How To Recharge an AC System - EricTheCarGuy

okay as some of you know I have just finished up work on my Subaru the a/c system had a leak in the low-pressure line I also replaced the accumulator that's in a separate video I'll put a link down below if you want to see the details on that but I thought it would make a completely separate video on the evacuation and recharging of the system because I feel this information is is pretty much across the board as far as a/c systems go there very few things in a see that like crossover but but this is one of those things so I'm gonna go through the process step by step of what you do if you've got a completely empty AC system okay as far as recovery goes if you've got some refrigerant remaining in the system and you've got it like say replace a compressor or something I would urge you to take it to some facility that has an evacuation machine that can actually suck all the refrigerant out of the system so that you're not releasing this the refrigerant into the atmosphere that's key here you don't want to just let this stuff just like go off it in the atmosphere you want to be responsible about it because I mean is this CFC it is one of those things that eats up ozone layers things like that so so we keep the tree huggers happy let's suck the system out make sure it's completely empty before we open it up once you've done that made all of your repairs next step which I'm going to show you right now is you need to put a vacuum on the system to remove all the moisture before you charge the system so you've got to evacuate it first and for that we need a vacuum pump let's go see what one looks like I'm gonna derail you a little bit now if you're gonna do any kind of AC work any kind of AC work at all you it's a must that you've got us have a set of manifold gauges you're not going to be able to do any diagnosis you're not going to be able to recharge it you know well there are some of those kits out there that you know just have that little hose that goes in to top off the system come on Nate no I'm just gonna come out and say it that's a hack way of doing it the best way to do it is with a manifold gage set because these pressures are everything when it comes to AC they tell you what's happening in the system so you need to set a manifold gages and you start off by okay you got the gages here turn these all the way to the right and close them up these are the valves that open and close these lines so this is the manifold here and this is going to tell you the pressure on the high side is is the red the low side is the blue and that's where you hooked them up and in fact with 134a systems they made it really convenient to hook these things up now I've already hooked up this vehicle if you're not familiar with these gauges what you do is this is to disconnect them is you twist these little nuts counterclockwise you find the high and low pressure the high is going to be the bigger one the low pressure is going to be the smaller one low pressure sucks into the compressor high pressure comes out this way I've done a video on basic AC operation I'll put a link in the description so you can see basically how an AC system works and understand the reason why you have a high and low pressure but what you do is this this is a like a little coupling you just take the coupling push it down onto the fitting let it seat once it's hooked on this is the part where I want you to be careful because some some gauge set some manifolds if you run these down too much you can actually bend the Schrader valve that's down in here so what I do is I just keep turning this down I know that these won't do that but I just would keep turning this down and keep an eye on the gauges and once I saw the gauge move or bump I knew that the Schrader valve was open and that's all I needed was to know that the Schrader valve is open so if you have a set that sometimes been Schrader valves or every time you do AC work you find you got a leak up about 80% of the leaks iPhone and AC systems or actually here at the Schrader valves themselves so that right there causes a lot of leaks the same kind of thing like an entire valve same here with a high pressure side sort of push the fitting down on there turn it clockwise until you see the pressure bump which I won't on this because this is already completely empty so there you've got your gauges and everything hooked up you're like Eric what's this one for well this is your way into the system you would either hook this up like say if you're gonna evacuate the system you would hook it up to a machine that would evacuate it for you or you would hook it up like we're going to now to a vacuum and then finally the refrigerant itself all goes through this line into the gauge set and that's pretty much the the heart and soul this whole system these little tips on the side here or so you can actually take your your leads here your ends and hook them on to this so that it stores better but I just hang mine up on the wall and it doesn't matter but that's what these over out here on the side are for they're just they're just there so you can hang your gauges they do nothing so don't pay attention to those all the way closed hooked up now we're gonna go get our vacuum pump okay this is my vacuum pump it's a relatively inexpensive vacuum pump and I had to put a little bit of oil in it it's an electric motor that basically sucks ha ha and pun intended there it has ports on the side here it has to I know that this one on the side is the one that actually fits my manifold gauge set and just as an FYI on the tip of mine like my guy here the o-ring down inside that wasn't there so that Oh ring was not present when I first started using this and that's important because it was allowing it to leak right here so if you're checking for leaks you're gonna close the these gauges and that's gonna basically isolate the system and cut this part of the hose out but I was noticing I was I was having a leak right here and it was causing me problems so make sure you do have seals inside these components and make sure that they actually do seal something so I'm just gonna hook this up to the vacuum pump here just screws on like that now with AC stuff don't try to tighten it so much don't grab a pair of pliers and squish this down let the o-rings do they work just just do it just enough to where you know that it's seated up against there now I've got to plug the pump in okay plug my pump in and we're ready to go and quite simply all I have to do just turn it off and it will begin to work but coming up here to the gauges you'll notice nothing's happening nothing at all in fact everything is pretty much zero doubt you need to open the gauges in order to let the vacuum get into the system and open up both gauges to do this your how it's changing same the high pressure side there we go and now we are putting a vacuum on the system so I'm gonna actually let this sit for half an hour I'm just gonna let let it well actually I don't really have to this time because I did have a vacuum on the system before but I'm just gonna let the system run for I would say at the very least 15 minutes the optimum would be run it on a vacuum for at least a half an hour all right and as you can see this one's this gauge is pegged out down below zero about the most vacuum you're gonna get is twenty eight inches of mercury you might get a little more a perfect vacuum as thirty inches it's theoretically not possible to gain that here on the planet but basically what we're doing is removing the atmosphere so we'll come back in a few minutes and recheck things and go to step two well whatever step this is I'm kind of losing track but go to the next step that's what we'll do okay it's been about half an hour it's time to shut off our vacuum pump but before I do I'm gonna close the valves on the manifold gauge set turn clockwise close that one close that one alright now that the pump is off I'm gonna verify my repair now that the gauges are and everything are closed I'm just gonna let it sit with the gauges closed for about another half hour to make sure there's no leaks in the system once I'm assured there's no leaks in the system then I can charge it up so first you want to remove the moisture by evacuating the system then you want to let it sit to verify that you don't have any leaks don't have any leaks then it's time to charge seeing about a half hour it's been well maybe a little more than a half hour actually went and did some other work but as you can see that needle hasn't moved a bit and that's a pretty clear indicator that you don't have leaks in the system and it's time to charge it up the exciting part now that I'm about to charge I can disconnect the vacuum pump if you replace like a compressor or a condenser or some major component within the AC system you may have to add a little bit of oil to the system and you could consult the service being able to find out how much oil needs to go in with a given component replacement I just replaced the receiver dryer and a low pressure AC line with this there are AC machines out there that actually add oil along with the refrigerant charge which is really nice you don't have to worry about it so if you need to add oil this is what I do at least with this setup with just a straight up manifold gauge so as you can take this Center hose and you can actually dump the oil into this hose because it's gonna be drawn up into the system and right now everything's sealed off back here so you don't have to worry about it but here's something else that you can also do which I am going to do now and that is get some AC die now this is a lot this is probably enough for like five or six cars you do not need to use a lot of this but what this does is it will permeate the entire system and if there ever is a leak in the future this will leak out along with refrigerant and you put on glasses similar to what I have here and go around with an ultraviolet light and you can actually find a leak this way so I usually add a little bit of dye whenever I charge a system and sometimes you'll find refrigerant that actually comes with dye in it and it's real convenient for situations like this so if you have a leak a really small leak that's difficult to find this dye is a great way to find it there's also refrigerant leak detectors which is actually in the other video that I did about this but what I'll do now is I'm just going to add a little bit of dye to the inside of this hose like I said you don't need a lot and honestly I already added refrigerant oil the last time I did this I just added a little bit so I'm not gonna add any oil but this is where you would add it you'd have to measure it out and all those kind of things adding oil is really tricky ac work is really tricky to be done properly but a little bit of dye down in this and call it suction hose not really sure what to call it but this is the supply hose to the manifold gage I wish I knew a name for this if you know what put it down in the comments anyway the middle hose a little bit of dye before you add refrigerant okay before we grab a refrigerant we need to know how much to put in every car with an AC system has one of these stickers somewhere or should have one of these stickers somewhere that tells how much refrigerant the system holds and in this case it's 19 to 23 ounces or point 55 to point 65 kilograms is the amount of refrigerant that needs to go into the system so this way you know with the capacity of the system you do not want to overcharge the system that would cause just as many problems as under charging it in fact in some cases it might cause more so the first thing to do is find out how much you need to put in there should be a sticker under the hood somewhere mine is right here 19 to 23 ounces not advertising for these people I just I'm using this because you know what most of you out there have access to this but this is how much is in this can that just so happens that there's 19 ounces in this can so this whole system would be charged up completely by one can of this stuff awesome real happy about that so all I really need to do is add one can of this now I've already got the I don't know what you would refer to this as on this can't because I already put it on here but the way this works is you've got to start out with this I can't open this now because I don't have a hose attached but you'll start with this gauge if you want to call it that assembly screwed to the top of this can because the can won't come like in fact I think I have another candle I'll show you you screw this down and then he makes sure that this is all the way up then you screw this down inside the can and as you do that it will pierce the top of the can then you have to back this off again in order for refrigerant to start to flow out of it once you've got your can prepped and ready it's time to hook it up to the center hose and the same hose that you used to hook up to the vacuum gauge once again make sure your rings down in there or your vacuum pump the same ho is that you hooked up to the vacuum pump you want to hook up to this now make sure it's secure but not so tight you're gonna gonna kill it but right now this valve is closed because it's got like a little a little pin that goes down to the top of the can to pierce it so now I need to open this back up so I'm just gonna gently turn this out and I should have mentioned earlier pretty much before you get started with any of this and you've seen me wear throughout this entire video safety glasses if you're working on AC systems you really should be wearing your safety glasses all right I'm hearing a little bit of leakage out there now okay so now the valve is open so this is the way it would normally come you run this debt if this is a brand new can you'd have to run this all the way down to pierce the top of the can and then back up like this with the hose attached because if not refrigerant is gonna go spraying on everywhere now I've got a refrigerant hooked up let's start the vehicle okay I'm gonna use the vehicle's AC system draw on the refrigerant and in order to do that I need to get the compressor to run and the compressor won't run initially until I start getting a charging system but since I've got a vacuum on there it will start drawing the refrigerant in there so I'm gonna start the car I'm gonna turn the AC on I'm gonna put it on the vents and actually this is what I would I'll also do I'm gonna go grab my thermometer so we can check our performance I just went and grabbed my AC thermometer here and I'm gonna stick it in the center vent this is traditionally where you take AC temperature in fact I will post the video link to a video that I did about checking AC performance using this very same thing so the first thing to do when you're you're checking this is you want to note the temperature right now it's really nice like 72 73 degrees Farenheit and i'll start the vehicle I'll also turn my fan on and I'll go on Vince turn the AC on so my AC is on my gauges in here fan is on and actually you just want the fan on low to do your performance check it actually it actually got hotter all right now let's charge the system alright the engines running my refrigerant is charged ready open connected to the manifold gauge set you want to charge on the low side do not open up the high side just charge on the low side and all you're gonna do is just open the valve and it'll start to draw it in I'm gonna give you a close-up of the gauge set as soon as I've finished as soon as I finished here so you can see what I'm doing in fact I'll do that now okay my refrigerants ready remember do not charge on the high side you charge on the low side so open up the low side valve and you see it got a little bump there and it's starting to draw refrigerant in already in fact I can turn the can upside down make sure that happens and you see the needles start to go up on the side and it will also start to go up over here and there goes the compressor it just kicked on you can see the refrigerant flowing through this sight glass here you can actually see the refrigerant going in pressure is kicked on and my cooling fans are on all these are good signs you can tell because the front of the compressor is now spinning and it wasn't before now to make sure this stuff is going in I'm gonna turn the can upside down and shake it a little bit I also want to make sure this fitting is tight and I know I'm gonna take this whole can so I'm just gonna let the whole thing go in I still feel that there's some weight here compressor kicked off that's actually a good sign it should it should cycle it shouldn't be on all the time sometimes it is on all the time there it goes again so now it's cycling on and off like it's supposed to my cans feeling about empty nesting virtually empty now so now that I know my kin is empty I'm gonna close off the low-side on the gauge the gauge is still going to continue to read it just won't be sucking and refrigerant from this hose anymore now I'm going to guess and say that this is the part that you have the most questions about and I'm afraid to tell you that there's not much I can offer here it's going to take experience to figure out exactly what the pressures need to be because the pressures will vary depending upon what the ambient temperature is so the hotter it is the more humid it is the pressures are going to change right now it's a it's actually a very cool day it's really not a day where I can say that that a/c is something that you really need so I'm not surprised to see the cycling on and off and seeing the pressures that I do here but on really hot days what I usually see is a compressor stays on continuously and you get actually a higher side high pressure right now we're right around the 125 mark which seems a little low to me and then the low side goes down the low side looks like it goes down to about zero this this gauge has several different measurements on it it measures in inches of mercury and measures in bar and something else I'm going by the inches of mercury in the center of the high pressure gage and on the low pressure gage I'm going on the outter which is a scale that's specifically for 134a but this on the inside here looks like the inches of mercury just like this so right now it's dropping down to 30 20 but once that gets below 20 it should shut off or somewhere yeah right around there's about where it shuts off but the high pressure is just as important as the low pressure and I'm not even going to get into AC diagnosis I'm just gonna give you a general idea of what you're supposed to look for when you charge the system inside the car this is what we're seeing I'm seeing a drop down to looks like about 48 or so it's actually nice of chilly but you don't need to put the fan on high when you do this check actually low it's fine but if you want to feel the full effect oh and the other thing is you don't don't put it in recirculate just put it in fresh air that's the best way to check the performance of the AC because you're actually cooling the outside air when you put it on recirculate you're actually cooling the inside air which works great for cooling the inside of the cabin but it's not the best way to check the performance I have seriously cold air now let's wrap this up okay I'm gonna take my gauges off now shoot with just a little bit refrigerants is sort of boiling have a problem reinstall your bus caps alright let's wrap this one up safety glasses wear those manifold gauge set is a must if you're gonna charge the system from empty make sure you vacuum it down if the system has been empty or open to the atmosphere for any length of time particularly in humid climates replace the receiver drier or accumulator assembly depending upon what kind of system you have the pressures that you're looking for vary greatly depending upon temperature there are charts out there that tell you in fact there might even be a chart on the back of this one yeah there's a chart on the back of this thing here that tells you roughly what you should see as far as the temperatures go it doesn't give you any high side readings which in my opinion high side readings are equally important because that tells you how well the condenser is functioning and how well it's able to transfer heat see that video on basics of AC operation for a little more information on that because basically you're taking heat from inside the cabin and putting it outside here in front of the radiator that's that's basically what an AC system does so the high side pressure is equally important and I've seen high side pressures on hot days go 3 you know above 300 psi sometimes because it's it's got a higher heat load is what that's called so as far as pressures I might dig around on the web and see if I could find an article or something like that so I can post a link to I'm trying to give you the most information possible because to me a/c work is not for the faint at heart it's not for the amateur you really have to pay attention to what you're doing and even professional technicians have trouble with this for sometimes so it's it involves so many things I mean it involves the pressure temperature relationship it involves mechanical components it involves electronic components then you've got the entire HVAC assembly that that could have issues going on there so you really need to have a broad understanding of all those different components of the system in order to properly service and repair it but if you want it to recharge it you replace the component like I said you can add your oil into the third hose here you can also add like any AC dye or anything like to that to get that to go up in there and I'm gonna stop talking now i am eric the car guy you can always find me at eric the car guy calm or you can find me on facebook twitter and google+ and around here I close with be safe have fun and stay dirty but today I'm going to add one more stay cool catch you later everybody

Channel: EricTheCarGuy

Views: 4,117,792

Keywords: AC, AC recharge, AC vacuum, vacuum AC system, remove moisture, air conditioning, air conditioning service, car AC, AC repair, recharging AC, refilling AC, AC refill, 134a, R12, refrigerant recharge, automotive AC, manifold gauge set, using a manifold gauge set, refrigerant oil, refrigerant dye, how to recharge AC, AC how to, AC work, working on car AC, automotive education, how to auto repair, how to truck repair, eric the car guy, ericthecarguy, etcg

Id: lglPJuBXVeE

Length: 23min 48sec (1428 seconds)

Published: Fri Jun 01 2012