difference between r12 and r134a expansion valve

You may need to adjust the valve in a bit to get desired superheat. 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. Flushed, vacuumed etc. Since the hose is the stock hose, you cannot tell what refrigerant is inside. -------------------------"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." The bad thing is I don't know what to do about it. All pre-97 XJs use systems with the same basic operating principle, although the parts do change a bit. When the sensor detects the refrigerant leak the sniffers lights glow and the sniffer makes a noise. I have some experience with auto a/c but not too much. The pressure at low temperatures is nearly the same between 12 and 134a. Table 1 summarizes the technical characteristics of three potential R134a alternatives. R12 is heavier than R134a and has smaller molecules. Best for varieties of operating conditions: Its boiling point is -21.6 Celsius. 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. It's helluva humid and hot here in north florida, and I drive around all day for my job. Is that why expansion valves are specific to R12 or R134A? 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. R1234yf is more environmentally friendly and has a global warming potential of 4. The global warming potential of R134a is 1430. 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. Some cars have both an engine coolant temp switch & a refrigerant temp switch, others only the refrigerant switch. At this point it is time to make an appointment with the a/c shop. Heres R12 vs. R134a pressure chart. The original expansion valves work very well with R134a. There is more to check.The evaporator must be clean as well as the condensor - was this a smoker's car?You should check the water control valve for the heater core. 2001-2023 Griffiths Technical Inc. All Rights Reserved. Even with proper fan operation, missing seals & air dams can effect condensor effeciency. How about evacing 1 pound of refrig from the system, and then putting 1 lb of pure R12 back in? And yes - expansion valves sometimes need replacing if they are sticky - but a proper AC flush should eliminate the need for a new one if it's already in good condition. of coiled cap tube on VCR system with R134a. PDF COMPARISON OF Rl34a AND R12 REFRIGERANTS IN A VAPOUR - AIVC In cases such as this, the required capacity value of the expansion valve with R134a is reduced by 30% (correction factor 1.42). From memory, I put in at least 8 ounces of oil, probably around 10 ounces in there. CLUTCH CYCLING SWITCH. Rules governing changing from the former to the latter differ between countries. My turn to LOL - greasiesel! It is mixed with the freon for the most part, and does accumulate in all components in small amounts. Jun 19, 2007. You will be fine with a 134a-compatible TXV running R12. Just leave it alone for now. However, R12 refrigerants are still used as fire retardants in aircraft and submarines. Vent temperatures slowly go down to around 50F with hi speed driving. An extra half ounce? Its chemical symbol is CCl2F2. Bottom line, R134a simply doesn't cool as well as R12. 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 . R1234yf. If the charge is low the compressor will cycle on/off in the max AC position. 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. I had a pair on my SAAB that seemed ok - but new ones ran 20% faster!Your best clue to airflow issues is a 60 mph test. Expansion Valve for R134a? | Team Chevelle 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. R134a has the chemical formula CF3CH2F and is known as tetrafluoroethane. It was later found that R-134a had a very high Global Warming Potential, or GWP, number. Post photos, respond to polls and access other special features. 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. Not going to mess up your 'do, but you can feel it. How dumb!I will jumper the aux fan and redo the test. Thread starter goldNSX; Start date 1 August 2009; Tagged . (On firewall where A/C lines go into cab.) 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. Make sure visiually that no large gaps exist that would allow the air to bypass the condensor on the way to the radiator.B. 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. Until 1995, most cars with air conditioning used R-12 Freon refrigerant which has shown to have an environmental impact. Paul:It is never a waste of my time to chat with someone that understands the problem, and wants to fix it. R134a systems operate at higher discharge-side pressures than R12, which can cause compressor seals to leak. 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. 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. Unfortunately, the R12 refrigerant doesnt always blow cold air. Electric fans do wear out. You can spend long evenings reading about the differences between the two refrigerants. Then again, there are two different expansion valves. Neuro spine Super Speciality Clinic - Above Apollo Pharmacy, Bangarpet Circle, Kolar - Bangarpet Road, Kolar Town. Its chemical symbol is CH2FCF3. Recomanem consultar les pgines web de Xarxa Catal per veure tota la nostra oferta. Low refrigerating effect per pound: In comparison to other refrigerants, the refrigerating effect of R12 per pound is low. As an example, let's say the R12 charge specification is listed at 2 lbs. One thing at a time here, and slowly, the knee is not up to jumping around like I used to at the moment. 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. The #1 question asked by NEW MEMBERS. Air Conditioning Expansion Valve R134a - R12 replacement kit If you have a perfectly operating system using R12 you do not have to drop what you are doing and convert to R134a. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. Talk about what services you provide. I just got some hi/lo side gauges so I'm going to take readings, if they are needed. Then again, there are two different expansion valves. With R-12, 30 is 28.4psi and 40 is 36.9psi, for a difference of 8.5psi. The primary function of the design engineer is to make things difficult for the fabricator and impossible for the serviceman. Hot coolant migrates up through the core by convection (is that the word? Tech Talk - Differences between R-1234yf and R-134a - FJC Inc #19. Thanks again. Catalog E-1, Thermostatic & Automatic Expansion Valves / Page 1 Table of Contents . Is the information not applicable to the old Pantera system? R12 to R134a change expansion valve? - HVAC-Talk: Heating, Air leading to corrosion of expansion valves, capillary tube plugging, and compressor bearing . I used a full can of evap cleaner. Refrigerators generally utilize R22, R32, or 410A-based coolants as their cooling agent. Carefully study the chart and compare the following: To a large extent, the choice is up to you. 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. 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? You do not want to exceed the systems high side recommendations. R134a is called tetrafluoroethane (HFC). It is also used in automotive car conditioning and the plastic industry. Since you will be using less R134a than R12 you do not want to rely on the driers site glass to determine if the system is full. 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. Also, it can be used with all types of compressors. compressor, condenser, evaporator and expansion valve are specifically designed for use with R134a. Where would I get some basic info on it, I know nothing about it. 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. PDF R134a R513A - Tecumseh Products The difference really shows up on the high side. 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. Though I have seen em run as cold as 12 deg F. If the thermo switch is malfunctioning. It runs between the condenser outlet, receiver/drier unit and expansion valve at the firewall. Thus, when the system is running, condensing the CO2 is not a problem. Fitting a PF condensor is not rocket science, but it requires some planning. To bless the system the technician should attach a R134a sticker somewhere in the engine compartment to note the car is using R134a. #4. 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. You'll get marginally better performance out of the change as the expansion valve is matches the refrigerant characteristics. Hopefully after you have read this entire page you will have enough information to determine which type of refrigerant is best for you. a 50f delta across the condensor is good, but I suspect that is an idle reading. Thus, when the system is running, condensing the CO2 is not a problem. Replace the drier with a drier that has a desiccant that is R134a compatible, use new R134a o-rings. I bought a relay to put on it connected to the compressor clutch. There is NO reason to retrofit a vehicle to R-134a as long as the R-12 system is cooling properly and contains a normal charge of refrigerant. All fans must work at 100% of the OEM rating. The higher the ambient temperature the higher the high side pressure. In short, NO! Expansion Valves Catalog E-1, July 2012. 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.

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