R134a refrigerant is lighter than R12. Its chemical symbol is CH2FCF3. In an AC system, the oil is constantly moving with the refrigerant. As an example, let's say the R12 charge specification is listed at 2 lbs. The substitute that we used for R-12 was the new HFC called R-134a. A discussion of the relationship between valve capacities and superheat set-tings can be found in Bulletin 10-9. This refers to BTU's (heat) moved per pound of refrigerant moved. Judging from the current manufacturer's use results, the R507's effect is indeed faster than the R404A's cooling speed. A final difference is that most (though not all) R-1234yf cars will have a Suction Line Heat Exchanger. 3) A TXV optimized for 134a will be ok with R12. You can use the R134a retrofit capacity chart for this purpose. 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. If liquid refrigerant were to exit the evaporator. 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. All pre-97 XJs use systems with the same basic operating principle, although the parts do change a bit. 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 . Then, subtract that result by 0.25 pounds to get the proper amount of R134a charge. The good thing is that after you convert to R134 you can top off the system easily and cheaply. R12 Expansion Valve = 201 830 06 84 R134A Expansion Valve = 201 830 04 84 Is there a difference after all? The chemical composition of R12 and R134a differ. ESP when a compressor has frozen. The R12 compressor design ports are even. There are significant differences between R12, R134a, and R513A, which must be considered when handling, processing, applying, or retrofitting with these refrigerants. Some say that a chemical reaction can harm the A/C very badly as R134a reacts with mineral oil in some way. The R12 compressor design ports are even. Expansion Valves Catalog E-1, July 2012. You can use any gauges you like to check the pressure of the system, with slight risk of cross contamination. #4. Then, subtract that result by 0.25 pounds to get the proper amount of R134a charge. 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 . A. Pressure/temperature table for R12, R134a, and R513A is shown in Figure 1. . Also, this will give you the opportunity to replace all the evaporator seals which are recommended to be done in a conversion. . 5) A/C System Failure. Thus, when the system is running, condensing the CO2 is not a problem. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. To discover the capacity for refrigerant, you want to use the specs for the current system and multiply the R12 charge by 0.9 or 90%. R134a is called tetrafluoroethane (HFC). The P H and T cond,sat of the HR12 at a T oa of 40 C were higher than that of the R134a, resulting in a higher P e than that for the R134a. Bad Car A/C Expansion Valve Symptoms. 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. R134a requires the use of synthetic oil! R134a compressors are built to run a higher head pressure (R134a has a higher working pressure than R12) and the lubricants are incompatible. 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. George Brayon Wed August 31, 2005 5:03 PM I believe the optimum supercool setting will vary slightly between an expansion valve for an R12, as compared to R134a, system. 3) A/C Compressor Always On. Take the R12 charge specification and multiply it by 0.9. R-12 "Freon" and 134a. R12 Expansion Valve = 201 830 06 84 R134A Expansion Valve = 201 830 04 84 Is there a difference after all? Bookmarks: Digg; del . 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 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. You have to replace EVERY O ring including the compressors manifold gasket O ring to the new green color for R134a. and he synthesized R-134a in 1936, 5 years after R-12 was . So, along with R134a came a new oil: Polyalkylene Glycolor PAG oil. R134a is roughly 9$ per lb. The Main change in the system is the expansion valve. = R134a Charge Level. A slow loss of cooling at city speeds is usually related to condensor capacity & airflow issues. It can be used applications like walk-in coolers, food and dairy display cases, domestic refrigerators, and beverage dispensers and vending machines. Subtract or 0.25 pounds from this number. -The cooling may not be as good as with R-12. 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. 2) Frost on the Vents. ing the expansion valve, a maximum opening superheat of 7F, and a standard factory air test superheat setting. In automotive air conditioning systems, refrigerants R12 and . There is a lot of differences between the R12 and the R134a fittings, you can't mistake them. 5. 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. Generally, the new amount is 75-85% of the quantity advised by the manufacturer. The expansion valve is designed so that the temperature of the refrigerant at the evaporator outlet must have 8 to 12F (4 to 7C) of superheat before more refrigerant is allowed to enter the evaporator. Are r12 and r134 fittings different? The difference really shows up on the high side. Also the new quick connect fittings for the high & low side. 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. How is 1234yf different from . 6. The adjusted tension of this spring is the determining factor in the opening and closing of the expansion valve. If the system was upgraded by a professional it should have an upgrade sticker. James10952001. The difference really shows up on the high side. R-401b is the mixture by weight of 61% R22, 11% R-152a and 28% of R-124. Take the R12 charge specification and multiply it by 0.9. 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. Large temperature difference between expansion valve inlet and outlet oReplace expansion valve Air . You will be fine with a 134a-compatible TXV running R12. The R134a compressor has a 1/8" step in on the high side port. Bottom line, R134a simply doesn't cool as well as R12. It is made up of carbon, hydrogen, and fluorine. Some vehicles' older hoses will allow the R134 refrigerant to 'seep' through the linings on the hoses. With R-12, 30 is 28.4psi and 40 is 36.9psi, for a difference of 8.5psi. Superheat you can consider to be the additional amount of heat. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. Is that why expansion valves are specific to R12 or R134A? How an A/C Expansion Valve Works. R134a. leading to corrosion of expansion valves, capillary tube plugging, and compressor bearing . Some vehicles won't be a concern. The primary function of the design engineer is to make things difficult for the fabricator and impossible for the serviceman. You will be fine with a 134a-compatible TXV running R12. This is especially likely on systems with a condenser that is too small for efficient operation with R-134a. (On firewall where A/C lines go into cab.) R134a refrigerant is about 10% less efficient in moving heat than R12! This part is part of the line assembly and is designed to improve efficiency. and feeds it through an expansion valve. Even if the system leaks, repairing the leaks and recharging it with R-12 is usually the best repair alternative. Comparatively, larger R134a molecules should take more space, and a smaller amount might be required. The cure is to use the newer R134a compressors is sealing washers that are different thickness. I'm just trying to help you avoid headaches in the long run. R-134a is widely believed to be the most acceptable R12 substitute. So you could likely put off buying those new hoses just a bit longer if you wanted. With new R12 no longer being manufactured, the market price soared to $100/pound. 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. R134a for cooling of product. Only show this user. Since then, the industry standard has been R134a, which is an efficient replacement. R134a has the chemical formula CF3CH2F and is known as tetrafluoroethane. The general practice of charging the system with 15% less refrigerant adds to the thermal deficiency of R134a. = R134a Charge Level R12, on the other hand, is called chlorofluorocarbon (CFC). It won't be optimal, though. They have no moving parts. The difference between R12 and r134a is the BTU carrying capability. The symbol implies that R12 is a composite of carbon, chlorine, and fluorine. #13. Until 1995, most cars with air conditioning used R-12 Freon refrigerant which has shown to have an environmental impact. R-401b is the mixture by weight of 61% R22, 11% R-152a and 28% of R-124. Minor adjustments to the expansion valve and other controls may be necessary for some plans. R134a systems operate at higher discharge-side pressures than R12, which can cause compressor seals to leak. Formula: (R12 Charge Specification x 0.9) - 0.25 lbs. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. Replied by Rich928 on topic R12 or R134a Since the hose is the stock hose, you cannot tell what refrigerant is inside. Expansion Valve. R-12 is no longer used or produced in many countries and remaining quantities have skyrocketed in price. A/C systems designed to use R-12 will cool best when charged with R-12 refrigerant. A/C Expansion Valve Replacement Cost. Jun 17, 2011. But as there's not a big difference, people say you can suffice with either. But R22 is almost equally damaging. For instance at 25 F the pressure of R-12 is 24.6 PSI and the pressure of R-134a is 22.1 PSI. All fans must work at 100% of the OEM rating. Catalog E-1, Thermostatic & Automatic Expansion Valves / Page 1 Table of Contents . . and feeds it through an expansion valve. In a car ac, using this type of freon 20 years ago was difficult. Can I just use an adapter and save $200? Mark Baker You'll want the expansion valve matched to whatever refrigerant you're using. Answer (1 of 10): According to this article, Real World Experience with R1234yf: The New Refrigerant is Finally Here; Are You Ready? Although the compressors are different the SD709 R-12 compressor can use R-134a, . Recommendations From A/C Shops and Aftermarket: Lower the adjustment of the clutch cycling switch to 21 to 22 PSI. The only mechanical differences between an . R12 is heavier than R134a and has smaller molecules. Above this temperature, the saturation pressure of R134a is higher than that of R12; below, it is lower. #19. I had a 1991 BMW switched to 134a by just changing the low pressure charging valve, flushing and refilling with 134 (maybe with 10% . Aug 3, 2018. The cure is to use the newer R134a compressors is sealing washers that are different thickness. R12 and R134 are of different chemistry. and he synthesized R-134a in 1936, 5 years after R-12 was . 4) Inconsistent Airflow. According to Wikipedia, There is such a thing as "r132a" (1,1-Dichloro-2,2-Difluoroethane), however there is no indication of it being a commercially produced refrigerant. Then again, there are two different expansion valves. A lower GWP alternative to R-134a had to be found and thus we have the new 1234yf. The pressure at low temperatures is nearly the same between 12 and 134a. However the real limiter on the conversion is the condenser. Compressor. 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). Joshua, You are correct about the (small) pressure and flow characteristic differences between R-12 and R-134a Expansion valves. The ratings for evaporator temperatures 40F, 20F, -10F, -40F in the capacity tables are in accordance with ANSI/ARI R-134a XV for R-134a use. Operating Pressure/Temperature Differences The pressure/temperature curves for R-1234yf and R-134a are very similar. You would do the following: This indicates that an . And with R134a costing only two bucks a can, converting to the new inexpensive refrigerant seemed the thing ELECTRONIC EXPANSION VALVES: High Efficiency The GWP value of the refrigerant used is 1.430 (refrigerant type R134a). It is good replacement for R12 in the applications where the evaporator temperature is -23 degree C and above. I dont know why the cost difference between compressors is so huge, though. might be due to charge or different compressor and age. . A capacity curve is shown in figure 2 for relative capacity of R134a vs. R12 for evaporating temperatures from 0F to 50F. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. "Howdy, Folks!" R12 refrigerant required this valve, to maintain the evaporator at a constant or nearly constant pressure, slightly above 36-38 psi to prevent icing. turns into a vapor before it exits. It's actually a reaction with chlorine in the mineral oil that may have been absorbed and leftover from the old R-12. Given their small cost, 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. During opening or closing . Later model cars that come with 134A will have 134A only connectors. This works when the R12 charge specification is listed in pounds. maintain the A/C of older cars. That would be the "black death" syndrome.