Charging R-22 into an Air Conditioner that is VERY LOW on Refrigerant!

hey guys this is AC service tech and today we're going over is how to add refrigerant into an R 22 outdoor unit so this is a outdoor condenser for an air conditioning system at a home and presently we can tell that we're low on refrigerant because the unit has a thermostatic expansion valve that looks just like this right here right at the inlet of the evaporator coil and so we got to tell what metering device it has in order to tell if it's low and refrigerant correct on refrigerant or overcharged or if there's another issue but basically because we have a TI ta we're going to be paying attention to this gauge right here and the small liquid line so we have a pressure reading of about a hundred and seventy-five psi J we bring that in and we're reading about ninety two point five or so on the liquid line right here so we have this 10 sensor t1 right here taped on to the small liquid line but reading 92 degrees so we have 0 to 0.5 degrees of sub-cooled up on the rating plate is calling for 10 degrees of sub-point so we know that we are low on refrigerant since we have a low sub cool if the unit had a fixed orifice such as this this is a piston inside this piston chamber or this is capillary tube you need to pay attention to superheat which is done on this gauge right here and right on the suction line but anyway we need to go ahead and add refrigerant to be able to increase sub cooling what will happen is we're gonna have to put r22 into the low side right here and a little at a time and what's going to happen is this pressure should rise this temperature may rise for a little bit but then it's going to end up falling and basically the gap between the pressure converted over to the saturated temperature right here and whatever the sat temp is on this r22 green in a ring - what's reading right here on t1 on the liquid line that's going to be our sub cool the very first thing that we need to do is purge the air out of the hoses if you just connected the hoses we want to make sure that we don't put air in the in the system so we need to get the air out of all three hoses before connecting this to the refrigerant bottle I always make sure that you're wearing gloves and safety glasses when doing this so what we're gonna do is we're gonna take this valve on the end of the hose we're going to shut that that's our service hose right here we're gonna open up our low side and we were going to do is we're going to take the pressure from the refrigerant and push the air right out of here so you're gonna do it just a short period of time until you hear an air like a noise change and then you're going to stop gonna close that valve and then you're going to open this one up and you're gonna purge this one as well when you see that the air change color and also the noise change that's that's the refrigerant you want to stop immediately you don't want to let that out into the atmosphere once you do that you're gonna go ahead and shut this valve right here so both of these should now be shut you have refrigerant all the way up to this hose right here and then we're going to connect this to the bottle so you see that right there what we're gonna do is we're going to open this up you want to get any remaining air out of there and then we're going to open this bottle up so right now we're gonna leave this bottle upside down just like this we're gonna put it on to the scale we're gonna turn this scale on I'm gonna make sure it's zeroed out so we can see how much refrigerant we're adding in that is for multiple reasons one reason is to see how much refrigerant you're putting in you know maybe for billing just so the customer knows so that you understand how much you're putting in all that so right now it's already zeroed out it's ready to go and since that bottles upside down the refrigerant gonna come out as a liquid so we need to charge it a little at a time into the low side you don't want to just open the valve up and allow a lot through because this is a vapor compressor in there and it should only have vapor refrigerant coming into it if you were concerned to make sure that only vapor is getting in you could put a liquid charge adapter onto the tank we're on to this port right here such as an imperial 535 - see they're pretty good it's called a liquid vaporizer but now we have everything hooked up we're gonna go ahead and add a little at a time right in so you see that little squirt that we just put in they pull up point three ounces into into the system every time we do that we're introducing the liquid and it's flashing with the vapor and going into the compressor but if you allowed a lot in it's not going to flash and you're going to have the compressor or getting slugged with liquid that would not be good we're gonna need to get some refrigerant into this and as we do that this pressure should rise in the set temperature dries we know we're really low on refrigerant but if we were close we wouldn't just keep charging we would wait maybe two minutes between adding refrigerant just to see what changes are taking place with our sub-point readings but we do know that we're very low on refrigerant right now you also want to make sure that if you don't have an isolation port on your scale maybe you tuck that this yellow hose where it comes out of the tank cap put it underneath of the scale or something so that you don't move it if you do move it your weights gonna get thrown off and you're not going to know how much you're actually putting in when you are really close you may want to wait five ten minutes and just kind of walk away from the unit do your billing do whatever other stuff that you need to do to finish up the job clean up the tools just a just a monitor with that sub pointing reading really is you want to give it a chance to kind of the refrigerant to circulate through the system presently we're at about 93 degrees right here I know you're looking down at it so it may look like 92 but we're at about 93 right now so 93-91 so we have about 2 degrees of sub cooling so our sub point has increased which is good and for real accurate sub cooling reading you want to give it a little extra time but I like I said I know that we're very low on refrigerant right now if as you're adding refrigerant into the system you hear the compressor noise change or something then that means you're putting liquid into the compressor you need to change what you're doing there don't as much refrigerant into the system at a time also when the the system refrigerant charge is getting very close like the sub cooling reading is is pretty close you really want to stop because this temperature may fall on you pretty quickly and they all the sudden just go ahead and drop so that may happen if you get close to the sub going reading so you want to give it a little bit more time at that point I've added 10 ounces in so far so that's a good amount of refrigerant up on the rating plate of this unit it says that the the entire unit and 15-foot worth of the copper line set and an evaporator coil it actually came with seven point six pounds of refrigerant to fill that out three unit fifteen foot with a line set and an evaporator coil so to add 10 ounces into a system that only is supposed to have seven point six is a considerable amount so this is what you would do after fixing a leak you know where if you just installed a unit in this Lo and refrigerant you're adding refrigerant in you want to make sure that the system has good air flow that the filters clean and you have the dip switches set correctly if there are dip switches right now we're reading about ninety three point five or so and we'll just call that eighty nine so we have four point five degrees of subcooling we're gonna add a little bit more they are getting there that the less you open the handle and you you know you only let a little bit in at a time that's going to be better for the system for the compressor I wouldn't keep adding like I am right now just due to you know getting an accurate sub coin reading but I do realize we are very very low in our group I'm gonna let this sit for now I'm gonna check back with you I'm gonna give it about five minutes just to make sure that our readings are accurate and then we'll go ahead and resume or Cartman so it's been about five minutes and it looks like we only have about five degrees of subcooling if this is reading ninety three point eight and that's eighty eight point eight that's about five degrees of sub going up on the rating plate it's calling for ten so we want to try to get to maybe 11 or 12 typically for subcooling you want to get you know as close to the sub point as possible I'd like to be one or two degrees above whatever the sub point rating is if you're working with superheat you want to get right right on that target but we're going to go ahead and add a little bit more refrigerant so almost a pound now we got about 15 ounces in so what's happening here sometimes what happens is this pressure and set temp will rise while this temperature rises but not that much and then what happens is a gap will be opened up in this case where we're at right now this saturated temperature is rising and this temperature is falling as we add or Fricker so like I said sometimes when you add refrigerant this temperature will rise at first but then will eventually go down a little bit you can charge r22 as a vapor to even be safer it just will take a little bit more time in order to charge that into the system r22 is a single component refrigerant so it can come out of the bottle as a vapor or a liquid refrigerant such as r410a or our 4:07 see those we need to come out of the bottle as a liquid and then it's up to you you know for you to try to flash it a little bit before adding it into the vapor line they said you can add a vaporizer either right here or on the refrigerant bottle it's basically acts like a little restriction in order to change it from a liquid into at least saturated state saturated state means liquid and vapor both at the same time right now we are at 94 degrees at temp and 87.6 so that is six point five degrees of support when you do add a whole lot of refrigerant you know maybe a pound or two pounds or something like that and if the sub cooling is not changing what you may want to do is you may want to allow the indoor fan to continue to run and possibly shut the outdoor unit off for our five minutes and then turn it back on if it has a TX v you want to wait five to ten minutes once it's on in order to check the refrigerant charge level sometimes you do need to do that if you add a whole lot of refrigerant at least that's what I found sometimes that just makes sure a completely sure that your you know refrigerant charge that you're reading is accurate sometimes it just does not add up correctly when you add that much refrigerant to quickly it's also important to note that as you add refrigerant well actually as the system is running both these pressures will fall because basically you're reducing the heat load in the inside of the building so it doesn't have to work as hard so as you're adding refrigerant as the system's running and as it's taking humidity and heat out of the building this pressure may not just continue to rise as you add refrigerant and that's due to a lower heat load from inside the building in a lower temperature inside the building so that's why this this pressure intense at temp is not just rising as we're adding refrigerant its kind of staying where it is it's at its rising a little bit but not a lot I just wanted you to know that's why but your temperature will continue to fall [Music] so right now our high side pressure has flown a little bit but we're about ninety 93 to 94 right there so we're still at about that same six degrees a sub point let's go ahead and let this set for a little while longer we have a pound and 6.7 ounces in so let's just go ahead and let it run for a little bit and I'll check back up on it in a couple minutes so right now we're at about 95 degrees at 10:00 9:00 t5 minus 88 and we have about seven degrees of subcooling it's been about four minutes so far it's been about five minutes and you see that we're reading right about 96 degrees right here and we have 88 right here so we have about six degrees of sub-point so we're gonna continue to add refrigerant now we're up to 1 pound 9 ounces let's just give it a chance for that refrigerant to circulate through the system so right now I worried about 97 and 89 so we have 8 degrees of subcooling we're pretty darn close [Music] [Music] [Music] we're reading about 99 right here saturated temperature - eighty nine point five and we have just about Loxy this has dropped a little bit so 98-89 so we get about 9 degrees of subcooling let's go ahead and let that sit there for a little bit and we'll check the refrigerant gauges again a couple minutes all right it's been about three minutes let's go ahead and add a little bit more I thought we were low but I realized we were about two pounds low here another thing is if you add refrigerant and you notice the pressure is not changing at all on the high side then what could have happened is this valve core depressor that's inside right here may not be pushing in on the valve core inside so that could be another issue if you're charging but then you're not really seeing any movement on that gauge whatsoever in this case it is tight though so right now it's about 99 degrees right here it may look a little different looking down at it but it's about 99 degrees there - 89 if that's about 10 degrees off sub core so what we're gonna do is I'm going to valve off this hose on the refrigerant bottle over here and then I'm gonna charge that in as well what I'm going to do is I'm going to disconnect here and I'm going to charge the liquid that was in this hose into the low side so now the bottle is valved off but we're going to charge the refrigerant that's in this yellow hose into the system you want to stop just a little bit before you get to the required sub cooling and go ahead and charge that in as well all right so as you can see that's all the liquid refrigerant that was in that yellow hose from the bottle and now what I'm gonna do is I'm gonna go ahead and move my temp sensor and we're not going to necessarily need it anymore because we can't check our subcooling once I disconnect this so I'm just going to go ahead and go ahead and move this out of the way I'm gonna move this [Music] so with this valve all I'm going to now since we don't have any connection here or to the bottle I'm going to open this one up and now we're going to go ahead and charge the refrigerant that was in this hose into the low side so now that that pressure and this pressure is matching we can go ahead and shut these handles and now we're going to leak test right here and we're going to need to leak test on the other side as well what I like to do is I like to just add the valve or removal tool and then put leak detector right in the end this way I can see if any bubbles form and I don't have to put the leak detector right into the valve port after about a minute and you don't have any bubbles then that valve core that's in right here it is receded everything's good and there's no leaks it's been about a minute so we can go ahead and disconnect this and this can be blown out with compressed air or nitrogen but basically going to do this on the other side as well and then you'll put the caps on [Music] so all that's left in the gauge is just a little bit of vapor there's no liquid so you want the least amount of vapor in the gauge set when you're done as possible after not seeing any bubbles right here what we're gonna do is we'll put our caps back on so you can use your piece from your vascular removal tool or another tool and you can go ahead and put your locking caps on all the tools using 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Channel: AC Service Tech LLC

Views: 111,672

Rating: 4.8541112 out of 5

Keywords: acservicetech, repair, maintenance, how to, fix, hvac, hvacr, how do you, test, ac, service, tech, check, measure, read, superheat, subcooling, adding, freon, condensor, air, conditioner, port, hose, temp, temperature, reader, calculate, level, txv, tev, eev, unit, system, central, r22, gauge, manifold, set, connection, vavle, scale, weigh, bottle, tank, cylinder, liquid, vapor, suction, head, discharge, sensor, sat, saturated, state, phase, coil, procedure, process, method, fixed, orifice, step by step, undercharge, under, charge, pound, upside down

Id: b0gsuh-Sno8

Length: 25min 13sec (1513 seconds)

Published: Sun Sep 09 2018