manifold gauge shows vacuum on low side and no pressure on high side. There could be several causes leading to this condition including compressor issues, low-level of refrigerant, trouble with the heater or AC controls, and others. 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 I checked the compressor from the high side hose and also from the suction hose. I Had It And The Accumulator Replaced. Compressor (engine) RPM and airflow across the condenser are always changing, thus engine speed is always affecting pressure. That Is As Far As They Got. The switch is located near the expansion valve. A/C or Heat Pump Compressor High Head Pressure Diagnostic Checklist 12 Causes of High Head Pressure at an Air Conditioner, Heat Pump or other Refrigeration System. If not the compressor may be worn out. Shop Says The Relay Is Good. The AC system in your car could go through all sorts of problems. Lower Low Side and Higher High Side Pressures. For this reason we simply can't … There is a slim chance that you have a complete restriction but that normally always presents itself as a very high pressure on the high side. One typical issue is the unit not blowing cold air, which could be punishing in hot weather. What could be the problem?? The compressor does cycle off and on. Top Four Types of Car Insurance Coverage – What Are They? 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. Similarly, the fan also has to spin when you turn the system on. I Have Auto Climate Control And Ac Will Not Turn On, Can't Get Compressor Clutch To Engage. The fact that you pulled it down and it held a vacuum shows there is no leak but the compressor itself is not building pressure. Look for oil residue around the hose ferrules, fitting connections at the compressor, condenser, and evaporator or expansion device. In general, it is not common to have a high reading with low side pressure reading and the normal one with high side. What Is Shift Lock Release And How To Use It? This happens when there is an unusually rapid cutting in and out of the cycle. The air compressor low side is at its normal psi. I Have A 2005. 1993 c1500 - 5.7L - 2nd style a/c system (originally r12, retrofitted) A few months ago I replaced my compressor, dryer, orifice tube (the expensive auto-adjusting extreme duty one), and condenser. 000569, Member of Tokyo Chamber of Commerce Boueki - 201650, The Reasons for AC Low Side High, High Side Low Pressure, 8 Common Symptoms of a Clogged Radiator You Must Know, How To Charge a Deep Cycle Battery Properly, Things To Avoid While Driving An Automatic, Best Tire Pressure Monitoring System Reviews. Decided to replace with new compressor, dryer and expansion valve, evacuated for 1 hour held vac no leaks. The dirt is clogging, and so there is an obstruction in the flow of air. What if the low-side pressure is low and the high-side pressure is high? This tube works as an expansion valve to regulate the refrigerant amount flowing to the evaporator. … In fact, the temperature is directly related to the system’s pressure. Start the car and turn the AC on. High pressure inside the condenser fan can causes the aluminium to distort and evaporator coils to leak. AC hi on low pressure side no cooling-fixed I have a 2000 beetle tdi. aircon is not cold. Condenser may be blocked. Insufficiently cooled freon automatically causes the pressure to increase. How Long Do CVT Transmissions Last? why? Watch your pressures.. watch to make sure the high side does not exceed 150 or that the low side does not go below 15 psi. Ac Does Not Work. We are a team of ASE certified When all of these components appear to work fine and the AC low side high, high side low problem persists, you may need to change the compressor to fix the unit. 20 plus year old 30,000 btu condenser with 50 lb suction and 285 head. Facts and Fallacies! Note: The most ideal pressure readings are around 150 high and 30 low. Center duct temperature: 36 to 46° F. Charge as follows: R134a = 1.8 lb. What Are the Reasons for BMW i8’s Rapid Depreciation? The air compressor may be building pressure, or trying to, but it cannot due to a major leak on the compressor. If The Truck Is... About A Month Ago, My Compressor Went Out. When compressor cycled off, low side pressure 100psi and high side pressure @400psi. Most AC system will still be able to hold the proper low side pressure even though they are overcharged, so by the time a low side only gauge would show the low side pressure being to high from being overcharged, it may be so overcharged the high side pressures may be so high they will burst the system or damage the compressor. The result is the compressor motor will overheat. Most high-pressure readings are a result of the freon or refrigerant not cooling adequately. Intermittently cold air will blow for a few minutes. Even though the compressor motor might shut down due to it having a thermal cut … Open the low side only valve and allow the charge to build to 30 lbs. system works and what to... After Running The A/c In Hot Weather, When The Truck Is Shut Off For A Short Period Of Time The A/c Will Not Blow Cold Air. Tsukasa Azuma is an awesome car blogger of Car From Japan. Below we list a dozen causes of high head pressure in an air conditioner or heat pump compressor motor. The ac also will not run without a signal from the high pressure switch. A pressure switch or sensor could be bad. 200 PSI / 70 PSI = There is a blockage somewhere in your system either before or at the expansion device. It could also be a failed thermal bulb that is unable to pick up the temperature signals or the TXV stuck to the open position. I have both presure and suction but when I connect the hoses to the system and put my gauges on with the correct amount of r134 my gauges stay at 150 high side and 25 suction with no change even when I … A complete system evaluation should be performed to prevent damaging the new compressor. Acceptable operating pressure ranges for Vintage Air systems (R134a): High-side pressure: 160 to 250 PSI. I evacuated the system and pulled a vacuum on the system and it held 28 for over 12 hours. The Best TOAD Vehicles for Frequent Campers. However, it is always better to consult a mechanic before deciding to replace any part. Yo… On 2017-09-21 by hal. mechanics that have created this guide for you so you can understand how the White Smoke From Exhaust: Main Causes and How to Fix, 10 Best Tire Companies In The World [Updated In 2021], Take Advantage Of These Ten Easiest Cars To Work On. But if you see the AC low side high, high side low , such as the low side is 100 and the high side is 150, there might be problems with any of the inner components. In other words, the cycles are moving out and in too quickly, which cause these high readings at the low side. When I put the gauges on the high side pressure is high, & the low side is normal. The high side does not move and it is at 30psi. What separates these two valve areas are gaskets. It should mean the system is not operating on its optimal capacity. The high side fitting and hose gets really hot. You can measure the refrigerant’s pressure at a given temperature. I check Freon and low side reads avg around 50 and high side does not read. It may also control the AC condensor fan. Does the pressure go up? Also, check if the compressor clutch engages and rotates the compressor when the AC is on. Use an Ohmmeter to find if it is giving the correct reading. Checked with gauges low side running at 60 -70 hi side normal 200-225. switched out expansion valve got same readings. Also compressor does not cycle on and off with sensor unplugged. When compressor cycled on, low pressure @ 35psi and high pressure @ 200 psi. Pressure Range Low side: 0 to -29.99 psi High side: 71 to 85 psi Indications Low pressure side becomes a vacuum High pressure as listed above Frost or condensation on the front and rear pipe connections of the receiver dryer or expansion valve Causes AC system is blocked by contamination or ice NOTE: A general rule of thumb is two times the ambient (daytime) temperature, plus 15 to 20%. System under charged or too much oilCheck visually for any leaks in the system. A low pressure switch disengages the compressor clutch when the pressure is too low on the suction side (low side) of the AC system in order to protect the compressor from damage. The ac suddenly was blowing warm. I'm not 100% positive, but I believe the high pressure switch is a cutoff switch for excessive high pressure to stop the system from damaging itself. Although mechanics tell owners that the high pressure is due to a problem with the accumulator or evaporator that is not likely the case. The pressure reading from the low side should be between 25 and 30 psi and the high side between 200 and 250 psi. on the high side. I have tried to add Freon and it seems to be full. Can the compressor build the pressure? It should be at 220psi. There are saftey switches for both side to protect the compressor. Your email address will not be published. Driving a Toyota Land Cruiser: Why Is It Appealing? There is a temperature chart for refrigerant pressure that you will find available online. Before deciding to replace the compressor, other components that you may check are the pressure switch, expansion valve, and the compressor clutch. On the low side of the chart, the pressure is low while the temperature is high. With sensor unplugged and a/c on highest setting, low @ 35psi and high @ 200psi. To gauge the pressure, hook up a gauge set to the AC system and record the pressures of both low and high sides. I'm checking because the rear AC is blowing ambient and the front is cool, 49F or so. 225 PSI / 80 PSI = It is likely that the expansion valve is opened too wide (not the case if your A/C system has an orifice tube) Also, you could have too much refrigerant in the system. A high pressure switch does the same thing if pressure builds too high on the discharge side (high side) of the system. Tsukasa’s blog is one of the best resources for information about keeping your favorite imported car running smoothly. On 2017-06-12 by (mod) - cleand cond coil ,ambient 87 f. head was 375 until I cleaned the cond coil. On the other hand, there is possibly a huge leak when the pressure is zero. Quite often, as noted on the previous page, an air compressor will have a “valve plate” on which will be found both the intake and pressure valves. Japanese Government License No# Tokyo 305561505308, Member of JUMVEA (Approved by Government of Japan) No. He owns a car repair shop at downtown Osaka, and he put all that experience to good use in his sharing posts. One symptom indicating a complication in the air conditioning is AC low side high, high side low pressure. How To Reset Check Engine Light: Follow These 4 Easy Ways! The same problem arises when the o-ring seal outside of the orifice tube wears out. I'm trying to figure out why the high and low side pressures are equal with the car idling and the compressor running/loaded. The front use to blow around 39F. An air compressor that will not build pressure runs on long past the point where it normally would reach the cut out pressure level and stop. Refrigerant does not circulate. on the low side and 150 lbs. One thing to check right away is the tank drain valve. Low-side pressure: 6 to 18 PSI in a steady state. It could be an issue with the orifice tube too. Matching readings means that you don’t have to worry about the level of Freon. Normally, if a compressor is weak or defective other issues within the system may be responsible for this occurring. Moreover, because of being passionate to learn about the recent happenings in auto industry, he doesn’t only provide great car maintenance tips, he also always updates latest trends in among car brands and share them in his own interesting viewpoint. Any time the compressor is cycling but no pressure is building, it typically means the compressor is not doing anything but spinning. Issues with the Condenser Then retest system to … They are usually located in the back of the compressor housing and held in with a snap ring. Chevy Silverado 4.3l And Have Ac Problems I Cehecked Refridgerent Its Good Actually All They Way In Red (but I Figured Its... https://www.2carpros.com/articles/replace-air-conditioner-compressor, https://www.2carpros.com/articles/re-charge-an-air-conditioner-system. So far example when the truck is warming up and the fan clutch is not engaged (several minutes), if I turn the AC the High side climbs to approx 350-400 (high side pressure sensor turns off compressor after 430 I believe), and the low side can get up to approx 60 – 70. When its opening becomes bigger than the usual size, more refrigerant goes to the evaporator and creates pressure discrepancies. Need to fix your car's air conditioner? I added oil, vacuumed the system, and then started … If you are low on refrigerant, it leaked out somewhere. If they are lower and the compressor did not come on, then it is undercharged and needs Freon to make the low side switch come on and activate the compressor. Compressor Does Not Engage. A Safe and Secure Way to Flush AC System After Compressor Failure, The 7 Best Car Batteries For The Money in 2021. If you leave your compressor tank drain open between compressor uses, as many folks do, make sure that the tank drain is closed before the compressor is started. But if you see the AC low side high, high side low, such as the low side is 100 and the high side is 150, there might be problems with any of the inner components. Check the ambient temperature and see if the pressures match the numbers on the pressure chart. One thing is that if you star the vehicle and turn on the ac you hear the compressor engage. It kicks the compressor on and off between 26 and 30 psi. This condition usually means there is a restriction in the system or the TXV/Orifice Tube is blocked or closed. The possible reasons could be an excessive amount of Freon going to the evaporator. If you do not feel any suction then you have a compressor that is bad. Compressor still will not build pressure Possible Air Compressor Gasket Failure. Problems with AC Pressure. Are Cars Designed to Fail At A Certain Point? There are several constraints that cause this state. If you are dealing with this issue, it would be because the compressor is cycling incorrectly. There also could be an obstruction of the refrigerant flow in the compressor. So if the pressure exceeds 150. If you feel a good suction then replace the expansion valve , evacuate, and recharge. The cost of repair and replacement of compressor is high (about $450 plus $700 labor - price fluctuates greatly depending on car) as the dash might need to be removed for repair. The pressure reading from the low side should be between 25 and 30 psi and the high side between 200 and 250 psi. Readings higher than the chart indicate an overcharged system while lower readings confirm a low level of refrigerant and a possible leak. System design, blower speed, mode setting, refrigerant type, all cause variance in high and low side pressure. It reads around 110 psi. Is the cooling fan running constantly? 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