Good morning everybody hey it's jake good, to see you and aaron man my good buddies. This is good too, because we're going to talk about some installer stuff. So if you remember was it last week, i think it was. Last week we talked about charging and weighing in a certain amount of charge or whatever.

So i did a little bit of looking, because you know it's the sort of thing that it felt like. I should just know off the top of my head and it turns out with carrier it's a pretty it's a pretty fixed number. So, let's take a look at this. This is a product data manual for a 24 acc which is kind of an old school carrier.

Straight cool, but it applies either way. So you add 0.6 ounces per additional foot of 3 8 line set 0.6 ounces after 15, correct after 15. Feet of line set, yep 0.6 ounces makes sense any questions about that is that universal across all brands and in all circumstances the part that's not constant. Some people shook their head, yes and some shook.

No. The part - that's not constant is what the standard line set length is, and this is important to know, especially if you work on equipment that has micro channel coils, because they're not necessarily even going to come charged for any length of line set, meaning you have may Have to make up even for a zero line set, so you have to know your product so that part's not universal, but the amount of additional charge for a 3 8 liquid line pretty universal. Now, why do they only say liquid line? Why doesn't it say for different sizes of suction lines? Any theories go ahead. What's your theory bert, because there's uh a lot more refrigerant on liquid? Oh, you all hear that a lot more refrigerant liquid line.

Why would there be more refrigerant in the liquid line, even though it is much smaller than the suction line say it again takes up more space as a liquid? That's not the exactly the way. I would say that i think i know what you're saying so. Is it more or less dense liquid is, is liquid, more or less dense? Liquid is more dense, significantly more dense, so that means that there are more pounds per volume. So if we were going to do like a really big volume of you know, a box would be like a cubic foot right, and so you can have a cubic foot of feathers or you can have a cubic foot of lead.

Liquid is heavier per cubic foot. So it has a higher density. Its mass is greater for the same volumetric size, so small changes in suction line size don't affect the amount of refrigerant as much as changes in your liquid line size. Now.

The right answer, though, is is that they are just adding in for a three-quarter inch liquid line. Actually, if if this was a 3 8 liquid line with an inch and an eighth, this number is slightly higher than that a fraction higher than 0.6, but they're, essentially just saying look just liquid line. Don't worry about the difference! If you wanted to get more accurate, you would still take into account for the suction line size, and there are some charts that do that. Some manufacturers do that.

Based on our conversation last week, i went ahead and charted out a calculator for the app that will do that. So you put in your liquid line, put in your suction line, put in your additional length and then it will tell you how much charge to put in also just because the whole like ounces conversion thing is kind of hard for some people, because this is a Fraction of an ounce, but then there's 16 ounces per pound, and because so when it's not base 10, it makes it a little bit makes the math a little more challenging. So in the app that one actually says what correct 0.6 ounces did. I say: 0.6 pounds.

I thought you were talking about something else i was. I was talking about something else. So talking about the ball game yeah, the ball game will tell you that the system is charged with, like 3.5 pounds right. A lot of people take the 0.5.

Oh right, exactly! That's and that's what i'm saying: that's what makes this math kind of confusing sometimes is because 0.5 of a pound is how many ounces tanner 8 ounces yeah, and that is you know it. Just it's not like a big deal, but it's just something you have to account for and can get you confused. So does that make sense! Anybody have a question about that. So if you go to a line set and your estimated length, your estimated total linear length is 40 feet.

How many ounces are you gon na add in addition to the factory charge, nobody pulled out the calculator two pounds, four ounces. Does that sound right? I didn't actually do the mouth math so 25 times .6. What i said i said 40 feet. Didn't i say 40 feet yeah.

I said 40 feet. 15 ounces, so you got ta. Take off the 15 feet correct correct! So if see 25 times 0.6 then 25 times 0.6 is 15 ounces. Okay, so we're just shy of a pound in that case, so that means generally for most of what we're doing you're going to be adding less than a pound, but makes it pretty easy at that point.

In fact, some people what they'll even do is they'll, add that charge in. If you know the additional length you can add that charge in before you even release your system charge. You can just go ahead and weigh that in to the lines go ahead and weigh that in especially, i mean if you want to be really safe, i'm trying to think of it. Yeah weigh it into the liquid line, but while you're still under vacuum, so actually break your vacuum with the tank and then release your charge.

That way you can get you can get that out of the way and then just run run test your system. At that point - and it just depends on how confident you are about your line - length um. Sometimes it's a little bit more of an estimate if it's concealed lines and we're reusing a line set or something like that. But if you are replacing a line set, then you can know exactly how much line set you used, and that should be part of your procedure is measuring that out when you, when you push it, having a sense of what you're pushing so that way you you Know already now again on a typical split system, a non-ductless system, you know being off a couple: ounces isn't going to change the world um on a traditional traditional system, but as we go to more and more micro channel as the system charges shrink, then smaller changes In charge make a greater difference in system operation as well.

So keep that in mind all right cool, any questions about that everybody comfortable with that now so here's the next thing i want to talk about, because i think this is fascinating. Fascinating, it's a long half! It's fascinating, you're gon na have to edit out all of my coffee drinking, because i'm really drinking a lot of coffee this morning. I'm really feeling it. This episode brought to you by coffee, so good all right.

So let's say we have a three ton unit: okay, what size line set should we have on a three ton unit, three quarter, three eighths, but what happens if i wanted to use a quarter inch liquid line. Would that be okay, yeah quarter inch liquid line? Would that be okay hold on you're, looking at the chart right now, so you're, not okay. Let's say that our line set length is 15 feet. Would that be okay? Oh you're sure it would be all right, so we're looking literally at the chart.

That tells you whether or not it would be okay right now. So now one thing you got to pay attention to is here: it says maximum actual length not to exceed 200 feet, and so these are total equivalent lengths. This is a little different than when we're charging a system and you're looking at lineal feet. Lineal feed is: how long is your line set? That's basically, the only question equivalent length is a little more different.

What does equivalent length take into effect, take into account not effect, take into account takes into account exactly it takes into account bends and those bends have a much longer equivalent length than the actual bend itself, and why is that? The resistance? Exactly so, when we're looking at lineal feet for the sake of charging, we're thinking in terms of how much refrigerant does it take to fill up these lines with refrigerant? Okay, that's one thing, and that doesn't equivalent length. It doesn't matter, but when we're looking at resistance, we're looking at friction we're looking at pressure, drop resistance. Friction pressure drop. You got those all the same.

We have to take into account not only the lineal length, but we have to take into account, lift or fall, and we have to take into account any of the additional resistances or the equivalent adders for every 90 bend all that sort of thing now i didn't Actually, look at it didn't feel super pertinent because, based on what i'm teaching here, but um equivalent lengths are fairly universal and there are a lot of charts that you can find the equivalent lengths for the bends. We're not going to focus on that right now. But let's look at our three ton system here: 36 000 btus with the outdoor unit below the indoor unit. So there's all of these rules outdoor unit below the indoor unit.

This is our vertical separation in meters. These are our allowable liquid line sizes that you can have or sorry yeah, our allowable liquid line sizes. This is our connection size, so the connection side is always three eighths. So if you're going to use a different size, you have to use a bushing or a adapter of some sort.

But if you look at 36 000 in this application with the outdoor unit below the indoor unit, you can see that there is no quarter inch option. So quarter inch no bueno what close enough no quarter inch, no bueno, but we could, but could we use 5 16 yeah in certain circumstances, in fact, in most circumstances so long as our equivalent lengths aren't too long. So, if our equivalent length, if we have you, know six to ten feet of separation and uh under 150 feet of equivalent length, which should be almost every situation on a three-ton system in almost every situation, again depends on the model. So you have to look at that particular unit, but in almost every situation we could use a 5 16ths liquid line instead of a 3 8 liquid line.

Now here's the question - and this is kind of what i'm driving at here. Why would we want to do that? Why on earth why in the sam hill, as my papi always says, it's not sam hell, it's sam hill? Okay, it's not i'm! Not i'm not saying a cuss here all right! I know you were worried. Why would you want to go down in liquid line size? Yes, we do it because we just want to okay all right. I respect your papi, i'm not gon na i'm, not gon na speak against your pappy.

You know that man wears overalls at times and i'm saying and he looks dang good in them, coffee all right. I want some theories. Why would you downsize liquid line? It helps with uh vertical lift, because your refrigerant is moving faster uh. No, absolutely not! That is not why i was gon na.

I was gon na okay. That is one potential reason. Good, that's one reason not a very good one, but it is a reason. Yes, that is the reason now.

Is it now why? Why would we want less refrigerant to save the environment, hey some folks. That may be the case want to save some trees. Like the lorax, you know, do you speak for the trees, all right, calm down all right? So so why do you want to have less refrigerant in the system? Nothing? Okay, here's the reason. The reason is, when you have less refrigerant in the system, you are much less likely to have a flooded condition, having additional excess refrigerant that sits in your liquid line.

While it's running because while it's running, it's no risk that liquid is in the liquid line. But what happens when the system goes off, that refrigerant migrates back and if there's more of it, there's more of it that can end up in that compressor. So that is actually the primary reason why you would want to downsize a liquid line now. Here's another interesting thing when the outdoor unit is lower than the indoor unit you're going to notice.

Actually i don't - let's see here now this one: isn't this chart's not showing it we're gon na have to out to our unit below oh uh, yeah. Sorry, opposite! I'm trying to i'm trying to pinch and zoom on the all right, yeah, okay, that was that whole chart now notice something here. So let's just look at this really big vertical separation. So let's say we have 151 feet of vertical separation or 176 to 200 vertical feet of separation notice.

What happens notice that? Let's, let's use the let's use the 30 000 btu system or well we'll go to the 24 000 btu system on a two ton system. You can use a quarter inch line set, but you can only have a hundred feet so long as your vertical separation is small, but your actual length that you can run increases the greater the vertical separation. So imagine the situation that we're running into here you've got an air handler, that's sitting low in a building and you've got condensers on the roof. That's what we're talking about here? Okay, when that distance between the air handlers and the condensers increases, when the condensers are on the roof, you can actually run a longer small liquid line and that's because of something called static, regain, which just means that now you have a column of liquid and the Actual weight of the liquid is gaining pressure, as it goes down the liquid line, rather than dropping it.

So if i'm pumping, i see, i see a lot of glossy eyes here. If i'm pumping liquid up a long distance, i pressure drop right, but if i'm dropping it down, i have pressure gain. So that means that, with the greater separation i can actually run smaller liquid lines. That's the point: now you always follow your manufacturer's chart and some charts are like this.

Some charts are actually a formula that you work, but the point being that this would be an ideal case. Let's say you did have a 200 foot equivalent length line set. Okay, long line set - and it was falling down to an air handler - you would want to downsize your liquid line and the reason being is because, in that case, you're going to have a lot of extra refrigerant. If you keep a 3 8 line, set, it's more cost, it's more cost to material, it's more difficult to work, sure, but mainly it's that now you have more refrigerant that can move they can migrate.

So, by putting a smaller liquid line in you're not going to get pressure drop because you're actually getting static, regain as it falls, you can use that smaller liquid line. The point being that a couple things first off just because, because i did this early on, i would go to these older systems that would have quarter inch liquid lines or 5 16 liquid lines. And, oh there's your problem right. There there's a couple in old, downtown claremont that i would go to and i'd be like.

Oh man, you have to have a 3 8 liquid line. You can tell there's a that's the connection on each side right. First off, that's not true! Okay, in the same way that your suction line doesn't always have to be the same size as the connections either you have to look at the chart in order to know what your suction line should be, but your liquid line, especially when you get into the longer Runs where it could potentially hold a lot of refrigerant, especially when the air handler is lower or the furnace is lower than the condensers. It may make a lot of sense to go down to a smaller liquid line.

Size make sense. So that's really do you have any yeah on the suction line, you're gon na get capacity, loss uh because of pressure drop and then and when you have pressure drop in your suction line, that results in higher compression ratio and higher compression ratio results in capacity loss. In terms of your liquid line as long as you're, not getting flash gas in your liquid line, which is what you're sizing it for that's what this chart is doing you're not going to see a capacity loss, you may see a pressure drop slightly, but again that Pressure drop isn't going to result in a problem until you get to where there's some vapors and boiling in that liquid line. Point being that, follow the chart you're not going to have a capacity loss on your liquid line.

Now again, we still don't pressure drop still. Isn't something that we want to have it's not like you know, because again it reduces the amount of sub cooling that you could potentially have at your inside metering device, and so it puts you at a greater risk if you have varying load conditions but regardless, if You follow the chart you're going to be safe, but again remember just because it says 250 feet. It still says maximum actual length not to exceed 200.. So they're saying your lineal length can't be under 200 in any circumstances, but that extra 50 is, if you have 50 additional feet, that's relegated to the pressure drop in your equivalent length, which would be your fittings make sense.

You have fittings that are making up that additional 50. again reasons. Why i'm doing this is to show you that these things that we often think are fixed aren't fixed. So i'm trying to prevent you from saying something stupid.

Secondly, think through sometimes you can use different sizes, sometimes the size. That's there might work given the circumstances, but also in some cases - and this is going to be the most rare if you're, in a position where you are helping out with a design. You do want to keep your liquid line sizes as small as you can keep them, because you do want the least amount of refrigerant you can have in the system, not just because additional refrigerant costs additional money, not just because the material is more. Not just because it's easier to work with smaller sized piping, primarily it's because you do want to keep system charges as low as you can and that's why you see a lot of these new design system designs like micro, channel condensers, even with all their problems and Irritations: it's because manufacturers know that if they keep the amount of refrigerant in the system as low as possible, the amount of refrigerant - that's not really doing anything is just sitting in there.

In order to maintain the uh, you know essentially you're maintaining the ferris wheel right. Wait is that the ferris wheel, the one that goes like this yeah, this carousel someone goes like this yeah yeah, ferris wheel, carousel. Remember that ferris wheel carousel, it's important! No! So you're trying to keep that you're trying to keep the the ferris wheel going in the sense that you have to have refrigerant that fills the entire system. So that way it moves through.

It's not like you have any gaps in your refrigerant circuit, and so the larger your lines, the more refrigerant it takes to fill up, that entire circuit make sense. So we ran into one um. What, where was this? Oh, it was that it was yeah. Okay, i'm not going to say where it was.

It was a. It was a house where they had to run half inch liquid lines and there was just a massive amount of refrigerant having to go in based on the charging chart and that's why and the danger in that circumstance is mostly that you, you can have a flooded Start in those conditions, much easier because you have more liquid refrigerant. So if you have a case where you literally can't rerun the copper without causing all kinds of problems and your liquid line is too large, then what you do. Is you just make sure that you put in gear to prevent that flooded start from happening, so that would be things like a liquid line: solenoid crankcase heater, maybe even a pump down strategy on a heat pump.

That's tough, but generally a liquid line. Solenoid is the way to go that just keeps all of the refrigerant in the condenser and in the liquid line, so it doesn't migrate into the into the compressor cool great any questions about that. So when i say flooded start what does that mean just want to make sure we're all on the same page liquid in the compressor when when it starts up right so liquid, getting in your compressor when it's running that's caused by having zero superheat, that's caused by Overfeeding, an evaporator coil, there's a lot of things that cause that low airflow over charge. You know whatever flooded start is just caused by the natural affinity for refrigerant to go and condense outside in the low point, in the compressor, as well as the affinity that the oil in the compressor has for a refrigerant.

So you're not going to stop that other than just keeping the refrigerant from making it over there. In the first place, our biggest strategies that are used in our market are the hard shutoff txv and the crankcase heater. So a lot of the systems that we work on have those two features, but the additional features of like uh. You know a liquid line, solenoid that just closes when the system goes off to prevent migration.

That's an additional uh adder that in some cases, if you look at the long long line requirements for the equipment, it's sometimes going to suggest that there's many cases where, based on the factory specifications, we should be putting in factory hard start kits right off the bat, Because a lot of them will say even with a heart just with a hard shutoff txv that you should have a factory hard start kit again, you have to read the manual in order to know that, so these are just things that i'm bringing up so that You're aware that just what comes in the box, just what size the stubs are on, the unit does not dictate exactly what should be going in. You have to know the application and the easiest thing to do. Read the manual and the product data, especially for carriers, where a lot of this information is hidden, it's not all in the installation, cool any questions. Great have a great week.

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