0 Points 0. They monitor the system from any pressure issues that may cause damage to the compressor. This product supersedes product no: 510030. The unit is cooling moderately well. It’s not a common occurrence, and requires a professional to resolve the issue. 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. Then after a few minutes the a/c blows warm/hot in the cab. When the compressor runs it is pulling a vacuum on the low side and the high side was at 150psi (i think). Eventually, it should stay engaged all the time. It should be at 220psi. I’m Stephen and I’ve been an auto mechanic for over a decade now. A/C compressor goes on and low side goes into vacuum. The low-pressure side, when connected to the gauge, should read less than 100 psi. 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 is located on the evaporator outlet Required fields are marked *. So ive done a regular ac recharge using a kit from autozone on my other cars but of course a bmw doesnt come without 200 more problems. The suction side (low side) and discharge side (high side) ports are . High side and low side refer to the pressure in the ac system. Get the BEST auto repair information Alldatadiy.com and Eautorepair.net are professional-grade shop manuals—period. In this case, pressure must be released by a certified mechanic. Commentdocument.getElementById("comment").setAttribute( "id", "af730c7ce217a6a627df98a45d6dc5e5" );document.getElementById("bb0c1476c9").setAttribute( "id", "comment" ); Save my name, email, and website in this browser for the next time I comment. Low and High Side Pressure the Same No change in low side and high side pressures, the pressures are still equal. Now, we’ll go into depth about each of these issues so you’ll have an idea how to address them properly. It has an a/c system that was installed by Trans/Air Mfg. B. Barney100golf Guest. With the car running at about 1800 rpm's and the AC setting on high I get 35lbs on the low side and just about zero on the high side. I just replaced my compressor after it went bad. Static pressure was the same when I started, around 120ish if I remember right. Today I hooked it up for pressure readings. Compressor is running, but not pumping freon thru sight glass. It’s easy to make a simple problem worse with a single mistake that will cost you big bucks later on. Ok, I have a little different problem. This switch is crucial for proper A/C performance. Add more refrigerant to low side with ac at full blast . Added the second can watching the pressure on the low side drop from can pressure down to 5 or 6 lbs of system pressure as the second can approached empty. That mean its been sucking air in the system. If the high side pressure is higher than the values listed you could have bad airflow from debris in condenser-rad-intercooler or fan clutch is not working properly or it has an obstruction in orifice. If you’re tracking down a wiring issue, Eautorepair.net is the better choice. You’re also likely to be dealing with a thermostat switch malfunction due to a wrong temperature gauge, and in such case, the thermostat switch needs to be replaced by a mechanic. High side stays around 100 to 120 psi. When checking low-side pressure you will get two different pressure readings, one when the compressor cycles on and one when the compressor cycles off. This allows the unit to pull heat from inside air, release it outdoors, and cycle the cooled air throughout the house. Both fans are running, High pressure side shows 75psi and the low side shows 65psi. After reading some info from the Google machine, sounded like system was still low, decided to start a third can. So I started adding a can r134a and after most of the can was in the pressure on the low side started going up at a much faster rate then the high side. My high side was perfect but my low side was hovering around 15-20 psi. That’s why I’ve decided to put up my very own website. AC just quit cooling suddenly. More specifically, there is restricted air flow in the condenser due to blockage. So today I am trying to fix it. Here’s a simple guide that you can use to compare your readings with: When the engine is off, the readings shouldn’t be close to 0 or over 150 psi. When testing your car’s AC system pressure, make sure to proceed carefully, follow instructions properly, and use your car manual as a guide on what you should expect the readings to be for your vehicle. Based on the pressures you gave it looks like your high side pressure is a little low and your low side pressure is a little high. When there is higher than normal air pressure if the engine isn’t running, this means that there is high pressure in the condenser fan, which is what cools the AC system by passing air through it. You Fix Cars: Automobile Air Conditioning ; Writer Bio. 25-30PSI, that the compressor clutch will engage. Shut it off, and low side very slowly returned to 100, after 30 minutes or so. The high side pressure does go up to about 10 lbs when I shut the system off. The correct reading will display once the clutch engages and the gauge stops cycling. Opened low side only for adding R134a after purging yellow line. This high pressure is commonly caused by two problems: First, there might be debris blocking the flow of air from the condenser fan motor, or the motor itself is damaged, leading to little to no airflow through the condenser. This happens when there is an unusually rapid cutting in and out of the cycle. When the pressure in your A/C rises or lowers too much, this switch turns off the compressor to protect it and the rest of the system from damage. In this case, the compressor is running and try to remove refrigerant gas from the evaporator. 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. In other words, the compressor is sucking, but there’s nothing to suck. My high side pressure is reading perfect at 225. The other day I purchased an AC manifold gauge set. When these things happen, repair costs can easily reach a thousand dollars. ice-n-tropics on Wed September 28, 2005 3:09 PM . The A/C system should not be overcharged. Technical / January 13, 2018 / by Jamco Auto Parts; 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. Cauliflower Fried Rice is an easy low-carb side or main if you add chicken, shrimp, or even leftover ham!2 Smart Points 108 Calories An A/C System that is working properly should have 150 PSI on the high side and 30 PSI on the low side. In most cases, their diagrams are right from the factory manuals. What causes high SH, low on charge or a restriction. When the engine is on and the AC is on high, low pressure readings should be around 30 psi and the high pressure side should be about 250 psi depending on your car. All are in working order. The pressure reading from the low side should be between 25 and 30 psi and the high side between 200 and 250 psi. 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