Flush with a garden hose - do not use a high pressure washer - you can bend the fins flat & damage the condensor.B. had writing on the side that said R134a. System has been working fine for a year. Generally, the new amount is 75-85% of the quantity advised by the manufacturer. You do not want to exceed the systems high side recommendations. Please enter the name by which you would like to log-in and be known on this site. R134a has an ozone depletion potential of 0, implying that it has a slight effect on the ozone layer. Use a drop light in the engine bay, and check the air path from the front of the car at night. 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. 4.3 out of 5 stars 491. (You must log in or sign up to reply here. Lasers don't do well on vent temps, a stick thermometer is better in that application. But as there's not a big difference, people say you can suffice with either. An extra half ounce? compressor, condenser, evaporator and expansion valve are specifically designed for use with R134a. Generally this works well for the whole system. Additionally, R134a was introduced as a replacement for R22 and R12 in high and medium-temperature refrigeration systems like domestic and commercial chillers. The condensor airflow drops off as the fan clutch dies slowly. 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. Debug the condensor (I am a computer nerd after all!)3. 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. If it splashes inside the eye, it could lead to a serious eye problem. The experimental values of C.O.P.H obtained with the R134a/ester charge were 20.2% It can be used applications like walk-in coolers, food and dairy display cases, domestic refrigerators, and beverage dispensers and vending machines. Also, they are mostly used in refrigeration and automotive air conditioning systems. (The .133 is the 300D Turbo).So, what does your compressor look like?B. 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. I used a full can of evap cleaner. If the charge is low the compressor will cycle on/off in the max AC position. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. 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. 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. 10,000BTU conduction heating? R404a for freezing of product. It is perhaps possible to locate a unit with a company that purchases close out or distressed merchandise. After the optimum refrigerant charge is determined the car should be test driven to check for performance of the system. An orifice tube is just a fixed nozzle that pisses refrigerant into the evaporator without any sort of feedback. Fitting a PF condensor is not rocket science, but it requires some planning. R12 contains a chemical called chlorine that destroys the ozone layer, thereby causing potential environmental risk. Besides, R134a refrigerant was manufactured after R12 was banned to help reduce the harshness of the old chemical (R12) on the ozone layer. Statisicaly your friend was lucky. 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. Use strips of foam to couple the two heat exchangers if necessary.B. Then, subtract that result by 0.25 pounds to get the proper amount of R134a charge. I could easily be over at least 2 - 3 ounces over on the oil. We sometimes use a relay switched from the compressor clutch to run fans. The cost of recharging the air conditioner is between $150 to $500. The old compressor used R12 and the new unit will be R134a. It's not just the poor performance - the cooling just stops working after a while. 37 in 2005 tacoma, R134A. This refers to BTU's (heat) moved per pound of refrigerant moved. Also called the orifice tube. difference between r12 and r134a expansion valve. Also the new quick connect fittings for the high & low side. Catalog E-1, Thermostatic & Automatic Expansion Valves / Page 1 Table of Contents . 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. Expansion Valves Catalog E-1, July 2012. Expansion valves are an active device, they regulate the flow of refrigerant to the evaporator depending on evaporator temperature. Unfortunately, the oil only mixes with the refrigerant as a liquid. James10952001. This is not to say that one of these small retro-fit kits cant be used, however to be used wisely. Further production of R12 was banned in some developed countries by the Montreal Protocol because of its harsh effect on the ozone layer. 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. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. Most vehicles manufactured before 1993 have the R12 A/C system. This is an electronic tool that sucks in air through a tube and across a sensor. Als nostres webs oferimOne Piece,Doctor Who,Torchwood, El Detectiu ConaniSlam Dunkdoblats en catal. It is made up of carbon, hydrogen, and fluorine. Superheat you can consider to be the additional amount of heat. In the automotive world, the replacement for R12 was R134a. As noted, measure up front as best as you can to get as close to the aftermarket dim. On the other hand, R12 has a global warming potential of 10,910. The only difference I can imagine would be the recharge connection. Where would I get some basic info on it, I know nothing about it. They examined the two configurations of capillary tubes i.e. A capacity curve is shown in figure 2 for relative capacity of R134a vs. R12 for evaporating temperatures from 0F to 50F. Whether R134a performs as well as R12 in any given a/c system depends upon system components and the amount of R134a used. Some 1993 and older R12 systems aren't as 'compatible' as you'd think to switch over. This would become an expensive investment for a repair or service station to have unique dedicated equipment for every type of alternative refrigerant. Before R12 was replaced with R134a in 1995, it was mostly used in trucks and cars. Sense ells no existirem. Ensure you contact a professional mechanic to do the work for you so you dont end up incurring more costs for yourself. Answer: OK, I'll bite. I'm going to check the condensor is way clean too. With R-12, 30 is 28.4psi and 40 is 36.9psi, for a difference of 8.5psi. 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. The flammables have hydrocarbons. We recently created this blog site to enable us to share our knowledge with other automotive mechanics and car owners. For example, if your system originally had 36 ounces of R12 then you multiply that by .80 and you have 29 ounce of R134a. Miscibility with oil: R12 can be mixed with the compressor oil no matter the operating condition. The system has been previously converted to R-134a. Lets take you through the advantages, disadvantages, and differences of these two refrigerants a detailed comparison including R12 vs R134a performance. Anyone know what happens when an R12 expansion valve is used in a system charged with R134A? The bad thing is I don't know what to do about it. A. Pressure/temperature table for R12, R134a, and R513A is shown in Figure 1. . In addition, R134a refrigerants are not only used in auto air conditioners, they can be used in freezers, aerosol cans, and refrigerators. I don't recall all the details, but starts off with the largest parallel flow condenser and improved fans. Some say that a chemical reaction can harm the A/C very badly as R134a reacts with mineral oil in some way. Any advice appreciated. Hopefully after you have read this entire page you will have enough information to determine which type of refrigerant is best for you. If you you dont have the free time to play then you are better off to pay a technician. You may have heard of a friend that did the job himself with borrowed equipment and 12 or 16 ounce cans of refrigerant. Its cylinders are colored white. With new R12 no longer being manufactured, the market price soared to $100/pound. Comparatively, larger R134a molecules should take more space, and a smaller amount might be required. I know this is bad, etc, and deposits on the metal can act as insulators. The R134a compressor has a 1/8" step in on the high side port. 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. You may need to adjust the valve in a bit to get desired superheat. Then I'll put the ball valve in on the coolant and test it and see what we have. A good T/C, clamped to the line & insulated gives a repeatable measurement of the tube. Figure 2 shows the different phases and pressures the refrigerant . R1234yf is more environmentally friendly and has a global warming potential of 4. 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. Replied by Rich928 on topic R12 or R134a. 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. The safe high side pressures are determined with a PT (pressures and temperatures) chart. Very nice! . With R12 you use to check to see if the site glass was full, if it had bubbles it meant you had a low charge. 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 . Low refrigerating effect per pound: In comparison to other refrigerants, the refrigerating effect of R12 per pound is low. we convert older systems where i work all the time and they work fine. Blows pretty hard on full. Bad Car A/C Expansion Valve Symptoms. 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. We, the Rxmechanic team, have presented a well-detailed comparison of R134a vs. R12. 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. I'm just trying to help you avoid headaches in the long run. R12 is CFC: Even though R12 is one of the most commonly used refrigerants, it is CFC. Unfortunately, the R12 refrigerant doesnt always blow cold air. On this website we are addressing only R134a and not other suggested drop in replacements. 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. Replacement expansion valve for R134a or R12 A/C refrigerants, with O-ring connections. R134a was selected as a replacement refrigerant for R12 because R12 contains chlorine and has a major effect to ozone layer depletion. R12 is highly destructive to the earths ozone layer. a 50f delta across the condensor is good, but I suspect that is an idle reading. The newer valves and switches will work with both refrigerants. The general practice of charging the system with 15% less refrigerant adds to the thermal deficiency of R134a. Yep, definately not a meat locker. R12, on the other hand, is called chlorofluorocarbon (CFC). R134a systems operate at higher discharge-side pressures than R12, which can cause compressor seals to leak. Instead, top off R12 with R134a refrigerant. Maybe a jerky locker.I cleaned the condensor with the off the shelf ac cleaner stuff from Home Depot that I used on my home evaporator. I had a 1991 BMW switched to 134a by just changing the low pressure charging valve, flushing and refilling with 134 (maybe with 10% . Besides, you have a greaseisel. A. Pressure/temperature plot of R134a vs. R12 is shown in figure 1. The difference between the two is about 10,000 btu/h. . R 134A is designed for the high demands of an automobile AC and cannot be used on refrigerators due to pressure differences. It didn't seem too dirty though - I don't think it is the problem, but I could be wrong. Ask Our Pros-Owner Assistance - NO DIY advice will be given. Any ideas from the info above? The #1 question asked by NEW MEMBERS. Is that why expansion valves are specific to R12 or R134A? The first vehicle that used the R1234yf refrigerant was the 2013 Cadillac XTS. If the system was upgraded by a professional it should have an upgrade sticker. Below are the major differences between R134a and R12: Chemistry The chemical composition of R12 and R134a differ. I've straightened the fans I can and sprayed simple green on it, let it soak then hosed it down well. 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. Disconnect the two hose lines to the compressor, protect the ends from getting dirty. 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. The current expansion valve is FF - 1/4 - C. Is it neccesary to replace this valve? 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. The AC usually does not work at all. Edited: Sat July 14, 2007 at 10:22 PM by fonebone. (On firewall where A/C lines go into cab.) 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 common problem when converting from R12 to R134a is lack of knowledge or equipment. _____ 2012 E350 2006 Callaway SC560 . 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. All pre-97 XJs use systems with the same basic operating principle, although the parts do change a bit. And, unfortunately a small high side pressure gauge on a short hose. So to keep things simple and to avoid controversy and politics we have R134a. 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. don't know enough about the subject to explain the choices.However, a few days ago I called the dealer to see about an OEM TEV and they said something that made me feel a little bit better; the same part number superceded every application back to the '60s, and that they couldn't do that without engineering signing off on it.Still, I would feel a lot better if I could see something written officially that compared the flow characteristics and performance of r12 and 134a TEVs are concluded that they were interchangeable in automotive applications.If someone knows of such a document I would sleep much better!Walt Edited: Mon September 12, 2005 at 8:13 PM by wamcneil. Most importantly, the oil used in the plant must always be compatible with the refrigerant used. Condensers designed to release greater amounts of heat help to expel the greater amount of heat which R134a removes from the cars interior. At 2000rpm, windows open, highest fan, hi pressure stabilized at 225 psi, low 25psi.Ambient 81F, vent 61F. Table 1 summarizes the technical characteristics of three potential R134a alternatives. Gain access to our free AOP (Ask a Professional) Section to get real answers for your questions. leading to corrosion of expansion valves, capillary tube plugging, and compressor bearing . The name of the oil is Polyol Ester (POE). A/C receiver difference between R12 and R134a? That way I will have reduced the oil by about 1/3 (assuming the oil is mixed evenly through the system). However, R12 refrigerants are still used as fire retardants in aircraft and submarines. However, it was found to be a very bad gas for the environment. 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. It can be used applications like walk-in coolers, food and dairy display cases, domestic refrigerators, and beverage dispensers and vending machines. R12, on the other hand, is called chlorofluorocarbon (CFC). With the A/c off hi and lo were both at 105psi. This works when the R12 charge specification is listed in pounds. R134a has the chemical formula CF3CH2F and is known as tetrafluoroethane. 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 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). R12 is used in several applications like low temperature, medium temperature, and high-temperature applications. The original expansion valves work very well with R134a. If you have a perfectly operating system using R12 you do not have to drop what you are doing and convert to R134a. Generally the system will be initially charged with approximately 80% to 85% of the original amount of R12, using R134a. Thanks again. This may be the source of your oil confusion. In a comparison between R12 vs R134a vs R1234yf, R1234yf will pass as the best refrigerant. Its among the greenhouse gases and will keep adding the current problem of heat not leaving the earths atmosphere. 3) A TXV optimized for 134a will be ok with R12. I would suggest you do stay away from R-134a since with the hot gas bypass of your system (if it is to be just as the original) extremes of temperature and pressure will be very hard on your compressor and the rest of the system. I found that in the..Maxposition on the control it will have the compressor running all the time. The original rubber a/c hose lines in your car will leak out R12 through the hoses lining. -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. Its chemical symbol is CH2FCF3. GWP is a measurement of Greenhouse Gases and their effect on Global Warming. Why wait for 200f on the engine coolant to start the fan? 3) A/C Compressor Always On. Not going to mess up your 'do, but you can feel it. Do a pre-inspection and then Evacuate (vacuum down) the system, the longer the evacuation the better but there is a point of diminishing return, 2-3 hours is generally very good. 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. Have a look in the FAQ Section, and look for "Fan clutches & testing them". The larger fitting goes on the discharge port and the smaller fitting goes on the suction line or compressor inlet / suction port. What is the refrigerant property involved that has caused this? This would be a custom install, there is no "drop-in" condensor upgrade for that car.Check for proper fan operation, and clean the air path on both the condensor & radiator. 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. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry.
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