";s:4:"text";s:22421:"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. However, theyre still used in older plants, systems, and the automotive industry. 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. I put one in my old daily driver '79 Chevy tank (r-12), and it really made a difference. June 21, 2022 difference between r12 and r134a expansion valve . . Safe but sorry! Please enter the name by which you would like to log-in and be known on this site. Condensers designed to release greater amounts of heat help to expel the greater amount of heat which R134a removes from the cars interior. GWP is a measurement of Greenhouse Gases and their effect on Global Warming. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. It was later found that R-134a had a very high Global Warming Potential, or GWP, number. Helical and Serpentine coils. If your a/c system is empty/low on refrigerant, if your system has a leak or if you need to open the system, then now is the time to decide which refrigerant you want to use. The pressure/temperature curves for R-1234yf and R-134a are very similar. 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. The ARPA Zone/Open Membership Discussion Forums. 4) Inconsistent Airflow. The common problem when converting from R12 to R134a is lack of knowledge or equipment. 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. Stability: RR12 doesnt disintegrate even under extreme operating conditions. As noted, measure up front as best as you can to get as close to the aftermarket dim. In a comparison between R12 vs R134a vs R1234yf, R1234yf will pass as the best refrigerant. The symbol implies that R12 is a composite of carbon, chlorine, and fluorine. A/C systems designed to use R-12 will cool best when charged with R-12 refrigerant. As per their results . Can I use the one for the R-12? The Main change in the system is the expansion valve. At 40, it is 35psi, which is a difference of 8.9psi. hardly noticable. 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. 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. Not going to mess up your 'do, but you can feel it. CONCLUSIONS The differences in the theoretical C.O.P.H calculated for R12 and R134a are consistent with values quoted in the literature. As an example, let's say the R12 charge specification is listed at 2 lbs. The exact amount will vary with each car. Just because the radiator does not boil people assume that the cooling system is ok. When ever possible you should ask the technician to note the same information on your repair bill and keep a copy in your glove box for future reference. Are r12 and r134 fittings different? The cure is to use the newer R134a compressors is sealing washers that are different thickness. Even if the system leaks, repairing the leaks and recharging it with R-12 is usually the best repair alternative. 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. -The amount of R-134a needed will typically be 80-90% of the R-12 charge. The best replacement for R134a is R1234yf, while R12 refrigerant replacement was R134a. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. Additionally, R134a was introduced as a replacement for R22 and R12 in high and medium-temperature refrigeration systems like domestic and commercial chillers. R134a has the chemical formula CF3CH2F and is known as tetrafluoroethane. Trinary Pressure Switch quantity. R12 is used in several applications like low temperature, medium temperature, and high-temperature applications. In practice this means that the car can overheat and the aux fan will stay off! Measure what you have now.3) Go back to the page in step one, and find the largest condensor you can put in your vehicle. -------------------------"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." With the knowledge of the differences, youll be able to draw a comparison between R12 vs R134a efficiency. Hot coolant migrates up through the core by convection (is that the word? After the optimum refrigerant charge is determined the car should be test driven to check for performance of the system. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyers guides, and car and tools comparisons. Most of all the differences gravitate to longevity, functionality, and safety. In addition, R134a refrigerants are not only used in auto air conditioners, they can be used in freezers, aerosol cans, and refrigerators. They should be able to keep you comfortable on a long trip, but don't expect vent frost in 3 minutes or lesss.2) Too much oil can reduce cooling capacity, and the effect is not linear. -------------------------"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." 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). The mechanical fan & clutch should be checked as well. The crossover point is approximately at 64F. R12 is highly destructive to the earths ozone layer. Are you sure you have an R4? 5. 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. R1234yf. leading to corrosion of expansion valves, capillary tube plugging, and compressor bearing . It can be used applications like walk-in coolers, food and dairy display cases, domestic refrigerators, and beverage dispensers and vending machines. in /nfs/c05/h04/mnt/113983/domains/toragrafix.com/html/wp-content . 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. However, if it is taken close to a fire flame or any electrical heating element, it disintegrates into toxic products. If your car does not have a high pressure cut-out switch in the AC system then youll need to have one installed (call us if you need help). Moreso, it had been banned. In large application systems, the vapor density of this refrigerant is usually high. Be sure to test @ 1500 to 2000 engine rpm, and record the ambient temp as well. 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. Paul:It is never a waste of my time to chat with someone that understands the problem, and wants to fix it. That would be the "black death" syndrome. The current expansion valve is FF - 1/4 - C. Is it neccesary to replace this valve? 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. Expansion Valves Catalog E-1, July 2012. A Lot of the fins are bent, especially at the top. The difference really shows up on the high side. Rules governing changing from the former to the latter differ between countries. That way I will have reduced the oil by about 1/3 (assuming the oil is mixed evenly through the system). R12 contains a chemical called chlorine that destroys the ozone layer, thereby causing potential environmental risk. and he synthesized R-134a in 1936, 5 years after R-12 was . Jun 19, 2007. R12 is otherwise called dichlorodifluoromethane is a colorless gas (chlorofluorocarbon halomethane (CPC) that is used as an aerosol spray propellant and a refrigerant, and is soluble in organic solvents. Hence, the effect of R12 on global warming is up to 10,000 times higher than carbon dioxide. The R134a compressor has a 1/8" step in on the high side port. There is a lot of differences between the R12 and the R134a fittings, you can't mistake them. Some cars have both an engine coolant temp switch & a refrigerant temp switch, others only the refrigerant switch. and he synthesized R-134a in 1936, 5 years after R-12 was . What is needed? 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. R12 and R22 are both now banned by the EPA in the United States. The only mechanical differences between an R12 system and an R134a system are that R134a systems typically have larger condensers and more powerful compressors. Depending on which circuit diagram fits your car (cough, no vin list exists) you have either one or two switches controlling the aux fan. Unfortunately, the oil only mixes with the refrigerant as a liquid. Besides, you have a greaseisel. Whenever its exposed to the environment, it changes to a gas. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. 2001-2023 Griffiths Technical Inc. All Rights Reserved. . 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. They can be mounted quite easy,and there is a mounting kit that helps to hang it. The butylcellusolve or the citrus solvent will dissolve the carcass in a few minutes. The general practice of charging the system with 15% less refrigerant adds to the thermal deficiency of R134a. 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. compressor, condenser, evaporator and expansion valve are specifically designed for use with R134a. 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. It is made up of carbon, hydrogen, and fluorine. Unfortunately, the R12 refrigerant doesnt always blow cold air. The difference between R12 and r134a is the BTU carrying capability. For those of you who are considering what the cost is for R12 you can think of it this way: Dont go out to dinner this weekend. The original rubber a/c hose lines in your car will leak out R12 through the hoses lining. Edited: Tue July 17, 2007 at 3:25 AM by bohica2xo, I believe there is only one switch - the refrigerant switch. R12 is CFC: Even though R12 is one of the most commonly used refrigerants, it is CFC. At 2000rpm, windows open, highest fan, hi pressure stabilized at 225 psi, low 25psi.Ambient 81F, vent 61F. Just leave it alone for now. This leads me to labor over every small decision. Kommentare . To prevent refrigerant loss you should consider replacing your old hose lines with barrier type hose. R134a systems operate at higher discharge-side pressures than R12, which can cause compressor seals to leak. 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. I remember I had the wrong seals and it leaked some oil, so I put some more in.Bohica - I tested the pressures. The typical scenario here is when the car owner buys an inexpensive retro-fit kit from the local auto parts store. Biggest you can fit in there is best. El juny de 2017, el mateix grup va decidir crear un web deDoctor Who amb el mateix objectiu. Pray I can let some oil out of the compressor without losing my precious R12. R-12 is no longer used or produced in many countries and remaining quantities have skyrocketed in price. When the sensor detects the refrigerant leak the sniffers lights glow and the sniffer makes a noise. Table 1 summarizes the technical characteristics of three potential R134a alternatives. Your decision could be made based on economics, environmental concerns, or both. All fans must work at 100% of the OEM rating. Can I just use an adapter and save $200? 42 (at best) w/ 134A in 2000 isuzu trooper. Carefully study the chart and compare the following: To a large extent, the choice is up to you. is good, then I should be looking elsewhere? Paul -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. 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. The bad thing is I don't know what to do about it. This is because R134a. R134a is called tetrafluoroethane (HFC). 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. Is it exponential, squared? I'm thinking of jumping the temp switch and leaving the fan on to see how it does. The non-flammables can have R22 type gas which is not compatible with most rubber hoses or they have gases that contribute to global warming. But as there's not a big difference, people say you can suffice with either. MB has specfic test parameters for performance, but you can always test at max load - doors open fan on highest speed.The oil overcharge looks like a parabolic curve. Can I just use an adapter and save $200? Questions About Becoming A Professional Member? Thread starter goldNSX; Start date 1 August 2009; Tagged . 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. What effect would it have on performance, if any? gital control scheme. 37 in 2005 tacoma, R134A. They have no moving parts. It is made up of carbon, hydrogen, and fluorine. He used thermostatic expansion valve and Capillary tube for analysis with R12. So I probably put the highest suggested amount in to be safe. However, R134a is better than R12. A lower GWP alternative to R-134a had to be found and thus we have the new 1234yf. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. 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. This is an electronic tool that sucks in air through a tube and across a sensor. Flushed, vacuumed etc. -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a, Hi pdrayton- If you can remember the oil capacity that you found in all your research and post that, then bohica and others can have a better idea if you have too much; see if you can find that info! -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. In more serious, it could result in cardiac irregularities or death. I don't recall all the details, but starts off with the largest parallel flow condenser and improved fans. Operating Pressure/Temperature Differences The pressure/temperature curves for R-1234yf and R-134a are very similar. 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. We sometimes use a relay switched from the compressor clutch to run fans. It is perhaps possible to locate a unit with a company that purchases close out or distressed merchandise. 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. These two refrigerants are the older types and are not used in newer refrigeration and air conditioning systems. If you have a York, and it is equipped with service valves, you can check & adjust the oil level without discharging the system. Vent temperatures slowly go down to around 50F with hi speed driving. R134a refrigerant is about 10% less efficient in moving heat than R12! What is a good differential? Instead, top off R12 with R134a refrigerant. R12, on the other hand, is called chlorofluorocarbon (CFC). R12 is heavier than R134a and has smaller molecules. About four or five years ago, I guy with an MB came here with the same problem, that tread was over six pages long. Use a drop light in the engine bay, and check the air path from the front of the car at night. 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. 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. _____ 2012 E350 2006 Callaway SC560 . With R134a you do not rely on the site glass. I've done the FSM test and with 81F ambient, the vent should be 50F. Is there a source of valves by, say, eaton number? Your average garage that works on a/c on the side probably would not have this. Below are the major differences between R134a and R12: Chemistry The chemical composition of R12 and R134a differ. What is a T/C?4. If there is no pusher fan, and you have the room, put one in. To ensure the right charge, you must fill the new system with between 75 and 85% of the factory-set capacity for optimal cooling. -------------------------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. Debug the condensor (I am a computer nerd after all!)3. July 3, 2022July 3, 2022. R 134A is designed for the high demands of an automobile AC and cannot be used on refrigerators due to pressure differences. And, unfortunately a small high side pressure gauge on a short hose. 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. You do not want to exceed the systems high side recommendations. Generally the system will be initially charged with approximately 80% to 85% of the original amount of R12, using R134a. Nice to use new gadgets! Disconnect the two hose lines to the compressor, protect the ends from getting dirty. R404a is a zeotropic blend with a temp glide , because of the mixture of 2 or more refrigerants. R134a and R12 are both refrigerants used in vehicle air conditioning systems. Performance doesn't seem to have improved. Usually, mechanics charge around $200 for conversion. asia pacific stevie awards 2021. gin, amaretto cocktail. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. . R12, on the other hand, is called chlorofluorocarbon (CFC). For instance at 25 F the pressure of R-12 is 24.6 PSI and the pressure of R-134a is 22.1 PSI. (On firewall where A/C lines go into cab.) and an evaporator core and expansion valve that are optimized for R134a . sparkee said: Thanks for the Service Bulletin. _____ 2012 E350 2006 Callaway SC560 . Is there a difference in the expansion valve for R12 as opposed to R-134a? R12 was once used in many air conditioning units as a refrigerant or cooling agent. 1) Look Here at the available sizes of PF condensors.2) Go look at your vehicle's condensor & mounting. . Thanks again. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. 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? R134a refrigerant is lighter than R12. I am ordering new parts, and planning to convert my system to R-134a. R134a and R12 are among the most popular types of refrigerants. difference between r12 and r134a expansion valve. In cases such as this, the required capacity value of the expansion valve with R134a is reduced by 30% (correction factor 1.42). 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. 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). Do I leave the orignal condensor in, etc?Thanks. Ensure you contact a professional mechanic to do the work for you so you dont end up incurring more costs for yourself. ";s:7:"keyword";s:48:"difference between r12 and r134a expansion valve";s:5:"links";s:702:"Euro 6 Diesel Fino A Quando Possono Circolare,
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