All right we're not going to be using gauges, we're going to be using just a hose and our tank, which is tan nowadays, instead of pink and whenever you pull a recovery tank, really any kind of tank charging tank recovery tank off. The truck also pull your scale off the truck at the same time, all right so in this video we're going to set the charge using sub cool on a two-stage txv system. Now, in addition to that, this is a system that we just installed. We got it running, but now i want to go through and dial in the sub cool.

I know the line sets a little bit longer than the factory specified length, and so i know we're going to need to weigh a little charge in, but i'm not exactly sure the true length because it's a pre-existing line set. But i want to go step by step through the process, i'm actually going to use a couple different tools just so i can show you an old school way of doing it actually using an analog gauge, as well as some digital field, piece job link probes. So here we go all right just for some basics review before we get started, this system is a heat pump, but currently we're going to be charging it in cooling mode, which is the preferred way. Our current outdoor temperatures are about 78 degrees uh in the shade which i'll measure here shortly with a thermometer, but this is our suction line, going back to our compressor.

If this were in heat pump mode in heat mode, this would actually become the discharge line. A lot of people just call this the vapor line as a more generic name, because it is vapor whether it's in heat mode or in air conditioning mode. But this is where we're going to actually add refrigerant in while it's running because the system already has charge in it. This is what we call true, suction or common suction, or always suction.

This remains the suction port, whether it's in heat mode or in cool mode. So, if you're in heat mode, this is where you would connect your low side gauge and then in cooling mode. This is your liquid line. You wouldn't want to use this port in heat mode, because this port's actually passed the heat mode orifice.

This is a piston orifice in cooling mode, it's being bypassed, so the liquid is going this direction towards the evaporator, but in heating mode. The flow goes the opposite direction and is restricted right here. Making this reading kind of a not a very useful measurement at all. So in heat mode, you would want to connect your high side gauge here and your low side gauge here, but since we're in cooling mode we're going to charge it into the suction line.

But we also need to be monitoring our liquid line pressures, which we correlate to a saturation temperature, otherwise known as a condensing temperature and our actual physical liquid line temperature in order to calculate our sub cooling. First thing, though, this system is not running right now. It's actually cycled off, so i'm going to go in and drive the temperature way down and make sure that it goes into stage two. While we're doing our charging.

When you have a multi-stage piece of equipment, you always want to make sure that it's in its maximum flow rate or its highest stage when you're doing your charging again, that's you know, follow the manufacture specifications, but generally that's going to be the case, and so you Can do that by using the installer test mode in the thermostat, or you can do it by just driving that temperature way down and then giving it sufficient time to make sure that it's in high stage, so i'm gon na go, do that now. So now we've got the unit running we're gon na, let it run a while before we make any changes, and so, while we're waiting, i'm gon na go ahead and show you the old-fashioned way of checking superheat and sub cooling. Now i'm going to be using some gauges rather than a gauge manifold, because in this case we're just doing testing and of course, it's the core depressor that pushes down on the schrader core that allows refrigerant to flow through the hose and to be measured in the Gauge now, in this case, we don't need this additional hose. I have this on here in case it's in a tight application, where i can't fit the gauge on so we're going to remove this now.

A lot of people still like to use analog gauges. I like to use analog gauges for teaching purposes, because it's a kind of an old-school way. It shows the saturation temperature for the corresponding pressure on the gauge, which makes it nice for learning. They aren't nearly as accurate as digital tools.

So nowadays, when we're working on equipment for our customers, we only pretty much use digital tools. Safety glasses are now on we're going to connect to the liquid line first now. One thing that i do like to do in order to prevent that sort of spray of refrigerant is to use a quarter pressure. If i push this on and i start twisting it, it will make a little.

You know it'll lose a little bit of refrigerant as i connect, because that core depressor is engaging at the same time that the seal is sealing, and so we get a little bit of that blowback and so on the liquid side. It's nice to use a quarter. Presser, because it helps prevent that and i'll show you how that works. So this is an accutools otherwise known as blue vac brand core depressor, and this is a back seating design, which means when it's fully open it actually doesn't allow any flow through the quarter.

Pressure itself, which is kind of nice for a couple different reasons. The way it works is, i can attach this to the service valve and there won't be any flow until i turn this knob clockwise, which then engages the core so i'll show you how this works. So right now, because this is completely back seated - that quarter presser isn't engaging and there's no flow. Now i can go ahead and connect my gauge, so we're going to use this small extension hose just for visual purposes for the video, because it's kind of hard to get in here and show the gauge location, but you can see there's no flow right now.

If i i can control the flow out of this valve very easily, so we're going to connect this hose now when we depress the core, you see the gauge jumps way up where it's supposed to be to purge any of the air out there. So now we're seeing our pressure, which we can correlate to what we call a saturation temperature or a condensing temperature for the specific refrigerant that we have now this is r410a, so the scale is the pink scale on this gauge i'll. Give you a better view all right. So if you take a look at our pressure, our pressure is reading just about 250 psi, and this is the challenge with an analog gauge, because is it really 250? Is it 245? You know it's right in there.

If you look, this equates to just about 82 degrees. But again is that 82? Is it 83? Is it 84? Is it 81.? It's really really hard to see on that fine scale, which is a disadvantage, but we're going to go ahead and just say: 82 degrees is our saturation scale, and so what that means is is that is the temperature that the refrigerant is condensing inside the condenser. So when it's changing state, that's the temperature that it's changing state at, given the current pressures that we have, and so when we compare our sub cool to this number, we're looking for a number on the line that's lower than that number. And that tells us that we're fully liquid and that we have sub cool or sub cooling.

So again, we're going to go with the old school method, we're going to use just a simple cooper, atkins line temperature clamp and see if we can get our line temperature that way all right. So right now it's showing 79.1! That's about the outdoor temperature, we're going to clamp this line onto our liquid line, which again should be fully liquid if it is we'll, have a sub cool rating all right, so we are measuring a line temperature of 82.4 on our liquid line, with good, solid contact On that line 82.2, and if you remember, we were measuring about 82 on our saturation temperature, which means that we have about zero degrees of sub cooling. Now again, because of the inaccuracy of these measurements, we could have one or two degrees of sub cooling. But at this point we pretty much know that we are low on charge and the way we can know that, because our data tag lists a liquid line.

Sub cooling of 10 degrees fahrenheit. So that means we need to add a refrigerant charge slowly and carefully, because this is a heat pump with an accumulator until we get 10 degrees of sub cooling. But we're going to do that with more modern digital tools, so that we can monitor it more carefully. Also real quick.

I wanted to show you super heat same basic process. Only it's the other direction, whereas sub cooling is the temperature that drops below our condensing temperature or our high side. Saturation temperature superheat is temperature that is gained, sensible heat that is gained above our evaporator temperature, our boiling temperature, or often called our low side saturation temperature. So we would first hook up to our low side and you'll notice.

We don't get nearly as much refrigerant loss on the low side, so the cord oppressor isn't as useful there. I can see here that our pink scale is showing 40 that's a 40 degree, suction saturation, otherwise known as a 40 degree evaporator temperature, and then i'm going to measure our suction line temperature and we are measuring, give it a second to acclimate. So that's reading 51 degrees and we have 40 degree suction saturation, so that is an 11 degree superheat. So that's 11 degrees, sensible, that's gained in addition to our evaporator temperature and that's about what we would expect, in fact, maybe even a little lower than i would expect, given the length of line set that this has, but so long as it's well insulated um.

That would be what we would expect and so we're in good shape on that side of things, but we still need to charge the system by sub cooling. It's a txv system internally, that is the metering device type, and so we've got to get this sub cooling. Where it should be so now we're going to go ahead and hook up our digital probes, our field piece, job link, probes and get our sub cooling dialed in using a tank and a scale and our probes. Let's get all these disconnected now on the jawblink probes, you can change them either from suction or liquid and you'll see the indicator here.

So this one here i have set as my liquid side and this one here i have set as my suction side. You can see it's got the little blue flag. There just hold down the buttons in order to get them to come on and they'll light up with a green light. Actually i have to zero them out.

First, all right, so you can see that my high pressure probe is flashing. Green battery looks good, but this one's flashing red. So i need to replace the batteries real easy to do just need to grab some batteries real, quick and we'll be right back all right. So we just got some aaa batteries, so we go into the probe manager on measure quick, i'm going to go ahead and zero these both out to atmosphere.

So you can see it's successfully zeroed, the the other one is already successfully zeroed. So we're good to go to connect now, let's just make sure that we have an accurate measurement every time now again on the high side, because i have the core depressor. I've got to go ahead and give this a twist in in order to measure the pressures and then, if i check on my probe manager, i can check and make sure that i am measuring my pressures as i should, and i am so now we're ready to Go ahead and profile the equipment using measure quick, all right, so my next step is to go ahead and connect. My clamps same thing with my clamps one has the blue for suction.

The other has the red for the liquid side and all i've got to do in order to get these working same thing. Push the button down until we get a flashing green light, it'll make the beeping sound. These are the rapid rail clamps, so blue here and then liquid. Here all right batteries are good on both of these.

We are measuring, as we would expect our um. We need to need to reset the mappings on these, because the liquid line is uh. They're they're mismatched, just how i had them set originally now i have this one set to liquid line temperature because it's higher temperature - if this one set to suction line temperature, so we're good to go there and then our high pressure is our high pressure. Low pressures are low pressure.

So that's good! I'm going to take my indoor probe, my induct cyclometers, i'm going to position them inside and the return in the supply, and then we also need to get an accurate outdoor temperature, which i'm just going to use a pocket thermometer and stick it out here or actually. I could use the back side of my cooper here. The cooper actually has a probe thermometer. Now again, a lot of people will tell you this, isn't the best air thermometer that there is, and that's true it'd be better.

If you had another one of these that you could stick out here my set, though i only have two in my current set, so we're just gon na use this to measure outdoor temperature, and it is currently showing about 81 degrees, but we'll kind of let it Sit out here in the shade, where it's not being affected by anything else, see what we get yeah we're getting right about. 80 81 degrees. So i'm gon na go put these in the ducks i'll, be right back all right! So now we're looking through all of the different measurements that are coming in in the toolbox. We've got liquid line temperature, suction line temperature, low pressure, high pressure, supply air and return air.

So now we're ready to go ahead and set up our system info. So we need to tell the program a little bit about the system. This is a two ton heat pump, so we're gon na go two tons. 24.

000. Now these are all nominal ratings. If you wanted to get really specific, you would have to put in the extended performance information, but we're going to use just sort of general information. This is a high efficiency, evaporator coil, meaning that it's a larger evaporator coil than the tonnage match carrier.

Does that a lot and it is a rated match, our sub cooling is rated at 10 degrees. So you see that so we're good total external static. 0.5. That's correct factory charge! Let's go ahead and do this put our factory charge in 13, pounds 13 pounds almost right on the dot, there's like a tenth of an ounce, but we're not going to worry about that.

We're not going to put in the extended performance ratings so that all looks as it should. I'm going to hit submit all right, txv, r410a 350 cfm per ton. You can see up here on the screen. It's showing that it's unstable right now system is not stable.

Please wait until system stability is achieved now it may not get stable because of my low sub cooling, but let's go ahead and enter our outdoor temperature because i think i forgot to do that. So, let's go into our outdoor measurements, i'm going to scroll over here to outdoor measurements put in our outdoor air temperature, which currently we're measuring 78 degrees, i'm actually measuring the two thermometers. Now you can see our head pressure up here is lower than our green target, which would go along with having some low sub cooling, but, as you can see, our sub cooling number really isn't as bad as i would have thought. So, let's take a look here at our kind of warning: it's saying that liquid line temperature is below the outdoor air temperature.

So, let's see what we've got here, liquid line is saying 77.9 and actually, if we look at the outdoor air temperature, our outdoor temperature is right at 78 degrees. So it's just right there. On that number. Your liquid line temperature should never be able to go below your outdoor air temperature, but again you know these thermometers could be two one two degrees off in that range and, as you can see now it's cleared up and now we've got a green flag.

It's saying: there's no major issues, but we're just right on the line of having zero approach see we got 7.3 degrees of sub cooling, so it's actually not quite as bad as i thought it was. One thing i want to definitely make sure of here, though, is i want to make sure that we are running in high stage, so let's go ahead and confirm that with a meter, real quick, so in this particular unit it has a two stage: copeland scroll, that Either unloads or loads, depending on whether or not you have a y2 call that goes to a solenoid on the valve itself, and so when you have the y2 call, it closes some little ports inside the scroll causing full compression. So we need to make sure that we have a call in between this blue wire and common. So you see here this y2 in common.

We need to make sure we have 24 volts just to ensure, as best we possibly can, that it is in high speed. High stage before we begin adding charge to it safety glasses on and we're going to do this. The simple way which is just to this is the blue wire here, we're just going to unhook from this wire nut, leave it all twisted together and then we're going to measure that to common, which is this one right here now again, when you're working on running Equipment be very, very careful with where you put your hands, so we're going to put it on volts ac, just going to first check it to high voltage just make sure that it's working sure enough 245 volts. So now we're going to check and see if we've got 24 volts here and we do 27 volts.

That means we are in high stage just as expected again to the best of our knowledge. I'm not going to actually go in. You know test the solenoid itself, but at this point i have every reason to believe that this compressor is running fully fully loaded, the highest mass flow rate highest compression that it's going to operate. At conclusion, we're coming to is that the sub cooling is just a smidge low, but just a smidge.

So at most we should probably add a couple ounces. This is only a two ton system, and so we will begin to add a little bit of refrigerant to this in order to get our sub cooling closer to ten um, but really plus or minus. Three degrees is within the acceptable range on this. So we wouldn't even really have to add any.

But again this video was to show adding refrigerant charge. So that's what we're gon na do here, but only only a tiny amount, and this is where a scale comes in really handy, because we definitely wouldn't want to overdo this, especially since this unit is a heat pump with an accumulator. And that means that it takes a little while for the system to respond, when you add refrigerant charge, try to get it as flattened level, as you can now. One thing we definitely are going to do is we're going to add in this little charging tool that will prevent it, just as a tiny orifice in there, which will prevent us from slugging the compressor, because with r410a you're really supposed to charge it by a liquid, Which means the tank upside down, and so that is what we're going to do.

It'll also help us meter it in a little bit more slowly, because i don't use a manifold. I just use this ball valve on the actual hose. It's just going to ensure that we get the refrigerant charge in nice and slow all right. So the first thing i'm going to do, put it on the tank and i'm going to get this hose purged out.

I'm going to do it with some vapor. Just make sure the hose is all purged, then once i get the tank open, then i'm going to flip it upside down. Now i need to take this off so that i can attach my t-assembly here, which i just leave on my charging hose and then again, i'm just going to purge it just a little bit before i thread it on all the way. Just to make sure we don't have any air in the hose, then i'm going to put my probe on this side port.

So now i've got my little ball valve here and i can throttle the charge in very slowly via this ball valve and it will go in very very slowly. Now. First, i'm going to zero my scale, so i can actually see how much i'm putting in my scale is now zeroed out just leave this set up here. I'll show it to you periodically.

I always forget it. Has this nice magnet that flips up on this particular scale? So now it's all zeroed out! I can just throttle it in really carefully and i can see how much is going in so so far. I've put in two ounces, i'm gon na start by putting in something like three ounces, maybe four ounces. Again, it's a very small system.

It's got a large condenser, but it's a small system, i'm just gon na. Let it stabilize see what we get here in a minute or so gon na. Do everything very slowly to make sure that i don't result in an overcharge all right, so i've, given it good long, run time literally only added three ounces total and we are now at 8.6 degrees of sub cooling. It was actually just up at nine.

A second ago, so i'm going to add just a little bit more here, but i'm not going to bore you with watching all of it. You can see our sub cooling is coming up, our target is to get to 10, and so we're already well within the sort of acceptable range. I'm going to go ahead and put in 4.75. Ounces is what i've got in now, but you see - and this is kind of what i wanted to show you - you really have to do this slowly.

You really have to do this carefully for those of you who are concerned about the low head pressure on this, because that's something that some of you may point out. You know suction pressure's right on, but our head pressure is low. This is a massive condenser coil for the tonnage. This is a two ton and it's just a gigantic condenser coil.

It's just the way this particular unit's made, which is also why the approach is low on it. So if you look here, our approach is showing zero and again that's just an inequity between how we're measuring our outdoor air temperature and our liquid line temperature, but essentially it's our liquid line. Temperature is the same as our outdoor air temperature, which can only happen when you have a really large condenser and again it can't get exactly the same, but you can see now we're showing 0.2 degrees approach very, very low approach. It's a high efficiency system about as big of a condenser as you're gon na see on a two-ton system, and you can see now.

We've got the green flag, we're in good good range. As far as measure quick is concerned, i'm gon na let it run a little bit more and get it dialed in right at 10. Degrees of sub cool, but key thing here is when you're adding charge. Add it slowly when you're charging with liquid? It's a really good idea to use that charging tool to make sure you're, not overdoing it and to make sure you're, not slugging the system again, if you're charging a system that is completely absent of charge, charging it in the liquid line, pure liquid, is a strategy.

That's often used in order to get more refrigerant in more quickly and that's fine, but when you're charging a running system when you're just making fine adjustments, that's where that charging tool and always always always use a scale. That's a really big thing, always use a scale to make sure you're not overdoing it, but you can see the manifold-less application is actually pretty easy to do. I'm just going to do a quick run through of the data on screen here. So everything here is in the green, our liquid line temperature's a little low like it mentioned, because we have a really big condenser, that's also driving down our compression ratio.

If we take a look at our capacity, let's go over here we're in the green. As far as our capacity goes, our total capacity is 22 900, which is when it's adjusted for the current conditions, we're in the green well on the green from a capacity standpoint, i didn't do the eer or anything like that. Our sensible heat ratio is nice and low, which means we're still pulling a lot of moisture. So everything on this piece of equipment looks how i want it to look in terms of measurements and the only thing we see kind of jumping around is uh associated with that low liquid line temperature and low head pressure.

Due to that really big coil. But main thing is sub cooling right now is at 8.2, like i said i'll, get it up a little bit more but plus or minus three degrees on our sub cooling is sort of in that acceptable range that we would list. You can see we're in the green, so we're in pretty good shape there. All right so basic lessons here, sub cooling in super heat, sub cooling is the temperature of your liquid line below saturation super heat is the temperature of your suction line, physically above your suction saturation.

We showed all that in the beginning of the video when you're charging a system, especially when you're already really close, you want to put it in ounces at a time, not pounds at a time and wait for it to adjust, always use a scale if you're charging A blended refrigerant, like r410a you're supposed to charge that as a liquid, but use a charging tool to make sure that you're not slugging that compressor and that it's going in nice and slowly and digital tools are more accurate than analogs. That's another thing that we showed got to give it long enough run time using your six standard probes, your two line, temperature probes, your two pressure transducers and your two induct cyclometers, really helps you get an accurate look at how that equipment's running so that you can Know that it's doing exactly what it's supposed to do, even from a delivered capacity standpoint. Hopefully you found that helpful, we'll catch you on the next video you.