R134a systems operate at higher discharge-side pressures than R12, which can cause compressor seals to leak. The old compressor used R12 and the new unit will be R134a. difference between r12 and r134a expansion valve Hope this helps. and recharged with mineral oil and 2.2 lbs R12. 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. I would not do a 134a conversion without a PF condensor. 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). It won't be optimal, though. What is needed? You either get a system that will function well with R1234yf or get any other type. maintain the A/C of older cars. Yes, I don't trust the heater valve either. Before landing on the debate of R134 vs R12 you should know that both R134a and R12 are AC refrigerants types used in refrigeration and air conditioning systems. difference between r12 and r134a expansion valve R12 is simply too expensive for a 25+ year old A/C system. Performance doesn't seem to have improved. 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. (On firewall where A/C lines go into cab.) What is a good differential? 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. You can use the R134a retrofit capacity chart for this purpose. CONCLUSIONS The differences in the theoretical C.O.P.H calculated for R12 and R134a are consistent with values quoted in the literature. Can I use the one for the R-12? To bless the system the technician should attach a R134a sticker somewhere in the engine compartment to note the car is using R134a. A. Pressure/temperature table for R12, R134a, and R513A is shown in Figure 1. . Anyone know what happens when an R12 expansion valve is used in a system charged with R134A? leading to corrosion of expansion valves, capillary tube plugging, and compressor bearing . Above this temperature, the saturation pressure of R134a is higher than that of R12; below, it is lower. Then I'll put the ball valve in on the coolant and test it and see what we have. 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. Could that be screwing up the systems performance?Anyway, when I installed the system, the new TXV (is that short for expansion valve?) R12 and R134 are of different chemistry. PaulJerky King -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. A thermostatic expansion valve (TXV) (see Figure 1) is a refrigeration and air conditioning throttling device that controls the amount of refrigerant liquid injected into a system's evaporatorbased on the evaporator outlet temperature and pressurecalled the superheat. These two refrigerants are the older types and are not used in newer refrigeration and air conditioning systems. That is a good thing. Mine was 61, so the system is not working as it is supposed to. Temp switch works the aux fan. It is perhaps possible to locate a unit with a company that purchases close out or distressed merchandise. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyers guides, and car and tools comparisons. and an evaporator core and expansion valve that are optimized for R134a . Not going to mess up your 'do, but you can feel it. 4) Inconsistent Airflow. 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. If the charge is low the compressor will cycle on/off in the max AC position. The higher the ambient temperature the higher the high side pressure. Effects of alternative refrigerants on the ejector dimensions for In addition, R134a refrigerants are not only used in auto air conditioners, they can be used in freezers, aerosol cans, and refrigerators. Fitting a PF condensor is not rocket science, but it requires some planning. link to How to cut off a Catalytic Converter. Be sure to test @ 1500 to 2000 engine rpm, and record the ambient temp as well. If you have 10 ounces of oil in the system, that is contributing to the poor performance as well. The safe high side pressures are determined with a PT (pressures and temperatures) chart. As per their results . The R134a compressor has a 1/8" step in on the high side port. Yes, this was a smokers car. Since then, the industry standard has been R134a, which is an efficient replacement. Expansion Valve for R134a? | Team Chevelle Once you have replaced the OEM condensor with a PF unit, you will need to make custom hoses to mate with your OEM system. 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. Make sure to get the R12 EXP valve if that is the way you go. . 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. The adjusted tension of this spring is the determining factor in the opening and closing of the expansion valve. On the other hand, R12 has a global warming potential of 10,910. 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. -------------------------"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." You are indeed 20% out of the OEM spec for cooling. So that indicates it is cooling well there doesn't it? BTW, I use a stick thermo in the vents and the laser on the condenser. (You must log in or sign up to reply here. Can I just use an adapter and save $200? 1) Look Here at the available sizes of PF condensors.2) Go look at your vehicle's condensor & mounting. The current expansion valve is FF - 1/4 - C. Is it neccesary to replace this valve? The name of the oil is Polyol Ester (POE). 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. Shorting the plug for the refrigerant switch should run the fan when the compressor is on. James10952001. I bought a relay to put on it connected to the compressor clutch. Condensers designed to release greater amounts of heat help to expel the greater amount of heat which R134a removes from the cars interior. Even if the system leaks, repairing the leaks and recharging it with R-12 is usually the best repair alternative. R-134a can actually cool better than R-12 in a well designed R-134a system as it has better thermoconductive properties, but all the high pressure issues have to be addressed.But even when these cars were brand new, didn't cool worth a damned, recall almost dying in one in Las Vegas at the time, but a good way to lose weight with gallons of perspiration pouring out, just don't let that drip on the seats, that is inappropriate. There is only a temperature switch on these cars as far as I recall, and it just switches on the aux fan. How an A/C Expansion Valve Works. -------------------------Just another brick in the wallHad a little mule I fed him castor oil and every time he jumped the fence he fertilized the soil, The older expansion valves were filled with the refrigerant they were used with, the replacement valves (today) are filled with a different chemical to work with both refrigerants..Hope this helps-------------------------ChickEmail: Chick---------------------------------------------Freedoms just another word for nothing left to lose, I believe the optimum supercool setting will vary slightly between an expansion valve for an R12, as compared to R134a, system. 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. 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. R1234yf. In more serious, it could result in cardiac irregularities or death. hardly noticable. By: james smith underoath; Comments: 0 . 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. And I already have so much time and money in this a/c project that I REFUSE to cut any corners as small as a TEV.It doesn't help that most people in the business (at least that I come in contact with, present company excluded, of course!) One thing at a time here, and slowly, the knee is not up to jumping around like I used to at the moment. 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. Further production of R12 was banned in some developed countries by the Montreal Protocol because of its harsh effect on the ozone layer. GWP is a measurement of Greenhouse Gases and their effect on Global Warming. how to get to disney springs from boardwalk / bb dakota plaid jacket canada / difference between r12 and r134a expansion valve. I think so. What effect would it have on performance, if any? Are r12 and r134 fittings different? Took me a while to figure that one out, and how to say that. Right now you know you have a bit too much, but with a CR4P compressor this is an insurance policy. Well, I'm not sure it is 'fine' - it doesn't cool very well in 95F weather. You will be fine with a 134a-compatible TXV running R12. Your average garage that works on a/c on the side probably would not have this. If the water valve is not closing all the way you will have re-heating of the cabin air.The cabin blower was not exactly a powerhouse - it was rated at 200w. There are significant differences between R12, R134a, and R513A, which must be considered when handling, processing, applying, or retrofitting with these refrigerants. The mechanical fan & clutch should be checked as well. Later model cars that come with 134A will have 134A only connectors. Expansion valves are an active device, they regulate the flow of refrigerant to the evaporator depending on evaporator temperature. July 3, 2022July 3, 2022. This is 11F off the FSM performance graph - vent should be around 50F. The pressure at low temperatures is nearly the same between 12 and 134a. Moreso, it had been banned. 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. look at the difference! 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. I'm putting r12 back in my system, but all of the valves I can for the application (1990 jeep grand wagoneer) say r134a on them. Unfortunately, the oil only mixes with the refrigerant as a liquid. Warning: "continue" targeting switch is equivalent to "break".Did you mean to use "continue 2"? In a car ac, using this type of freon 20 years ago was difficult. And no, you cannot "drain' excess oil out. R134a. ). A slow loss of cooling at city speeds is usually related to condensor capacity & airflow issues. This kit comes complete with Expansion valve, o-ring kit, and 1ft. 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. Why wait for 200f on the engine coolant to start the fan? A/C Expansion Valve Replacement Cost. Crap! 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. The cable is adjustable at the valve arm. of refrigerant insulation tape. The symbol implies that R12 is a composite of carbon, chlorine, and fluorine.