). Changed out that schrader. You can also buy tools to pull the valve cores for larger equipment or a faster pulldown. Switched to a different set of gauges and everything went to plan. I swapped low and high valves under the hood. A/C & Refrigeration systems are designed to operate with only oil and The reason I recommend you always change the oil is it is hard to see how cloudy is is through a small unlit sight glass. If the micron level does not rise above 500 microns the evacuation is complete. Otherwise, repeat the pressure test - there's a hole somewhere. Kept under pressure, nothing appears out of the ordinary. Within narrow limits, the purpose of the vacuum ballast is to prevent water vapor from condensing in the pump during the discharge stroke of action. Afterthecoreshavebeen installed and core tools removed, purge your manifold hoses and install gauges to finishcommissioningthesystem. When oil is wet, the vapor pressure increases to a point where a deep vacuum can not be created. (something that gives stability)The ballast, when it is open introduces free air into the pump during the discharge stroke to keep this moisture in equilibrium. I got a couple SUR&R fittings from a shop nearby, and some AC hose, and made that repair, as well as replaced the receiver/Drier (one of the bolts stripped out the aluminum in the drier). Cut piping should be reamed or deburred. If done correctly the vacuum in the system (presumed repairs are done right) will not leak atmospheric pressure back into this vacuum. I agree. Removal of the air and other non-condensibles is called degassing and removal of the moisture dehydration. Sludge and solids can be removed only by correct filtration (Air conditioning system flush). cause increased head pressures and increased operating cost. Privacy Statement - Evacuation is the name given to the process that pulls all traces of air and moisture from the system. (Note: When the vacuum gauge indicates "high pressure" you are above 20,000 microns but still in negative pressure.) Zero is as shown in the picture below (click on the picture to open a new page with a full screen view of the gauge) with zero vacuum, gauge is disconnected/connected with zero pressure. Isolate the vacuum pump with the core tools and disconnect the vacuum hose from the low side of the system. I can unsubscribe anytime to withdraw my consent. Went to check that out. Just behind my repair & just upstream from the rear extension tubes. There's also some dedicated bubble leak detector solution you can get which may fare better. Only used store bought cans to fill. Put in 3oz of dye then found a leak below the pressure switch. Had some a/c work done and there's an issue with the a/c system holding pressure but not vacuum. Hook your micron gauge right to the vacuum pump and verify that it pulls down and reads properly. Press J to jump to the feed. One of the best moves I made. The labor savings using this kit are very substantial and will reduce manpower requirements and down time of the equipment being services. There is no need to pressurize the system unless you are performing a leak check. 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. Refrigerant oil as a fluid is like water; apply gas under pressure and a fluid absorbs gas. Leaking in a vacuum, but not under pressure? The hoses all look great, and makes me think that someone replaced them as I found a 134a fitting on the low pressure side hidden under the pressure switch. Static low before I started was near 30. Great, thanks. I pulled 3 splits down to less then 150 microns yesterday. 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. I have a shelf full of these rattle traps. Use the second band of numbers (referenced from outer to inner bands of numbers) - the blue band. So, I got a a hold of an a/c leak detector (sniffer). JavaScript is disabled. (You must log in or sign up to reply here. 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. Ive put this on hold for the time being. Purging will not only carry out small drops of water (if present) but it will also pick up some of the system moisture. Has anyone used an oil change vacuum system? We only ever pump nitrogen once typically, and just to check for leaks. Release pressure like removing the cap off a bottle of soda water and gas comes out of solution. //-->. an air conditioning system. I think triple evacuating is often overlooked. For the evacuation and test I left my equipment on overnight- I have no ability to read what the pressure is otherwise. Cant get system to hold vacuum at the moment. So, I know this is old, but wanted to update everyone. replacement. I put a tiny charge in and it bubbles there. if corny was a part on a washing machine,,, he'd be the agitator. An open gas ballast prevents the pump from reaching its ultimate vacuum levels and should be closed after you reach 15,000-10,000 microns. Once the suspecting valve stem is replaced, a vacuum is needed to check on any more leaks; running the vacuum pump about 20-30 minutes is more than enough for an initial leak check by shutting off the manifold valves and pump while observing both gauges but pay attention to the low side gauge as it has more sensitivity to display low pressures and vacuum. I can get some refrigerant, what I hear you saying is that creating vacuum would be required to put it in, right? If it is a continuous source, then leave it on and you will be able to find the leak. Drive Accord forum, a community where Honda Accord owners can discuss reviews, service, parts, and share mods. Allow at least 10 minutes to see if vacuum holds. 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. Use core tools to isolate the pump and the hoses thus minimizing any chance of gas permeation through the hoses. When I came back up front, wasnt pulling in Freon high pressure had dropped. Moisture destroys vacuum pump oil by increasing its vapor pressure so much that a high level of vacuum cannot be created. Even if the evaporator is leaking you should be able to feel or hear the air/nitrogen leaking. Yes. There is not better place for the working men than the union! Refrigeration systems are designed to operate with only refrigerant and oil circulating inside them. Once the liquid gases off the pressure will drop quickly. Went to testing again & added just enough freon to kick on the compressor. "Negative Pressure Leaks?" I'd put in a can of oil first and let it pull through the system. from the high to the low side letting it vent out the open port of the core tool. If in doubt change it out! When releasing this high pressure gas do not relieve the pressure all the way to atmospheric. Its the head gasket. (1) Therefore in the words of David Boyd at Appion, "Keep it clean dry and tight". The #1 question asked by NEW MEMBERS. Use a calibrated flow meter to avoid using excess nitrogen. Micron gauge displays can be electronic analog, digital, or light emitting diode (LED). It was reading about 25 low & 150 high, while running compressor. Even single appion 3/8 hose with no core I can achieve that. Privacy Policy. The gas ballast is only effective in removing small amounts of moisture, so a very wet system will require frequent oil changes if you want to make fast work of getting the job done. Performing this test will again pick up some additional moisture that will not have to be removed during the evacuation process. I honestly didnt pay attention to high. I know playing with small volumes I could get the readings to change quickly with temp change. If the system is drying out you will notice that deeper levels of vacuum are quickly achieved indicating progress in the job of dehydration. Do Not Sell My Personal Information -, By logging into your account, you agree to our. 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. What are you using to pressurize the system? Hook up an additional vacuum pump if you have it. If installing a typical residential system, the test can be performed and verified in about 15 minutes. If you only look for convenient places to find dye leaks, you'll be disappointed, Dye leaves its tell tale sign in any part of the a/c system. Could it have gotten a bunch of water in it somehow after the refrigerant leaked out? Advertising - 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). ChryslerMinivan.net is the best forum for Chrysler Town and Country owners to discuss mileage, price, problems, towing and more. Then it takes forever to remove it. A good quality pump will easily achieve levels or below 50 microns. Looks like I prob. "It is not practical to remove large amounts of water with a vacuum pump as boiling water produces large amounts of water vapor. Back at it tonight. I converted my system over to 134a. Eliminates so many headaches. 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. 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. I agree to receive emails from the site. Contact Us - google_ad_width = 728; No problems in 2 1/2 years. Join now! Do Not Sell My Personal Information -, By logging into your account, you agree to our, Location: Deep in the Pisgah National Forest. Break the vacuum with nitrogen to that equivalent to atmospheric pressure (760,000 microns) then purge nitrogen through the system at 1-3 psig. After the second drop test check the condition of the vacuum pump oil. degassing and dehydration. 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. VACUUM RIG, (1) Refrigeration Air Conditioning Technology 5th Edition Copyright 2005, (2) Review of Vacuum for Service Engineers 1988. 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. Terms of Service - No pressure loss whatsoever any time. Oxygen, nitrogen and Must be of the size most don't bother looking for. For a better experience, please enable JavaScript in your browser before proceeding. There's a difference. Compared to system breakdown, oil is cheap change it often. Isolate the vacuum rig with the core tools and allow the system to stand for 15 to 30 minutes. How high does system pressure get when its working with Freon in it? We left it for 2 hours and came back, still says OL. If you suspect the TEV is the issue consider first it might be an o-ring seal issue, inspect: I'm running in circles on this and will need to return to a pressure test. Since refrigeration oil hasn't been reported as being blown out, completely emptying the system of oil, dye remains with oil. A rise in the pressure after a short stabilization period indicates there is still moisture in the system or the presence of a small system leak. On a split I set up that hose on the suction side and put my micron gauge on the liquid line. contaminate line sets. Many assume once refrigerant is lost, dye cannot be seen. Refrigerant comes out of solution from oil to appear as boiling. Both of these problems result in intermittent cooling or no cooling at all. You could charge it with 3 lbs, and a can of UV dye. Lo and behold I found an 134a port hidden under the switch. Join the discussions on EcoBoost, aftermarket performance, and more! A perfect vacuum remains long after the vacuum pump is shut off to allow recharging a repaired system. Terms of Service. 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. It is this reserve liguid Freon that is gassing off slowly to keep the pressure up. You can also get an ultrasonic leak detector but that doesn't sound particularly useful with something like this. 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.