Get the BEST auto repair information Alldatadiy.com and Eautorepair.net are professional-grade shop manuals—period. For instance, on a 90-degree Fahrenheit day, … R-134a TEMPERATURE PRESSURE CHART (Tabla de Temperaturas y Lecturas) Ambient Temperature °F / °C (Temperatura Ambiental): Low-Pressure Gauge (Puerto de Servicio del Lado de Baja Presion): High-Pressure Gauge (Puerto de Servicio del Lado de Lado de Alta Presion): 65°F (18°C) 25-35 psi / 172-241 kPa: 135-155 psi / 931-1069 kPa Evacuate the system and recharge with the correct amount of refrigerant. An A/C System that is working properly should have 150 PSI on the high side and 30 PSI on the low side. This can essentially destroy your entire air conditioning unit. If you are low on refrigerant, it leaked out somewhere. On a properly working system, high-side pressure will be about twice the ambient temperature, plus 50 PSI. If the expansion valve fails then the, What Happens When Your Heater Core Goes Out? Is It Cheaper To Rebuild An Engine Or Replace It? Check condenser fan operation. How can you tell when a system is low on refrigerant? 3) The heater core is leaking warm coolant into the heater box. Check again when the temperature rises. 5. Getting your air conditioner serviced, especially if you need to drain the refrigerant and put new stuff in, is something that has to be done using the exact right tools by a professional. Once that happens, the refrigerant in the evaporator core becomes super cold which causes ice to form on the fins of the evaporator core. Possibility #3 AC low side pressure is low because of a restriction on the high side. There can be a number of problems that crop up with air conditioning not working at all to working at a diminished capacity. If the pressure is too high than what the chart indicates is normal then that means you have an overcharged system and if it’s lower it means that you might have a refrigerant leak somewhere in the line If you have zero pressure then it means you have no coolant at all and it's likely leaking entirely from someplace. If you're finding that the low side pressure is higher than it should be while the high side pressure is about normal, then you're probably having an issue with your condenser. Although there are a number of reasons that can make your low side pressure go too high, and the high side pressure go too low, when it comes to both of them happening at the same time you have some limited options. Car AC Pressure Too High – The Causes And Solutions. If the pressure is too high than what the chart indicates is normal then that means you have an overcharged system and if it’s lower it means that you might have a refrigerant leak somewhere in the line If you have zero pressure then it means you have no coolant at all and it's likely leaking entirely from someplace. From that point all you need to do is compare it to the ambient temperature and the pressure is listed on the number chart for your particular air conditioning unit. If you have too much, going through the system it could end up freezing and if there's too little then the evaporator may overheat and cause damage. It absorbs the moisture from the refrigerant so that it doesn't get contaminated with water. One of the problems that can pop up with your air conditioning is when the pressure on the low side of the compressor is running high, while the pressure at the high side of the compressor is running low. Your expansion valve is located at the evaporator and regulates the flow of refrigerant through the AC system as a whole. The pressure switch is mounted on both the high and low sides of your air conditioning system and it monitors the pressure of the refrigerant as it travels through. Generally, these can be found online, and you may also be able to find the correct pressure listed in the owner's manual for your car. If you have too much water in your system, and the receiver / drier is overloaded then it will not be able to continue doing what it's supposed to do. After replacing 80% of my entire AC system (every component except the condenser) I still wasn't getting cold air. (very common especially if you’ve tried to add refrigerant yourself). This could be the result of a problem with your thermostat switch or temperature gauge but you're going to need a mechanic to diagnose this one properly for you. The high side pressure was roughly 150. The air conditioning system in any car is one of the most finicky systems that you have. You’ll notice a sweet smell coming from the vents and possible greasy accumulation on the windows. The system should be about 25 to 30 psi on the low side and 200 to 250 psi on the high side. They usually have a label on them that warns you not to eat them. That's about average for the low pressure and will only change a little bit based on the ambient temperature around your engine compartment. If the pressure is high when it's running, then that might just be normal operating procedure. Your condenser has a cycle that it goes through in order to allow your air conditioning to run properly. manifold gauge shows vacuum on low side and no pressure on high side. Engine coolant levels will be low. Let’s Find Out The Pros and Cons Of Each! RE: 1995 Mercury Villager GS Problem: AC only cooling intermittently. To know for sure that this is the problem you do need to test it when the engine isn't running as pressure goes higher when you do have the engine on, as they're supposed to. If you’re tracking down a wiring issue, Eautorepair.net is the better choice. Clogged condenser fins or an inoperative condenser fan can cause low side pressure to be too high. There can be a number of problems that crop up with air conditioning not working at all to working at a diminished capacity. Evacuate and check for blockage. : The other reason you might be experiencing high pressure is even when the engine is off is that your whole air conditioning system has been overcharged. Fix: Replace a bad blend door actuator or faulty heater control valve or repair a faulty blend door or blend door linkage. Some of them can be quite a bit more expensive, but if all you're doing is simply checking the pressure that should get the job done for you at a fairly reasonable price. If you turn your car on and turn the AC to high and check the AC pressure lines, the low pressure side should read around 30 psi and the high pressure side should read around 250psi. This will reduce the airflow through the condenser and that in turn means it's not going to be able to cool down the AC system. Recharge. If the ambient temperature is higher or lower than normal (70 to 80°F) the pressures will go up or down accordingly. Be it the car AC pressure too high, not cooling properly, or other issues. The system is overcharged. Second symptom: Obviously, this would be a clear place to look if there's a pressure issue in your AC system. Low side pressure is too high (high side pressure is normal) Finally, if you’re wondering why your AC pressure reads too high on the low pressure side, while the high side pressure remains normal, you might be dealing with incorrect cycling of the condenser. or so if you want to do this yourself. If both of your numbers are in these ranges, then everything is working the way it should be and you shouldn't have too much to worry about in terms of your AC system. This could be normal if outdoor temps are very low. Obviously the main issue that people deal with when they have a broken A/C system is that the air coming out the vents is not cold enough. R134a Pressure Gauge Chart This chart details how ambient temperature correlates with the system refrigerant charge pressure, and how it affects high and low side psi readings. Low side AC pressure is VERY low and high side pressure is low: restriction Low and High AC pressures are lower than recommended in an expansion valve system where the valve … Some of them can be quite a bit more expensive, but if all you're doing is simply checking the pressure that should get the job done for you at a fairly reasonable price. If no obvious leak is found, recover the refrigerant and replace the service ports or valves, evacuate and recharge the system, and add dye in case there is another leak. Engine Problems with Honda CRV: Customers Had To Pay Up To $3700 On Repairs! If your car has a heater valve, make sure it’s not allowing hot coolant into the heater core when you’re running the AC. , your expansion valve, or the receiver / dryer also. It can be used for recharging refrigerant, or to diagnose an a/c system based on pressure readings from your gauges. This can essentially destroy your entire air conditioning unit. The only way to properly charge the system is to remove the refrigerant, vacuum down the system, and then charge it with the specified amount of refrigerant. Your expansion valve is located at the evaporator and regulates the flow of refrigerant through the AC system as a whole. Almost sounds like your thermal expansion valve is not opening completely. . This will reduce the airflow through the condenser and that in turn means it's not going to be able to cool down the AC system. The compressor is the part of your air conditioning system that actually creates the pressure that the coolant is under in your vehicle. The expansion valve failing is another thing that can cause the pressure on the low side to go too high and the high side to go too low. The reason you have a high pressure side and a low pressure side at all is because the compressor increases the pressure and as it runs through your AC system to the condenser where it changes from a gas to a liquid and it will eventually lose pressure again as the cooling process takes place. Cool Automotive Products and Tool Recommendations, Read AUTO REPAIR ARTICLES sorted by topic, Compressor clutch not engaging after blower resistor replacement, Initialize Ford auto up/down one-touch feature, Custom Wordpress Website created by Wizzy Wig Web Design, Minneapolis MN. Then, since no more refrigerant is flowing, the evaporator warms up, the ice melts and you get warm air. A common mistake that many amateur mechanics would make is putting too much refrigerant into the system without removing their systems first. Engine Problems Chevy Equinox: Will You Stand Excessive Oil Consumption and Complete Engine Failure? Fix: Clean condenser fins and check for dented condenser tubes. The high-side pressure, which the FSM gives only somewhat roughly as higher than 2xx psi (my GM manuals have pressure tables based on humidity and ambient temp, it changes a lot), never goes above about 150 psi at 1500 rpm as specified. Anyway, I hooked up my manifold gauges and the low side pressure maxed out the gauge! And for a lot of drivers this is something they may let slide for a while since air conditioning is not required for the proper functioning of a vehicle. As we've established, there are two different sides to your AC system that have two different pressures. It has something inside of it called a desiccant, which is similar to those little packets, but you might find in a pair of new shoes or other products that are meant to stay dry. Fix: Remove excess refrigerant or evacuate and recharge with the correct amount. If the switch fails, then this is not able to happen and it can result in your pressure being thrown out of whack. The point of the switch is to turn off the compressor to prevent damage if the pressure is too far out of line for the system. It's also possible that air has gotten into the coolant system and is raising the pressure as well. The pressure is going to need to be released somehow, and it's best to leave that to a mechanic to get the job done safely and properly. The expansion valve controls the flow so that it stays at optimal levels and keeps the evaporator temperature where it needs to be. © 2020 Cash Cars Buyer. However, if there’s a restriction on the high side of the system in the receiver/dryer, a crimped tube in the condenser or crud accumulation in the condenser or the expansion valve or orifice tube, there’s … Once you know that your pressure is off and that's the reason your air conditioning is not working the way it's supposed to, then you should hopefully be able to troubleshoot one of the causes that we've gone through which led to this pressure imbalance in the first place. You can even look up the recommended temperatures and refrigerant pressures that are required for the particular kind of air conditioner in your vehicle. 3. All Rights Reserved. If the high side pressure drops from around 150-200 to around 28-psi quickly and then falls gradually after that, you’ve got air in the system. A/C compressor goes on and low side goes into vacuum. 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