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In short, NO! 34 in 70 series w/ R12 in 100+ Tucson, AZ summer heat w/ hd-t, w/ 13B-T is was unbearable about 31 at vent w/ R12. Please enter a password for your user account. Besides, its technology has been tested and trusted. Compared with the cost-performance ratio, R507 is 30-40% . 4.3 out of 5 stars 491. The R134a compressor has a 1/8" step in on the high side port. #19. Is there a source of valves by, say, eaton number? Is that why expansion valves are specific to R12 or R134A? But as there's not a big difference, people say you can suffice with either. Hope this helps. Expansion valves are an active device, they regulate the flow of refrigerant to the evaporator depending on evaporator temperature. I know this is bad, etc, and deposits on the metal can act as insulators. Is it exponential, squared? As an example, let's say the R12 charge specification is listed at 2 lbs. . Discussion in 'Technical' started by Jsarnold, May 25, 2012. SO here's my question. Temp switch works the aux fan. The #1 question asked by NEW MEMBERS. This is 11F off the FSM performance graph - vent should be around 50F. american sniper longest shot; how to adjust sunsetter awning arms; pastor jeremy roberts texas. The cost of recharging the air conditioner is between $150 to $500. Condensers designed to release greater amounts of heat help to expel the greater amount of heat which R134a removes from the cars interior. Compressor. Edited: Tue July 17, 2007 at 3:25 AM by bohica2xo, I believe there is only one switch - the refrigerant switch. 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. I put one in my old daily driver '79 Chevy tank (r-12), and it really made a difference. They have no moving parts. However, if it is taken close to a fire flame or any electrical heating element, it disintegrates into toxic products. After the system has been tested out it should be checked for leaks. . Hence, the effect of R12 on global warming is up to 10,000 times higher than carbon dioxide. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. Post photos, respond to polls and access other special features. R1234yf is more environmentally friendly and has a global warming potential of 4. Yep, definately not a meat locker. Gain access to our free AOP (Ask a Professional) Section to get real answers for your questions. Please enter a valid email address for yourself. R134a and R12 are among the most popular types of refrigerants. R134a requires a different oil. 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. Anyone know what happens when an R12 expansion valve is used in a system charged with R134A? R-12 expansion valves can be re-used, but will not be as efficient as R-134a specific ones because of the slightly different pressure specs of R-12 vs. R-134a. This allows the refrigerant in the condenser to be void of oil particles. Moreso, it had been banned. Participate in over 40 different forums and search/browse from nearly 3 million posts. 42 (at best) w/ 134A in 2000 isuzu trooper. VerticalScope Inc. All Rights Reserved. When I compare parts, 93 uses one part number and 94 has a different part number. 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. Even if the system leaks, repairing the leaks and recharging it with R-12 is usually the best repair alternative. If it splashes inside the eye, it could lead to a serious eye problem. Energy usage: R134a is less efficient in cooling compared to R12. I have just bought gauges. 4) Repeat step 2, making sure it will fit. Typically 5 to 6 ounces of a/c oil is adequate but this may vary depending upon the car. Look at where the lines will end up. The sticker typically has a place to note the amount of refrigerant used, the type of oil and amount of oil, the technicians sign off or name and the date of the conversion. There are three different refrigerants officially sanctioned by the EPA for automotive usage: r-12, r-. We mention using ester type refrigerant oil. The mechanical fan & clutch should be checked as well. If you're getting a R134a compressor, might as well finish the job - replace the receiver/dryer, flush everything else, and convert to R134a anyhow. The chemical composition of R12 and R134a differ. It can be used applications like walk-in coolers, food and dairy display cases, domestic refrigerators, and beverage dispensers and vending machines. 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. R134a is called tetrafluoroethane (HFC). Concentration level: The R134a vapor dilutes the oxygen concentration in the air to a low level, thereby causing harm. Carefully study the chart and compare the following: To a large extent, the choice is up to you. R12 is highly destructive to the earths ozone layer. Hence, let us continue to fix it. The car never overheats, if that has any import. Above this temperature, the saturation pressure of R134a is higher than that of R12; below, it is lower. It has already been clearly stated that R12 is a chemical that damages the earths ozone layer and shouldnt be released into the environment no matter the circumstance. #13. Bohica, I appreciate your help with this. It can be used applications like walk-in coolers, food and dairy display cases, domestic refrigerators, and beverage dispensers and vending machines. 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 could easily be over at least 2 - 3 ounces over on the oil. Is there a graph? Best for varieties of operating conditions: Its boiling point is -21.6 Celsius. Usually, mechanics charge around $200 for conversion. This means that it has a high potential of causing depletion to the ozone layer. of coiled cap tube on VCR system with R134a. difference between r12 and r134a expansion valve. (You must log in or sign up to reply here. This refers to BTU's (heat) moved per pound of refrigerant moved. If the system was upgraded by a professional it should have an upgrade sticker. 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. Low refrigerating effect per pound: In comparison to other refrigerants, the refrigerating effect of R12 per pound is low. difference between r12 and r134a expansion valve. I dont know why the cost difference between compressors is so huge, though. When the temperature is reduced to-7C or below, the plants ability to cool the airdrops significantly. As for R134a and R1234yf, theres no room for conversion. R134a has an ozone depletion potential of 0, implying that it has a slight effect on the ozone layer. Also, since R134a uses synthetic oil, it has a low global warming potential, unlike R12 which uses mineral oil which poses a negative environmental impact. However, the supply houses don't indicate a difference. Bad Car A/C Expansion Valve Symptoms. R134a is called tetrafluoroethane (HFC). Minor adjustments to the expansion valve and other controls may be necessary for some plans. -------------------------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! difference between r12 and r134a expansion valve. R404a is a zeotropic blend with a temp glide , because of the mixture of 2 or more refrigerants. We've updated our forums!Click here to visit the new forum, Year: 1991Make: Jaguar Model: XJ6Engine Size: 4.0. The aux fan didn't switch on though and I didn't check the high side temperature. Ask Our Pros-Owner Assistance - NO DIY advice will be given. Besides, R134a refrigerant was manufactured after R12 was banned to help reduce the harshness of the old chemical (R12) on the ozone layer. 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. Should I do the test again with the the aux fan jumpered? Just leave it alone for now. is good, then I should be looking elsewhere? 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. You will be fine with a 134a-compatible TXV running R12. and an evaporator core and expansion valve that are optimized for R134a . Since there is only about a 10% difference between R-12 and R-134a, the expansion valve being self-compensating really doesn't make that much difference. #4. The OEM spec is 2300 rpm @ 12.6v (engine stopped fully charged battery). I don't have the FSM matrix handy for that 123.123, but a 123.133 shows a test rpm of 2,000 - and vent temps between 54f & 66f at 91f to 95f ambient. 1) Look Here at the available sizes of PF condensors.2) Go look at your vehicle's condensor & mounting. If you have a perfectly operating system using R12 you do not have to drop what you are doing and convert to R134a. Some compressor manufacturers or OEMs suggest PAG type oil for R134a. The adjusted tension of this spring is the determining factor in the opening and closing of the expansion valve. I've done the FSM test and with 81F ambient, the vent should be 50F. You'll want the expansion valve matched to whatever refrigerant you're using. In most cases, the systems used have varied components, designs, and service ports. The system has been previously converted to R-134a. 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? That would be the "black death" syndrome. It was later found that R-134a had a very high Global Warming Potential, or GWP, number. Unfortunately, the R12 refrigerant doesnt always blow cold air. Make sure to wear safety gloves, goggles, and shoes when theres a possibility of exposure to the chemical (R134a). I would not do a 134a conversion without a PF condensor. -------------------------"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." ing the expansion valve, a maximum opening superheat of 7F, and a standard factory air test superheat setting. Agram a retevis rt22 password i bastrop county district clerk records el material que oferim als nostres webs. R12 is otherwise called dichlorodifluoromethane is a colorless gas (chlorofluorocarbon halomethane (CPC) that is used as an aerosol spray propellant and a refrigerant, and is soluble in organic solvents. Skin contact: If the R134a (liquid) comes in contact with your skin, it could cause a burn. I bought a relay to put on it connected to the compressor clutch. Using R134a requires that Polyolester (POE) lubricant must be used in the compressor. In a comparison between R12 vs R134a vs R1234yf, R1234yf will pass as the best refrigerant. Therefore, the R12 refrigerant is illegal, and emitting it is illegal. GWP is a measurement of Greenhouse Gases and their effect on Global Warming. Electric fans do wear out. Can I use the one for the R-12? Comparatively, larger R134a molecules should take more space, and a smaller amount might be required. They can be mounted quite easy,and there is a mounting kit that helps to hang it. 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. Safe but sorry! Its not that difficult but the procedures of evacuation, charging and testing should be done by a licensed a/c technician that is experienced with R134a and your particular car. 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. I'm curiousSo there is work to do, ie performance should be able to be improved. Is there a difference between a R134a expansion valve and an R12 TXV? The problem with these so called drop in replacements is that to properly handle them you may need dedicated equipment to identify the gas and evacuate it for proper disposal. Generally the system will be initially charged with approximately 80% to 85% of the original amount of R12, using R134a. The difference between R12 and r134a is the BTU carrying capability. Below are the major differences between R134a and R12: The chemical composition of R12 and R134a differ. ESP when a compressor has frozen. Failure to abide by the EPA regulations can result in expensive fines for either you or your service technician. It's not just the poor performance - the cooling just stops working after a while. R134a and R12 are both refrigerants used in vehicle air conditioning systems. If the charge is low the compressor will cycle on/off in the max AC position. Depending on which circuit diagram fits your car (cough, no vin list exists) you have either one or two switches controlling the aux fan. It didn't seem too dirty though - I don't think it is the problem, but I could be wrong. Break out the new gauges and measure hi and lo at 1500rpm, and do the Merc FSM test to see how we're doing performance wise. R134a systems operate at higher discharge-side pressures than R12, which can cause compressor seals to leak. But as there's not a big difference, people say you can suffice with either. Consider using the newer valve, even with 134a stamped on the valve. 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. Thomas Jefferson, Thanks,OK, I'm starting to feel a little better about it. I don't recall all the details, but starts off with the largest parallel flow condenser and improved fans. 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. R134a vs R12 refrigerant? Then again, there are two different expansion valves. In 1994 they switched from R-12 to R-134a. Is that why expansion valves are specific to R12 or R134A? 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). Since 2010, all home AC systems manufactured use a refrigerant like R134a that has zero ozone depletion potential (ODP). R12, on the other hand, has an ozone depletion potential of 1, implying that it can damage the ozone layer. Formula: (R12 Charge Specification x 0.9) - 0.25 lbs. R134a refrigerant is lighter than R12. Neuro spine Super Speciality Clinic - Above Apollo Pharmacy, Bangarpet Circle, Kolar - Bangarpet Road, Kolar Town. Use strips of foam to couple the two heat exchangers if necessary.B. Further production of R12 was banned in some developed countries by the Montreal Protocol because of its harsh effect on the ozone layer. Mine was 61, so the system is not working as it is supposed to. System has been working fine for a year. Have a look in the FAQ Section, and look for "Fan clutches & testing them". This may be the source of your oil confusion. and recharged with mineral oil and 2.2 lbs R12. I'll report back on the aux fan on performance next. R404a for freezing of product. The system has been previously converted to R-134a. A good T/C, clamped to the line & insulated gives a repeatable measurement of the tube. We recently created this blog site to enable us to share our knowledge with other automotive mechanics and car owners. Until 1995, most cars with air conditioning used R-12 Freon refrigerant which has shown to have an environmental impact. The R134a compressor has a 1/8" step in on the high side port. Sense ells no existirem. 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. An orifice tube is just a fixed nozzle that pisses refrigerant into the evaporator without any sort of feedback. However, R12 refrigerants are still used as fire retardants in aircraft and submarines. Not osmosis, but you know what I mean). I've got a ball valve I'm going to put in the coolant line before the coolant goes through the firewall to the core. This refers to BTU's (heat) moved per pound of refrigerant moved. Right now you know you have a bit too much, but with a CR4P compressor this is an insurance policy. 4 Stars & Up & Up; 3 Stars & Up & Up; 2 Stars & Up . look at the difference! Big . The typical scenario here is when the car owner buys an inexpensive retro-fit kit from the local auto parts store. There are other refrigerants: some of which may work, some of which dont work, some of which will destroy your a/c system and some of which are dangerous. MB has specfic test parameters for performance, but you can always test at max load - doors open fan on highest speed.The oil overcharge looks like a parabolic curve. But, what is considered a good temperature differential across the condensor? Lasers don't do well on vent temps, a stick thermometer is better in that application. R12, on the other hand, is called chlorofluorocarbon (CFC). Trinary Pressure Switch quantity. The non-flammables can have R22 type gas which is not compatible with most rubber hoses or they have gases that contribute to global warming. Swapping the components isnt a herculean task, but recharging the AC is a challenge. . At this point it is time to make an appointment with the a/c shop. The pressure at low temperatures is nearly the same between 12 and 134a. R134a refrigerant fittings are different size. With R-12, 30 is 28.4psi and 40 is 36.9psi, for a difference of 8.5psi. These efforts to balance the system can not be realized if there are problems within the a/c system, such as: poor performing compressor, dirty condenser or poor air flow through the condenser, malfunctioning expansion valve, water or air in the system, improperly operating fresh air or heat input in the climate-air mixing system. -------------------------"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." Expansion Valve. Blows pretty hard on full. Even with proper fan operation, missing seals & air dams can effect condensor effeciency. Once you have replaced the OEM condensor with a PF unit, you will need to make custom hoses to mate with your OEM system. R12 and R134 are of different chemistry. 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. The crossover point is approximately at 64F. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. As noted, measure up front as best as you can to get as close to the aftermarket dim. 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. Large temperature difference between expansion valve inlet and outlet oReplace expansion valve Air . R134a is NOT less efficient than R12 Actually R134a is more efficient. The problem with using an approved alternative refrigerants other than R134a is that when the system is serviced it requires certain types of fittings, labels and dedicated equipment. This works when the R12 charge specification is listed in pounds. This is due to many facts: R134a refrigerant is about 10% less efficient in moving heat than R12! A lower GWP alternative to R-134a had to be found and thus we have the new 1234yf. A capacity curve is shown in figure 2 for relative capacity of R134a vs. R12 for evaporating temperatures from 0F to 50F. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. Is that reasonable?Vent airflow is good, I think. It is made up of carbon, hydrogen, and fluorine. Statisicaly your friend was lucky. gital control scheme. Quick View. 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. 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. 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 . -------------------------"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." Thanks so much Bohica - you've save me many more hours of fruitless speculation. To prevent refrigerant loss you should consider replacing your old hose lines with barrier type hose. Most vehicles manufactured before 1993 have the R12 A/C system. Looks like a couple of things happening here1) 80's vintage Eurocars were not "meat lockers". The value of carbon dioxide is 1. Additionally, R134a was introduced as a replacement for R22 and R12 in high and medium-temperature refrigeration systems like domestic and commercial chillers. If the system was upgraded by a professional it should have an upgrade sticker. Thread starter goldNSX; Start date 1 August 2009; Tagged . 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. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. 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. "Jerky Locker" LMAO I am using that one in the future!Florida = BUGS! Expansion Valves Catalog E-1, July 2012. 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. There is a lot of differences between the R12 and the R134a fittings, you can't mistake them. R-12 to R-134a Conversion. The larger line at the expansion valve is the suction line. Vent temperatures slowly go down to around 50F with hi speed driving. Generally this works well for the whole system. From memory, I put in at least 8 ounces of oil, probably around 10 ounces in there. We consider the the various types alternative refrigerants that are illegal or not approved to be in two sectors: non-flammables and flammables. . Anyone know what happens when an R12 expansion valve is used in a system charged with R134A? At 2000rpm, windows open, highest fan, hi pressure stabilized at 225 psi, low 25psi.Ambient 81F, vent 61F. The substitute that we used for R-12 was the new HFC called R-134a. $21 . Use a drop light in the engine bay, and check the air path from the front of the car at night. Below are the major differences between R134a and R12: Chemistry The chemical composition of R12 and R134a differ. The difference between the two is about 10,000 btu/h. You can spend long evenings reading about the differences between the two refrigerants. CLUTCH CYCLING SWITCH. 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. The larger fitting goes on the discharge port and the smaller fitting goes on the suction line or compressor inlet / suction port. Attach the R134a charge port adaptors, there are two types.. one of which you need to remove the old R12 valve cores. The exact amount will vary with each car. 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. Bottom line, R134a simply doesn't cool as well as R12. On the other hand, R12 has a global warming potential of 10,910. The higher the ambient temperature the higher the high side pressure.