But I don't want to waste your time. You'll get marginally better performance out of the change as the expansion valve is matches the refrigerant characteristics. A capacity curve is shown in figure 2 for relative capacity of R134a vs. R12 for evaporating temperatures from 0F to 50F. As per their results . Look deep into the fins. had writing on the side that said R134a. For instance at 25 F the pressure of R-12 is 24.6 PSI and the pressure of R-134a is 22.1 PSI. Heres R12 vs. R134a pressure chart. With that said, I would source the TXV from another source such as NAPA just to avoid any problems. For example, if your system originally had 36 ounces of R12 then you multiply that by .80 and you have 29 ounce of R134a. 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 . R 134A is designed for the high demands of an automobile AC and cannot be used on refrigerators due to pressure differences. Took me a while to figure that one out, and how to say that. Can I use the one for the R-12? Please enter a valid email address for yourself. R-401b is the mixture by weight of 61% R22, 11% R-152a and 28% of R-124. -------------------------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! a 50f delta across the condensor is good, but I suspect that is an idle reading. What is the refrigerant property involved that has caused this? 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. Instead, top off R12 with R134a refrigerant. Big . The adjusted tension of this spring is the determining factor in the opening and closing of the expansion valve. That would be the "black death" syndrome. Very interesting! 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? 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. 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. 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). 4.R404A R134a increased mass transfer resistance to reduce the transmission chamber heat coefficient, while R507 heat transfer coefficient is higher than R404A. Hopefully after you have read this entire page you will have enough information to determine which type of refrigerant is best for you. Just had knee surgery yesterday, so I"M not exactly hopping around too well. R-134a XV for R-134a use. With the oil leaking out and being told all sorts of things about how these compressors don't have a sump etc, I wanted to be on the safe side. difference between r12 and r134a expansion valve. I just got some hi/lo side gauges so I'm going to take readings, if they are needed. AFAIK, there is no clutch on the engine fan on the 240D. R134a was selected as a replacement refrigerant for R12 because R12 contains chlorine and has a major effect to ozone layer depletion. 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 . By noting the ambient temperature you can look up what the preferred high side pressure should be. However, the supply houses don't indicate a difference. and he synthesized R-134a in 1936, 5 years after R-12 was . ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. Statisicaly your friend was lucky. Safe but sorry! This is due to many facts: R134a refrigerant is about 10% less efficient in moving heat than R12! He used thermostatic expansion valve and Capillary tube for analysis with R12. 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. Still, I have some simple green, so may as well give it a go. There are significant differences between R12, R134a, and R513A, which must be considered when handling, processing, applying, or retrofitting with these refrigerants. Stopleak is also risky. How about evacing 1 pound of refrig from the system, and then putting 1 lb of pure R12 back in? Later model cars that come with 134A will have 134A only connectors. 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. The best oil that runs well with R134a is PAG oil or Polyalkylene Glycol. Bad Car A/C Expansion Valve Symptoms. The ratings for evaporator temperatures 40F, 20F, -10F, -40F in the capacity tables are in accordance with ANSI/ARI = R134a Charge Level R12 Expansion Valve = 201 830 06 84 R134A Expansion Valve = 201 830 04 84 Is there a difference after all? At 40, it is 35psi, which is a difference of 8.9psi. Gain access to our free AOP (Ask a Professional) Section to get real answers for your questions. When you add fluorescent tracer dye to with the refrigerant oil it helps to track down leaks that push oil out of the system. Automotive Replacement Expansion Valves & Parts; Industrial & Scientific; Customer Reviews. Paul:A 1983 240D should have a York compressor on an OEM system. Paul:It is never a waste of my time to chat with someone that understands the problem, and wants to fix it. Edited: Tue July 17, 2007 at 3:25 AM by bohica2xo, I believe there is only one switch - the refrigerant switch. As for R134a and R1234yf, theres no room for conversion. 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. It cycles on off in med (or low for that matter)Gotta tell ya. That is for the compressor, drier, expansion valve and condenser. The evap is hard to get at. If you have a perfectly operating system using R12 you do not have to drop what you are doing and convert to R134a. This refers to BTU's (heat) moved per pound of refrigerant moved. 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. Yep, definately not a meat locker. ESP when a compressor has frozen. The MB chart shows 360 psi with R12 in some conditions. Hence, let us continue to fix it. video clubhouse baseball; nick fairley draft profile; ben davis work pants 05-25-2017 02:14 AM. 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. As noted, measure up front as best as you can to get as close to the aftermarket dim. Therefore, the R12 refrigerant is illegal, and emitting it is illegal. difference between r12 and r134a expansion valve . I bought a relay to put on it connected to the compressor clutch. . About four or five years ago, I guy with an MB came here with the same problem, that tread was over six pages long. Paul -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. With R134a you do not rely on the site glass. Lets take you through the advantages, disadvantages, and differences of these two refrigerants a detailed comparison including R12 vs R134a performance. Even with proper fan operation, missing seals & air dams can effect condensor effeciency. It does not "pool" to any degree in a large amount anywhere. 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). Sense ells no existirem. Concentration level: The R134a vapor dilutes the oxygen concentration in the air to a low level, thereby causing harm. Shorting the plug for the refrigerant switch should run the fan when the compressor is on. 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). R12 is heavier than R134a and has smaller molecules. R134a and R12 are both refrigerants used in vehicle air conditioning systems. The cure is to use the newer R134a compressors is sealing washers that are different thickness. Trinary Pressure Switch quantity. The system has been previously converted to R-134a. we convert older systems where i work all the time and they work fine. This is a great space to write long text about your company and your services. Is there a graph? ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. How an A/C Expansion Valve Works. and recharged with mineral oil and 2.2 lbs R12. The old compressor used R12 and the new unit will be R134a. 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. In the automotive world, the replacement for R12 was R134a. It is usually sold under the brand name, Freon 12. All fans must work at 100% of the OEM rating. Whether R134a performs as well as R12 in any given a/c system depends upon system components and the amount of R134a used. I cleaned the evap as best I could, if that is what you are getting at. ). The substitute that we used for R-12 was the new HFC called R-134a. Before we mentioned that you can add approximately 5-6 ounces of ester oil to the compressor. R134a. I could easily be over at least 2 - 3 ounces over on the oil. 4) Inconsistent Airflow. . look at the difference! Though I have seen em run as cold as 12 deg F. If the thermo switch is malfunctioning. System has been working fine for a year. Some 1993 and older R12 systems aren't as 'compatible' as you'd think to switch over. The Main change in the system is the expansion valve. In 1994 they switched from R-12 to R-134a. Below are the major differences between R134a and R12: The chemical composition of R12 and R134a differ. and feeds it through an expansion valve. I remember I had the wrong seals and it leaked some oil, so I put some more in.Bohica - I tested the pressures. The money you will save by will pay for the R12. 42 (at best) w/ 134A in 2000 isuzu trooper. 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 Originally Posted by goldNSX. A good T/C, clamped to the line & insulated gives a repeatable measurement of the tube. You are indeed 20% out of the OEM spec for cooling. You can use the R134a retrofit capacity chart for this purpose. 3) A/C Compressor Always On. Its highest value is 1. Yes, this was a smokers car. The catalytic converter is an essential component of your car's emission system that helps save the environment from harmful emissions.
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