It is possible I have 10 ounces (250 ml) in the system. Could that be screwing up the systems performance?Anyway, when I installed the system, the new TXV (is that short for expansion valve?) Plus, not releasing the chemical into the air is morally justifiable. For instance at 25 F the pressure of R-12 is 24.6 PSI and the pressure of R-134a is 22.1 PSI. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. 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. . -------------------------"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." difference between r12 and r134a expansion valve . Answer: OK, I'll bite. I don't know where it is getting the switch off command, or why the vent temp drops steadily. difference between r12 and r134a expansion valve. The exact amount will vary with each car. Where would I get some basic info on it, I know nothing about it. (On firewall where A/C lines go into cab.) in /nfs/c05/h04/mnt/113983/domains/toragrafix.com/html/wp-content . difference between r12 and r134a expansion valve. You should keep in mind that recharging your air conditioner improperly could result in more serious damage. The adjusted tension of this spring is the determining factor in the opening and closing of the expansion valve. video clubhouse baseball; nick fairley draft profile; ben davis work pants |. When the ambient air temps get above 80F the gauge readings can run a bit higher on the high side and lower on the low side when using R134a. 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. Its highest value is 1. Nice to use new gadgets! What was the ambient when you took that reading?Jumpering the aux fan is a common thing here in the desert. However, R12 refrigerants are still used as fire retardants in aircraft and submarines. The original CFC expansion valve used for R12 needs to be replaced with an HFC one for 134a to feed the evaporator correctly. Concentration level: The R134a vapor dilutes the oxygen concentration in the air to a low level, thereby causing harm. How is the vent airflow?I would jumper the aux fan & check the performance. Participate in over 40 different forums and search/browse from nearly 3 million posts. We've updated our forums!Click here to visit the new forum, Year: 1983Make: MercedesModel: 240DEngine Size: 2.4Refrigerant Type: R12Ambient Temp: 90Pressure Low: 35Pressure High: ?Country of Origin: United States, Hi, this is my first post, so please take it easy on the noob. The flammables have hydrocarbons. hardly noticable. Quick View. How about evacing 1 pound of refrig from the system, and then putting 1 lb of pure R12 back in? Stopleak is also risky. An orifice tube is just a fixed nozzle that pisses refrigerant into the evaporator without any sort of feedback. Different correction factors are applied to other refrigerants. Should I do the test again with the the aux fan jumpered? 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. 42 (at best) w/ 134A in 2000 isuzu trooper. This allows the refrigerant in the condenser to be void of oil particles. The aux fan didn't switch on though and I didn't check the high side temperature. Some cars have both an engine coolant temp switch & a refrigerant temp switch, others only the refrigerant switch. If your cars system has a sufficient condenser design and air flow to expel the greater amount of heat extracted by R134a, then by all means you should convert over when the time comes. But R22 is almost equally damaging. The R134a compressor has a 1/8" step in on the high side port. Formula: (R12 Charge Specification x 0.9) - 0.25 lbs. A/C receiver difference between R12 and R134a? A. Pressure/temperature table for R12, R134a, and R513A is shown in Figure 1. . Pray I can let some oil out of the compressor without losing my precious R12. leading to corrosion of expansion valves, capillary tube plugging, and compressor bearing . R134a and water have the same abilities to change the state but R134a can do this more rapidly and at a much lower temperature than water. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. 4) Repeat step 2, making sure it will fit. compressor, condenser, evaporator and expansion valve are specifically designed for use with R134a. Energy usage: R134a is less efficient in cooling compared to R12. Ask Our Pros-Owner Assistance - NO DIY advice will be given. El juny de 2017, el mateix grup va decidir crear un web deDoctor Who amb el mateix objectiu. The mechanical fan & clutch should be checked as well. 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. Can I use the one for the R-12? R12 is used in several applications like low temperature, medium temperature, and high-temperature applications. You either get a system that will function well with R1234yf or get any other type. The original expansion valves work very well with R134a. I think so. I'll put the relay on for that. Lets take you through the advantages, disadvantages, and differences of these two refrigerants a detailed comparison including R12 vs R134a performance. Fitting a PF condensor is not rocket science, but it requires some planning. To ensure the right charge, you must fill the new system with between 75 and 85% of the factory-set capacity for optimal cooling. Very interesting! The pressure/temperature curves for R-1234yf and R-134a are very similar. 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 . 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. asia pacific stevie awards 2021. gin, amaretto cocktail. This is a great space to write long text about your company and your services. Is that reasonable?Vent airflow is good, I think. The symbol implies that R12 is a composite of carbon, chlorine, and fluorine. 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. It is made up of carbon, hydrogen, and fluorine. R134a refrigerant fittings are different size. Have a look in the FAQ Section, and look for "Fan clutches & testing them". A capacity curve is shown in figure 2 for relative capacity of R134a vs. R12 for evaporating temperatures from 0F to 50F. Recharge the compressor with a/c ester oil and a tracer dye. When the sensor detects the refrigerant leak the sniffers lights glow and the sniffer makes a noise. By using a qualified a/c shop with the proper equipment you odds are in your favor of having the job done correctly the first time. Get to the point where I can walk without crutches2. If liquid refrigerant were to exit the evaporator. You can also check the Aux fan in your case. You can use the R134a retrofit capacity chart for this purpose. and he synthesized R-134a in 1936, 5 years after R-12 was . $21 . 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. Consider using the newer valve, even with 134a stamped on the valve. What is needed? The difference between the two is about 10,000 btu/h. Talk about what services you provide. Also called the orifice tube. Then again, there are two different expansion valves. A capacity curve is shown in figure 2 for relative capacity of R134a vs. R12 for evaporating temperatures from 0F to 50F. 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. And I lied about the compressor switches on this car - there are 2 switches on the drier - a temp and a pressure switch. absorb by the evaporator to insure all liquid refrigerant entering the evaporator. The difference between R12 and R134a TEV (exp valves) is primarily the 'superheat'. Also, it can be used with all types of compressors. Expansion valves are an active device, they regulate the flow of refrigerant to the evaporator depending on evaporator temperature. A good T/C, clamped to the line & insulated gives a repeatable measurement of the tube. That's a lot isn't it? The oil used in R12 systems is not compatible with R134a refrigerant. R12 and R22 are both now banned by the EPA in the United States. There are R134a specific valves that operate at a slightly different pressure, but not for any "old" automotive application that I'm aware of. R12 and R134 are of different chemistry. 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. 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. However, the supply houses don't indicate a difference. 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. The old compressor used R12 and the new unit will be R134a. The oil is spread all over your system when it is at rest. Then at least I'd know really where I am on it. Please enter a valid email address for yourself. Best for varieties of operating conditions: Its boiling point is -21.6 Celsius. . Just because the radiator does not boil people assume that the cooling system is ok. It runs between the condenser outlet, receiver/drier unit and expansion valve at the firewall. 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). had writing on the side that said R134a. 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. 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. R134a is called tetrafluoroethane (HFC). 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. 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. Its chemical symbol is CCl2F2. To bless the system the technician should attach a R134a sticker somewhere in the engine compartment to note the car is using R134a. I have one can left, so maybe a plan can be made. B. 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. 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. This is because R134a. Further production of R12 was banned in some developed countries by the Montreal Protocol because of its harsh effect on the ozone layer. Operating Pressure/Temperature Differences The pressure/temperature curves for R-1234yf and R-134a are very similar. This would become an expensive investment for a repair or service station to have unique dedicated equipment for every type of alternative refrigerant. July 3, 2022July 3, 2022. Your average garage that works on a/c on the side probably would not have this. I'm curiousSo there is work to do, ie performance should be able to be improved. Hence, the effect of R12 on global warming is up to 10,000 times higher than carbon dioxide. 1) Look Here at the available sizes of PF condensors.2) Go look at your vehicle's condensor & mounting. Rules governing changing from the former to the latter differ between countries. 2001-2023 Griffiths Technical Inc. All Rights Reserved. Catalog E-1, Thermostatic & Automatic Expansion Valves / Page 1 Table of Contents . 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. Low refrigerating effect per pound: In comparison to other refrigerants, the refrigerating effect of R12 per pound is low. Besides R134a there are some other refrigerants that are approved to replace R12 and there is a long list of refrigerants that are not approved. R134a refrigerant is lighter than R12. They plug all the time. It's actually a reaction with chlorine in the mineral oil that may have been absorbed and leftover from the old R-12. is good, then I should be looking elsewhere? Miscibility with oil: R12 can be mixed with the compressor oil no matter the operating condition. Looks like a couple of things happening here1) 80's vintage Eurocars were not "meat lockers". 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. Superheat you can consider to be the additional amount of heat. That way I will have reduced the oil by about 1/3 (assuming the oil is mixed evenly through the system). Therefore, the higher the factor of the chemical (compound), the greater its effect on global warming. 37 in 2005 tacoma, R134A. Replied by Rich928 on topic R12 or R134a. The first vehicle that used the R1234yf refrigerant was the 2013 Cadillac XTS. After the optimum refrigerant charge is determined the car should be test driven to check for performance of the system. Some 1993 and older R12 systems aren't as 'compatible' as you'd think to switch over. How an A/C Expansion Valve Works. R12, on the other hand, is called chlorofluorocarbon (CFC). It can be used applications like walk-in coolers, food and dairy display cases, domestic refrigerators, and beverage dispensers and vending machines. As per their results . Table 1 summarizes the technical characteristics of three potential R134a alternatives. 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 . The chemical composition of R12 and R134a differ. "Howdy, Folks!" One thing at a time here, and slowly, the knee is not up to jumping around like I used to at the moment. In a comparison between R12 vs R134a vs R1234yf, R1234yf will pass as the best refrigerant. Rules governing changing from the former to the latter differ between countries. But R22 is almost equally damaging. The oil used in R12 and R134a are different and not compatible. maintain the A/C of older cars. Don't like the sound of custom parallel condensor. Big . You do not however need to replace all the o-rings or seals for a simple conversion, it is simply a logical thing to do when and if the time comes to work or replace certain components because of age issues. Questions About Becoming A Professional Member? If 50 degrees across the cond. Please enter a password for your user account. This can be very very expensive. 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. R-12 is no longer used or produced in many countries and remaining quantities have skyrocketed in price. GWP is a measurement of Greenhouse Gases and their effect on Global Warming. Is there a difference between a R134a expansion valve and an R12 TXV? (You must log in or sign up to reply here. Minor adjustments to the expansion valve and other controls may be necessary for some plans. If you find any of these conditions you will want to liquid flush (with dedicated AC flush solution) all the lines, condensers, evaporator (remove the expansion valve) before you proceed further. R1234yf. R12 is simply too expensive for a 25+ year old A/C system. 2) Frost on the Vents. The difference between R12 and r134a is the BTU carrying capability. A/C Expansion Valve Replacement Cost. You can spend long evenings reading about the differences between the two refrigerants. Post photos, respond to polls and access other special features. The general practice of charging the system with 15% less refrigerant adds to the thermal deficiency of R134a. Generally, the new amount is 75-85% of the quantity advised by the manufacturer. Formula: (R12 Charge Specification x 0.9) - 0.25 lbs. 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. 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. R12, on the other hand, is called chlorofluorocarbon (CFC). If you are replacing other system components, such as condensers, driers or hoses, you may need to add more a/c refrigerant oil to the system. Crap! In the automotive world, the replacement for R12 was R134a. Most importantly, the oil used in the plant must always be compatible with the refrigerant used. There is a lot of differences between the R12 and the R134a fittings, you can't mistake them. Agram a retevis rt22 password i bastrop county district clerk records el material que oferim als nostres webs. You'll get marginally better performance out of the change as the expansion valve is matches the refrigerant characteristics. The problem with not being an expert is that you don't know what is important and what's not. This implies that the discharge pressure of the compressor should be moderate so it can produce the refrigerants condensation in the condenser at the atmospheric temperature. Thanks for the input. I had a 1991 BMW switched to 134a by just changing the low pressure charging valve, flushing and refilling with 134 (maybe with 10% . I don't think it has any air dams or seals, I'll check to make sure. 3) A/C Compressor Always On. R-401b is the mixture by weight of 61% R22, 11% R-152a and 28% of R-124. You may have heard of a friend that did the job himself with borrowed equipment and 12 or 16 ounce cans of refrigerant. 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. I don't recall all the details, but starts off with the largest parallel flow condenser and improved fans. Additionally, R134a was introduced as a replacement for R22 and R12 in high and medium-temperature refrigeration systems like domestic and commercial chillers. Unfortunately, the oil only mixes with the refrigerant as a liquid. It cycles on off in med (or low for that matter)Gotta tell ya. For R12, its mineral oil. Reattach the hose lines using new R134a compatible o-rings, lightly lubricate with compressor oil. So the steps involved are cleaning out the old oil, replacing all the O-rings, replacing the dryer, replacing the expansion valve, and converting the high and low side connectors from Schrader to quick connect valves. Ensure you contact a professional mechanic to do the work for you so you dont end up incurring more costs for yourself. System has been working fine for a year. Add to cart. The car never overheats, if that has any import. R1234yf is more environmentally friendly and has a global warming potential of 4. That is for the compressor, drier, expansion valve and condenser. gital control scheme. 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. This may be the source of your oil confusion. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyers guides, and car and tools comparisons. The original rubber a/c hose lines in your car will leak out R12 through the hoses lining. This refers to BTU's (heat) moved per pound of refrigerant moved. The pressure at low temperatures is nearly the same between 12 and 134a. If the charge is low the compressor will cycle on/off in the max AC position. The butylcellusolve or the citrus solvent will dissolve the carcass in a few minutes. By: james smith underoath; Comments: 0 . Instead of using R12, its preferable to use R134a because it is very easy to find in the market, its sold at an affordable price, and is environmentally friendly. As noted, measure up front as best as you can to get as close to the aftermarket dim. Later model cars that come with 134A will have 134A only connectors. Besides, R134a refrigerant was manufactured after R12 was banned to help reduce the harshness of the old chemical (R12) on the ozone layer. The Main change in the system is the expansion valve. 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. That is a good thing. If there is no pusher fan, and you have the room, put one in. And, unfortunately a small high side pressure gauge on a short hose. R12 systems used mineral oil, but unfortunately mineral oil doesn't dissolve in R134a. Attach the R134a charge port adaptors, there are two types.. one of which you need to remove the old R12 valve cores. 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. Also the new quick connect fittings for the high & low side. A. Pressure/temperature table for R12, R134a, and R513A is shown in Figure 1. . The condensor airflow drops off as the fan clutch dies slowly. -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a, Bohica, You say the drop in performance is not linear with too much oil. Expansion Valves Catalog E-1, July 2012. 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 Wolfpack Brothers Where Are They Now,
Milford, Ma Police Accident Report,
13th Virginia Regiment Revolutionary War,
Late Ki Three Forms Of Verb,
Articles D
