Thanks for joining me again on the HVAC School podcast My good buddy Craig Migliaccio Did I say that right? Oh yeah, that's absolutely right. Thanks bro! Was it actually right that time? Yes it was I think I always say it wrong. but Neil Comparetto Neil Comparetto taught me that. The way you have to say Italian last names is you do this and then it makes it.

That's all right. Yeah, yeah. I Hope that's not like gonna get me banned or canceled or anything. It probably will happen.

Actually worse than that when you make fun of Italians they just kill you. Um, so that's all. Don't worry, we'll handle this later. We'll just yeah, it'll Yeah, it'll be fine.

It's no problem. no problem. Anyway, so today we're going to be talking about, uh, mini splits. So apparently you've been working on a book, so let's get that out there out out front and center.

First off, what, how's that going and what's that all about? Yeah, so Inverter Mini Split Operation and Service procedures. We've been working on that for two years and we have over 400 custom images in there and we were Pain's takenly going over all the words in there. so we have 326 pages and the whole point is to try to demystify how an inverter mini split works, Why? They're becoming more and more popular and basically allowing technicians to feel more comfortable in troubleshooting because you can divide the system out into individual parts and if you know how the individual Parts work, so then you're going to know how to troubleshoot them better and feel more comfortable. So we have the refrigerant side, then we have the electrical side and so we got the books put up into two sections and so I I Just think that's how you have to to do it.

You have to split it down to the very small level and then you can add up all the details later. That's one of the things that you're always really good at is breaking things down to their constituent parts. So many of your videos you know you'll have the parts all kind of laying out in front of you and and talk through them in a really sequential way. And so I think it's great that you're tackling this because it's one of the things that we get so many quests from people about.

I'm sure you you get it all the time. It's like I need to know more about how to troubleshoot and install ductless systems or Mini Splits So let's start with the basics here. Um, because again, this obviously we're going to talk a little bit about the book but then and kind of what's in it, but also just introduce some of these topics. Um, and at the end we'll we'll talk more about when to expect it out and all that.

but um, mini splits in general. So what makes a mini split? a mini split and how do you kind of think about that? What makes it unique? I guess so they're compartmentalize. you have a side air discharge outdoor unit. You might talk about them in that manner.

the electrical cabinet is separated over to the side you don't have. Uh, like with with a central heating and air conditioning system or Central ducted system. you know you have the rain water coming right into the compressor area where the accumulator is. All this stuff is is shielded.

A lot of people think of Mini Splits as the ductless units and that's you. know how they originated. But now you have ducted units and so you're always going to be playing around with what to call them. So you have many different types of indoor units connected to, uh, an outdoor unit.

Or you you could have a multi-zone outdoor unit connected with a bunch of different indoor units. So a mini split covers a lot of different, uh, different indoor uh types and so a lot of these are all inverter driven and so it's higher electrical efficiency and more of a capability to draw heat out of the low temperature air outside in order to heat the building during the winter time. Yeah, it took me so long before I really understood how that worked. Like when I heard things like hyper heat or when I You know, like these heat pumps they can, they can work down to a much lower temperature.

It took me a long time to get that like yeah, how they do it is that They spin the compressor faster like you know, like it just it never caught on. But but if you'd hear it like when I first started working on a green speed unit or whatever and they would, uh, it would be low temperature outside you'd hear you know it'd be kind of loud. And really, that's at least to my understanding. that's the big difference now.

obviously all the controls that support that and a lot of times you have to have some form of interstage cooling and some method of vapor injection or the compressor. You know, something that that kind of keeps the keeps the compressor from overheating. That's where the secret sauce is. But really, at least to my understanding, that's a big part of how these inverter driven compressors get that additional heat out of that outdoor air.

Yes, so a lot of the hyper heat systems are. If you, if you're talking about say like a 12 000 B2 unit, it may actually be a 15 000 BTU unit that is limited down due to its programming and so they have a the Eprom chip uh in that and they're programmed by the factory. So basically it's going to be limited down to a lower capacity for the sort of, say, the compressor until the outdoor temperature gets down gets down low, say 32 degrees or 20 degrees and then it's going to allow it to run at say 100 or 110 of its actual capacity. So then you're running at 15 000 BTUs Even though it's it's technically rated at at 12 000 and so it's It's pretty cool when you look at the performance charts and you can look at the cop Uh, so that your coefficient of performance and the actual BTU output of say a hyper heat system at negative 11 or negative 22 degrees and you kind of walk it through up to say 50 degrees and you can see how much output you really have.

So maybe on a on a a negative 22 degree day like say a 22 Seer unit, you might have half of the BTUs is then it's rated for. So if it's 12 000, the system size may actually be fifteen thousand, but you wouldn't know that and then it might produce say six thousand when you get down to that low of a temperature. But basically it all comes down to the sizing for your building and what you really need. Uh, for for the building.

Yeah, it's um, the way I Kind of like to think about it and this may be a stupid way, but it's I'm kind of a stupid person so it makes sense. Um, to me at least. Uh, when you have an ECM motor when we replace PSC with ECM, it's kind of similar to what happens when we replace inverter driven or a regular. Um, you know I Guess it's again a PSC compressor with a inverter driven compressor um in in terms of the programming because what happened was and I recently just did a did a podcast on this uh with Chris Mahali where we talked a lot about ECM ECM motors which I know I'm saying motor when I say that Okay so just waiting for the the trolls to correct me on that but when we went to these ECM Motors Now we had programming where we could maintain our airflow at least certain degree so you could have.

You could have the same airflow at you know 0.1 static that you had at 0.6 static say as an example. and but that doesn't happen for free that motor has to actually spin up in order to maintain it. And so now with inverter driven equipment that traditionally you would have seen this massive drop off in capacity as those temperatures get lower. now they can help maintain that capacity because like you said, you have a little bit of oversizing, but you basically have the ability to bump up that capacity in order to compensate for it because you're still fighting against those same forces.

In the case of a compressor, you're fighting against higher compression ratio because as that outdoor temperature drops your evaporator which is your outdoor coil in this case is now in much lower conditions and so in order to get heat out that of course that temperature is going to be lower and so your compression ratio is much higher. So they just have that kind of intelligence that allow that to happen which gives you that capability of of low ambient heating. which is super important for heat pumps because obviously in the past that's why in Northern climates a lot of people couldn't use them and wouldn't use them is because they just couldn't perform on the coldest days. Yeah, and so at the zero degree Mark you know, zero degree outdoor ambient temperature.

So for say a 12 I'm just using a 12 000 BTU single zone system. But if that's a hyper heat system, you might actually get 12 000 BTUs of heat output when it's zero degrees outside. If it's a non-hyper heat, you might get uh, maybe 100 like 12 12 000 BTUs of heat. maybe at 20 degrees outside.

And so the hyper heat system may allow you to to operate at a at a decent rating down to a lower temperature. But yeah, it's really cool because the system takes many different temperature measurements with the thermistors and it makes decisions for operation based on these pre-programmed algorithms. What's not cool is we can't see them and that's what's frustrating. and a lot of technicians go around there and they want to go to a training class and they're saying tell me that secret Sauce Tell me.

Tell me the secrets. No No No no no You know you're telling me the sales things you know. Tell me. Tell me more details.

Yeah, and so that's kind of. That is going to be the frustrating thing is because a lot of times you you can't see it. Yeah, and that's one of the distinctions between Mini Splits and Vrf Vrv is that usually in the Vrfvrv world, the engineer, the service technician has a lot more ability to adjust the parameters. Not only can you see what's going on a lot more, but you have the ability to adjust it whereas a mini split, which is generally designed for more like commercial residential applications, is a little bit more locked down.

It's sort of like it's sort of like your Apple phone where your iPhone where it's like you can't do as much with it. Whereas if you have like a you know, like a Linux computer or something like that where you can program everything. but it's not as user friendly so that's kind of the balance that they're always playing. And it's understandable because a lot of people who are going to install Mini Splits or ductless systems are going to be not quite as experienced as the people are going to be doing Vrf Vrv.

Um, but another thing that that distinguishes them and I Want to wonder if you could talk about this a little bit is the location of the metering device because in Vrfvrv, the metering devices tend to be in Branch boxes or sometimes even at the heads. But it's different with mini splits. Yeah, so a lot of times. So in this book we draw a comparison between say a single zone system and a mini split inverter system.

So any mini split is going to have the metering device in the outdoor unit. So and what's funny is actually some Mini Splits You can technically get away with calling it an inverter, even if you have say a capillary tube. As a metering device, you're either going to have Kepler tube or an Eev. And the term inverter is really talking about the compressor compressor drive.

and so. but the the high efficiency inverter systems are going to have your inverter driven compressor, you're going to have an Eev electric expansion valve metering device in the outdoor unit, and then you'll have a fan motor in the outdoor unit as well. It's most likely inverter driven, and at the indoor unit, you're going to have a either speed control board inside the fan motor or outside the fan motor and some of those are also inverter driven as well. But the metering device itself which where you're where you're talking about is kind of a question.

Why we don't have filter dryers in in a inverter mini split. and the problem is you don't have sub cooled liquid in the same spot at all times regardless of whether you're going in air conditioning mode or in heating mode. And so that's like a major reason why we don't have that as well as them have a lot of them having PVE oil which doesn't necessarily develop into acid when you have water getting trapped in there, but it it doesn't allow for as good of a lubrication if you have water mixed with the PVE. But yeah, the so the the meeting device is always in the outdoor unit and something that was pretty cool.

We were forced to have to learn all the little intricacies of the Eev and how it works. And you know, when we come down to the Uh HVAC Symposium uh, I'm sorry Hvacr Symposium down there in Florida at your place, you know we're We're going to start discussing uh, those things and so thanks for having us down there. Uh, for that so that'll be exciting Now You ruined it. I Was going to save that for the end and now everybody already knows the main secret which is yeah, they're just gonna be down there.

Um yeah. So when we're talking about and so like, there's a couple distinctions. When we're used to working with unitary equipment, we're usually working with Poe oil and our metering devices are usually right in front of the evaporator coil. Which means that we have this liquid line that just changes directions and so we can put a liquid line filter dryer in that liquid line.

Uh, because it's always liquid and it's just changing back and forth well with these ductless systems. or Mini Splits Um, and again, not Vrf Vrv. They're different and again because they typically have traditional liquid lines, but with mini splits. The metering devices are in the outside unit and that's one of the ways that I that's one of the distinctions that I would make.

If it doesn't have the mirroring device in the outside unit, but it's side discharge and has heads that look like ductless heads, then I would call that a Vrv or Vrf system even if it's single phase. But that that distinction of having it in the outside unit means that you don't really have access to. at least in cooling mode, you don't have access to a high pressure line, so at least not not outside of the equipment. Um, and then like to your point.

That's also why putting a line dryer in doesn't make sense because then any pressure drop creates a real problem you don't have. You know a pressure drop would be a major issue with the operation. and then that leads to the reason why we don't braise on the lines as well and the reason why it's so important that we handle them really carefully in terms of getting contaminants in it because you don't have that filter dryer. Yeah, yeah, absolutely.

And and same thing say in heating mode when you just have a vapor pour and and somebody wants to check the uh, total superheat, you know you have your discharge gas right there. you know going to your indoor indoor unit and so you can use a total Superheat. You can measure it you know in air conditioning mode and that may help you with troubleshooting, but you can't necessarily check the refrigerant charge with it unless the manufacturer gives you some type of guide and in some way to say lock the system at certain operating parameters and that's that. That's a frustrating thing for a lot of the a lot of the technicians.

but going back to your point once again, in reference to the Eev in the outdoor unit, both lines are going to be low in temperature during during air conditioning mode and so they both have to be insulated and we make sure to seal the ends of the insulation. We're trying to avoid any type of moisture getting up in there and air getting up in there and any type of corrosion happening with the the insulation in the lines as well. You want to have both the liquid and the vapor lines insulated outside and and through the building to make sure that they don't sweat and they're both going to sweat during air conditioning mode, so that's a big deal. Another big thing with ductless systems in terms of installation is the flaring piece and we have a we have kind of a funny history with that I don't know if you remember when we were trying to make flares, uh, in in the office and I was really bungling it but uh.

anyway, that's it. That's neither here nor there. Uh, we're not going to bring that up, you don't want to embarrass me. Um, so what are some of your kind of like top tips As far as that goes, because we've already mentioned.

um, yeah, it's got PVE oil in it, which means that you don't want to get moisture in it. but at least it's not quite as uh, hygroscopic. In terms of, it's not going to change. Well, it's very hygroscopic, but it doesn't change into an acid so it doesn't have that hydrolysis that Poe has which is a good thing.

but we still need to make sure obviously that we don't have leaks. Um, again, they don't want us Brazing in most cases because they don't want the they don't want the cupric oxide getting inside the tubing. But what are some of your like best practices as far as doing the flaring part? I Really like eccentric flaring tools, ones that have an offset cone so that when it's drawing out the flare, it's not pressing on the entire tube the whole time so it produces less friction. It's easier to turn, especially if you have a manual one.

You know there's plenty of of battery operated electrical ones and ones that you can attach a drill to to do your flaring process faster. and that's absolutely fantastic. And and they have a depth guide and and so you can just set them right in there and and keep making flare after flare after flare after flare. It's a lot different than when say I came into the into the trade and just using a standard flaring block I I Love using any type of form of eccentric flaring tools because it doesn't scratch the flare when it's all done and I like to make the flare face a little bit bigger than maybe somewhere.

some of the stops are on the Uh, on the on the flare blocks. but anyway, getting to the point is that uh I use a round reaming tool to to deburr or a round the burning tool to deburr the Inside Edge of the copper tube after cutting it because you have that sharp edge and then I like to have like a little refrigerant oil on The Eccentric cone in reference to making the flare, basically drawing it out. obviously or maybe not obviously. you know, putting the flare nut on ahead of time.

It's a big deal, nothing more frustrating than that. Yeah, yeah. I I Like I've confessed I've done it three times in a row where I've made it and like, shoot, I forgot to put the flare on it and made it again. shoot I forgot Literally, that's how bad I am.

So yeah, do as I say not as I do in this case. Well, that also comes to doing a lot of different things Your mind is in like 20 different places, you know, trying to set up multiple jobs and things, and sometimes that kind of stuff just happens unfortunately. But but yeah, so you put the flare knot on you. you make your flare, and what you want to do is you want to slide your flare nut back over the finished flare when you're done.

When you release it from your block or from your tool, and you want to make sure that the the flare that's drawn out basically is taking up the majority of the inside of the of the flare nut. And speaking of the flare nut, by the way, you want to make sure to use the manufacturer's flare not not necessarily just the flare nut that came with the line set because it might be too small, might be like a plumbing flare instead of something that's rated for high pressure and from the manufacturer and is rated for the torque values that you're going to tighten it down to. But anyway, you slide your nut over the flare and then, so that's good. Then you slide your nut back again.

you can kind of just eye up where the flare goes and connects over to the flare face and the flare adapter. make sure it's covering the entire surface. That's a big deal. A lot of flares that I see, especially ones that are pre-made are only like halfway made.

Halfway done. Uh, so. and this was a a bad flare nut. So you end up cutting it off and just making your flare anyway.

So you make sure that's all seated right, make sure it's a 45 degree flare you you fit it to the flare face. Everything looks good. You then go ahead and hand tighten your flare nut onto the flare face. It's usually on a Uh two, wet, on a two-way or three-way service valve, but you have that, you're tightening it down and then you're going to hold your service valve with an A wrench, a whole back wrench, maybe an adjustable wrench.

but you just want to make sure you're holding that. and you're going to use a torque wrench. and you're going to tighten the flare nut down to the specified torque value for the copper tube diameter size, and some manufacturers recommend two tightening torques. one or and some a lot of them are just one tightening torque.

If they recommend two tightening torques, you tighten it to the first torque, then you loosen it, you tighten your uh, you adjust your torque wrench to a higher setting. it's usually like I don't know around say five percent higher and then you adjust it and then you're tightening it a second time. You just follow. You want to make sure to follow the manufacturer specifications for their specific flare nut.

And another thing I see a lot of people doing is putting lubricant on the threads of the flare face. That messes up the torque value. A lot of them are dry flare phase but once again you read the manufacturer's literature in reference to doing that. Also a lot of people including myself have done and you can do.

You can put a gasketing material such as refrigerant oil or Nylog on the flare face before you tighten it in. I've also done experiments where it's just dry, you know, just copper against brass tightening it to the proper torque specifications, putting it up to 600 PSI letting it sit and seeing how much I can get the leak out over like a one month period and pretty good I didn't really see any drops uh and I had like uh I don't know 12 well maybe about 30 flare joints just testing it, playing around with it now. I did a video on that but I was kind of curious myself I don't know I know you everybody does them differently. you just I don't know what your perspective is on that.

Everything you said is wrong. no I'm just kidding. no. so those are all those are all the those are all the high points.

Yeah I mean there's a few little price like we're a little bit more heavy with the Nylog um in general. but to your point. if you follow the ways the manufacturer tells you to do it, you're gonna be You're going to be safe. And the biggest thing are these sort of just obvious best practices like making sure you don't have scuffs in the flare face, making sure the flare is the right size, making sure that you're kind of mating it up against and it just does it.

Line up is everything the way it's supposed to be using the manufacturer's flare. uh, flare nut? that's actually a really big one that I often forget to mention. Um, so thank you for mentioning that and then pressurizing it up to that high test pressure and letting it sit, putting some still soap bubbles on it and making sure you're not getting any microfoam. Um, those are your best practices.

If you follow those, you should be just fine. Um, it's something always worth mentioning though, because in terms of challenges that people face with ductless systems, the flares are often really high on the list. Yeah, absolutely. And to your point with pressure testing: I Always recommend digital gauges.

Uh, either probes Wireless probes or just did digital in general because it's it's very important you'll see the pressure drop real quickly instead of a compound gauge where you have to wait a longer period of time. Likewise though, with a used system, you don't want to pressurize it too high because you could make a leak. It's kind of that old situation we had with the old R22 coils. When you're pressure testing it, you can make a leak instead.

so the digital pressure readout is going to give you a quick turnaround time as far as if you have a leak or not and using non-corrosive bubble protector on the joints anytime. I Pressure test I Always put the non-corrosive bubble detector on those joints to see if I see any glistening whatsoever and and absolutely that's that's what you want to do. I Like the term glistening, that's a that's a new one I Haven't heard that one before, but I like it I Like it. Another thing that a lot of people, uh, mistake when they think about pressure testing on these is they'll see.

They'll say well, high, low pressure. How does that work? You know low side pressure versus high side pressure. Well keep in mind that in this case, on a heat pump, your evaporator coil is on the high side because in the heat mode, it's going to be on the high side. Both of those lines are going to be on the high side.

Uh, in heat mode. So because of that, you can pressurize the evaporator coil on the line set to that higher pressure. Just keep in mind your only risk there is pushing back through the valves. The weakest point in the system, and this is almost universally true, is the actual fusite or the terminals.

The kind of glass terminals on the compressor. And this is something that I I didn't know for the longest time, is that the actual body of the compressor is on the low side because your suction gas dumps into the shell of the compressor and then it's pumped out. so only the head of the compressor is on the high side. So really, what you got to be careful with when you're pressurizing on any system is pressurizing the shell of the compressor to that higher pressure.

That's where you can generally do the most damage. But to your point, on an older piece of equipment where you may already have some corrosion going on in the evaporative coil, maybe you already have some tiny leaks? That's where, pressurizing it to that higher pressure you can. You know if that's the old saying like if if you didn't have a leak, you just made a leak by uh by using such high pressure. So yeah, that's the that's the shame of it.

And yeah, you need to be careful. In the same thing with diagnosis over the compressor. you do it at the wires connecting to the compressor before removing the plastic cap. If you get your good readings there, then you know that your connections are intact.

But if you're going and pulling on those terminals once again, like you said, that's the weak point. and you better darn be wearing safety glasses in case that was to to pop off and have refrigerant come at you. Uh, you got to be careful with those types of things. So you start with the wires connecting to the compressor, with your diagnosis, with the with the system off, checking your resistance values and then you kind of move closer to the compressor as you need to because if you have an improper reading at the wires it could be that maybe a connection has melted or was loose or something that like that at the compressor terminals themselves.

And this is what I love about you is that you're so like you're so rigorous in terms of your processes like I'm all over the place. Even today when if I were to diagnosis system I'd be like well check this and check that and try this and try this like you're very very rigorous and thoughtful on how you how you describe those things. it's a really good point. All uh, all very true.

So okay when you're thinking about like the parts and service of the equipment, what are some other things we've talked a little bit about, some installation things, obviously you know it's worth mentioning. Before we move on here, you pull a vacuum like you would in any other system. Um, weighing in the charge properly is massive with ductless systems also in Vrf and Vrv. Same thing, especially when you have multiple heads and all that there's You have to pay attention to what the manufacturer tells you in that you got to get that dialed in exactly right.

But what are some other things that we need to think about in terms of you know, Operation Parts and Service. So let's start with the the main causes for failure and a lot of them like you just hit on was refrigerant leaks as you you come up to the system and it's it's either flashing an error code or it's just running at very low low pressures. That's that's one of the big things. number two and of course you're gonna have to.

You know a lot of times it's at your flare joints or the corrosion due to that insulation on the tubing or something like that. Uh, you could also have evaporator coil or whatever or indoor coil leaks. uh. But in reference to the other things, you could also have voltage spikes or lightning or something that has uh, damaged the the main PCB and the outdoor unit or the IPM uh, the intelligent power module.

And so you want to have a surge protector on the on the outdoor unit. and and you could also potentially install some type of a voltage monitoring system with surge protection to temporarily short that to the to the ground when you if you have a lightning strike. That's a big thing is with these uh, circuit boards are very sensitive. but another thing is the thermistors and a lot of times people ignore those and they get out of calibration.

You have a tube thermistor or a bead thermistor and that's something that with a system powered down you can check the electric, uh, the electrical resistance values of that and compare that to the temperature. So a lot of times I'll take a temperature meter, I'll tape that temperature sensor to the the bead or the tube to make sure that they're at the same temperature. and I'll use the manufacturer's chart while measuring electrical resistance and making sure it's very close because if you're I forget what it is, it's like maybe seven percent off. You're talking like three to five degrees off.

and the whole system's parameters is like it's based on that and so you're totally jacked up at that point. you know, with your efficiency. So that's a huge deal. and you have multiple thermistors to check.

It's a really good point. Um, because everything is so algorithmic. Everything is based on these, uh, these interdependencies. uh, boards and temperatures and thermistors.

They can drift. It's something that can happen, uh, and kind of to your point. That's how you test them. is you just power it down, disconnect, take your own meter, connect it in, reference the chart, and see if you're actually matching.

Um, what it's supposed to be. Yeah, yeah. so um, you know. another big thing is when you're doing preventative maintenance.

you mentioned as far as the dust on the back, people think, oh, it's just my efficiency that's lowering a little bit. I'll get to it when I get to it. Well, it's a big thing. and in fact, the Intelligent Power Module usually has a aluminum coil, a heat sink coil that is in the Airstream of the outdoor unit so that outdoor fan is pulling error not only across the coil, but across the IPM.

Uh, the not the whole module, but just the the heat sink and the IPM Because it's doing that conversion. Uh, for the electricity to to change basically single phase electricity into three imitated phases of DC power to power the compressor. Uh, we can get into that in a little bit, but uh, it needs to. It needs to lower in temperature because it's going to have a lot of heat on it and so if you have dust on that upper corner upper part of the coil, you're not going to have that good airflow across the IPM and it could overheat and fail.

Yeah, really good point. Also, another thing to mention, just while we're on the subject of that particular feature, in some cases, you're going to be replacing circuit boards and you have to actually Mount them to an existing Or or a heat sink that stays in place. If they send you that little tube of paste, you need to actually use it. That's actually important.

Talk about that just a little bit. Yeah, the thermal conductivity of it. You definitely need to pay attention to that and and and apply that so you have proper heat transfer. If you do not, you'll have a separation and that's all you need is a tiny little air gap in there.

air is insulation and so it will not work properly. It'll be a kind of a fake thing and you'll be replacing the circuit board again. Uh, and some Ipms they have refrigerant tube heat exchangers. Uh, so it'll just be maybe a YouTube of copper of the of the Uh the vapor line heading before it goes to the accumulator on the side of the compressor.

It'll cross the the IPM or it may even have its own Zone that is to lower the temperature you know at on that on that heatsink. so that I just refer to that as a block like a two block on the Uh on the IPM and so it could have either one of those in in order to lower the temperature. So just be aware of that now. I Believe manufacturers are moving to that because of the poor maintenance that's being done on these systems.

So it's kind of like one of these things where maybe the manufacturer gets blamed. Hey, your electrical components keep failing and it's prevented a maintenance issue. And so that's a kind of a big point for for cleaning these things. It's not only efficiency, it's the it's the lifespan of the unit.

Another thing I'm going to mention and and you don't necessarily have to, um, agree with this one because this is probably kind of controversial. So I'm just saying that off the off the top. but in our Market where it's very hot a lot if anybody who's been to Florida you kind of know. and this is true of other uh, markets too.

It does seem that you have more circuit board failures. uh, more issues. Uh, when the system is in direct sunlight and so even just thinking about the location, if you can kind of decide where it's going to be now don't do something dumb like put to put something over it. that's then going to restrict the airflow or something you know like.

that's not what I'm saying. But if you have a choice of where to locate and this is really true not only of ductless, but also of unitary equipment. If you can locate it in the shade or if you can locate it on the north side of the building, then do that because it does matter. I mean like it, it it, it doesn't matter massively well.

I mean maybe not, but especially when you have circuit boards that are heat sensitive. I've just noticed in in non- what I would say is not insignificant amounts that we seem to have higher failures on systems that are in direct sunlight, especially on those exposures that tend to be the worst, which the south of course is generally the worst. Well, I I Wouldn't say that's controversial at all as far as my perspective. I Think that's right on the right on the base.

You know, Like that's that's absolutely what you want to do. And when you talk about say, single speed systems, you have a capacitor in there. If you're replacing the capacitor every year, well guess what? There's a there's a problem, you know. and it's most likely that that capacitor is overheating because the electrical cabinet is just sitting in the sun.

And so it's just that's it's failing because of that. and so guess what? You have capacitors on circuit boards and so if that cabinet, the electrical cabinet is just overheating, that sun is a lot of heat energy. I Mean that's what heats the Earth You know, like that's the last time I Checked Yeah? I think I think so Yeah yeah. uh.

so I I That's a big deal. Yeah, if you could locate these systems where they're going to stay in the shade, that's a huge deal no matter what system. No wonder what system you have. And the same thing for efficiency too.

If you're trying to reject heat and you have the sun beating on the on the coils and everything I mean that makes sense. So so definitely that. and then the other thing is with a mini split outdoor unit. The other big thing is, don't try to spin it away from the house and do it kind of long ways.

I've seen some weird stuff before where they're in just different orientations, where now you have the sun beating on the exposed temperature sensor which is the thermistor outside and you're totally throwing things off. then it's it's no good at all. Yeah, they're really designed to have that coil up against the the building because that does it that Shades it naturally and also keeps that temperature sensor in the shade, which is huge I mean any sort of thermistor? any sort of temperature sensor at all. whether it's a thermistor or a thermocouple.

If it's indirect sunlight, it's not going to measure correctly. and so that's a huge factor and something that honestly I don't know that I've ever thought about. at least not in that way. So I always learn when I do podcasts with you.

So I'm a man who speaks the truth. Okay, all right, that's all it is. Do I use all your fancy words and I just not. and I'm like you're right, You're right, you're right.

I don't know what you're saying, but he's you're right. Um, so even even things like when when technicians are checking the charge, that's a big deal. You have your temperature clamp or your bead, sir, you know, bead temperature sensor in that case. Uh, and you're trying to check the refrigerant charge or something like on single speed systems, you have the sun beating on it? Well, guess what? You know your temperature is not correct.

You want to put some insulation on that? or make sure that you're in the shade, Even putting a glove on it or something like that to cover it while you're doing. This is is is a big deal. So yeah, talk a little bit about charging because it not only in initially because we talked about that a little bit. but if you go to a system and now there was a flare leak I mean I know that's never going to happen.

but as in it happens all the time with ductless systems or you have one of these line sets that fails on you or whatever and now you have to recharge the system. What's the what's some best practices there? So you're if you have. If you suspect a refrigerant leak you can. I Would suggest just searching for at the flares real quick with non-crosive bubble detector.

What does that cost you? How much time? Not a whole lot. The indoor unit. That's kind of a different thing. You're trying to lift the unit off off the wall a little bit and and you're trying to cut the insulation back.

That's a kind of a big deal, but if you could at least start at the outdoor unit just at the flare connections. Uh, that's that's one thing with the system off. If it's been off for say 10 20 minutes, the refrigerants most likely have equalized. But you also don't know in the equipment manufacturer's programming if the Eev is shut in the closed position or if it's open, you don't you just don't know.

Uh. But basically it should be able to equalize and you can check the the pressure at the outdoor unit so you can say it's 80 degrees outside and 74 degrees inside if you measure the pressure and you convert that to a saturated temperature for the refrigerant that you believe to be in the system like it's it's a fairly new system. it has R4 tonight or something like that. Obviously, we're going to be switching over to R32 here soon, but r410a You know it.

It's in there and you are measuring a saturated temperature of like 30 degrees. Well, then you've leaked out 7 8 of your entire refrigerant charge because you your refrigerant is no longer saturated and so that's a key indicator. But that will not tell you if you're just a little bit low. that's like a massive amount low That that means that there only is vapor left.

When I say you need to come take your pressure and convert it to saturated temperature of what you believe in. to be in the system, you need to look at the rating plate. You could even look at the compressor on the side. You know you need to verify that you're not talking about an old R22 system.

You know most of the inverter systems are are for tonight. Here in North America A lot of them have been R32 for two decades you know over overseas so you know that's one thing that you can do. Another thing is if you see that the the line is severely frosted or iced over, it's most likely undercharged or or it could be other things as well. like a thermistor is telling, telling uh, the system that it's reading a a, uh, incorrect temperature.

Or you could even have the Eev maybe has rust between the head and the stainless steel shell. And the uh, the magnetic field is not really getting to the inner permanent magnet within the Eev and it's not able to open open up more so it could be multiple things. You can't just blame it on the refrigerant charge now while it's running. If you measure maybe a total superheat of 30 degrees or 40 degrees, well then you know once again, you think it's low in refrigerant, but it could be some of these other electrical devices so that that's what you can do.

Now if the system is running with say a super a total superheat of say 20 degrees or lower, then that's more along the lines of the range in which it's going to be operating. It's normally a lot of times these systems are running with a very low superheat, low total superheat because the entire coil is a lot of times is filled with saturated refrigerant to absorb a a larger amount of heat. So talking air conditioning mode, you know you're from Florida You understand this? Yes, I am last time I checked I went outside it was Florida Yeah some people were good. It's cold here and you're like sweating when you go outside.

Down it is. It's raining so I would be wet and not from sweat but you know that's you. Know it's hurricane country. So yeah, yeah.

so um, you know you don't know the programming right so you don't know what's happening. You also don't know if the user uh has set the indoor AirSpeed at a certain amount. So the system, even though it wants to control that, it may be locked at a certain amount. you may want the air speed at the indoor unit at a low amount.

Well, then the system can increase that air speed just a little bit. It's not allowed to, you know, increase it to medium speed or high speed at that point. And so you've limited the system. So when you're checking, you're trying to quote unquote.

Check the charge. There's a lot of factors that are going to change what your refrigerant charge level is. You don't know the speed or the capacity to the compressor. You don't know the speed of the outdoor fan.

The indoor fan. Is it set on auto or is it set on medium? Do you have it all the way up in high speed? You know the indoor fan because then you're going to have a higher heat load at that indoor coil. and these systems measure these thermistors maybe every 20 seconds, 30 seconds, maybe every two minutes. And it's making operational decisions and changes that you don't You don't know.

So the manufacturer would have to give you some way to lock the system at a certain amount and have to give you like a Target Target superheat guide that it should be. It should be ranging at. But the big secret here is that these systems don't work on necessarily sub cooling and superheat. They they work on the temperature.

Well, let me let me rephrase that. they're not trying, they're not trying to. Uh, don't laugh at me. I was laughing with you.

You were laughing first and I laughed. So it's weird. A lot of people are laughing with me. That's so weird.

Yeah, the superheat and some cooling does not exist in these systems. She worked on electromagnetic fields anyway. sorry. yeah, yeah, yeah, yeah.

no. Uh. so they're measuring temperatures right? and they have programmed algorithms to work on. uh, monitoring all these temperatures from these thermistors and and some systems.

You know they'll have pressure transducers, but the majority of them are going to have thermistors because they're lower costs. and they're They're simple and so when all these things and the parameters are functioning properly, you're going to be at an efficient superheat and sub cooling. That's the bottom line. And so it's not measuring superheat and sub cooling to adjust the system.

A lot of times, it's measuring temperatures to maintain a efficient superheat and subcoin. So what you may measure if you run the indoor fan at medium speed, medium air flow speed and you set the temperature down low and you give it say 10 minutes and you're like, hey, it's adjusting to hopefully what it wants to be at, you know, But once again, it's constantly adjusting. You may measure a total superheat outside of 0 to 10 degrees or even zero to five degrees. It may be one degree and it's allowed to run at zero degrees of total superheat because it has that accumulator on the side of the compressor that's going to be a protection device for the compressor to make sure that you don't have liquid or just a saturated refrigerant entering into that Vapor compressor.

And so it's It's able to do its job in a real efficient manner. Yeah, so to start with I guess um I guess to kind of summarize, it's it's hard to check the charge in the traditional ways we would be used to. It's not that it's completely useless, but it's it's not the same. It's not like you hit a Target um super heater sub cooling.

But the first thing to do I would say would be just make sure everything's clean like especially if it's not an if it's not a new system. Make sure the condenser coil is clean, make sure the blower wheel is completely clean. Those things get gummed up a lot on. Mini Splits Make sure the evaporator up close clean.

Make sure the airflow is how it's supposed to be. It's not, doesn't have bushes growing into it or whatever. Uh, make sure that you have proper clearance up above, Make sure your filter is washed. all those things.

So that way your airflow is going to be properly set. and then if ever, if all of that is good and you're still not getting the performance out of it that you would expect maybe it's continuing to freeze or whatever, well, then at that point I would probably weigh the charge out and just see, are we low or not? I Mean would you agree with that? Absolutely Yeah, That's that's the thing. because when you recover the refrigerant charge out of the system, you say turn the system off and you just you recover all the refrigerant. You're going to see if the system is low compared to the factory charge that's listed on the outdoor unit rating plate, and then you also have to.

In some cases, it's a guesstimate of of the lines that lengthen the path, you know, so you're trying to go. Okay, A Lot of times you can't see. it's in the walls and so you see where the indoor unit is. You're measuring the floor length and then the Heights And when there's multi zones, you're adding it all together to come up with a cumulative line set length and then you're taking that and looking in the in the manufacturer's literature and or the rating plate.

Sometimes it's not on the rating plate where it says if it's r410a, it might be say 0.16 ounces for every foot. Uh, whereas some other manufacturers might say it's 0.24 ounces for every one foot of, say a quarter inch liquid line. And so you. That's the other crazy thing about it is half the manufacturers have the low amount of uh, liquid refrigerant weight per foot and and the other half have a high amount.

And and it's just based on their accumulator accumulator fill rate when they're designing their systems. and and so the technician really needs to pay attention on what manufacturer they're working on. So anyway, with that being said, you recover the amount of refrigerant you check the you look at the factory charge. you also have to look at how much line set that is, um, supposed to cover.

It may cover up to say 35 foot, you know, and then anything. After that you have to add. So if the factory charge says it has three pounds of refrigerant, you have to, then add. if it's another six ounces due to the additional line set length or maybe four ounces or whatever, then you compare that to what you just recovered out of the system.

If you recovered only two pounds of refrigerant or one pound, you know you're severely low. You know the answer right away. You don't have to guess and that's the problem is if you recover the refrigerant and you you know it immediately, you have a leak. You already know the problem and that's the majority of the problems with these systems is due to some poor installation procedure, especially if it happens a year after it was installed.

You kind of have a general idea. it's probably the refrigerant charge. So you make a great point and that's the that you need to recover the refrigerant to to weigh it, to see to see if you have a refrigerant leak. in.

Every other test that you're going to do is going to point to more than one possible cause, so you're not going to know. Yeah and then from there it gets real tricky if you didn't have a refrigerant leak and you thought that you did and now you've got to go through all the other components and and all of that. But in most cases you're going to find that you do. To your point, as soon as you suspect you might have a refrigerant leak before you even pull the refrigerant out, go ahead and soap up um the the uh, the flares that you can get to easily and then even if you after you pull it out if you like okay now I know I'm low.

Well then you can use your favorite leak detector and even go back in with nitrogen and maybe not full pressure if it's an older system. But maybe maybe you go back in 300 PSI something like that. And now you can use that ultrasonic leak detector to to further locate the league. So definitely yeah, you can use the ultrasonic detector.

Uh, because you have oil inside the tubing. It's going to make that squealing noise. that's that's you know, a nice tool. There's a lot of tools you can use, you know, so you just want to make sure that it's it's one that's for that correct refrigerant.

Some some different refrigerant Leak Detectors are made for specific types. If it's a Hcfc versus Hfc, it just depends on what kind anyway. So definitely if you if you don't find a leak when you recover the refrigerant charge, then you're gonna have to do that whole process. You're gonna have to vacuum it.

You're going to have to then weigh your whole refrigerant charge back in again. and you're going to typically do that out of your new refrigerant bottle not your old recovery bottle because you might have multiple charges on there. and you're not allowed to basically take somebody's refrigerant from one owner site and put it into another owner's site. And plus you have dirty oil in there.

Possibly you don't want to put any air contaminants, You want to make sure that you are doing everything. That's right. So after you do that whole procedure, then you still have to do the whole checking the electrical resistance values of the thermistors checking. You can see the Eev head to see if there's rust on it.

That's a big one, but a lot of times those are insulated and so you have to peel off the insulation in order just to see the Eev head. You want to make sure to not Nick The wires. Sometimes even with the thermistors, it's not the thermistor itself, it's the wires have got chafed and that's that's a problem. But during this whole time the big thing is you have to notify or or can continue to speak with the building manager to let them know because this can.

It can be a decent amount of work and you have to let them make their decisions on can I go to this next step. Are you willing to pay for this next step because you can get into a problem when you spend too long on a job and maybe potentially can't fix it. You you know, maybe you need to stop at a certain point, or maybe you need to call tech support or maybe you don't have the manufacturer's literature. You got to find it, you know? Or you can look it up with the online app and so you definitely want to to keep the say, the homeowner you know informed of your of your process through the whole thing.

Yeah, for sure. because it can. It can be really simple or it can take a while, especially when you deal with certain electrical problems that you're kind of chasing. Sometimes they can take a little bit to go through with tech support and work through.

you know, checking everything you got to make sure you're not condemning incorrect parts. All right, we're already at 45 minutes. There's so much more that we could cover on this. but rather than covering all the rest of this on a podcast I Think we'll just have people buy your book.

So when is it coming out? Where can they? Where can they get it? Where can they find out more about that? So at our website over at Aecservicetech.com that's going to be the the main place where we sell this book. Uh, we're also going to be selling it on on Amazon and also Google play Apple iBooks so you can get it at all those places and that'll be starting January 1st and and the reality is, we're gonna be taking some of the books down to the Hvacr Symposium and so we'll be there as well and we'll be speaking about it there. so I Look forward to to seeing a lot of the uh, the hungry technicians that want to just soak up everything when we come down there. So I'm really excited about that figuratively hungry because we will be feeding them.

Um, so they won't hopefully be now. Don't diss the food. the food is good. We got Chick-fil-A the Lord's chicken.

We've got some great uh Latin Fair we had we have some barbecue. it's going to be the same uh Smorgasbord Now we're super excited to have you down. um it's uh, it's been great getting to know you if for any of you who aren't subscribed to uh Craig's Channel Ac Service tech I think the entire AC world is at this point. he's got like 40 zillion subscribers.

but but if you have not, then please go and do that. and then he'll make more fun of me when he gets his gold but play button well before. I Do Um, it's going to happen. You know? Do you? Do you know that the only to this day the only silver play button that I have is the one that you made for me.

They never sent me my silver play button and are you kidding me? Yeah! I think you called Mr YouTube to make sure that I didn't get mine I think that's I think that's what happened here Anyway, Uh, go subscribe to AC Service tech on YouTube um follow Craig he's getting more Savvy uh on all of the social media platforms you see more of him out there now and go into events and all that it's it's good to see you I Think you're going to be Are you going to be at Ahr as well? Yes yes HR as well. Awesome! So uh yeah, you get a chance to. Okay, great, yeah, oh the uh yeah. HVAC Excellence you're gonna be speaking there as well.

Yeah, so these are all things that I'm going to also be at Ahr HVAC Excellence in Vegas Those are all places that you can chase Craig down and tell them how much you love him. Um, appreciate you for all the all the stuff you do. And yeah, everybody, go out and get the book on. January 1st it's going to be a amazing book.

The book that you already put out on, you know, just regular version cycle. All that stuff is. uh, basic service practices. Again, remind me the name of that book as well.

the name of my head. That's that's fine. It's refrigerant charging is service procedures for air conditioning. and that's like checking the refrigerant charge troubleshooting while measuring superheat and sub cooling.

and all the practices that you would do to prepare a system for refrigerant and service. Yeah, it's it's all refrigerant based. Yeah, great book. Uh, super well.

Illustrated Really, really nice. Um, we've I've bought a bunch of them giving them to all my technicians. That's how good it is. Um, so yeah.

go ahead and get this book when it comes out. Uh, for anybody who's doing a lot of servicing on Mini Splits or if you've kind of avoided it because you've been afraid of working on Mini Splits I Know, there's a lot of contractors out there who are that way. This is a good way for you to kind of get more comfortable doing that. So Greg thank you as always for coming on and I look forward to seeing you soon! I Appreciate everything you're doing Brian Thanks man! Thanks for watching our video if you enjoyed it and got something out of it.

If you wouldn't mind hitting the thumbs up button to like the video, subscribe to the channel and click the notifications Bell to be notified when new videos come out. HVAC School is far more than a YouTube channel. You can find out more by going to Hvacreschool.com which is our website and hub for all of our content including Tech Tips, videos, podcasts, and so much more. You can also subscribe to the podcast on any podcast app of your choosing.

You can also join our Facebook group if you want to weigh in on the conversation yourself. Thanks again for watching foreign.