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In this class, Bryan teaches the Kalos techs about long-line applications, accessories, and allowable line lengths. Many techs don’t fully understand the challenges of long lines. So, Bryan covers a wide range of issues and practices with long lines.
You can find the long-line piping guide we’ve used at
Long lines can cause refrigerant migration. Long lines simply move more refrigerant, making migration much more likely. On top of that, a pressure drop is possible throughout longer suction lines. When you have a lot of refrigerant inside the suction line when a unit is off, it will often migrate to the condensing unit. (In a few specific cases, liquid refrigerant may migrate to the evaporator. Your unit is at risk of a flooded start when that occurs.) We also shouldn’t bury suction lines for long distances to reduce the risk of a flooded start. The ground is typically colder than the air, so the refrigerant is more likely to condense in the suction line if it is underground in a cold place.
When the system is off, you ideally want liquid refrigerant to be in the liquid line or condenser coil. Anywhere from the discharge line to the metering device is in the “safe” zone for liquid refrigerant. So, when adding liquid refrigerant to a system, you will want to add it to the liquid line so that it can vaporize in the evaporator before making it to the compressor. We NEVER want liquid in the compressor, and we only want vapor to be in the compressor while the system is running.
Straight-cool long-line A/C systems require TXVs if the line’s total length is over 50 feet. If the outside unit is above or below the indoor unit, that system will require a TXV if the line length exceeds 20 feet. TXVs are required in long-line applications because they have hard shutoff (HSO) or non-bleed valves that help prevent refrigerant migration.
A long-line A/C system may also require long-line accessories. These requirements depend on the liquid line diameter, the presence of a TXV, and where the outdoor unit is located in relation to the indoor unit (above, below, or level). The range for minimum lengths can be between 35-175 feet, depending on each of those factors. (Most of the time, we use ⅜” liquid lines with a TXV, so the minimum is usually 80 feet.)
Heat pumps with a ⅜” liquid line diameter and TXV will need long-line accessories if the lines exceed 80 feet in length (or if the vertical difference between the indoor and outdoor units exceeds 20 feet).
Pipe fittings add equivalent length, so be sure to take those into account when you measure line lengths to determine if you need long-line accessories or not.
Your allowable line lengths will be significantly greater when your condenser is above your air handler. When your condensing unit is higher, the refrigerant going to the air handler will maintain pressure more easily as it moves downhill towards the metering device. The static regain keeps the pressure drop from getting too strong.
In the case of our Carrier heat pump, we have level indoor and outdoor units situated 100 feet apart. We have a ⅜” liquid line with a TXV, so we will need a long line because the distance between the indoor and outdoor unit will exceed 80 feet in length. As a heat pump, the unit will need a standard accumulator. Based on our accessories guide, we need a compressor start assist capacitor and relay (hard start kit), crankcase heater, and hard shutoff TXV. However, we also need a liquid line solenoid valve (LLSV). These LLSVs are NOT for pump-down applications; this LLSV shuts down the liquid line when the system shuts off.
The hard start kit helps start up the compressor. The capacitance needs to be properly matched to avoid putting too much current on the start winding, so it’s a good idea to use the manufacturer’s hard start kit, not a universal one.
When it comes to installation, we start off by installing the bellyband crankcase heater. The schematics can tell you how the crankcase heater attaches to the wiring. Remember, we only want the crankcase heater to energize when the unit is OFF. When we power up the condenser ONLY, we no longer read voltage to the crankcase heater. When we shut the unit off again, our meter begins to read voltage again.
The next step is to install the hard start kit. We can test it by measuring our start amps with it in and without it in.
We install the liquid line solenoid on the liquid line. It is a normally closed valve that opens when energized. It should be installed two feet from the condenser, and the arrow on the valve must point towards the outdoor unit.
We also discuss:
Pump-down or pump-off systems
Potential relays
Capacitor windings and startup amperage
Wiring diagrams
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We're talking about long line applications, there's a couple things with long line. Applications that you don't initially consider - and the main one is - is that the problem with long lines is what question mark. I want one of you to answer. What is the problem with having long lines, what problems does it cause for the equipment, migration of the refrigerant? Why why would it cause migration of the refrigerant because it usually well typically, it's because there's a big difference between the height of the air handler and the condenser in long lines also means you have a lot more refrigerant boom to move full stop more refrigerant.

That's actually the main thing is that there's more refrigerant, but then you also have the potential for pressure drop on the liquid line, but you can also have static regain on liquid line two and we'll talk about that. So, but the main factor with long lines is that you have more refrigerant and when you have more refrigerant, what can that more refrigerant do when the system turns off? If no one else wants to, i mean if ronnie doesn't want to participate, he's too busy stuffing his face full of hungry howie's, yeah yeah, yeah migration, refrigerant migration, which means what it means that the refrigerant will move, uh-huh and it'll pile up either in the evaporator Or in the condenser it's going to pile up in the condenser if it bites up in the evaporator, it does sometimes no, it is true. There are certain applications and that can cause a problem when why is it a problem if refrigerant piles up in the evaporator? Oh yeah, okay, so there can be some oil that moves there, but not not normally like you're not going to have oil that moves out of the compressor during the off cycle. That's not going to happen, but if you get refrigerant that gathers in the evaporator coil, so liquid refrigerant gathers in the evaporator coil, what is what's the problem there? Why do we care it's? Because if there's liquid refrigerant in the evaporator coil and the compressor starts up, what's going to happen to that liquid refrigerant instantly vaporize, it's going to dump down the suction line, it can actually dump down the suction line.

Have you ever seen an inverted trap before or a specification that talks about an inverted trap, a trap that actually, rather than going down out of the evaporator coil, actually goes up? Oh yeah, have you seen that before you especially see that in applications with um with refrigeration, so you'll see inverted traps a lot of times in refrigeration, because in refrigeration you tend to get more of that effect? Do you know why? Why do you get more refrigerant? Liquid refrigerant piling up in the evaporator coil in refrigeration, so much cooler, because the evaporator coil is in a cold space, whether it's on or off right. When we shut off an air conditioner that evaporator coil warms up pretty quick right when we shut off a freezer. That evapo coil stays very cold, and so in comparison to the outdoor, where is liquid refrigerant going to want to condense? It's going to refrigerant moves from high pressure to low pressure right, where's, the lowest pressure going to be at the evaporator coil right. The coldest point is going to be at the evaporator coil so that refrigerant is going to condense in the evaporator coil, so that is that can result in a flooded start so where you have liquid refrigerant that comes down out of the evaporator coil.

So, where do we want liquid refrigerant, or even we say liquid refrigerant, because that's the primary mass? That's where most of the density is? Where do we want that refrigerant to be in the system when the system is off the liquid line or condenser liquid line or condenser coil right? That's where we want it. If you have a receiver, it can be in the receiver, but you want it to be somewhere from the discharge line of the compressor all the way to the metering device. That's the safe space for liquid refrigerant. So if you're going to add liquid refrigeration to a system, say you have a system that has no charge in it whatsoever, just put a vacuum on it and you're going to dump liquid refrigerant in the system.

Where are you going to dump it liquid line? You're going to dump it into the high side right! Why? Because when you start that compressor, it's going to have to make it through that metering device, it's going to have to be expanded and turn to vapor before it makes it back to the compressor, because the compressor is not a liquid pump, it's a vapor pump right. It moves vapor, so we only want it to move vapor when it starts up. We only want it to move vapor uh. We only want it to have vapor in it when the system is off and we only want vapor to be entering it when the system is running.

So those are kind of three different things right, because you could have a situation where the compressor has no liquid. In it, but then it starts up liquid dumps down. The suction line goes into the compressor, that's what we were just talking about, that's where the inverted trap can come in. You can have a case where liquid refrigerant is entering the compressor when the system is running.

What is that called zero superheat? That's another name for it right yeah, the liquid is still at saturation in the refrigerator still at saturation in refrigeration, especially in grocery refrigeration. They like to call that wet gas. Your gas is wet right. I mean it is true, because it's still you're making this into a fart joke.

Aren't you that's what's happening, think that? Well, that's what happens right. I mean if you feed that compressor wet gas too much. You end up having to change his pants. You know what i mean all right: okay, okay, good time, so we don't want to have liquid refrigerant.

Now, it's not when we say liquid refrigerant. In the compressor. We don't mean a full column of liquid. That's not going to happen right, you're not going to have a full column of liquid.

It's still going to be mostly gas. There's going to be a little bit of liquid into it. Some compressors can handle more liquid than others, and it has to do with how much is left, because, if that liquid, if there's a tiny bit of liquid refrigerant and it enters that really hot crankcase. In some cases it's going to flash off before it really causes much damage, but as that liquid begins to saturate that oil more and more, it gets worse and worse right.

We definitely can't get liquid refrigerant into the head of the compressor, the actual compression chamber whatever, depending on the type of compressor it is. We don't want to get it in where it's actually doing compression, although with certain uh scroll compressors, they can actually even deal with a little bit of liquid refrigerant all the way through the head because of that ability to move and flex. So if it didn't have an ability to move and flex that axial radial compliance that a scroll has, if you put wet gas into it, and it tried to compress it, it would just immediately destroy the compressor now wet gas is going to destroy the compressor either Way, liquid refrigerant entering the compressor is going to destroy it one way or another: it just will be a slow death. If it does it, you know if you have some ability to handle it, when i'm doing this, i'm doing a scroll.

This is a scroll compressor by the way you know, yeah in case you couldn't tell literally, i was born with a scroll compressor for hands. It was a. It was dead, burned anomaly. The doctor mentioned it right away.

He's like this boy is going to be a refrigeration tech, and my mother said i agree: god bless america and then the bald eagle flew over sorry. I just sometimes sometimes my patriotism just cannot be harnessed all right all right. So, let's talk about what constitutes a long line now this is specific to a particular model. It's actually.

This is the carrier universal long line guide. If we go up real, quick, let's just go up and show you what this guide is residential piping and long line guidelines. So it's pretty much for all of their ac's heat pumps. All that we're going to go over the specific guide for the condenser that we have here just to show you that as well, but this is pretty much universal ac with pr refrigerant long line description beyond these lengths, a txv is required.

So that's the start, total length txv required beyond 50 foot outdoor unit above or below indoor unit, txv required beyond 20 feet. So this is an interesting thing, because we've been getting shipped systems with pistons in them for this entire time and has anyone ever thought about the fact of well if the outdoor unit is above or below the indoor unit, either one which is interesting? No specific distance listed just above or below it, so that's pretty much every one um! If it's beyond 20 feet, a txv is required. Now, why does a txv? Why would a txt be required with long line now? In this case i mean i wouldn't even call that long line over 20 feet. Why would it be required? What does the txv do to help this problem? Anybody know when pressure's equalized the txt will close down? Okay, true? What do they call that, what's the term that at least carrier uses for it, hso right another term, for it is non-bleed, so you can describe it a couple different ways, so you have a bleed valve.

You have a non-bleed valve, also known as a hard shut off, or you could call the bleed valve a non-hard shut off ao, so many names. But what the reason why the txv hard shuts off is just simply how txvs work you have this balance of forces, and so when the system begins to equalize and that suction pressure starts to rise, your external equalizer is the closing force of the valve that closing Force quickly increases and overcomes the opening force, so the valve goes shut. Now. That valve isn't necessarily going to be like perfectly shut because you're relying on the seat in the valve, and they can bleed a little bit.

So you may get a little bit of bleed, but in terms of your normal cycle times in a system you are going to prevent massive amounts of liquid are. Is it going to not equalize at all? Have you ever taken a i mean, of course you have you shut off a txv system does do the pressures equalize yeah. They do right. So it's not that they don't equalize.

It's that it's not allowing a lot of refrigerant to move and because it's going to it actually won't even shut off until they get near equalization. That's how that valve works. But it's going to prevent that slow migration of liquid out of the condenser and liquid line. Where we want it, because that's where it is when the system's running the majority of our refrigerant, when the system is running, is in the liquid line and the condenser right, because it's liquid liquid is more dense, it's heavier! So there's more of it in the condenser and liquid line.

So when that system shuts off that, first little bit allows it to equalize. But after that, it's going to prevent that slow motion of liquid refrigerant going through the evaporator coil and then entering the compressor. Because that's where we don't want it, actually we don't want it evaporative, coil, suction line or compressor. Another side note: what's the reason why we don't like burying suction lines for a long distance? Why wouldn't you want to bury a suction line for a long? This, like a distance side, note no, it's it's directly, uh related to what we're talking about right now, what temperature is the ground in comparison with the air for most of the cooling season, colder it's colder right and when the system goes off, what is the lowest Point in the system now, if you have a buried suction line, the suction line right and what is the coldest part of the system now, if you have a buried suction line, the suction line? So where is liquid refrigerant going to condense, the condenser? That's what it's for when the system is off, it's going to condense in the suction line.

So what's going to happen when it's off for a while and then it comes back on sucked into that compressor right right, so we don't we do it all the time. I mean i get these it's just like people complaining about flex and why we bare very line sets is the same thing. Why do you do that in florida? You know it's just because, okay, stop asking us all these questions all the time. All right.

You know. It's the same reason: everything happens in flow. The way it does it just is how it is. Okay, we have a special exemption from the government to be how we are so it's not a good practice is the point.

We really shouldn't be burying suction lines. If we can help it and if you are going to bury suction lines, what are some things you can do in order to prevent this problem? Well, i'm about to tell you that's, what's about to happen all right, if you don't know, i'm about to dad burn. Tell you now, let's go to the next one, on the line on the list ac with pure refrigerant, longline description. Beyond these lengths, long line accessories are required.

If you have a quarter inch liquid line plus a txv. You guys following me here right now. Do you see this here up here on this deadburn screen? Are you serious, yeah, well you're, just sitting in a dumb place? That's why all right, all right, wow, you guys, are being very difficult. All right quarter, inch plus a txv.

Now, how often do we use quarter inch line sets i mean uh liquid lines, not buried, and that's because it's not allowed right we're not allowed to use quarter inch liquid lines are we we are allowed, we are allowed. Actually we just never do why? Because we don't pay attention to the specs, and so it's easier for us for two reasons: we don't pay attention to the specs and it would be annoying to have to stop quarter inch liquid lines. But actually, if we can, if we have a short enough line length and it depending on it, depends on the tonnage too of the system, some allow it some down. You have to look at the specific product data for the system you're using.

We can reduce the need for some of these long line accessories by using a smaller liquid line, so you can see if we have a quarter inch liquid line with a txv and the units are on the same level. It doesn't matter how long it is within the acceptable allowable length that no accessories are needed, outdoor below indoor, no accessories needed outdoor above indoor now above 175, then you need accessories. So this chart here is just telling you, when you do and do not need accessories, and so it's not just a single number right. This is the point so for our typical applications, 3h liquid line and a txv is going to be standard if the units are on the same level, 80 feet and longer is going to be considered a long line if the outdoors below the indoor 35 feet.

If the outdoors above the indoor 80 feet now why, why is it worse when the outdoors below the indoor, why is the problem more pronounced when the outdoors below the indoor, because then uh you would have coming down the lines into the compressor correct there's to so You have that gravity force. That's going to drive more liquid into the compressor right. So here's the point, though, actually - and i didn't even i didn't even read it right so 80 feet if it's on the same level. 35.

If the separation is vertical or 80 feet total length and then 80 feet, so in some cases it's going to be as low as 35 and as much as 80 somewhere in there. But you know: there's lots of systems that have longer than even 80 feet. Think about this decay. It's a good example.

I just named a name subdivision right. A lot of those units are long line applications. Did they look at that and pay attention to do. We need additional accessories? No, no for heat pump systems the chart below is when the application is considered long line.

So in heat pumps, it's even worse now we only have 20 feet, and this is going to be very typical outdoor being below indoor. That's going to be very typical in residential applications. You look at equivalent lengths too, because if you have fittings fittings, add some equivalent length as well. So if you have a 3 8 or sorry, a three quarter, inch 90 - that's equal to uh 1.5 1.8 feet as an example.

Now again we're getting a little bit pedantic here, we're just going to start with the things that are actually going to help. You first pay attention and notice: do you need long line accessories? This is we talked about this recently the refrigerant charge, adjustments. We did a different video on that, so we're going to move on from that additional charge. That has to be added, and so let's go.

This is just showing you your maximum total equivalent length, that's allowable, so that's what those that's, what those equivalents with the fittings and all that are one thing, that's interesting to notice, for example, is that if you look at let's look at a two ton unit here, If you have a two ton unit and you have a quarter inch liquid line, you have a shorter total equivalent length that you can have it be. So you couldn't use a quarter inch liquid line on a two ton system with the outdoor unit below the indoor unit, vertical separation for greater than 75 feet, even in the best of circumstances. So you see here up here this with this row are the separations. This is the vertical separation, and then these are our total equivalent lengths.

One thing you're going to notice pretty quickly is that when your condenser is above your air handler, you can get away with a lot because you get what's called static regain. So if you have a system, you could have a uh we'll go here. We could have a two and a half ton system with a 5 16 liquid line, we're just going to use 5 16 because, obviously, with quarter inch you can only go 30 feet. You can go up to 250 feet all the way across the board.

Why is that? Why are your allowable line lengths so again we're not talking about what qualifies as long line length or not we're talking about allowable line lengths? Why are your allowable line lengths so much greater when your condenser is above your air handler? I think it's because you're not as likely to push liquid all the way to the compressor, because you have to go uphill for so long. The gravity would help you, no because this is actually a different question, so when it comes to allowable line lengths when it comes to allowable line lengths, we're really not talking about this whole liquid return issue to the compressor we're actually looking at pressure drop on the Liquid line, so all of this is about pressure drop on the liquid line. If you get too far, and your liquid line is too small, for example, you can get too much pressure drop, but when your condenser is above your air handler, as that liquid falls, you get static regain. So the pressure down at the bottom near the air handler is actually higher than the liquid pressure at the condenser and the longer the line is the more that static, more static, regain there is so longer lines, don't cause a greater problem in that circumstance now you Could have long enough lines that you could have returned gas temperatures coming back to your compressor.

That could be too high, but that's all the question of suction line insulation, so you could, theoretically just keep adding more insulation to your suction line in order to keep your suction gas cool enough. By the time it returned right, you're not going to get significant pressure drop across your suction line, because it's such a you know, suction gas is so light, make sense so that this is all about maximum total equivalent length. This isn't about whether or not it qualifies for the long line length for long line, uh accessories or not. We did that in the first chart.

That's why there's separate charts you have your maximum total length. This is how far you can possibly have it based on the size, and then you have the one that we already looked at, which is about do we need accessories or not all right. So now, let's go into and again it's you know two-stage single stage. You know different different applications um, but let's go down into the accessories now, because this is what we're really going to talk about today.

So this is actually the product data for this specific unit that we're going to be installing this on. So we've got our crankcase heater kit, our factory crankcase heater kit. We have our factory hard start kit and we have our factory solenoid kit, liquid line, solenoid kit, and so we're going to look at which one of these would we need, and just for the sake of making this simple we're going to pretend that we have 100 Feet of level so there, the air handler and condenser are essentially level and they're 100 feet from each other. So let's first see does that qualify as long line we're going to actually look at the look at the guide here so again here it talks about maximum equivalent length and maximum total length.

Do we need a long line if it's above 80, we do okay, so we're 100 feet so we're at the point that we need to follow the long line application guidelines so now we're going to go into what do we need? So this gives us all the different all the different accessories, but here's going to tell us do we need them or not? So, first thing this isn't accessory usage guidelines for long line applications, it's all accessories, so it gives us a couple different columns. One of them is required for low ambient cooling applications below 55 degrees. What does that mean? What is a low ambient cooling application below 55 degrees? So in the winter you may still have be getting a cool call like if you're a commercial building. You have a lot of internal generated heat yep, and you have to be trying to run your system when it's 30 degrees outside right.

So if you're trying to run the system when it's cold outside which you have to do in a lot of applications, server rooms are a really good example of that we'll run into that from time to time. Even even some people will try to run into like a media room where there's a lot of internal heat generated, and they may want it all year long if you're trying to run air conditioning when it's below 55 degrees on this equipment, then you have to have These accessories, and so these are the things that you need to have. Well, the accumulator is standard. You need a ball.

Bearing fan motor. You need a compressor start assist. You need a crankcase heater, you need evaporator, freeze, thermostat, you need a hard shutoff, txb isolation relay you don't need a liquid line. Solenoid valve motor master and support feed are recommended.

Now, let's go to what we're talking about required for long line applications over here. It's for seacoast applications but long line accumulator standard on this unit. So we're talking about a specific unit. So they know it's standard because it's a heat pump.

It comes with an accumulator. Why does an accumulator help in long line applications? It's the ability to collect a lot of liquid before it should compress it collects liquid before it hits the compressor right. So that makes sense, and especially during that start. So if you had say wet gas dumping down that suction line for any reason - and it made it into the accumulator that accumulator within reason is going to prevent it from making it into the compressor right.

So that's good! So that's the first one ball. Bearing fan motor, no, we don't need that because that's for the motor master control, that's for ramping down the condenser fan speed. We don't care about that. That's a low ambient condition thing compressor, start assist capacitor and relay.

Why would we want a compressor start, assist capacitor and relay in a long line application? You need more power power, wonder working power yeah, but more refrigerant to move more refrigerant to move sure yeah. I mean that that is that i mean that's really what it comes down to. Okay, you have a lot more that you're pushing against when you're trying to start so they suggest. Now again, we could talk for three days about what a compressor starter says.

Capacitor relay actually does, but what it comes down to is is it applies more current to the start winding and applies more force during start. That's that's really what it does. It does not reduce start amps so just say that quickly, because a lot of people have that misunderstanding. We put it on cases in cases where the lights are dimming, because it reduces the time that it takes to start, but it does not actually decrease start amps.

It actually applies more current to the start winding and the run winding. Current remains the same that it would have been anyway, so it's actually more current, but for a shorter period of time, and so in terms of like violence, it's actually applying more violence to the rotor of that motor uh eli liked the word violence for some reason. He's smiling yeah, it's kind of weird um kind of weird all right, so crankcase heater! Yes, why do we have a crankcase heater and a long line application? Why a crankcase eater first off? What's the purpose of a crankcase heater? What does it do? Let's just start with like breaking the name of it down, it heats the crankcase, but why do we want to heat the crankcase? If there's liquid, that is sitting inside the compressor, the heat will help boil it off before startup. Well, it'll prevent it from going there in the first place, it'll prevent it from condensing in the first place, when does a crankcase heater run? When should it run when system is shut off? Well, the system is shut off now.

Ideally, it would also only run when the compressor has cooled off fully right because, initially after it stopped running, it's not gon na you're, not gon na condense liquid in there for a little bit. That's how training right so there's some variation here. We're gon na we're gon na cover that as well, so crankcase heater helps prevent liquid from condensing in the compressor. By keeping it warm.

That's what it's for a lot of people have misunderstanding. Oh, it just keeps it warm, so it starts easier. No, no! It's not what it is. It's just.

It has a specific purpose and that's to keep liquid from condensing it. Evaporator freeze, thermostat nope, because that has nothing to do with long line hard shut off txv. Yes, that's pretty much across the board right hard, shut off thvs if you're over remember what we read in the last guide like if you're over 30 feet. In a lot of cases, you should have a hard shot of txv, so we already talked about what that does.

Isolation relay no liquid line, solenoid valve c long line application guidelines interesting interesting. The liquid line solenoid valve is the one that's sort of like. Do we really need it or don't we now? I didn't actually prepare for this. So let's see what it says here accessory description.

A liquid line. Solenoid valve is an electrically operated, shutoff valve, which starts and stops refrigerant liquid flow in response to compressor operation. It is installed at the outdoor unit to control refrigerant off-site off-cycle migration in the heating mode usage guidelines and lls is required in all long-line heat pump, applications to control, refrigerant, off-cycle, migration and heating mode see long line guidelines. So specifically, it's saying in this in this case, if it's a heat pump, it requires it now.

Why don't? They say it's required, because they already know that this is a heat pump based on the guide. I'm not really sure it says right there all do. We ever install any of these on anything ever, oh, no, pretty much. Nobody does right uh.

I had it's funny because my friend josh berg, some of you, know josh uh. He built a house in groveland many many years ago before i started calos and the guy who installed his ac in his house put one of these in there and i first time i'd ever seen one and he told josh that it just helped make it run Better, but the funny thing was, is he only had about a 10 foot line set and it was just in the garage. So he just thought it was a cool thing. He probably just went through all the accessories and got all of them.

So definitely not a case where it helped now some people are used to liquid line solenoids um in a pump down or pump out application and in refrigeration you'll. Do that a lot? That's actually the way that many refrigeration systems are designed to turn on and off. Uh, in fact, we've done in air conditioning applications. There was a case where there was never a control wire run to a to a split system, uh on a grocery store, and it's the only way that it ever been set up and it's actually not a terrible way.

What it does is is down at the evaporator coil the valve closes whenever the system cycles off. So that's all it does. The contactor is powered all the time the valve closes when it's supposed to cycle off, and what does the unit do when you shut off the liquid line, pumps down right and then you have a low pressure, switch that shuts it off once it hits whatever the Designated low pressure is, and so at that point you're cycling, the equipment and you're pumping it down each time if you're pumping it down each time, where's the liquid staying in the liquid line and in the condenser right, which is where we want it to stay. So it's actually kind of a cool design, but there's a problem with it.

What's the problem with it bert, with that design, i would say the strain it puts on your compressor at that low pressure, so that is actually one side of it and that's why you wouldn't want to set your low pressure control very low at all. You don't need to set it very low. You don't need to pump it down to a really low level, you're, not trying to open the valves right. So, if you're working on a 410a system, you would just you would just set it.

You know. Maybe i don't know 80 psi something i'm just making that up, but you wouldn't need to set it that low at all. So, yes, it is a little additional energy. So there's a little bit of energy.

If you do it right, though, but the problem is your low pressure control, your low pressure control needs to be set right and it needs to not fail, because if it does, you know that can be a real problem and also if the valve starts to leak At all, it's going to sit there and short cycle now you can set it up so that it only does it so many times and then it stops doing it. You know, but then you're still going to get some of that if it's off for a long time, so there's some challenges with that. But that's not what this is. So if you've ever heard of a pump down or a pump out system, that's not what this is.

This is literally just a liquid line, solenoid that shuts off the liquid line when the system goes off, and why would we need that on a heat pump, specifically on a carrier system in heating mode only, why would it only matter in heating mode and not in Cooling mode interesting perplexing any thoughts yeah what yes elijah, very good, no txt in the condenser. So what does that mean? That means that while you have hard shut off capability, when the system is running in cooling mode in heating mode, you don't have that so where's your condenser in heating mode inside right. So when that system cycles off where's all that refrigerant going to go, which is the compressor right, you don't have that you've lost your hard shut off capability now, because now it can just back up through that piston and make it back right make sense. So that's why they have this as as an option as part of the long line now is it you know, am i being pedantic to say that we should do this every time in long line applications.

Maybe, but i'm telling you what the manufacturer says for this particular piece of equipment: that's not going to be the same for everyone. Some pieces of equipment have hard shutoffs inside outside on a heat pump system and even carriers going to that on a lot of systems. Now so you know, may not be something that that happens for that long. Moving forward.

Also, this liquid line this shot off hard, shutoff liquid line valve sorry say that again, this liquid line, solenoid valve setup, is also going to be better and more reliable than a hard shutoff txt a hard shut off txv. You know the shutoff ain't that hard necessarily, you know it's not it's not really closing that hard, so you still can get some bleed through it all right. So that is our long line. Application and those are your most common long line components, hard shut off, txv accumulator crankcase heater liquid line, solenoid valve.

What's the last one, i forgot one oh and harsh circuit. Now, whenever you're going to put a hard start kit on a new piece of equipment, i strongly recommend putting in the one that's recommended by the factory versus a universal one. And why is that? Why do i recommend putting in a factory heart start versus a universal heart? Start anybody know? Yes, i don't. You know what turns a start.

Capacitor on and off brings it in and out of the circuit, correct nope, it's something called a potential relay okay, so you have a potential relay and you have a start, capacitor the size of that start, capacitor in microfarads and the the point at which that potential Relay opens and closes because it starts off closed right. The relay starts off close, so it starts off with a lot of extra capacitance feeding the start winding and what extra capacitance does - and this is whenever i talk about this, it's like i get a thousand complaints about it, because it's just not something that people talk About a lot, but it is how it works. Extra capacitance results in additional current moving in and out of the start winding. So it means the start.

Winding gets more current because normally the capacitance of your regular 30 40 50 60 microfarad capacitor limits your run. Capacitor limits how much current is going in and out the microfarad's limits. If you check the current on your start winding, have you ever noticed what it is if you've done, the under load uh test for capacitors you've done this, where you've and put your clamp on the start winding about what is that current on average? Well, let's say like between four and six: the point is it's low, yeah right, it's low. Why is it low? It's the start winding right and a lot of people say well.

The short winding comes out of the circuit. No, it doesn't not in a psc motor. In a psc motor, it's a permanent split capacitor that start winding is always energized right. I'm going to guess it's limited by the it's limited by the capacitor by the capacitance right.

If we connected that start running across the line, the current would be significantly higher in that start winding, so the capacitance limits it. So when we start it up and we give it a lot more capacitance what happens to the current in the start winding it increases, it increases the current right. But what takes that potential relay and opens it if it was a current relay, it would be current, but it's not it's a potential relay. So what do you think activates a potential relay potential potential? It's not potential current potential.

That was a joke. It's not potential! Current it's potential right and potential is what what's the name for potential voltage voltage right. So when a motor is running up to speed, have you ever checked the voltage between um start and common yeah, and is it higher higher it's higher? Why is it way higher? Why is your voltage between if you go on your run, capacitor between start and common on your run capacitor or between start and common on your contactor, either way? Whichever way you want to do it it's higher than the applied voltage, why you don't know really yeah? Oh, i thought that you were joking with me: i'm not trying to be a that's. Not i just thought you were joking um, it's because your motor produces back emf.

So your motor acts as a generator, a motor is being turned by electricity, creating electricity, creating an electromagnetic field, but once that motor gets up and spinning it actually has this responsive magnetic field that produces this additional potential. That's what we call back emf or counter emf. Okay, that's why your voltage is higher. Your voltage isn't higher, because your capacitor is a magical voltage increasing machine because it isn't capacitor is literally just a storage device in and out in and out.

That's all it is right, creates a phase shift. Everybody always wants me to say phase shift, because that means something to everybody. So the magnetic field of the motor, the magnet actually higher voltage, is actually producing. No, no, it's producing higher voltage, it's actually acting as a generator as it's spinning and because your start winding isn't connected across the line.

It's it's just dead, ending into a capacitor there's, actually that stored additional potential is showing up, so it has to be set up. So that way, initially those contacts and that potential relay are shut so that way, the start capacitor actually does its job and starts right. But then that's that difference in voltage between when it started and when the motor got up to full speed has to be enough to open those contacts. Otherwise, if those contacts don't open in that potential relay what happens to the motor, if this start capacitor go ahead and grab our grab, our start capacitor from our old kitty roo here just in case, i see ronnie about to fall asleep on me.

I appreciate you being here ronnie, you know you just had a baby, probably not sleeping a whole lot, how's the baby sleeping, not a lot, not a lot. So that's good, i'm very proud of you. What is the microfarad rating on that capacitor? 88 through 108.? Okay? So is that for, like a smaller tonnage system yeah, this would be a small one, 108 yep. So this is it's specifically for this unit.

Actually, 108 microfarads right. So let's say that it starts with a i don't know we'll say: there's a 30 microfarad faster and i'm not sure what it has. But if this, if the contacts in this relay don't open and this additional 100 microfarad stays in and now it's running, 130 microfarads all the time, what's going to happen to the current and the start winding it's going to be really high. It's going to be really high and it's higher than it's designed for right.

So, what's going to happen to the start, winding it's going to fail! It's a funny thing. A lot of people who sell hard circuits tell you that hard start kits help prevent start winding. Failure opposite hard start kits that fail cause start winding failure full stop right. I could take a under normal circumstances without a hard start kit and a properly sized run capacitor a start winding is almost never going to fail.

Why? Because it has very low current because that run capacitor limits the amount of current that can go through it. A lot of guys will be hold on a second. What about start amperage? I know that when a compressor starts it draws higher. Amperage draws higher current right.

Sam pressure start is draws higher current, but where does it draw higher current on which winding the runwinding? If you check current on your start winding and you do a startup, it's going to be the same as it was when it it's going to be the same. All the time you don't get start a spike in start current on the start winding and last you have a hard start kit, then you will because the hard start kit takes the cap off of that limit of current, because again, the only amount of current that Can go in and out of a start winding if it's not connected across the line from l1 to l2 is dictated by how much capacity and the frequency, but the frequency is fixed, the capacitance of that capacitor, and so, if you have a capacitor, that's undersized what Happens to your start, winding current yeah really low right. What what is your start winding current? If you have a bad capacitor, open, capacitors bloated up, looks like a toad. What's your start winding current zero, but what's your run winding current? If you measure on common and that thing's trying to start what is it real high right, so it's a misconception to think that compressor start starting causes high current on the start.

Winding i mean it's. Of course it makes sense. That sounds like that's how it work, but it isn't right. So why is it important that start gear is properly matched to the piece of equipment? Well, because this capacitance needs to be properly matched because we don't want it to be higher than it needs to be.

You know just as high as it needs to be, and no higher higher means more. What, on the start, winding more current, which means that you can damage the start winding right. What happens if the relay isn't sized appropriately for the potential of that motor when it's starting so this? So the contacts don't open what happens to the compressor or the motor it wouldn't matter. As long as you have a big enough, capacitor you're going to have more current, i mean it's not going to open, so it will, it will burn out the start winding right.

What would happen if this was sized up so that way, it came out too quickly. So the contacts open too quick too soon. What would what would that do? That's true that would be a point, difficult universal yeah. It would render the start capacitor less effective right and that's what most universal start kits do is because they want to be safe right.

They want to make sure that they're not going to burn up a compressor because they don't want to pay for that. Even though, if you read their marketing, you go to one of their trainings they're going to tell you that it helps prevent start winding failure. I literally have a powerpoint presentation from a very large creator of hard circuits that explains how, because of all this, and they even show the graphs and charts and everything they say that these help prevent start winding failure and completely false right. For example, if you have a compressor that has a completely bad run, capacitor and no start capacitor, how likely is it that the start winding is going to fail? It is impossible for the start winding to fail.

Why? Because when i say impossible, yeah somebody could hit it physically damage it right, but electrically it would be impossible for it to fail because there'd be no current going through it. What increases the likelihood of start winding failure increase current anything that increases current right, oversized, run capacitor oversized, start capacitor relay that doesn't come out soon enough right make sense. So this is why, on certain units and and bert named one you, you put the universal and it doesn't work. Then you put the factory one in and it does work it's because in some cases it's bringing it out too quickly or the capacitor is undersized.

But the on the opposite side. It may work like oh hey. This started the compressor. That's great! You walk away.

Oh three days later, it must have been going bad anyway, because now it's failed. You know she was on her last legs and that's why she needed a hard start kit right. You put it on because the lights were dimming, you put it on because the lights were dimming a week later. The compressor has a failed start winding.

Well, you see, the lights are dimming because there's that compressor's on her last legs, she didn't have much life left in here right. So if we use so, if we use the training relay, it's all about the capacitance. So if the capacitance matches the factory capacitance, you don't need to use a factory kit, you could get a potential relay of the right size and you could get a start. Capacitor of the right size put them together and you've got yourself a hard start kit.

That's what a hard circuit is now there are other types of start components: ptcr's um, some ptcrs use capacitors, some, don't all of a sudden. My mind went blank about what ptcr stands for, like literally positive temperature coefficient resistor, sorry, positive temperature coefficient resistor and all of all those do is they just allow a temporary connection across the line? They actually allow a lot of current through the start one and they don't do a phase shift unless they have a capacitor with them. So some have a capacitor, some, don't yes, sam. So obviously it's gon na vary system, the system and size the size.

But, what's the what's the time frame that the capacitor is taking out of the circuit after the initial start, real fast, real, quick yeah? No, it's! The goal is to take it out at right about 70 to 80 percent of full motor speed, because that's when you'd have enough back emf correct! That's how you size it so once you're to 70 to 80 percent of full motor speed exactly and the universal stay on a little longer. The universals generally don't stay on quite as long. Okay. Now, there's a lot of people who say: oh you're, talking about a two wire.

It's a three! If you do a three wire, it's no problem! No, i'm not i'm not talking. No, it doesn't matter if it's a the brand that has three wires of the brand. That has two wires. They both work on potential.

It's just that the brand that has two wires looks at potential between start and run and the one that has three looks at potential between start and common, which is the more typical way people say well, because this is what the manufacturers do. It's better. No, it's not if it's not the factory capacitor and the factory relay, then, and again it doesn't matter. If it's factory or not it matters whether or not the rating is the same as what the factory had right.

You could look it up if you wanted, but it's a lot of extra rigmarole. Now, i'm not actually. It sounds like i'm hating on universals, i'm not universals for the purpose of putting on units that aren't starting as they're as they start to age and as there's problems with the equipment. Fine, it's not practical to keep a zillion different heart circuits on your truck.

So for that purpose it's fine, but i do not suggest using universals in newer equipment where you have a long line specification that says it's required make sense. Now some people will say well, it doesn't apply to scroll compressors. Is that right, i'm gon na go with? No, that's a very good point, because right here it says, compressor start assist required for reciprocating compressors in the following right: heart shut off expansion valve liquid line, solenoid low ambient cooling, long line required for single phase scroll compressors. In the following applications, long line low ambient, so a scroll, it's okay to use it! If you uh it's okay, not to have one with a hard shutoff, txv.

Otherwise, we'd have to have one like every single unit we do, but if it falls into the long line category we are supposed to be putting a factory heart start kit on it. Do you see why i wanted tyler to be in this class and i'm not joking like we should be doing this? We should be it's not it's not like, oh well, it doesn't really matter. No. We should be doing it right.

It's not that big of a deal to have to do it. You just order the right kit and when the install goes out, the installers install the hard start kit, sorry for laughing sorry for laughing ronnie will go back and rewire it later and put the new compressor in. So we're not going to go any further through the guide. You get the point, though, that all of this exists within the guides and it's uh.

It's pretty self-explanatory if you're just paying attention to it up on the screen here, for you guys to reference. We've got it, but i wanted to give so so come on up here. We're going to first install the crankcase heater. I want you to go ahead and take a look at that, so this is our.

This is our crankcase heater. We call this a belly band, crankcase heater. Why do you think they call it that? Because this is like the belly bands which looks like a belly band yeah, you know all of us wear a belly band, we're going to install this around the compressor now you're going to notice here. If we look at the, if we look at the guide, it says for this kit, because this kit is kit number 1401, that's the one! That's designed for this unit.

It says route crank case heater wires from the control box and attached to quick connect line, voltage, terminals 11 and 21 on the contactor reinstall the control. That's the wiring part very simple. Now you're going to notice, it doesn't say, use a line thermostat or a compressor. Thermostat or any kind of thermostat, which means that this needs to still shut off somehow, so how is it going to shut off i'm going to give this to ronnie see if you can find the cch in this wiring diagram? Sorry, it's just ch: 11.

21. Okay! Yeah it's right here now they don't give us a thermostat for this. This shows an optional thermostat and it even shows the crankcase heater as being optional, but in this case they give us a crank case heater. This is the kit there's no thermostat in it and initially, when i saw they're supposed to send one, but then you pay attention.

Some of them here say that it does need a a temperature switch and then some don't. This kit doesn't have a temperature switch. So what shuts it on and off contact contactor? So i'm going to let you wire it and then we're going to talk about how it actually works so go ahead and gather around. I want a couple of you, i'm actually going to get out of the way.

I want a couple of you here in the front and then some on the back yeah we want. We would want to make sure of that yep all of our breakers are off. You know. Normally we would test and all that jazz, but whatever let's go ahead and yeah, let's go ahead and take the entire fan out, so that way we're not damaging it all right.

So one thing that i want to note quickly on the crankcase heater - and i don't know if it says it here or not the the connector on the crankcase heater the place that you actually make the connection. You want to place that over the seam on the compressor, so, if you're mounting that around the base - and there is a seam anywhere on the compressor right here - you don't want the heater element portion to be on the seam. You want the place that you tighten. The band to be around the seam that makes sense, because otherwise, that heater is going to be in contact with the seam, it's going to be more likely to burn up, and it's also not going to make good connection with the compressor body.

It's going to be very hard to see. Why is that wrong? No, it can't go over the scene. It seems right here, yeah, don't listen to him, he's being difficult on purpose. Do you want to get some spade connectors, of course, from over there, because i think we're going to need those you're doing that right, real stack, those don't already have spades on them.

Do they really do? Oh, they do never mind. Does it have to be tight? Tight on the compressor, it needs to be tight, tight yeah. Are we gon na test it? No, but we're gon na leave it on there. I mean i mean we're gon na leave it on there.

So you should i mean in real life. You would test it. Absolutely you would make sure that when you energize a power to the unit - and actually we will test it, why wouldn't we test it? Let's test it. Yeah that'd be great we're going to test it, the one at the bottom or the middle.

Does it matter? Probably the bottom: what is he saying, the very bottom of the compressor yeah you want it at the bottom of the compressor. That's the coldest point! Well, it's where the it's where the oil would be, but you don't need to heat the oil you're trying to eat the case, you're trying to hit the oil no the case. It's called a crank case, heater. Okay, i'm not gon na sit here and argue with you come on where's our cmat right here, yeah, so our seam.

We want to have lined up with the uh with the actual connection point and that's it. You scrape yourself up there a little bit on the coil, i'm sorry to hear that um copeland in their specs actually talks about that. It's not in this guide, but in the copeland specs. It talks about that all right, so we're good.

We can go ahead and put our top back on and then we are going to power up only the condenser and we're going to see how this works because uh, when we get a close-up in this you're, going to see it it's a little. It's a little odd, it's a little strange. A lot of people would have made the mistake of not paying attention and connecting them both to the top, because you would think that's how you generally power things up. But in this case we want the crankcase here to be energized when, when the unit's off, when the unit is off now we don't have a temperature sensor.

So it's automatically going to come on when it's off all the time. If we had a temperature sensor, that would keep it off or a thermostat that would keep it off for longer, even after it cycled off based on temperature, but he wired it up in such a way that when the contactor is open, there will be potential across These two points: okay and i'm going to show you what that looks like this crankcase do we have this 240? It needs 240. and these it needs 240 volts right, so we're gon na get the display here. Do we have the condenser breaker on no, but i can turn that on whenever you're all right, not the air handler.

Only the condenser do. We know which is which uh 25 the higher one ready yep go ahead: you're ready, yep all right, so we notice the thermostat doesn't light up. So we only have power here, we're just going to confirm at the bottom sure enough, because this is a commercial building. We have 208, so that's why we're seeing 212.

up here we're going to have nothing? I mean next to nothing because our contactor is not pulled in, but why would we have potential in between 11 and 21 and, as you can see, we do we have 212 volts there? Why would we have 212 volts across an open contact because again we're relying on this to energize our crankcase heater? When the compressor is off? We don't want it to be on when the compressor is on. Are you gon na say anything?.

30 thoughts on “Long line applications”
  1. Avataaar/Circle Created with python_avatars K K says:

    Like the class 👍. Great explanation. Thanks for your awesome classes!

  2. Avataaar/Circle Created with python_avatars Warfare Octopus says:

    I am learning so much. 🙏 Thanks Are you in Kanata ?

  3. Avataaar/Circle Created with python_avatars mhockey23 says:

    Where's Aaron?

  4. Avataaar/Circle Created with python_avatars Jayden s says:

    Finally some quality entertainment

  5. Avataaar/Circle Created with python_avatars Glen Schmidt says:

    Thanks for discussing problem and doing training. It is going to change again with new A2L's coming next year. (Long lines may disapear)

  6. Avataaar/Circle Created with python_avatars Phillip Joy says:

    Great videos 😜

  7. Avataaar/Circle Created with python_avatars HVACker says:

    Great class. Thank you! But when are we going to learn about burying the linesets? 😄 Thats an interesting topic I am in Canada and everybody says that it is not allowed. What I read in manufacturers bulletins, they are also against it, but I see that in Florida everybody is burying them 😄 it would be great to hear your experience of burying them and how to prevent flooding.

  8. Avataaar/Circle Created with python_avatars HK HSM says:

    Very nice video. Really enjoyed and learned alot.

    Thanks for sharing Are you in Barrhaven ?

  9. Avataaar/Circle Created with python_avatars jerry lockhart says:

    AC nerds101 lol 😎🤣😍👍🥶🔥😱👌

  10. Avataaar/Circle Created with python_avatars Яков Ботяновский says:

    Было бы неплохо если были русские субтитры

  11. Avataaar/Circle Created with python_avatars Bara Sabri says:

    I never clicked so fast on a YouTube video 😀

  12. Avataaar/Circle Created with python_avatars 2purplemartin1 says:

    Great video! Service area Ottawa??

  13. Avataaar/Circle Created with python_avatars kenny cole says:

    What can we do to prevent having problems with a buried pipe?

  14. Avataaar/Circle Created with python_avatars Richard Tillett says:

    Current is real lazy it always find the shortest path to its source.

  15. Avataaar/Circle Created with python_avatars Roger F says:

    Excellent class! I like how the instructor engages with the students and asks why. It forces them to think and formulate an answer in their head, whether or not it is correct. This feed back is important to the instructor as to how well the students are absorbing the material. Also consider that people are much more likely to remember mistakes in thought or action and therefore correct their actions in the future.

  16. Avataaar/Circle Created with python_avatars Nolann’s Auto Detail says:

    Please negative comments need not apply lol. Thank you for another great video with an awesome instructor 🙂

  17. Avataaar/Circle Created with python_avatars Say Please & Thank You says:

    Power power wonder working Power 😂

  18. Avataaar/Circle Created with python_avatars InsideOfMyOwnMind says:

    That was interesting, entertaining, informative and fun. Now a question that may seem odd to a proper tech. What keeps the liquid out of the compressor during a power-on reversal like entering defrost mode? Probably stupid obvious to most but I don't know.

  19. Avataaar/Circle Created with python_avatars SuperVstech says:

    Your guy asked why wire the solenoid on the y call, not on the O call. I hope you answer him… most thermostats energize the O terminal when in heat mode, the entire season, the valve would remain open.

  20. Avataaar/Circle Created with python_avatars SuperVstech says:

    Ya missed a test. The crank case heater not only heats via the band, it also pulls watts through the compressor windings, and the motor windings ALSO produce a small amount of heat. Ya can measure the milliamperes on the common winding.

  21. Avataaar/Circle Created with python_avatars John D says:

    I'm glad your taking your time to teach the guys coming up in the trade. I never got that. One time I asked an owner about training. His respones was who needs training, don't you know what your doing. I asked another owner and his response was we don;t have time for training. That company had a 75 percent call back rate. Great for making overtime.

  22. Avataaar/Circle Created with python_avatars John D says:

    I thought this was about fishing. We use to long line in the Ocean.

  23. Avataaar/Circle Created with python_avatars Eassyheat/ Cooling says:

    Sometimes you get a class that you need to help you along in your career,I know your investing in your business!!!
    Stay safe.
    Retired (werk'n) keyboard super tech. Wear your safety glasses.

  24. Avataaar/Circle Created with python_avatars Angelo Cedeno says:

    love this class thank you

  25. Avataaar/Circle Created with python_avatars O Indigenous says:

    Thanks Brian!!! I’ve learned a lot by watching your videos Service area Orleans??

  26. Avataaar/Circle Created with python_avatars Eddy Baez says:

    Fuck no subtitles…

  27. Avataaar/Circle Created with python_avatars Chuckles says:

    I skipped your video yesterday. The thumbnail was not good.

  28. Avataaar/Circle Created with python_avatars Bermcannon says:

    Teachers who constantly (ask the class why?) (who can tell me ? ) is such a bad method and flow. It causes students to mind wander and decreases participation. Only the me,me,me guy will always answer. Just teach the goods. Service area Nepean??

  29. Avataaar/Circle Created with python_avatars Robert Blando says:

    I never even knew "burying Suction Lines below ground" was a thing O.o

  30. Avataaar/Circle Created with python_avatars edobor robert says:

    What is the weakness of piston of metering device?

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