Charging R-410A into an Air Conditioner that's Low! Connect, Measure, Add Refrigerant, Disconnect!

this is craig igliaccio from aec service tech and today we're adding r410a refrigerant into a running air conditioning system step-by-step using our hillmore 2-valve manifold our dual readout thermometer and a digital wireless scale [Applause] [Music] step one is to put on our safety glasses and our gloves and then we're gonna get over to our ports and we're gonna take our locking caps off so we can get access to the system so these are locking caps we can't just unscrew them with our hand so you need to have a locking cap key and as an hvac service deck you're going to need various types of keys to make sure that you can get into these units now we're going to connect into the ports right here and you want to make sure that all of your hoses are snug and so you want to make sure those are are tight and also the handles are closed clockwise and so we can take our red hose right here and you're going to want to have a low loss fitting such as this right here on the end and we're going to screw that right into here you want to do this fairly quickly we're going to take our blue hose right here and we're going to connect that in over on this side which is our vapor line this is our large vapor line so we have our handle shut we're gonna shut our yellow hose as well we're gonna open this up we're gonna take it and just crack it open just like this we're going to open both and we want to purge the air out of the lines so we don't want to contaminate our refrigerant charge by pushing air into the system and so we have refrigerant now over to our our yellow hose we're going to put this back on right on here actually you know i'll leave this out of the way and then what we're going to do is we're going to turn our temperature clamps on and they should be very close to each other so same thing with the gauge you always want to make sure that they're zeroed out before use depending on your elevation you just want to check on that but on this side right here we're going to connect this to our vapor line which is our large large line right here to make sure we have good surface contact we're going to use some emery cloth and you want to make sure that that's on a flat surface so it gets good contact with the copper this one right here we're going to connect over on our liquid line once again you just want to lightly sand any uh corrosion or anything like that off of the outside of the tube that may detract from getting a good temperature reading so our air has been purged we have our temperature clamps on we're going to make sure to have our handle shut and then we can go ahead and turn the system on and what we're gonna do is we're gonna have to wait for about five to ten minutes before checking the refrigerant charge because this unit has a thermostatic expansion valve next we're gonna remove this cap off of the r410a bottle since this is a disposable rfinae bottle we're going to have it upside down because we want liquid to exit from the tank and so if this was a non-disposable bottle like a recovery cylinder you'd want to have it upright because there's a dip tube in order to get to the liquid but the whole point is that the refrigerant is mixed it's a 50 50 mixture of r32 and r125 and you want it to maintain that mixture so that's why we take it out of the bottle as a liquid and put it into the system so what we're going to do now is we're just going to purge this a little bit of air right here we're going to open up this valve we're going to then we're going to tighten this back down again [Music] our manifold handles are shut so what i can do now is i can open up the tank next we're going to put the r410a on top of the digital scale now we can zero this out you can see that the liquid inside the bottom of the r410a bottle is still sloshing around for me putting it on there we can just hit the zero i will hit it again once it just kind of stops rocking one thing to note is that any time that this hose rises or lowers it's going to change the weight of the bottle right here so what you want to do is you want to isolate this hose by putting a little weight on it and then making sure that you're not going to hit this hose while you're charging so that goes for any digital scale so now i'm going to zero it now we're going to turn the system on [Music] the big thing that we want to monitor for is the not just the pressure on the outer ring but we want to monitor the r for tonight saturated temperature on the inner ring so if you see right here it says 20 and then over here it says 40 well what we want to make sure of is that the saturated temperature on this loci gauge on the large vapor line does not lower below 32 degrees because that's the temperature in which water freezes and any humidity in the air crossing the indoor coil is going to freeze onto that coil so we are going to need to just verify that it is above 32 degrees we do have the proper airflow inside the building it's also about 77 degrees inside the building right now and it's 85 degrees outside so there is a heat load inside of the building and so we just want to give this a little bit of time to run this unit is equipped with a thermostatic expansion valve so we're mainly checking the refrigerant charge with the sub coin method which means we're using the saturated temperature on this gauge right here on that inner ring that's the pink inner ring and the temperature on the liquid line so we're going to take the saturated temperature we're going to take that and then we're going to minus off the liquid line temperature and that's what's going to give us our sub cooling reading but let's just go ahead and let this sit for a few minutes i'm gonna let this system run for about five to ten minutes before showing you how i'm able to tell that this system is low on refrigerant so we're gonna measure the refrigerant charge first then after that i'm gonna show you how to add the refrigerant in step by step [Music] the system's been running for about 10 minutes now we're going to read our pressure on our high side which is our small liquid line and we're reading about 304 to maybe 305 psi we bring that into the r4 today pink inner ring and we see it's measuring about 97 degrees as a r for today saturated temperature in the middle of the outdoor coil now we can also use a an app like the refrigerant slider app we can put in 304 psi and you see that we have our for tonight at 96.7 degrees as our saturated temperature and so we take our saturated temperature right right here 97 degrees minus our line temperature measured right here and we get about 3.6 to 4 degrees of sub cooling so sub cooling is measured with our saturated temperature minus our line temperature in order to get our sub coin now we're going to compare that to the target sub coin posted up on the outdoor unit reading plate so on this rating plate we see r410a as the refrigerant in the system and a target sub coin of 9.7 so because our actual sub coin is lower than our target that means we're undercharged so we're low on refrigerant now let's look at the low pressure side and we see that we're measuring a pressure of about 116 psi right here we bring it into the r410a pink saturated temperature inner ring and we're reading about 39 degrees and so that's what it says right here on our app so about 38.96 so 39 degrees so what we do to figure out our total superheat is our line temperature on the large vapor line which is 47 46.8 right now so 47 minus 39 and we're left with eight degrees of total superheat which is good the the txv is able to maintain a superheat of about say eight to fourteen degrees presently so our txv is good we do have a solid column of liquid going to the txv but we are definitely low on sub cooling so we want to add some refrigerant in order to do that we're going to do it on our low side handle because the pressure in the bottle is higher than the low side pressure so we're going to monitor our sub coiling but we're going to go ahead and add a little bit of refrigerant so you can see we're measuring maybe 0.2 let's just zero this out one last time we're going to make sure not to hit this yellow hose and let's go ahead and add a little bit of refrigerant so we only want to do it a little at a time because you don't want to add saturated refrigerant or liquid refrigerant right into the vapor compressor because you got to remember that this large vapor line right here it just goes right into the compressor right in so it's only like say one or two foot of line before it goes into the side of the vapor compressor the job of the vapor compressor is to increase the pressure of the vapor refrigerant there should not be any any liquid before or in the compressor that's going to damage it so presently we have about 1.9 ounces in and we're just gonna add a little bit more and then we're gonna we're gonna wait and check the refrigerant charge again 2.6 ounces in our pressure rose a little bit but here's the other thing i want you to to realize is that while this system is running it's taking and removing heat from the building it's removing humidity from the building so just because you add refrigerant into the low side it does not mean that the high side and the low side are both going to be increasing it may actually stay stable but your readings for your sub coin are what's going to change the reason is that if the inside of the building if the the heat remained the same in the inside of the building and you didn't lower in temperature then yes you're going to raise the pressure on your high side raise the pressure on your low side but that's just not what's happening so i just want you to be aware of that let's let this sit for about two minutes and then we're gonna check the refrigerant charge again and see if our sub coin has changed we added 3.9 ounces in so far [Music] so it's been about two minutes and we're measuring a pressure of about 315 psi we bring it into the r410a pink inner ring and we have about say 99 degrees 99 degrees is a saturated temperature in the middle of the outdoor coil 99 minus 92 and we're left with seven degrees of subcoin so because we added our four ounces our sub coin has increased but we do need to add a little bit more refrigerant so here we go we need to get up to about 10 degrees of sub coin so 9.7 you can tell if you are adding too much refrigerant at a time if you hear the compressor the noise change and that would that would definitely say slow down on your charging so we have eight ounces in let's go ahead and hold that and we're gonna wait a couple more minutes and we'll check the refrigerant charge again [Music] so [Music] it's been about two minutes and we're reading a pressure of about 324 and so we take 324 and bring it into the saturated temperature inner ring for r429 and we're looking at about 101 degrees so we say 101 minus 90 we'll call this 92 and we're left with nine degrees of sub coin and so we're just slightly low now and what we want to do is we're going to shut our bottle off because we don't want to add necessarily any more refrigerant from the bottle but we can add it from our hose right here and we're going to want to charge our liquid back into the system that's in this red hose so we're very close to what our target sub coin needs to be so i'm gonna go ahead and shut this off we could also just have shut this valve for now and what we can do is we're just going to add this in so we can power off our scale now right now all we're doing is we're charging the remaining liquid refrigerant that's in this yellow hose into the system so we don't want to just disconnect that and then just have that stuck in the hose there all right so that's all added into the system let's give it about two minutes let's just check the refrigerant charge again because it will be preferable to go ahead and shut this valve right here and disconnect this and then to add the liquid refrigerant that's in this hose into the low side before disconnecting [Music] [Music] so it's been about two minutes and we're reading a pressure of about 323 we bring that into the r4 tonight saturated temperature in a ring and we have about 101 degrees and so 101 minus 91 and we're left with about 10 degrees of sub cooling so that's that's all good we have roughly a 19 degree delta t which is a temperature change across the indoor coil from the supply plenum to the return plenum so what i want to do now is i'm going to shut this shut this right here and i might as well just go ahead and move this temperature sensor and i'm going to quickly disconnect here so i have my valve off this is a low loss valve and so that's very important to use those and so what i'm going to do now is i'm going to open both my high side and i'm going to open my low side a little at a time so you want to have your high side completely open because we are not connected you would never want to have both of these hoses connected onto the system and have both of these handles open because you'd have liquid refrigerant heading right into the compressor would actually use this as a bypass to go right into the compressor you don't want that to happen but at this point right now we have our high side hose disconnected and so we can just charge any remaining liquid refrigerant into the system so all we're left with in our hoses is just the low pressure vapor and that's it so both these handles are open we're not going to be able to check our sub coiling again now because we've already disconnected and what we can do now is we can disconnect over here now you're going to notice there's condensation over here so when we go to disconnect we don't want to wait very long at all i'm going to disconnect from here i'm going to wipe the port and then i'm going to put our cap back on because i don't want any water getting into the system even if it's not in the system and it's just on the cap i still still don't want that so that's what i'm going to do next [Music] now after i turn this system off i'm going to also check these valve cores right here and right here just to make sure that they're they're not leaking any refrigerant these caps have o-rings in them and they are made out of metal so they have an o-ring and a metal cap so it should be able to hold in any pressure if the valve core was leaking but i'm still going to do that test the small amount of pressure left in the gauge set is just low pressure vapor that can be vented unless there's some other way of recovering it but that would fall under the de minimis rule you also want to make sure that your epa 608 certified before handling refrigerants in this case a universal certification or a type 2 cert would suffice because this is a type 2 system now we're going to leak check our ports we're gonna add our test caps with these little holes in the end onto the ports and then we're gonna add a little bit of non-corrosive bubble leak detector onto the ends to see if any bubbles form if there are any bubbles that would show that we do have a leak because pressure is escaping out of the caps so we just let that sit for about a minute and see if we see any bubbles forming there i don't see any bubbles so we can go ahead and take these off and put our locking caps on so we're locked up and good to go i hope this video has helped you understand how to add refrigerant into a system and how to check the refrigerant charge while doing it so if you want to learn more about the hillmore tools used in this video i have them linked down in the description section below as well over at our website at adcservicetech.com we have our refrigerant charging and service procedures for air conditioning book so we have the full outline there you can check it all out see what's inside we also have our quick reference cards and these can be used out in the field they're made out of polystyrene so they'll hold up real well in your service bag so we have these both available over at amazon and also at our website at ac service tech dot com we also have free resources at our website such as quizzes calculators quick tips and articles hope you enjoyed yourself we'll see you next time at ec service tech channel

Channel: AC Service Tech LLC

Views: 139,229

Keywords: acservicetech, repair, maintenance, how to, fix, hvac, hvacr, how do you, test, ac, service, tech, check, measure, read, superheat, subcooling, refrigerant, procedure, voltage, charging, temp, multimeter, freon, hvac class, hvac school, hvac training, R-410A, Sat Temp, Saturated Temperature, Air Conditioner, Digital Scale, Refrigerant, hilmor, valve, manifold, system, digital manifold, guage, hose, vapor, adding refrigerant, air

Id: -pN9EoUZX8c

Length: 20min 4sec (1204 seconds)

Published: Sat Aug 27 2022