ac holds pressure but not vacuum

Isolate the vacuum pump with the core tools and disconnect the vacuum hose from the low side of the system. into its fundamental components, it can clog the metering device and ), 2) The system has a small leak that was not detected by the initial high pressure test. We do these weekly and never have it take this long.So I'm stumped. ). Keep connections to a minimum and points of access to the maximum. "Negative Pressure Leaks?" In other words, connect to as many places as you can on the system but eliminate unneeded hoses or fittings. Not sure how much rattling you say. As the gauge can handle up to 500 psig, you need not be concerned with damaging the micron gauge by overpressurization. I did do an evaporator and expansion valve on my 06. I had this happen to me once where one of the hoses had a leak at the connector crimp. Switched to a different set of gauges and everything went to plan. They just do. Tubing benders should be used to minimize the number of fittings and reduce internal restrictions. Im not an AC guy, but what kind of issues does moisture in the system cause? Maybe it was just whoever made the ones you bought were different. Problems with oil contamination, field calibration, and work flow have all been addressed. Generation 1-4 Taurus, Sable Platform (1986-2007), The Fora platform includes forum software by XenForo, VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. It has several advantages of all other vacuum gauges. How high does system pressure get when its working with Freon in it? A standing pressure test is used to check for leaks by using a dry gas again like dry nitrogen. The air conditioning system is virtually divided in two sides, one side is a high pressure high temperature and the other is a low pressure low temperature. Keep this in mind, if it's rattling, then there's concern that if it grenades, it will send metal throughout the system, and that stuff can't be removed, especially in the evap and condenser. It was already boogered inside on the threads there and at top of the valve. No refrigerant with dye injected into an empty system is necessary. Because POE breaks down Advertising - Shop says rear expansion valve and line leaking. A high quality, high resolution vacuum gauge like the ones found on this page Vacuum Measurement, can indicate a leak much faster than a pressure gauge due to the sensitivity of the instrument. No problems in 2 1/2 years. They make noise, and they don't last. Dye is permanently mixed in oil and remains viable for years despite claims against this. It will not flow to the condenser outlet like liquid refrigerant does after its been condensed, but instead it will remain trapped inside the condenser tubing. Its the head gasket. On third can, When compressor was not spinning, high dropped all the way down almost to vacuum. A vacuum of about 500 microns or 29.92 hg gauge pressure is needed for removing any moisture that may have entered the system along with the non-condensable gases while it was open. If only two points of access are available, connect directly to the vacuum pump eliminating the need for a manifold. All hoses leak, and at .1 micron resolution that will be very apparent. Only used store bought cans to fill. The pumps ability to clean the system is directly related to its ability to reduce pressure, create a vacuum, low enough to boil off all the contaminating moisture. Content on driveaccord.net is generated by its users. Drive Accord forum, a community where Honda Accord owners can discuss reviews, service, parts, and share mods. system has been opened to atmosphere is critical to proper operation of Increasing the system pressure will actually cause the water to drop out of the nitrogen similar to that of compressed air in an air compressor. If a leak still exists its due to; poor sealing of gauge hoses to fittings, worn out gauge valves or another leak exists in the a/c system. I recommend vacuum rated hoses, using a core removal tool and not pulling through your gauges. To preform this procedure, reduce the system pressure to between 1000 and 2500 microns. Although evacuating removes moisture, the evacuation process does not remove oil or debris from the air conditioning system.Sludge, and deep vacuum procedures will not take the place of liquid-line or suction line driers for the same reason. Used as shown, it will reduce evacuation times by a factor of 16 over 1/4" hoses. They shouldn't make any noise, especially if it was built correct. (Note: a system that continues to level off at 3500-4500 microns may have turned system moisture to ice. Discharge pressure and compressor temperature will go up which can lead to increased lubricant breakdown and shorter compressor lifetime. Copyright 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Once i turn off the pump, it goes almost immediate to atmo. Evacuation is the name given to the process that pulls all traces of air and moisture from the system. The #1 question asked by NEW MEMBERS. Post photos, respond to polls and access other special features. Isolate the vacuum rig with the core tools and allow the system to stand for 15 to 30 minutes. If the system indicates moisture, a multiple evacuation with a nitrogen sweep will significantly reduce the amount of moisture in the system. About Us - Fittings require tube cutting, cleaning, deburring, assembly, brazing, nitrogen purging, and leak testing. But in any case, just commenting to add that I think the speed of pulldown to X threshold can be very telling once you learn your equipment. degassing and dehydration. Afterthecoreshavebeen installed and core tools removed, purge your manifold hoses and install gauges to finishcommissioningthesystem. Terms of Service. cjc15153, when you state "zero" on the low pressure (blue) gauge, do you mean zero as in '0" or a vacuum with the needle pointing to -30in hg? Ultimately, I bought the hoses from Auto Cooling Solutions, installed them, and have had no issues since. When a typical system is installed and/or serviced, air and moisture enter the system. Mechanic says he can do it for 1200-1300. Removing water vapor from a system is known as dehydration. Anyone else ever run into this? Flushed the system with an expensive can of cleaner, then blew out with compressed air. A vacuum of about 500 microns or 29.92 hg gauge pressure is needed for removing any moisture that may have entered the system along with the non-condensable gases while it was open. Thats a little above my pay grade. Refrigeration systems are designed to operate with only refrigerant and oil circulating inside them. bluevac..bluevac..bluevac..run the bluevac zombies are coming. A good set of benders will pay for themselves in short order. When oil is wet, the vapor pressure increases to a point where a deep vacuum can not be created. 1997 SW2 used 12/29/2011 with 124,200 -27 mpg. google_ad_height = 90; JavaScript is disabled. Look up triple evacuation method. The process of condensation requires the refrigerant to get close to the walls of the condenser, transfer its heat to the surface, which then flows out to the fins and gets into the surrounding ambient air. Join now! Schaefer valves had significant leak. The blue band represents zero to 350 psi. Non-condensable gases (ambient air) inside the a/c system. Performance & Competition Discussion Areas, European Delivery and or Porsche Experience Center, Rennpository Video Clips and Other Online Videos, Rennlist Regional Forums (Regional Events, Discussions, Announcements, Etc. Press question mark to learn the rest of the keyboard shortcuts. My manifold had a loose hose; without the hose it held a vacuum. A subreddit for Heating, Ventilation, & Air Conditioning technicians - please visit r/hvacadvice to ask general questions, and r/thermostats for thermostat issues! Discussion in 'Traditional Hot Rods' started by AGELE55, May 31, 2022. I store my o-rings in Ziploc bags, sorted by size, immersed in oil. But when we attach our vacuum to get it down to below 500 microns, it won't vacuum. Take it down to about 1 psig. moisture (all make up our air or atmosphere) are detrimental to system operation. If I had to guess, you may have used the wrong size o-ring in one of the fittings or missed an o-ring, or the evaporator may have been damaged. Could exhaust smoke be unrelated to ac? Thanks for the input so far. A vacuum gauge is used to determine the level of atmosphere (degassing and dehydration) in the system. The block off is a piece of cake. replacement. Tonnage, lineset length, moistureetc. contaminate line sets. The Fora platform includes forum software by XenForo, VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada, driveaccord.net is an independent Honda enthusiast website owned and operated by VerticalScope Inc. It's 90+ degrees out and sunny, the hole was punctured on the roof, so I doubt water is the issue.We pumped it up to 300psi, 3 times now. If it is a continuous source, then leave it on and you will be able to find the leak. Contact Us - Ive found the coolant leak and white smoke issue. Since refrigeration oil hasn't been reported as being blown out, completely emptying the system of oil, dye remains with oil. The ARPA Zone/Open Membership Discussion Forums, http://hvac-talk.com/vbb/showthread.e-TEST!!/page2. This means straining to look over, under, around and behind the entire system. Again, pulled vacuum. If you find you have a leak under vacuum, break the vacuum with dry nitrogen and try to find it under a pressure. Join the discussions on EcoBoost, aftermarket performance, and more! If I charge without swapping whats my worst case scenario? If in doubt change it out! With a vacuum pump connected to both, low and high air conditioning system sides pull a deep vacuum for at least 5-45 minutes. Test posts are permitted. That will stall it at several thousand microns vacuum until all the water is gone, which could take pretty much forever if there's a lot. Attach the micron gauge directly to the vacuum pump via the 1/4" connection and verify that the pump is capable of achieving a vacuum level of 100 microns or less. (Note: When the vacuum gauge indicates "high pressure" you are above 20,000 microns but still in negative pressure.) Removal of both is typically referred to as evacuation. While at first it may seem counter intuitive to use large diameter hoses the value rapidly becomes apparent after starting the evacuation. For a better experience, please enable JavaScript in your browser before proceeding. Losses associated with improper evacuation can be very high. Remember even the best vacuum rated hoses will leak and that is why isolation is a necessity. (1) Therefore in the words of David Boyd at Appion, "Keep it clean dry and tight". If the gas ballast is closed, the pressure created in the discharge stroke will condense the water vapor and drop the moisture out into the oil. What's the benefit, or reason for charging it 3 times? This will allow the evacuation rig (hoses and fittings) to be completely isolated from the system during the "standing pressure tests" where the quality of the vacuum will be measured. If you dont pull under 10,000 in about 30 minutes sweep with nitrogen. Moisture destroys vacuum pump oil by increasing its vapor pressure so much that a high level of vacuum cannot be created. If you get 100 lbs of air in the system with a leak that big you should be able to hear it. Do not pressurize the system as this will not remove moisture. Privacy Policy. I went back underneath, & now Ive got hissing in two different places. DO NOT open the system to atmosphere under a vacuum! /* 728x90, created 4/10/11 */ BTW, I would never use a rebuilt. (With a good pump 50-100 microns is easily achievable.) A dryer equipped with a moisture indicator installed right before the metering device will efficiently remove trace moisture and help quickly identify potential moisture problems. The last few compressors Ive bought, all Sanden style, came with the proper oil in them. Re-assembled with new green o-rings everywhere except at the original condenser, which I left due to not wanting to remove the hood. Speaking of leak points, when I disconnected my hose I heard a hissing from the low side and there was fluid effervescing in and around the valve. Degassing removes non condensibles which Once the suction line iscompletelyopen, open the liquid service valve,re installthe valve cores and remove the vacuum gauge and core tools. Pull a vacuum until a level of 1000 microns is reached, (if using large diameter hoses and core tools, evacuation of the line set and evaporator coil will take less than 15 minutes for a typical residential system of up to 5 tons). The automotive A/C system must hold the vacuum of 29.92 in Hg for at least 1 minute. With the system operating at a higher pressure, extra load will put on the compressor which will decrease overall energy efficiency for the system. Terms of Service - But its not AC oil. Nitrogen does not absorb water, but entrains it and helps it move along out of the system, allowing the liquid water to warm, evaporate, and increase the water vapor pressure without introducing additional moisture into the system. If I can't, I know I need a nitro purge, and keep doing so (pull down until it stalls, break w/ nitro & purge) until that happens. If there is no leak, the 2nd leak rate in the system the leak rate should be considerably less than the first indicating progress in the job of dehydration. However if the system is vacuum tight but still contains moisture the rise will level off when the vapor pressure equalizes in the system typically between 20,000 and 25,000 microns between 72 and 80 F. At that point that vacuum reading will become stable. Ive put this on hold for the time being. I don't want to blow seals out that were fine. I had so much bad luck with them that it just isn't worth it. google_ad_slot = "4972140983"; Cant get system to hold vacuum at the moment. failure. It was reading about 25 low & 150 high, while running compressor. failure, decreased capacity and increased compressor wear and potential Those all seem tight. What are you using to pressurize the system? Questions About Becoming A Professional Member? Lo and behold I found an 134a port hidden under the switch. Using the OP's graph this test case doesn't have a leak but it indeed does, why? There is no need to pressurize the system unless you are performing a leak check. Leaking in a vacuum, but not under pressure? Sometimes if the O rings are dry the oil will seal them. Isolate the vacuum with the core tools allowing the pump to continue to run and record the leak rate (after about a 5 minute stabilization period) indicated by the vacuum gauge if equipped. After the lines and the various components have been installed, it is necessary to make sure that there is flow through the entire system by purging with a dry gas such as dry nitrogen from the liquid line to the suction side of the system. I think people are super impatient about vacuum and it's the single most important thing you can do, but it shouldn't take HOURS to do. //-->. google_ad_client = "pub-8306900413359372"; I think it's also overlooked to keep vacuum gauges clean and calibrated - I really love that my bluvac can be easily calibrated. Here's the link for the hose kit. bachands, thank you. The saga continues. This means push the nitrogen through the system, one side to the next WITHOUT significantly raising the system pressure. Components Coils, Heaters, Motors, etc. (Not condenser) I did the one on my 06 a couple years back. About Us - Micron gauge displays can be electronic analog, digital, or light emitting diode (LED). The two service valve couplers remain connected and open so the gauges can monitor system pressure or vacuum in this scenario. Looks like I prob. There is not better place for the working men than the union! As mentioned above, I wound up having the head gasket work done, but finally got aroung to looking this over, again. A/C & Refrigeration systems are designed to operate with only oil and If marked progress is not achieved during this process, repeat the nitrogen purge to remove liquid moisture that may exist. Sludge and solids can be removed only by correct filtration (Air conditioning system flush). Purging will not only carry out small drops of water (if present) but it will also pick up some of the system moisture. Usually when a vacuum holds, pressurizing a system will hold pressures. I gotta disagree with you there. The best way to remove non-condensable gases (NCGs) is to pull a deep vacuum in the system. windings. sounds a lot like when I was getting my non-operational (major components missing) AC system up and running on my '90 S4. You can replace the rear lines and/or evaporator extension, or just slap on a rear AC block off kit like I did on our 2010. Otherwise, repeat the pressure test - there's a hole somewhere. Do Not Sell My Personal Information -, By logging into your account, you agree to our. I cant seem to figure it out. Participate in over 40 different forums and search/browse from nearly 3 million posts. I have some yellow jacket 3/8x1/4 vacuum rated hoses. Moisture can cause freeze-up at the metering device (Thermal Expansion Valve/Orifice Tube), which restricts refrigerant flow or blocks it completely. They all had a tag on them telling you not to drain the oil out of them. Where high temperatures are frequent, non condensibles combined with moisture will also cause oil "It is not practical to remove large amounts of water with a vacuum pump as boiling water produces large amounts of water vapor. The guy at the parts counter said that the maximum pressure would be about 25psi; I knew he was wrong from reading these forums, but the AC Systems Performance Test PDF said that 26 to 30 psi was normal on the low end at 80 F and the combination of these two statements worried me. I swapped low and high valves under the hood. While the micron gauge is quite capable, testing for a leak in a vacuum is not acceptable practice over a standing pressure test as moisture is drawn into the system during the evacuation process. The black band represents vacuum from zero to -30 in hg. Static low before I started was near 30. Air contains oxygen, nitrogen, and water vapor, all of which are detrimental to the system. When air leaks in, moisture comes along for the ride which can take hours to remove if the amount is excessive. Ac compressors come shipped with oil in them. When I came back up front, wasnt pulling in Freon high pressure had dropped. Moisture brakes down POE oil in HFC All the following is assuming the pressure test held and there is no leak- Replace the oil in your vacuum pump. On third can, I noticed exhaust seemed to be smoking. Hook up an additional vacuum pump if you have it. 100% UA the only HVAC union! Moisture is the second issue. Just let it pump over night. The gauges keep showing OL microns, over load, more than it can read. from the high to the low side letting it vent out the open port of the core tool. Have rear expansion valve but not sure if it's worth it to replace lines. Looking for the perfect vacuum rig? Typically no more than a triple evacuation with sweep are required. (keep it open until you are at 15,000-10,000 microns,) Moisture is what kills the vacuum pump oil. In the end I bought a 2kg bottle of nitrogen and a regulator and pressurised the system - and could hear a leak, which then under pressure became a major leak. A perfect vacuum remains long after the vacuum pump is shut off to allow recharging a repaired system. harvey. A vacuum of about 500 microns or 29.92 hg gauge pressure is needed for removing any moisture that may have entered the system along with the non-condensable gases while it was open. Hey guys. (Some leaks are more apparent under vacuum than pressure.). The Vacuum Pump reduces system pressure in order to vaporize the moisture and then exhausts the vapor along with all remaining air. No pressure loss whatsoever any time. Clean vac oil, nylog, etc. Oil that is milky contains moisture and will not allow a finishing vacuum to be achieved due to the increase of vapor pressure and loss of sealing caused by the moisture in the oil. I honestly didnt pay attention to high. Troubleshoot that - could be seized, bad pressure sensor, With two cans in. I'm more curious about the explanation of the different value. It is this reserve liguid Freon that is gassing off slowly to keep the pressure up. Ask Our Pros-Owner Assistance - NO DIY advice will be given. I found a few worn spots, where refrigerant seemed to be leaking. When it comes to system evacuation only small amounts of moisture are practical to remove this way. Moisture refrigerant and mineral oils form acids that will The following errors occurred with your submission. compressor kicked on, pressures rising. If it was rebuilt, I would return it. Many times several oil changes are required to remove significant amounts of moisture from a wet pump. FIRST.. you are only giving low pressure reading I assume..you need to read BOTH gauges, The following errors occurred with your submission, CorvetteForum - Chevrolet Corvette Forum Discussion, V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette, In loving memory of lost CorvetteForum Brothers and Sisters. driveaccord.net is not in any way affiliated with Honda Motor Company. Then it takes forever to remove it. I think triple evacuating is often overlooked. Compared to system breakdown, oil is cheap change it often. For the evacuation and test I left my equipment on overnight- I have no ability to read what the pressure is otherwise. Thanks for the link. Im hoping its not the rear evaporator. I can unsubscribe anytime to withdraw my consent. I have pulled down a 330lb circuit for a screw chiller in 8 hours using a 7cfm pump. Break the system vacuum with nitrogen introduced at the side port of the core tool. Had some a/c work done and there's an issue with the a/c system holding pressure but not vacuum. Generally speaking it is better and faster to change the oil rather than to wait for the gas ballast to remove excess moisture from the oil during pump operation. You disconnected refrigerant lines while pressure remained. Sweeping the system with nitrogen during installation will significantly decrease evacuation times. Pulled a vacuum. Having the ballast open during the initial pull down of a wet system will help to prevent condensation within the pump. Would have been my first choice. Think I'll just do rear ac block off. At this point your system is holding pressure but the compressor isnt working. Connect the hoses directly to the vacuum pump with a brass flare tee or with a vacuum rated manifold. Well I got the o ring I was looking for, & got everything tightened back up. A vacuum begins at zero pressure on the gauge and as the vacuum pump draws out air and moisture in a repaired system, the needle moves counterclockwise (ccw) to negative pressures/numbers (in black). JavaScript is disabled. Cookie Policy - If the pressure rises above 500, open the core tools again and allow the evacuation to continue. Nitrogen should be purged through the piping during the installation and during brazing to avoid the introduction of contaminates and moisture into the piping and also to avoid the formation of copper oxides during brazing. We recommend the Accutool BluVac for several reasons. Started refill, all good. What is the high side running pressure wise?