How To Use AC Gauges

hey my name is ben thanks for stopping by today i'm going to be talking about the basics of how to use a standard charging manifold or gauges for an air conditioning system so we're going to go through explaining what the different dials mean and the different temperatures that are represented on these gauges how they correlate to refrigerant and then also show you how to attach this to an air conditioner if you don't already have a set of gauges make sure that you check out the link right in the description under this video i will link to this same set of gauges if i can or something very similar i highly recommend picking up something from either yellowjacket or cps or some american-made company buying a set of those cheap chinese ones honestly just not worth it in my opinion pick yourself up a nice quality set of gauges because you're going to have these for many years to come all right let's take a closer look at these gauges and i'll show you exactly how to use them so real quick we'll go over the gauges themselves and just kind of explain a few different things about them right here on the top these are our actual gauges that we're going to be able to read for our different pressures and temperatures and these are attached to this manifold right here now we have a valve on the right hand side and a valve on the left hand side correlating both to the high pressure side which is the red and the low pressure side which is the blue so right here this is our high side manifold valve and this is the low side valve i'll explain how these valves work in just a second but let's look at these hoses down here in the way they're connected these three right here straight on the bottom you can see these are connected straight up into the manifold so this is the the side of the hose that stays connected to the manifold all the time now this other port here on the back this is actually just a spot for your hose to hang there there's this port doesn't go anywhere it's just a dead end where you can attach your hose when you're not using it so in order to keep the hoses from getting moisture in them and whatnot so the manifold only connects to this port this port and this port nothing goes out the back so the way these valves are set up they're made in such a way that when they are turned off they this is basically a dead end this is the low side hose comes up into the manifold and it will not go into the rest of the manifold when this valve is fully seated closed however even with that valve being closed it will still allow the pressure to be red up here in the actual gauge so when this valve is turned off we're still going to be able to read our pressures in the system the same thing applies to the high side this hose connects to the manifold and if this valve is closed it does not connect into the center portion of the manifold but rather is just passed straight through to this gauge up here so the purpose of these valves then is basically to allow access to this center port so this yellow hose is either going to be connected to a vacuum pump typically or a refrigerant cylinder a cylinder that has r22 or r410a or r134a in it so these outer valves give us access to whatever happens to be connected to that center port the majority of the time when you add refrigerant you're going to be adding it through the low side at a nice slow pace so you'll have your refrigerant cylinder connected to the center yellow hose and open the low side just a tiny bit and slowly add refrigerant to the system you can sometimes add refrigerant to the high side of the system if the system is off and you need to be charging it from a basically zero starting point you can charge a portion of it through the high side also if you had a system that was overcharged you can connect this to the high side port of the system while it is running and dump refrigerant out into a recovery cylinder through this center tap of the gauges so i think that gives you a pretty good overview of the physical aspects of the gauges themselves and now let's go ahead and move on to understanding what all these numbers are about here on each individual gauge so here we have a close-up of the gauges themselves the low side and the high side you can see how we have numbers around the outside edge of each gauge and that corresponds to psig so it's going to be relative to the atmospheric pressure so zero right there represents zero psig when we connect our gauges to the system it's going to tell us what pressure is in the system whether it be on the high side over here you can see there's a much higher range where this can indicate what the pressure is versus the low side so once we know our pressure that's when these inner numbers here that you can see marked come into play let me get you a close-up of one of these gauges in particular so you can see a little better so these particular gauges are set up for three different types of refrigerant as you can see this center ring right here is orange and it is marked for r404a the middle ring which is pink is marked for r410a and that's your most common air conditioning refrigerant type the next ring is this green one right here and that is for r22 which historically has been the most common air conditioning refrigerant but now has been taken over mostly by r410a the colors actually correlate to the color of refrigerant cylinder that is designated for each type of refrigerant so your 404a cylinder is going to be orange pink for r410a and green for r22 which really helps a lot when looking at this gauge you can very quickly identify which chart we need to be in so let's say that we had a pressure on the low side of a hundred psi so if we come straight in from where that 100 is marked you can see that that would correlate to 59 degrees for the vapor saturation temperature for r22 coming in one more from there to the pink which represents r410a you can see we'd be running pretty close to 31 degrees and again in from there it looks like we'd be at about 44 degrees for our 404a now technically we wouldn't need any of this information other than the psi because you can look up pressure temperature charts for different types of refrigerants for example this doesn't have r134a which would be a light blue color and that is a very common refrigerant in both automotive applications and small appliances like refrigerators and freezers so even though we don't have our 134a markings we can look up a pressure temperature chart and correlate 100 psi to whatever the vapor saturation temperature may be for our 134a over here on the high side it's exactly the same thing with the exception of the pressures just going up a little bit higher we have the r22 r410a and our 404a charts built into this gauge so we can see exactly what we are working with when we connect these to a system so now that you know the basics of how a charging manifold works we can connect it to a system and i'm going to show you the process for how to do that real quick i just wanted to ask you guys if you are interested in this type of content would you do me a huge favor and hit that subscribe button right under this video and ring the bell to turn on notifications 90 plus percent of the people who watch my content never subscribe to the channel totally get it if you can't or if you are only interested in that specific video but if you want to help me out and help the channel hit that subscribe button ring that bell and i would really really appreciate it alright let's keep going now before i connect this i just want to say that this should be one of the last things that you're checking you should be making sure that you have adequate airflow for your indoor unit and make sure that everything else is working properly before you connect your gauges because oftentimes air conditioners and other systems that have refrigerant in them don't leak substantially over the years overcharging units is extremely common because people assume that oh hey my air conditioner is not working it must be low on gas or low on refrigerant or low on freon so it's one of the last things that you want to do but the purpose of this video is showing you how to use these gauges so we're going to go ahead and connect it to this system and i'll explain a few different things regarding that whole process all right let's go ahead and get these things connected and i'll show you how they work so right here where the small line and large line come into the air conditioner this is what we would call the access ports to the air conditioner now typically they have this style valve this is the most common i would say and we're not going to have to worry about the position of the valve at all if this was a king valve then you would have to potentially adjust this but it's very uncommon for air conditioning that's mostly in refrigeration i'll put a link in the description to what king valves are if you are curious about that so we're just going to remove the caps that protect these ports and make sure that the rubber gasket comes off of there sometimes the rubber gasket will stick on the end of that port just make sure that that comes off and if if it does come off make sure that it sits back in that cap again it's very important that you have a good seal on those and then we'll remove the the low side cap now typically when we check refrigerant levels a lot of the time we'll just connect onto the low side but for today's video i am going to connect to both sides so that you get a good picture of what a system should run like before we attach our gauges we're going to go ahead and make sure that both of these valves are closed so the high side valve is closed and the low side valve is closed if you connect the hoses while those valves are open the refrigerant could leak out of this center port here assuming your your hoses were loose which usually this back hose back here is just loosely tightened onto there so if you hear hissing after you've connected your ports it's probably because one of the valves on the gauges got left open or one of these connections is loose these hose connections on the gauges just need to be finger tight if you have good quality gaskets in them you do not have to use a wrench or anything like that to connect these and that brings me to the next thing is on the end of each hose before you connect it you'll be able to inspect the gasket that is on the end there make sure that there's no cracks or major damage to them even if they do have minor blemishes they usually will work fine but just make sure that they are at least going to be usable you can also see in the middle of each one of these that there is a core depressor which is going to press that little pin that sticks out of the schrader port and allows you to access the pressure inside of the system now that both of the valves are closed and we inspected the ends of our hoses we're ready to go ahead and connect them to the actual ports now we're going to connect the low side of the system first and as you have already noticed the system is currently off and we could technically connect them while the system was running which we do fairly often in the field but with it being off it's a little bit nicer because your pressures are just kind of averaged in the whole system technically the low side pressure here which is what we're hooking up first would be lower while the system is running so that's really convenient when an air conditioner is operating and you're just going to check the low side you can attach this with no risk of there really being liquid present inside of this low side line now wearing gloves for this is a good idea honestly i don't know how many refrigeration techs always wear gloves i know they should but i'm just going to connect it without gloves today and show you a couple tactics to help prevent from getting refrigerant burns on your hands which is basically freezer burn not freezer burn which is basically like frost bite so when we first start attaching this it's not going to do anything so we can kind of get it started before it's going to start accessing the system it has to be partially tightened down before it will start to release that little pin that schrader core to allow refrigerant access i'll go ahead and set my gauges down here so you can see the pressure go up all right so now i'm going to try to keep my fingers on either side of the port and try not to get your hand your whole hand behind it if your whole hand is behind it like this if any refrigerant sprays out it's going to go straight onto your skin if you keep your fingers off to the side you're a little bit more safe i will link to the proper gloves that you should use for this in the description right here we go so actually this is kind of a good example you saw how the pressure didn't go up there just now and the reason for that is that this core depressor is not far enough out so we're just going to bring it out a little bit further this one is technically not it doesn't thread in and out but we can just pull it out a little bit by friction and that should allow us to get an accurate read on our system so let's go ahead and connect it again now that we've pulled that core depressor out just a tiny bit and there we've got a reading all right now we'll go ahead and connect our high side hose again our valve is closed on our manifold and this one is usually a little bit more exciting when you attach the high side especially if the unit is running because you're going to have liquid in this line at a pretty high pressure so we'll go ahead and connect this now we'll see if this core depressor is far enough out if it isn't we'll just adjust it here in a minute so we'll go ahead and get it started and then i'll get my hands off to the side as much as possible all right here we go and we are reading a pressure right there so we were able to get that one connected without adjusting the the core depressor so we have our gauges connected now and is showing us the pressures inside of the system and at this point you also need to know what type of refrigerant you are working with you can see right here we are working with r22 in this case so this is a little bit older unit most of the newer ones are going to be r410a but with r22 then we're going to be paying attention to this green circle of numbers that's going to tell us our vapor saturation temperature and our liquid saturation temperature i might make a separate video about this but i just want to point out that with the system being off we can actually see that the pressure temperature correlation is the same as the coolest point in the system which right now is inside of the building the thermostat says roughly 74 degrees and you can see that on an r22 chart it's also saying that it's about 74 degrees so it's like having a thermometer you can tell what the temperature of your system is even while it's off now that we have everything connected we're going to go ahead and fire up the system and i'll explain a little bit about what the pressures are reading and whether or not it looks like there's any issues with this particular system you want to also make sure the unit is clear of any obstructions is clean and that you have a new air filter or a fairly new air filter in your entire system if you don't have adequate air flow your pressures are going to get thrown off the particular system we're working with today is a fixed regulating device meaning this does not have a thermal expansion valve so these pressures correlate very directly to what our ambient conditions are going to be all right i'll go turn it on all right we have our system up and running and we can see our active pressures that the system is reading now generally you want the system to run for several minutes before taking a final reading but they usually balance out fairly quickly i can feel right away here that this condenser is pulling heat off of the refrigerant which is a good sign it means that most likely the compressor is working properly and we just have to now look at our finer details of the pressures once everything kind of levels out you probably saw how at first it pumps down a little bit lower and then now it's been gradually climbing back up as the refrigerant circulates through the system and everything gets to where it's working properly basically initially when it turns on you have an imbalance with where the refrigerant is located in the system right here we can see our outdoor ambient temperature which is 76 degrees now typically we're going to see a liquid condensing temperature above that we should at least by around 10 degrees but the maximum that you would ever want to see is 30 degrees above ambient so if we look at our pressure temperature correlation we shouldn't have a temperature greater than 106 degrees which would be way on the high end of what we would want to see especially for an air conditioner so looking at our gauge we can see that we're running at about 195 psi and we're looking at our r22 chart so if we correlate that it comes out to be roughly 96 degrees or so right there so our ambient temperature is right at about 76 and we are at 20 degrees above ambient for this particular unit so our high side pressure looks fantastic if we had a dirty coil or something out here on this outside air conditioner this pressure could be upwards of 250 psi or even greater or if we had a bad fan motor in this unit that's this pressure would be way higher or even a bad capacitor oftentimes a bad capacitor is kind of a misleading thing for these condenser fans because sometimes the fan can still spin even with the bad capacitor just not spinning fast enough but given everything we're seeing here it looks like this is just fine all right let's turn our attention to the low side pressure and we'll explain that a little bit more so at first glance i would probably tell somebody that this looks like this system is a little bit low or very close to being low now the only way to know if it's low for sure is to make sure that everything else in the system is working properly i happen to already know that there is a air filter in this system that is towards the very end of its life and needs to be replaced so i'm going to go pull that air filter out and we'll see what that does to this pressure here on the low side the main thing that you don't want to happen is you don't want this pressure to drop blown up to where we get below freezing if you get below freezing the inside coil can ice up and basically block off your airflow and then your your pressure will dive way down if your unit actually freezes up so right now we are on the razor edge of 32 degrees so instinctively looking at this i would say huh it might be just a tiny bit low let's go pull out that dirty air filter and see how much that changes the equation i will be right back in one minute all right here we are looking at the air filter let's go ahead and just pull that thing out of here so now the furnace is able to handle the air in an unrestricted way it could be a furnace or it could be a regular old air handler but in this case it's a gas furnace which is pretty typical for our climate alright it looks like by pulling out that air filter that did make a pretty substantial difference in the operating pressure of this unit you can see we went from being on the razor edge of 32 degrees for r22 chart all the way up to maybe 35 or 36 degrees so having a fresh clean air filter in the system would help it to run a little bit more efficiently and keep that vapor saturation temperature a little bit higher on the low side of the system if i were on a service call though right now i probably would bump this up just a little bit i'd probably put in eight ounces of r22 and bring it up to around 40 degrees or so now as far as a range of pressure is concerned anywhere from 65 to 75 psi is totally acceptable and even down a little bit lower than that is okay if this was your air conditioner i would tell you that it probably will work fine even if we don't add any refrigerant but if your air filter gets a little bit plugged you might end up with a iced up a coil inside of the basement another thing i want to mention real quick is that when you have these connected like this we want to make sure that we don't allow any air back into the system and if we were going to add refrigerant through this yellow hose we would first want to bleed off the air that's inside of these lines and optimally they would still have r22 from the previous job in them but it's still a good idea to just take and bleed a little bit out of these hoses before you would connect them onto a tank of refrigerant or other device like if we were going to be recovering this refrigerant with a recovery machine we would bleed the air out of the lines first before we connect this all together in this case we're just checking the pressures so it's not that big of a deal because there's no refrigerant that's going in and out of these ports right now it's just a little bit of refrigerant pushed into these lines but none is going back into the system so if we had a low charge we would go ahead and connect this to a cylinder of r22 turn it upside down and slowly add a few ounces of refrigerant probably like eight ounces in this particular case if it was overcharged we could connect this hose directly to a recovery cylinder not even a recovery machine and we could dump off that r22 from the high side into that recovery cylinder or at least some until the recovery cylinder heated up or got a little bit more pressure in it so if we were to connect this to a recovery cylinder that had r22 in it the ambient temperature which is like 76 would correlate with a pressure of 130 psi and since our condenser is running at close to 200 psi we'd be able to dump some refrigerant out of this yellow hose directly into that tank once we bled the air out so we're able to confirm that our pressures are operating correctly and now it's time to take the gauges back off of the air conditioner now we can do this while it's running or we can do this while it's turned off now these gauges are very standard they have standard hoses and standard fittings now because they have hoses that have little valves on them that are available where you can basically turn off a little valve right here and then it's a lot easier to disconnect this without refrigerant spraying everywhere unfortunately that's not what we have here today and i'm going to show you guys what that normal process looks like it's not pretty and it's not fun but it's necessary now we could turn the unit off to disconnect the hoses but it doesn't really change the situation that much it technically would lower the pressure on the high side just a little bit but it would also raise it on the low side of the system so we'll start by disconnecting the low side and then move to the high side sometimes refrigerant oil sprays everywhere so hopefully that doesn't happen to my camera so i'm going to get my fingers on either side of this fitting here and really quickly just turn it off see how that was not a big deal at all just a little bit of vapor escaped not a big deal we're going to do the high side now and this is absolutely no fun at all i'm going to keep my fingers on either side again it's much better to wear gloves that are non-porous for this and i'll link to the gloves that you should use in the description but just being honest here guys a lot of times you don't wear gloves for this and so you just need to be aware of this if for some reason refrigerant like kept spraying out of this unit don't try to plug it or block it off with your hands it's just not worth it you'll freeze the skin off your hands by doing that all right here we go i'm just going to get it started where i can kind of feel it you can turn it the first little bit and it won't start to leak yet so now we know that it's it's loose and we'll go ahead and turn it off as fast as we can and it's going to kind of spray refrigerant all over the place because basically it's going to release a little bit of liquid that was in this particular hose here we go all right there it was you saw how it was spraying both directions but it did not get on me at all because my fingers were out of the way now we can go ahead and reattach the caps and after you're done using your hoses make sure that you reattach them onto the manifold so that dirt and moisture doesn't get into the actual hoses alright well that has been how to use refrigerant gauges the standard charging manifold from yellow jacket in particular i'll link to this set of gauges in the description of this video as well as my favorite pair of digital gauges should you want to splurge for a fancier option where it does all the math real time with being able to calculate super heat and sub cooling and all that kind of stuff so make sure to check out those links in the description i'll be releasing several more videos in the coming weeks about air conditioning in particular so if you guys want to learn more about air conditioning make sure that you hit that subscribe button right under this video and hit the bell to turn on notifications if you want to keep learning about air conditioning with me i'll put a couple of videos right here on the screen this is the one i think you want to watch whereas this one up here is the one that youtube thinks that you want to watch alright thanks ton for watching we'll talk to you right over there if this video earned your subscription hit that subscribe button right under this video and click on the bell to turn on notifications

Channel: Benjamin Sahlstrom

Views: 433,811

Rating: 4.9351883 out of 5

Keywords: air conditioning, how to, recharge ac system, ac gauges how to use, hvac troubleshooting, hvac training videos, hvac technician, hvac training, air conditioner, how to recharge your ac system, gauge manifold set, yellow jacket

Id: xlJ98622Khs

Length: 26min 33sec (1593 seconds)

Published: Sun Jul 26 2020