Then again, there are two different expansion valves. 5. of coiled cap tube on VCR system with R134a. -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. Thanks for the input. Yep, definately not a meat locker. -------------------------"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 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. Most of all the differences gravitate to longevity, functionality, and safety. Instead, top off R12 with R134a refrigerant. 2001-2023 Griffiths Technical Inc. All Rights Reserved. Production of R12 ceased in 1996, although it can still be reclaimed, purified, and resold, and small cans of New Old Stock R12 are still widely available on eBay and Craigslist. If there is a resource I should read first to save you time, let me know. In most cases, the systems used have varied components, designs, and service ports. Since 2010, all home AC systems manufactured use a refrigerant like R134a that has zero ozone depletion potential (ODP). Recovery & flushing is the only way out of an oil overcharge in your vehicle.B. R12 is used in several applications like low temperature, medium temperature, and high-temperature applications. There is a lot of differences between the R12 and the R134a fittings, you can't mistake them. The #1 question asked by NEW MEMBERS. Replace the drier with a drier that has a desiccant that is R134a compatible, use new R134a o-rings. It's not just the poor performance - the cooling just stops working after a while. Therefore, the R12 refrigerant is illegal, and emitting it is illegal. Rxmechanic.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for website owners to earn advertising fees by advertising and linking to Amazon.com. You either get a system that will function well with R1234yf or get any other type. How thermostatic expansion valves work | Danfoss Though I have seen em run as cold as 12 deg F. If the thermo switch is malfunctioning. Since then, the industry standard has been R134a, which is an efficient replacement. This works when the R12 charge specification is listed in pounds. I know this is bad, etc, and deposits on the metal can act as insulators. 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. This is a great space to write long text about your company and your services. The larger fitting goes on the discharge port and the smaller fitting goes on the suction line or compressor inlet / suction port. The primary function of the design engineer is to make things difficult for the fabricator and impossible for the serviceman. Whether R134a performs as well as R12 in any given a/c system depends upon system components and the amount of R134a used. in /nfs/c05/h04/mnt/113983/domains/toragrafix.com/html/wp-content . The pressure/temperature curves for R-1234yf and R-134a are very similar. R12 to R134a change expansion valve? - HVAC-Talk: Heating, Air For instance at 25 F the pressure of R-12 is 24.6 PSI and the pressure of R-134a is 22.1 PSI. This refers to BTU's (heat) moved per pound of refrigerant moved. difference between r12 and r134a expansion valve 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 . You can spend long evenings reading about the differences between the two refrigerants. In a car ac, using this type of freon 20 years ago was difficult. As per their results . Read on for more information about using automotive r134a in a refrigerator and vice versa. R12 or R134a - 928 Owners Club Forum R134a refrigerant fittings are different size. For R12, its mineral oil. 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). The butylcellusolve or the citrus solvent will dissolve the carcass in a few minutes. By: james smith underoath; Comments: 0 . What is usually sniffed are all the connections in the system: hoses and compressor, condenser, drier, expansion valve and evaporator fittings. It is a known suspect that lets heat into the heat exchanger/core even when off because the mono-valve is on the exit side of the heater core. Thanks again. This is due to many facts: R134a refrigerant is about 10% less efficient in moving heat than R12! By noting the ambient temperature you can look up what the preferred high side pressure should be. The oil is spread all over your system when it is at rest. What was the ambient when you took that reading?Jumpering the aux fan is a common thing here in the desert. Is there a graph? Boiling Point: R134a refrigerants boiling point is -26.3C (-15.34F). 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. Is that reasonable?Vent airflow is good, I think. With R134a you do not rely on the site glass. The evap is hard to get at. The system has been previously converted to R-134a. B. R-12 is no longer used or produced in many countries and remaining quantities have skyrocketed in price. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. 5) A/C System Failure. Bottom line, R134a simply doesn't cool as well as R12. Hopefully after you have read this entire page you will have enough information to determine which type of refrigerant is best for you. Below are the major differences between R134a and R12: Chemistry The chemical composition of R12 and R134a differ. -The amount of R-134a needed will typically be 80-90% of the R-12 charge. It won't be optimal, though. Expansion Valve for R134a? | Team Chevelle After the system has been tested out it should be checked for leaks. We consider the the various types alternative refrigerants that are illegal or not approved to be in two sectors: non-flammables and flammables. Pray I can let some oil out of the compressor without losing my precious R12. Put a relay on the compressor clutch to the aux fan (I like that idea - makes a lot of sense)How does that sound? The compressors used by refrigeration plants to compress gas require oil to help lubricate its moving parts. shown for the parallel flow, aluminum condenser that is listed. 4 Stars & Up & Up; 3 Stars & Up & Up; 2 Stars & Up . So if you car has a large amount of rubber hose, such as a 40 feet with the 911, then you will be re-charging the system often and that is expensive no matter which refrigerant you use. Further production of R12 was banned in some developed countries by the Montreal Protocol because of its harsh effect on the ozone layer. 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. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. R134a is called tetrafluoroethane (HFC). However, theyre still used in older plants, systems, and the automotive industry. Paul:It is never a waste of my time to chat with someone that understands the problem, and wants to fix it. They can be mounted quite easy,and there is a mounting kit that helps to hang it. I'll put the relay on for that. We ALWAYS want to know the pressure readings! Carefully study the chart and compare the following: To a large extent, the choice is up to you. Skin contact: If the R134a (liquid) comes in contact with your skin, it could cause a burn. 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. Is it exponential, squared? PDF R134a R513A - Tecumseh Products Miscibility with oil: R12 can be mixed with the compressor oil no matter the operating condition. The pressure at low temperatures is nearly the same between 12 and 134a. difference between r12 and r134a expansion valve . Using R134a requires that Polyolester (POE) lubricant must be used in the compressor. Its chemical symbol is CH2FCF3. R12 is highly destructive to the earths ozone layer. 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. GWP is a measurement of Greenhouse Gases and their effect on Global Warming. Sense ells no existirem. To prevent refrigerant loss you should consider replacing your old hose lines with barrier type hose. However, you can convert R12 to R134a by yourself, save money and keep all the tools purchased. 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. 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. R134a requires the use of synthetic oil! Biggest you can fit in there is best. This kit comes complete with Expansion valve, o-ring kit, and 1ft. ). I am ordering new parts, and planning to convert my system to R-134a. R12 to 134A conversion. | Allpar Forums If you have a perfectly operating system using R12 you do not have to drop what you are doing and convert to R134a. 05-25-2017 02:14 AM. 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. We mention using ester type refrigerant oil. The MB chart shows 360 psi with R12 in some conditions. 30 deg is pretty coldSystems generally run between 40 and 43 deg. What is a T/C?4. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. A slow loss of cooling at city speeds is usually related to condensor capacity & airflow issues. Warning: "continue" targeting switch is equivalent to "break".Did you mean to use "continue 2"? 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. 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? Note that passwords are case-sensitive. Thread starter goldNSX; Start date 1 August 2009; Tagged . It is made up of carbon, hydrogen, and fluorine. 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. leading to corrosion of expansion valves, capillary tube plugging, and compressor bearing . PaulJerky King -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. At 2000rpm, windows open, highest fan, hi pressure stabilized at 225 psi, low 25psi.Ambient 81F, vent 61F. 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. R134a vs R12 refrigerant? = R134a Charge Level. and feeds it through an expansion valve. Make sure visiually that no large gaps exist that would allow the air to bypass the condensor on the way to the radiator.B. Once you have replaced the OEM condensor with a PF unit, you will need to make custom hoses to mate with your OEM system. Just had knee surgery yesterday, so I"M not exactly hopping around too well. Add to cart. The original CFC expansion valve used for R12 needs to be replaced with an HFC one for 134a to feed the evaporator correctly. Its chemical symbol is CCl2F2. I had to vaccum the system for 2 hours and recharge 4 oz of PAG oil plus 36 oz of 134A freon (3 cans). 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. R134a Refrigerant Recharge Kit with BPV31 Bullet Piercing Valve and R134a Quick Coupler, R134a/R-12/R-22 Freon Refrigerant Hose Can Tap Kit for A/C System - Easy to use. 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. Nick, I hear you - there maybe nothing to do here. 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. How about evacing 1 pound of refrig from the system, and then putting 1 lb of pure R12 back in? It can be used applications like walk-in coolers, food and dairy display cases, domestic refrigerators, and beverage dispensers and vending machines. This drop can affect energy consumption since the plant will operate for a longer period or a larger plant will have to be installed. Don't like the sound of custom parallel condensor. 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. We sometimes use a relay switched from the compressor clutch to run fans. The difference between the two is about 10,000 btu/h. Can I just use an adapter and save $200? Fitting a PF condensor is not rocket science, but it requires some planning. 3) A TXV optimized for 134a will be ok with R12. 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 . By using a black light the dye will glow in areas where oil leaks are visible. 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. Swapping the components isnt a herculean task, but recharging the AC is a challenge. 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. El juny de 2017, el mateix grup va decidir crear un web deDoctor Who amb el mateix objectiu. A/C receiver difference between R12 and R134a? | NSX Prime Concentration level: The R134a vapor dilutes the oxygen concentration in the air to a low level, thereby causing harm. ESP when a compressor has frozen. Your decision could be made based on economics, environmental concerns, or both. The best replacement for R134a is R1234yf, while R12 refrigerant replacement was R134a. 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. It can be used applications like walk-in coolers, food and dairy display cases, domestic refrigerators, and beverage dispensers and vending machines. Since the hose is the stock hose, you cannot tell what refrigerant is inside. PDF Tecumseh Guidelines for Utilization of R134a
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