I'm thinking of jumping the temp switch and leaving the fan on to see how it does. As illustrated in the chart below, the curves below run together nearly throughout the curve, only slightly breaking paths at around 250 psig/150 degrees and above Flammability/Safety R-1234yf has been designated as MILDLY flammable. Yep, definately not a meat locker. 1) Warm Air From Vents. 37 in 2005 tacoma, R134A. It slowly gets warmer and warmer in the car, even at highway speeds. The catalytic converter is an essential component of your car's emission system that helps save the environment from harmful emissions. 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 difference between r12 and r134a expansion valve Participate in over 40 different forums and search/browse from nearly 3 million posts. Add to cart. The pressure at low temperatures is nearly the same between 12 and 134a. 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. At this time you can still find R12, but, because it is no longer produced, availability is limited to current inventories and the price per pound is greater than R134a. R12 is CFC: Even though R12 is one of the most commonly used refrigerants, it is CFC. The newer valves and switches will work with both refrigerants. Inasmuch as R134a has a global warming potential thats over 1000 times more threatening than carbon dioxide, its better than R12. George Bray on 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. Formula: (R12 Charge Specification x 0.9) - 0.25 lbs. This is due to many facts: R134a refrigerant is about 10% less efficient in moving heat than R12! I'm not sure. 42 (at best) w/ 134A in 2000 isuzu trooper. Compared with the cost-performance ratio, R507 is 30-40% . Related products. difference between r12 and r134a expansion valve I cleaned the evap as best I could, if that is what you are getting at. 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. R12 is highly destructive to the earths ozone layer. If not, you just don't know unless a test is performed. You can use this space to go into a little more detail about your company. Still, I have some simple green, so may as well give it a go. The R134a compressor has a 1/8" step in on the high side port. and feeds it through an expansion valve. Components Coils, Heaters, Motors, etc. Anyone know what happens when an R12 expansion valve is used in a system charged with R134A? Is checking the temperature of the in and out of the condensor not the easiest way to tell if it is doing a good job or not? CLUTCH CYCLING SWITCH. So, instead of using R12, other better options include R401b, R134a, R401a, etc. Use a drop light in the engine bay, and check the air path from the front of the car at night. The exact amount will vary with each car. 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. 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. Right now you know you have a bit too much, but with a CR4P compressor this is an insurance policy. How about evacing 1 pound of refrig from the system, and then putting 1 lb of pure R12 back in? Look at where the lines will end up. By using a black light the dye will glow in areas where oil leaks are visible. Therefore, the R12 refrigerant is illegal, and emitting it is illegal. There are significant differences between R12, R134a, and R513A, which must be considered when handling, processing, applying, or retrofitting with these refrigerants. R12 to R134a change expansion valve? - HVAC-Talk: Heating, Air With R134a you do not rely on the site glass. Though I have seen em run as cold as 12 deg F. If the thermo switch is malfunctioning. _____ 2012 E350 2006 Callaway SC560 . Make sure to get the R12 EXP valve if that is the way you go. However, it was found to be a very bad gas for the environment. Heres some important advice Whenever you notice your R12 refrigerant is leaking, turn off all flames and open the doors so it can escape to the open atmosphere. Expansion Valve for R134a? | Team Chevelle When I compare parts, 93 uses one part number and 94 has a different part number. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. Kommentare . A capacity curve is shown in figure 2 for relative capacity of R134a vs. R12 for evaporating temperatures from 0F to 50F. PDF R134a R513A - Tecumseh Products Formula: (R12 Charge Specification x 0.9) - 0.25 lbs. On the other hand, R12 has a global warming potential of 10,910. The analysis focuses on Coefficient of Performance for . Also, it can be used with all types of compressors. Stopleak is also risky. 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. If you still find it difficult to use R134a in a home AC system, you can check out a comparison of R12 vs R134a fittings to know the refrigerant that best fits the AC system. compressor, condenser, evaporator and expansion valve are specifically designed for use with R134a. Ask Our Pros-Owner Assistance - NO DIY advice will be given. If the system was upgraded by a professional it should have an upgrade sticker. What is the refrigerant property involved that has caused this? It is common for eurocar threads to go multiple pages, and as Nick points out - sometimes cool is all you will ever get. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. A Lot of the fins are bent, especially at the top. They plug all the time. The chemical composition of R12 and R134a differ. Why wait for 200f on the engine coolant to start the fan? Interestingly, theres one oil type that works perfectly with both types of refrigerants. By after changing just about everything, he got what was termed, satisfactory cooling. Just leave it alone for now. 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. In the automotive world, the replacement for R12 was R134a. Generally this works well for the whole system. 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. -------------------------"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." Recharge the compressor with a/c ester oil and a tracer dye. Your decision could be made based on economics, environmental concerns, or both. 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. After the optimum refrigerant charge is determined the car should be test driven to check for performance of the system. 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). R12 is heavier than R134a and has smaller molecules. The cost of recharging the air conditioner is between $150 to $500. That is for the compressor, drier, expansion valve and condenser. Is that reasonable?Vent airflow is good, I think. There is a lot of differences between the R12 and the R134a fittings, you can't mistake them. Operating Pressure/Temperature Differences The pressure/temperature curves for R-1234yf and R-134a are very similar. The primary function of the design engineer is to make things difficult for the fabricator and impossible for the serviceman. Post photos, respond to polls and access other special features. This may be the source of your oil confusion. The OEM spec is 2300 rpm @ 12.6v (engine stopped fully charged battery). 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. _____ 2012 E350 2006 Callaway SC560 . It won't be optimal, though.On some/many valves, you can adjust them, but that might make matters worse unless you really know what you're doing (which I don't!).RegardsGeorge. R-12 to R-134a Conversion. R-12 is no longer used or produced in many countries and remaining quantities have skyrocketed in price. The safe high side pressures are determined with a PT (pressures and temperatures) chart. It's not just the poor performance - the cooling just stops working after a while. The typical scenario here is when the car owner buys an inexpensive retro-fit kit from the local auto parts store. I remember I had the wrong seals and it leaked some oil, so I put some more in.Bohica - I tested the pressures. An orifice tube is just a fixed nozzle that pisses refrigerant into the evaporator without any sort of feedback. $21 . Have a look in the FAQ Section, and look for "Fan clutches & testing them". 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. ambulance tailgate conversion Once you have replaced the OEM condensor with a PF unit, you will need to make custom hoses to mate with your OEM system. It is made up of carbon, hydrogen, and fluorine. The difference really shows up on the high side. I just got some hi/lo side gauges so I'm going to take readings, if they are needed. Tech Talk - Differences between R-1234yf and R-134a - FJC Inc R12 was once used in many air conditioning units as a refrigerant or cooling agent. 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. A. Pressure/temperature table for R12, R134a, and R513A is shown in Figure 1. . and he synthesized R-134a in 1936, 5 years after R-12 was . 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. Most importantly, the oil used in the plant must always be compatible with the refrigerant used. Its chemical symbol is CH2FCF3. This is 11F off the FSM performance graph - vent should be around 50F. The current expansion valve is FF - 1/4 - C. Is it neccesary to replace this valve? is good, then I should be looking elsewhere? Replace the drier with a drier that has a desiccant that is R134a compatible, use new R134a o-rings. Rules governing changing from the former to the latter differ between countries. 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 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 . I think the way to go here is1. 4) Repeat step 2, making sure it will fit. Plus, not releasing the chemical into the air is morally justifiable. american sniper longest shot; how to adjust sunsetter awning arms; pastor jeremy roberts texas. Biggest you can fit in there is best. Besides, R134a refrigerant was manufactured after R12 was banned to help reduce the harshness of the old chemical (R12) on the ozone layer. 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 . R134a has an ozone depletion potential of 0, implying that it has a slight effect on the ozone layer. Note that passwords are case-sensitive. difference between r12 and r134a expansion valve. A/C receiver difference between R12 and R134a? But with an R4, better too much than too little.3) A TXV optimized for 134a will be ok with R12.4) The airflow across the condensor is crucial to good performance. 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. It runs between the condenser outlet, receiver/drier unit and expansion valve at the firewall. It is usually sold under the brand name, Freon 12. Low refrigerating effect per pound: In comparison to other refrigerants, the refrigerating effect of R12 per pound is low. leading to corrosion of expansion valves, capillary tube plugging, and compressor bearing . James10952001. This works when the R12 charge specification is listed in pounds. Then when it is switched off for a few minutes and then back on, the air cools again. In practice this means that the car can overheat and the aux fan will stay off! You may have heard of a friend that did the job himself with borrowed equipment and 12 or 16 ounce cans of refrigerant. and he synthesized R-134a in 1936, 5 years after R-12 was . 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. 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. But as there's not a big difference, people say you can suffice with either. hardly noticable. The oil is spread all over your system when it is at rest. Make sure to wear safety gloves, goggles, and shoes when theres a possibility of exposure to the chemical (R134a). It does not "pool" to any degree in a large amount anywhere. PaulJerky King -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. It cycles on off in med (or low for that matter)Gotta tell ya. -The amount of R-134a needed will typically be 80-90% of the R-12 charge. R134a is called tetrafluoroethane (HFC). I don't want to be chasing ghosts. R12 systems used mineral oil, but unfortunately mineral oil doesn't dissolve in R134a. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. All pre-97 XJs use systems with the same basic operating principle, although the parts do change a bit. The larger fitting goes on the discharge port and the smaller fitting goes on the suction line or compressor inlet / suction port. Existing technology: R134a has been in use in the refrigeration industry for very many years, and theres so much information about the safe use of the product. At least you do not have 16 ounces in there ( yup seen it before).For now, straighten all of the fins that you can, clean the condensor well, and re-test with the aux fan running. It is possible I have 10 ounces (250 ml) in the system. The only difference I can imagine would be the recharge connection. Generally you follow the refrigerant flow moving from connection to connection, component to component, and you sniff the a/c vents to check for evaporator leaks as well. BTW, I use a stick thermo in the vents and the laser on the condenser. difference between r12 and r134a expansion valve . It is a haloalkane and hydrofluorocarbon (HFC) refrigerant that has thermodynamic properties, potential global warming for one hundred years, and insignificant ozone depletion. Expansion Valve. I recommend replacing the expansion valve when you do the swap. The AC usually does not work at all. B. Typically 5 to 6 ounces of a/c oil is adequate but this may vary depending upon the car. Safety: R134a is safe to use as its non-flammable and cant explode. That switch should close @ 52c. difference between r12 and r134a expansion valve Can I use the one for the R-12? R134a. -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. Shorting the plug for the refrigerant switch should run the fan when the compressor is on. That is a good thing. If the charge is low the compressor will cycle on/off in the max AC position. I have just bought gauges. For R12, its mineral oil. Is there a difference between a R134a expansion valve and an R12 TXV? A capacity curve is shown in figure 2 for relative capacity of R134a vs. R12 for evaporating temperatures from 0F to 50F. But, if your old compressor has lock-up or if your current expansion valve is not functional it would wise to replace the expansion valve with a valve designed for R134a. What effect would it have on performance, if any? How thermostatic expansion valves work | Danfoss Gain access to our free AOP (Ask a Professional) Section to get real answers for your questions. R12 was once used in many air conditioning units as a refrigerant or cooling agent. The system has been previously converted to R-134a. 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. The original rubber a/c hose lines in your car will leak out R12 through the hoses lining. Also, would a genuine R12 TXV be better, or is it too marginal to worry about?I think I should do the FSM test for performance - they have a graph with ambient temp and a/c temp. It was later found that R-134a had a very high Global Warming Potential, or GWP, number. But some types of PAG do not mix well with the old residual R12 mineral oil left in the system components whereas ester does mix very well. Be sure to test @ 1500 to 2000 engine rpm, and record the ambient temp as well. That's a lot isn't it? Should I do the test again with the the aux fan jumpered? Its highest value is 1. Very nice! Generally the system will be initially charged with approximately 80% to 85% of the original amount of R12, using R134a. Its cylinders are colored white. There is only a temperature switch on these cars as far as I recall, and it just switches on the aux fan. Use a strong surfactant like Simple Green or Zep Citrus, and soak the fins on the condensor. Recovery & flushing is the only way out of an oil overcharge in your vehicle.B. 5) A/C System Failure. Above this temperature, the saturation pressure of R134a is higher than that of R12; below, it is lower. And I already have so much time and money in this a/c project that I REFUSE to cut any corners as small as a TEV.It doesn't help that most people in the business (at least that I come in contact with, present company excluded, of course!) However, take note that R134a refrigerants are manufactured specifically for automotive air conditioners. There are R134a specific valves that operate at a slightly different pressure, but not for any "old" automotive application that I'm aware of. I bought a relay to put on it connected to the compressor clutch. The next piece of equipment to track down leaks is a leak sniffer. difference between r12 and r134a expansion valve The R134a compressor has a 1/8" step in on the high side port. 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). Could that be screwing up the systems performance?Anyway, when I installed the system, the new TXV (is that short for expansion valve?) Vent temperatures slowly go down to around 50F with hi speed driving. Bookmarks: Digg; del . Yes, I don't trust the heater valve either. The condenser water inlet temperature and flow rate are controlled with the use of a . 2001-2023 Griffiths Technical Inc. All Rights Reserved. . I know this is bad, etc, and deposits on the metal can act as insulators. I have one can left, so maybe a plan can be made. Hence, let us continue to fix it. You can buy bulk hose, and the proper fittings, then have them crimped off the vehicle.Be sure that no air bypasses the new condensor on the way to the radiator. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. For example, at an evap temp of 30 (your daughter's system is probably running around 25-28 saturated in order to give a 32 duct temp), the pressure of R-134a is 26.1psi. . Refrigerators generally utilize R22, R32, or 410A-based coolants as their cooling agent. The crossover point is approximately at 64F. Any advice appreciated. A York oil capacity is listed as "6.5 to 9.6 ounces". 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). We consider the the various types alternative refrigerants that are illegal or not approved to be in two sectors: non-flammables and flammables. AC R12 to R134A Conversion | MR2 Owners Club Forum Lets take you through the advantages, disadvantages, and differences of these two refrigerants a detailed comparison including R12 vs R134a performance. 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. July 3, 2022July 3, 2022. . 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. Miscibility with oil: R12 can be mixed with the compressor oil no matter the operating condition. Besides, you have a greaseisel. Carefully study the chart and compare the following: To a large extent, the choice is up to you. Nick, I hear you - there maybe nothing to do here. 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. If you have the work done, be sure you find a true "A/C" shop that can make up lines.