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. Instead, top off R12 with R134a refrigerant. R134a refrigerant fittings are different size. It does not "pool" to any degree in a large amount anywhere. Hence, let us continue to fix it. I don't believe it is but I had a service guy tell me it needs to be done. (On firewall where A/C lines go into cab.) The oil used in R12 systems is not compatible with R134a refrigerant. Edited: Sat July 14, 2007 at 10:22 PM by fonebone. Then I'll put the ball valve in on the coolant and test it and see what we have. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. ThanksPaul -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. This is a great space to write long text about your company and your services. You will be fine with a 134a-compatible TXV running R12. R-134a is widely believed to be the most acceptable R12 substitute. 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 . One thing at a time here, and slowly, the knee is not up to jumping around like I used to at the moment. This means that it has a high potential of causing depletion to the ozone layer. Energy usage: R134a is less efficient in cooling compared to R12. Refrigerators generally utilize R22, R32, or 410A-based coolants as their cooling agent. Later model cars that come with 134A will have 134A only connectors. It would make a big difference at idle ,in traffic!! 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. I just got some hi/lo side gauges so I'm going to take readings, if they are needed. It was later found that R-134a had a very high Global Warming Potential, or GWP, number. In practice this means that the car can overheat and the aux fan will stay off! If you are replacing other system components, such as condensers, driers or hoses, you may need to add more a/c refrigerant oil to the system. _____ 2012 E350 2006 Callaway SC560 . What is a good differential? 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. Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. Its chemical symbol is CH2FCF3. we convert older systems where i work all the time and they work fine. R134a is otherwise called 1,1,1,2 Tetrafluoroethane, Florasol 134a, Freon 134a, Norflurane (INN) or HFC 134a. With the A/c off hi and lo were both at 105psi. However, R134a is better than R12. R-12 is no longer used or produced in many countries and remaining quantities have skyrocketed in price. Since 2010, all home AC systems manufactured use a refrigerant like R134a that has zero ozone depletion potential (ODP). I think the way to go here is1. A vacuum pump, a refrigerant recover system, quality service gauge set with both low and high side gagues, and much more besides the lessons to learn what to do and what not to do. 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 only difference I can imagine would be the recharge connection. You do not need to replace the expansion valve in most cases. I'm curiousSo there is work to do, ie performance should be able to be improved. 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. With R-12, 30 is 28.4psi and 40 is 36.9psi, for a difference of 8.5psi. R12 is simply too expensive for a 25+ year old A/C system. For R12, its mineral oil. You can also check the Aux fan in your case. I put one in my old daily driver '79 Chevy tank (r-12), and it really made a difference. R1234yf is more environmentally friendly and has a global warming potential of 4. But as there's not a big difference, people say you can suffice with either. As per their results . 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. Some compressor manufacturers or OEMs suggest PAG type oil for R134a. R-134a XV for R-134a use. 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. . 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. The difference between the two is about 10,000 btu/h. The system has been previously converted to R-134a. Your old hoses of course will not fit. We mention using ester type refrigerant oil. This is not to say that one of these small retro-fit kits cant be used, however to be used wisely. About four or five years ago, I guy with an MB came here with the same problem, that tread was over six pages long. This refers to BTU's (heat) moved per pound of refrigerant moved. Low refrigerating effect per pound: In comparison to other refrigerants, the refrigerating effect of R12 per pound is low. But as there's not a big difference, people say you can suffice with either. Still, I have some simple green, so may as well give it a go. By: james smith underoath; Comments: 0 . In a comparison between R12 vs R134a vs R1234yf, R1234yf will pass as the best refrigerant. A comparison between R12 vs. R134a temperature will show that R12 has a higher temperature than R134a. Use a strong surfactant like Simple Green or Zep Citrus, and soak the fins on the condensor. Use strips of foam to couple the two heat exchangers if necessary.B. If the charge is low the compressor will cycle on/off in the max AC position. You can use the R134a retrofit capacity chart for this purpose. It cycles on off in med (or low for that matter)Gotta tell ya. 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? 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 . I have one can left, so maybe a plan can be made. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. Yep, definately not a meat locker. Bookmarks: Digg; del . Don't like the sound of custom parallel condensor. Whether R134a performs as well as R12 in any given a/c system depends upon system components and the amount of R134a used. Put a relay on the compressor clutch to the aux fan (I like that idea - makes a lot of sense)How does that sound? Please enter a password for your user account. Stay home and grill your own steaks and stir your own martini. This is because R134a. 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. 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. Make sure to get the R12 EXP valve if that is the way you go. It's helluva humid and hot here in north florida, and I drive around all day for my job. This would become an expensive investment for a repair or service station to have unique dedicated equipment for every type of alternative refrigerant. 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. The #1 question asked by NEW MEMBERS. 3 ounces? Nice to use new gadgets! The good thing is that after you convert to R134 you can top off the system easily and cheaply. By noting the ambient temperature you can look up what the preferred high side pressure should be. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. ). 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. Debug the condensor (I am a computer nerd after all!)3. 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. Hence, the effect of R12 on global warming is up to 10,000 times higher than carbon dioxide. Above this temperature, the saturation pressure of R134a is higher than that of R12; below, it is lower. Answer: OK, I'll bite. Mine was 61, so the system is not working as it is supposed to. Is that why expansion valves are specific to R12 or R134A? They examined the two configurations of capillary tubes i.e. ing the expansion valve, a maximum opening superheat of 7F, and a standard factory air test superheat setting. Formula: (R12 Charge Specification x 0.9) - 0.25 lbs. Safe but sorry! I'm not sure. -------------------------"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." I used a full can of evap cleaner. 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. The larger fitting goes on the discharge port and the smaller fitting goes on the suction line or compressor inlet / suction port. And, unfortunately a small high side pressure gauge on a short hose. R134a and R12 are among the most popular types of refrigerants. The difference between R12 and r134a is the BTU carrying capability. That is a good thing. -The amount of R-134a needed will typically be 80-90% of the R-12 charge. Most importantly, the oil used in the plant must always be compatible with the refrigerant used. Its cylinders are colored white. How dumb!I will jumper the aux fan and redo the test. Nick, I hear you - there maybe nothing to do here. R134a has an ozone depletion potential of 0, implying that it has a slight effect on the ozone layer. Though - the valve for a 1991 says R12 on it, and for a 1994, it says R-134a. Als nostres webs oferimOne Piece,Doctor Who,Torchwood, El Detectiu ConaniSlam Dunkdoblats en catal. and feeds it through an expansion valve. How is the vent airflow?I would jumper the aux fan & check the performance. CLUTCH CYCLING SWITCH. Add to cart. In the automotive world, the replacement for R12 was R134a. Once you have replaced the OEM condensor with a PF unit, you will need to make custom hoses to mate with your OEM system. Like say half a can or so recharge come springtime warm weather or something. sparkee said: Thanks for the Service Bulletin. It is mixed with the freon for the most part, and does accumulate in all components in small amounts. A Lot of the fins are bent, especially at the top. By after changing just about everything, he got what was termed, satisfactory cooling. A lower GWP alternative to R-134a had to be found and thus we have the new 1234yf. I have the original (R12) style expansion valve in the Maverick AC system. It is usually sold under the brand name, Freon 12. 2001-2023 Griffiths Technical Inc. All Rights Reserved. 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. The best oil that runs well with R134a is PAG oil or Polyalkylene Glycol. Skin contact: If the R134a (liquid) comes in contact with your skin, it could cause a burn. The larger line at the expansion valve is the suction line. All pre-97 XJs use systems with the same basic operating principle, although the parts do change a bit. We consider the the various types alternative refrigerants that are illegal or not approved to be in two sectors: non-flammables and flammables. Back in that era, my business associates drove those things, brand new, and maybe I should take my Cadillac instead, no they wouldn't be caught dead in a Caddy, people of our esteem should be driving an MB. Thus, when the system is running, condensing the CO2 is not a problem. If 50 degrees across the cond. Neuro spine Super Speciality Clinic - Above Apollo Pharmacy, Bangarpet Circle, Kolar - Bangarpet Road, Kolar Town. 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. At 2000rpm, windows open, highest fan, hi pressure stabilized at 225 psi, low 25psi.Ambient 81F, vent 61F. Any ideas from the info above? 1) Warm Air From Vents. Can I use the one for the R-12? Statisicaly your friend was lucky. Thanks again. 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. Replied by Rich928 on topic R12 or R134a. Stability: RR12 doesnt disintegrate even under extreme operating conditions. The mechanical fan & clutch should be checked as well. 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. I'll report back on the aux fan on performance next. Hmmmm. There is only a temperature switch on these cars as far as I recall, and it just switches on the aux fan. Attach the R134a charge port adaptors, there are two types.. one of which you need to remove the old R12 valve cores. Why wait for 200f on the engine coolant to start the fan? The problem with not being an expert is that you don't know what is important and what's not. . 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. 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. I have just bought gauges. Jun 19, 2007. R134a refrigerant is lighter than R12. If liquid refrigerant were to exit the evaporator. R134a is the most widely accepted alternative automotive refrigerant used to replace R12. These two refrigerants are the older types and are not used in newer refrigeration and air conditioning systems. Autor de l'entrada Per ; Data de l'entrada calexico west port of entry hours; 12 month libor rate 2021 a difference between r12 and r134a expansion valve a difference between r12 and r134a expansion valve The pressure at low temperatures is nearly the same between 12 and 134a. The higher the ambient temperature the higher the high side pressure. (You must log in or sign up to reply here. 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, 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. 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. 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. Inasmuch as R134a has a global warming potential thats over 1000 times more threatening than carbon dioxide, its better than R12. Yes, the 50F diff (160-110F) on the condenser was at idle, and ambient was about 90F. Can I just use an adapter and save $200? We say generally because the vehicle manufacturer may have a formula already worked out for the R134a conversion process. After the initial charge the system is then tweeked : you determine the optimum amount of refrigerant to match your system by monitoring the a/c outlet vent temperature and the high side pressure as you add or remove refrigerant. El juny de 2017, el mateix grup va decidir crear un web deDoctor Who amb el mateix objectiu. evarporator, expansion valve plus flushing out the full system and replacing all the o rings. Ensure you contact a professional mechanic to do the work for you so you dont end up incurring more costs for yourself. R12 contains a chemical called chlorine that destroys the ozone layer, thereby causing potential environmental risk. Some 1993 and older R12 systems aren't as 'compatible' as you'd think to switch over. In cases such as this, the required capacity value of the expansion valve with R134a is reduced by 30% (correction factor 1.42). VerticalScope Inc. All Rights Reserved. A good T/C, clamped to the line & insulated gives a repeatable measurement of the tube. -------------------------"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 money you will save by will pay for the R12.
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