Bryan teaches the Kalos techs a class about Flares and Preventing Leaks on Ductless Systems, covering important tips and rules for making leak-free flares along the way.
When tightening a flare nut, it’s a good idea to use a special flare wrench; flare wrenches are specifically designed to grab a flare nut and will let you tighten the flare nut without deforming it. You will, however, still need to apply the right amount of torque. Torque wrenches can be difficult to use in tight areas, so you can simply use them to check the torque and let a regular or flare-nut wrench take care of most of the tightening.
A wide variety of flaring tools can be used to flare copper tubing. Although you need to deburr the copper to prevent turbulence from happening inside the tubing, you don’t want to over-ream the copper and weaken it; over-reamed copper may crack when flared. Flares should also be made in the correct size; the goal of a flare is to have a clean, smooth finish on its face with as much contact area between the face and the cone as possible. Do a visual inspection to make sure a flare is round, properly sized, and smooth before you use it. Hold the flare against the cone to verify its shape and size.
The tension should go towards the connection, not away from it. So, pre-bending copper is an advantageous practice when you have to make a flare connection in a tight or tricky spot. We also put a tiny bit of Nylog on the mating surfaces, threads, and back of the flare. Although Nylog will affect the torque a little bit due to the reduced friction, it is a good practice to use an assembly lubricant as long as you know how to adjust the torque and don’t overdo it.
You should thread the nut with the copper in place, as you will establish the contact at the connection. Once you tighten the flare nut, you will want to do a pressure test to ensure that there are no leaks; these pressures should be quite high. Ductless systems with hard shutoff TXVs can be tricky, as the pressures may become unequal between the high and low sides; you don’t want a differential between the high side and the low side during the pressure test because the bleeding-through action could look a bit like a leak.
When you add a leak reactant to check for bubbles, you want to lay the reactant on flat, coat the flare connection, and let it sit for a substantial amount of time. The pressure test time may vary depending on the system type and size. Once you return, check for bubbles, including microfoam bubbles, using a mirror and a flashlight.
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All right. So let's talk about let's talk about flares. and I'm going to do the thing that annoys everybody. I'm going to ask you to tell me to start with what you think are some of the most important steps when making a flare so that it doesn't leak. So I'm just going to wait until you give me some things: Nice, clean cut. Okay, nice cut on the end. Nice cut in the end. Yes, that's that's really important. Uh, reaming it. Very good. What else good Were you raising your hand? Weren't you? No, no, you weren't. You were. just. um, you're just praying. Yeah, praying. I Don't ask you to talk. Okay, that's good. Um, what else. Clean cut. Reaming Copper. Seated into the fitting properly. Yep, we'll talk more about that. What else? I've got to use your dialogue. no use some Nylog. Okay, that's good. That's one of our favorites. One of the most controversial things we do. but but we're not gonna. but we ain't gonna stop. Make sure the flare nuts on before you actually make the flare. Yep, that's the number one who's done it more than three times in a row. Yeah, make sure it's tightened down the spec. Make sure it's tightened down to spec. Okay, that's good. That's good. What else? Yeah, yeah. just keep giving more and more. Uganda As do you start seeing copper pop out the other side? Yeah, make sure it's not cross-dressed Make sure it's not cross threaded. Very good. Yep, that's it. That's a good one. What else? We're coming up with a good list here. I Like it. You all have the experience to know. I Think tools are really important in this goodness, um, type of work. Whether it's a, you know, an accurate torque wrench, or just using the right size wrenches for this. A lot of the times we get to a tight location, whether it's in a piece of line height or up in an attic where you you're trying to do your best to get that that that nice seal on it and you're not quite sure about it. That's the time to slow down. you know, get some smaller wrenches if you need to do that. Do a really nice pressure test on those because those are the ones you really want to pay. Yeah, the tight ones. and the tight spots. Those are because those are also the ones that are going to be the most difficult to solve later. You know, the ones down at the condenser. It's like oh, bubbles. You know it's not nice, but it's not nearly as big of a deal when you're than when you're having a tear insulation apart and get inside. So those are the ones you really need to make sure you get right. So a couple things. Um, who here has a set of flare wrenches on their truck Flare wrenches. Anybody ever seen a flare wrench before? So flare Ranch actually has it actually wraps all the way around. It has a little opening on the end and it's designed specifically to grab a flare nut. Um, and they're really nice. If you've never used one, it's kind of like if you've ever, um, used an actual 9 16 wrench on a train. So when back in my Delaware days, we used to do a lot of train units so it's probably the most common brand that we worked on. And they had those actual hex nuts on the uh on the service caps and we would use. You know, you know, big old, you know, channel locks type thing. not channel locks. What am I trying to say crescent wrenches? Why did I say channel locks? It's early. these big old crescent wrenches and stuff and it was always kind of like, you know, tough to get them off whenever. But then I started keeping a 9 16 wrench in my bag and it just made life so much easier. Just was like man, this is this is nice and so sometimes those little those little things like that I'll give you a little bit more swing because now you don't have this big head in place and it also just makes sure that it grabs the nut and doesn't deform in any way. Um, especially when you're really trying to get something snug. Now to to the kind of the question of torquing with that. How would you go about doing that though? Because you know we're You know we're supposed to use the torque wrench, but sometimes the torque wrench. You know most of the torque wrenches we have are the big crescent wrench type head, and they're kind of difficult to get into tight spots. So what would you do if you were in a really tight spot and you still wanted to torque something down, make sure that it was torqued properly. Any thoughts: Small Torque wrench? Well, they make Yellow Jacket makes one. I think some others do too that are actual analog torque wrenches that have smaller heads. That's actually my preference. That's that's my favorite torque kit. Um, having said that, I I Get why you like the digital ones with the crescent wrench head? Just those tend to be kind of big and clunky. and also, the crescent wrench jaw has a little bit of give to it, which makes it a little bit inaccurate. Again, I mean how precise are we trying to get here? It's not like that level. what I would suggest doing though in really tight areas is using uh, either regular wrenches or flare knot wrenches. and again, if you ever use them, you're going to love them. I Think you can even get them at like Harbor Freight They don't have to be like the world's best. Yeah, they're not super expensive, but you can get it nice and snug with those and then just check with the torque wrench in a single position. So now you're not having to do a lot of turning with this big torque wrench. Now you're just putting it on there and just checking the torque of that last little bit. I Think things like that, Just having those right tools is going to make a big difference. especially in those tight spots where you kind of you want something a little smaller, a little more compact to work with. I Just I was just saying that because of what Sam said. so you got to have a good flaring tool, you got to have a, you know, got to have a torque wrench. I Would suggest having either a good set of regular wrenches or flaring wrenches of the correct size. so you know the standard sizes that we work on regularly. so just make sure you have the right sizes. Um, and that's sometimes where even as a company we should do a better job at like creating kits for you of like here's your here's your ductless kit. uh for those sorts of tools and that's something we can work on this winter. Get better at in terms of the flaring tool that you use? What type of flaring tool? do you? What type of learning tool is your guys favorite? What do you like to use best? Who uses? Do you guys? Some of you guys use the the Navac battery kit I Know we gave out some of them, but the battery flare tool? how's that working out for you? Wonderful! Do you think otherwise? It comes with a little. It's like a little measuring that you can actually measure the size. Make sure your flare is the right size. Yeah. so it has a measuring gauge for the flare to make sure it's the right size and you really just hit a button at that point. But again, we know that even when you do, you know it's not just a matter of cutting the copper hitting the button right. We have to make sure you mentioned that We have to deburr. We have to ream over. Reaming is a problem as well. You don't want to ream too little and you don't want to ream too much. So much that it actually thins out that edge and then it tends to crack on the edges. Anybody ever seen that when you flare and it's got little Cracks around the edge? It's pretty simple what our goal is with a flare. Our goal is to have a nice, clean, smooth finish on the flare face, and we want to make sure that we have as much contact area between the flare face and the flare cone or whatever you want to call it the you know between these two the two mating surfaces as possible, so you don't want a flare that's smaller than it needs to be and obviously you don't want a flare that's so big that it's getting into the threads on the flare nut. Other than that, it's not complicated. So I Think a couple of the biggest things that we miss when making flares. One is just looking at the flare. Just look at it. Is it round? Is the surface smooth? If you make a flare and you look at the surface of the flare and it's got like scuffs in it, or you know it's kind of messed up? Well, you know possible. One thing is possible is that the actual cone that you use for your flare could have had some sort of imperfection, some sort of metal shaving on it. whatever, So you want to make sure those are clean and generally oil them or put a little. just a touch of Nylog on them when you're making the flare itself. That's something we often miss is we put Nylog on when we're going to assemble, but in terms of just allowing the flare to be made, it actually makes a much nicer flare and it kind of polishes that surface a little bit. That's another thing for some of you who are really struggling with flares. Some of the best flares in terms of the surface are made with, like the spin tools, the tools that go on the drill. Now it's that's a whole different art form so you know it's something you've got to get comfortable with. But the reason why that is is because it actually burnishes the surface so as it as it spins it actually kind of polishes that metal and makes it really, really nice so long as you do it properly. But again, get done. Look at it. Is it round? Is it going to fit? And what I would generally do is again, you got to put the flare nut on first. But you put the flare nut on and you make your flare and then just hold it up against the cone. That's a step that I would never skip. just hold it up against. See? Does it cover that surface Well, It's not extending beyond the edges of the flare and it's not receding inside and it sits nice and flat up against that. up against that surface, you can look at it. You look at it. There you go. How's that look? If that's good, then that part of it. You're probably pretty good shape, right? That part of it's done properly. There's a yeah, so you're gonna. It's when I say it's not gonna generally be right up against the edge of the flare cone. Yeah. I Think bending the copper before you do it is really important everyone. I did Netflix and sauce I was like kind of bend it, measure it, cut it, and then make my flare. and then it was just like a half. Like a half an inch off. So it kind of like force it on. Yeah. and then it's like ah, I re-cut it, redo it, make sure that bed so there's no pressure. Yeah, yep. and this is true. So that yeah, that's a really good point. So where what direction does the tube want to go? You want the tube to want to go into the flare. If you let go of it, you want it to stay there or to actually have a little Force Pushing towards this is the same thing that drives me crazy with the with electrical connections. where guys, we'll pull wires banjo string tighter, they'll bring them in at a weird angle. and now if you unhook. if you ever, if you ever disconnect an electrical connection and the wire blings out on you, it's a bad sign, right? Because that means it's probably going to bling out at some point. That's a technical word boing out. It's probably going to do that at some point when you don't want it to. So you always want to kind of pre-bend everything so that it kind of wants to stay. You want the tension to be towards the connection versus away from the connection. That's just a that's just a really good workman-like practice that we should all follow. So yeah, to your point. make sure that it's make sure it's kind of pushing in to pre-bend it, make sure it's right there. And then the other thing is. So again we talked about Nylog. Um this is again gets controversial but we know from from practice of having done it a lot. a little bit on the mating surfaces where they connect just a little bit, not enough that it's going to get into the tubing. and then we put a little bit on the threads and even a little bit on the back of the flare because as that nut tightens down. Now this is where people say, well, that throws the torque. Uh, that throws the torque settings all off and it's not the same And we recognize that that is true. So you're not going to get this. So like, if you torque something with Nylog versus something without Nylog, you're going to get it a lot tighter. Meaning you're going to have a lot more turns on it with Nylog than you would without because that, uh, that lubricant reduces the friction. But we also know that using a little bit of oil on threads and on mating surfaces has been a standard for making flares forever. Like I was taught to do that with refrigerant oil from the guy who taught me how to make flares when I started in the trade and so long as you're not really overdoing it, we still get good results out of that. Is there anybody here who would dispute that? Would you dispute that at all? Bert No. Okay, so again, uh, generally that just means that you're gonna if you have a range of torque and you're using Nylog, you want to stay on the low range. So if it says between here and here, just stay on the low range because you are getting it tighter when you have a lubricant in place. Does that make sense? What I'm saying Okay I always have to say that because it just it just comes up all the time with with people who are who are torque purists. and I get it. It's not that what they're saying is incorrect, it's just practice. teaches us. okay. so we get that in place. We have it so that the tension's right. We've already checked the flare and now what I want you to do? Let me finish. now. What I want you to do is place it the flare against the cone, push it against it, and then begin to thread the nut on. What I don't want you to do is pull the the flare into the nut and then just start tightening the nut and so you're kind of like it's kind of a guesswork. does that make sense? So you're pushing them together and then you're threading on the nut. You're not pulling it back and then threading the nut on and just hoping that it's making good contact. I think that's really important I don't know how important it is because I've only ever done it the one way, but it just seems important to me so that's why I'm saying it the next thing and I would say and and to me is the most important thing of all is that once you get done, especially with ductless, you need to pressurize to a high pressure. So there's a challenge that we have with normal unitary equipment. Normal ducted equipment with pressurizing to high pressures. Does anybody know what that is TXV right? You get it to a certain point because we're putting pressure on the liquid line. We put it in the liquid line because we want the nitrogen to flow in the direction that the refrigerant is going to flow so that if anything gets caught, it's going to get caught in the screen or the dryer first, right? We don't want it going the other way. So it hits when you're pressurizing with nitrogen, not with refrigerant nitrogen. Okay, if you're pressurizing the nitrogen, you want to start the liquid line pressurized through. When you do that, eventually, that expansion valve slams down and now you have different pressures on both sides. Now, it isn't as big of a deal as we sometimes make it, especially if you're using good quality digital gauges because all you do is is you pressurize and then you just equalize through your manifold. Like once you're done, you shut off your nitrogen tank and you equalize to your manifold. So now they are exactly the same pressure and any difference at that point would just be a difference between the calibration of your pressure sensors, your transducers on both sides. Does it make sense what I just said there? So what you don't want is to have a differential pressure when you're trying to pressure test something between the high side and the low side because that TXV slammed down. Does anybody know why you don't want to have that? Well, you don't want to have a difference in pressure because as it bleeds through, it's going to look like a leak on one side, right? So because that TXV although it is hard shut off, it's not like perfect. So a lot of times you will get a little bleed. not always. but a lot of times you will get a little bleed. So let's say you pressurize the high side. To you know, 350 PSI and your low side is at 320 PSI And you're watching that high side. That high side is going to start creeping down on you and you're going to think you have a leak. But actually it's just bleed from the high side through the metering device into the low side. That makes sense. There's another reason why we don't want to pressurize way too high when we're doing and again, we're talking about an install pressurization here. We're not talking about putting pressure on the compressor when you are pressurizing a system. By the way, if you are putting pressure on the compressor, the compressor is your weak point. People are like, well, that doesn't make any sense. Your compressor's on the high side, so why would it be the weak point? Actually, it's not. Your compressor shell is on the low side of the system. Refrigerant comes into that compressor and those little terminals, those high voltage terminals through the fusite that's actually like a glass ceramic type material and that's actually the the most sensitive piece in most systems if you over pressurize. So the reason why we can use a lot of pressure is because we're not pressurizing the compressor. We're just pressurizing the lines and the evaporator which are just metal. like. It's not a big deal. Other than that, TXV that TXV is in there and that creates a little bit of a problem in a typical system point. Being on a ductless system, you don't have a TXV You have an electronic expansion valve and does anyone know where it is? It's in the condenser so it's already. It's not on the part that you're pressurizing. So now all the problems are eliminated. All you've got is tubing in a coil. That's it. So tubing in a coil you can pressurize pretty high. Does anybody know what Mitsubishi recommends to pressurize it? To me? Yeah, 600 PSI was the was what they used to say and I haven't looked at an install manual in a while. But really anything 400 to 500 that's that should be our typical because it doesn't matter like it doesn't up to a point. The weak point of course is the weak point Of course is we don't want the pressure to be so high that it can push back through the service valves and actually contaminate the refrigerant. Those service valves have a point at which if we get the pressure too high because again, there's pressure in the condenser and if our nitrogen pressure gets to be too high, it could push back through the valves and get nitrogen into the system. It's not normally going to happen under most circumstances that we're going to provide, but we've got a lot of pressure on that nitrogen tank. If we just opened or full up with a non-regulated regulator that would just allow us to put as much in, we could actually do some damage. So Ductless systems 400 to 500 PSI So long as you know exactly where you set it, it's going to be much more functional and then use bubbles. And when you're using bubbles, you do what Bert said where you don't just put bubbles on and watch for Big Bubbles and wipe it off and move away. You put bubbles on nice and flat and then you let it sit there for five minutes and then you come back and you look at it with a mirror carefully and you see do I have any of that microphone forming anywhere at that point if you don't have microfoam at 400 or 500 PSI We're talking about regular ductless here because there's some people are going to be. like. the spec says, you got to do it overnight, you know it's like, okay, if you're talking about a Vrf system where you've got multiple heads and thousands of feet of pipe. yeah, you need to multiple days of pressure test to make sure that it's not dropping at all. But when we're doing a regular ductless install, ain't nobody gonna wait 24 hours unless it's a multi-head system and a multi-day job. And at that point it would make sense. Get everything under pressure, let it sit overnight, make sure there's not a big temperature change because the temperature change will affect nitrogen pressure. If the temperature goes down, pressure is going to go down. That's why we have that calculator in the HVAC school app that can help you calculate that. but does that make sense What? I'm what I'm saying though. So pressurize whatever you guys have been doing. Sounds like you've been doing 200 250. Just up that a little bit because we have had some leaks and you can do a lot. This is the whole you know the the saying that I said in a class recently like you can wire things wrong so long as you don't leave it that way you can make a bad flare so long as you don't leave it that way. Before you leave, you cut it out and you fix the flare. and you fix the leak. And now you before you. Before you move on basic practices, make sure you cut it square. make sure you debur it. Don't let the Burr fall into the tube. Don't over deburr it. Make sure you're using a proper tool. use a little nylog. make sure you look at it, hold it together, make sure it looks good, push it together, pull the flare over it. use a torque wrench. I Would suggest having some flaring wrenches as well and some regular wrenches so you don't. You're not always using these gigantic crescent wrenches. My grandpa called those shoemakers tools for some reason. It was like an insult of some sort. and I don't know why I mean the shoemakers have bad tools I don't I Don't know. Using crescent wrenches for everything just isn't a great practice. anyway. it's just it's something we all do and but it's It's not the best practice because they don't fit the best and you're not gonna. They're big and sloppy and kind of tough. so especially. like Sam said, make sure before you're going to insulate something and you're going to kind of bury it. Just make sure that we've done all these tests. and at that point, if you're doing that four to five hundred PSI test and you're waiting 30 minutes and you're doing a bubble test and you've done all these practices with flares, you're going to have next to no flare leaks. But if you leave one leak, our 410A is expensive. Customers get cranky. it's a pain in the butt to go back. You're creating a lot of chaos because of the unwillingness to do like One little extra step. So just don't do it. Just make sure that we make sure we get it right and the customer loses faith in the equipment altogether. Customer loses faith in the equipment, customer loses faith in us, and it's just there's no reason for it. Costs a lot of money. costs a lot in terms of customer trust. It's just it. it costs in terms of our relationship with the manufacturers. In some cases too, when customers you know end up putting it back on them. We've always done a really good job with flares. So I'm not like throwing shade here, but there's just been a couple recently and that should it should just be zero. Player leaks should just be zero for us. there's no reason for them to leak. We know how to do it properly. It's not that big of a deal if you. If you're worried about your tool again, there's a lot of focus in the trade about. well, there's a proper tool, degree angle. all that stuff. I mean again, when you put the proper torque on that thing, it's going to form to the flare face. Again, there's gonna be people. Oh my Gosh! I Can't believe you're saying that. It's like, no, it, trust me like we used to use the old Imperial flares. They're like, well. 410A flares are different than 22 flares. We just use the old Imperial flaring kit on 410A flares from the time that ductless came out and we did not have problems with leaks with any consistency. it's all about checking. Just check. Make sure that it looks good and you'll be fine and pressure test and bubble test and don't just bubble and no bubbles wipe off which is another thing. I Mentioned this to the service decks. I Would like to see a start keeping actual flashlights on us again, having a nice smag light or just some something accessible to you rather than a cell phone flashlight. A cell phone flashlight is not a great flashlight and it's kind of clunky. Sometimes it comes in handy for taking pictures of things not and that's fine. and I understand why we do it. but a lot of times I Think we don't use a flashlight because you got to open it, your hands are dirty, you got to scan through. we're grabbing a MAG like we flash with your flashlight and just checking is so much easier. So I would suggest going back to that or something like that. whatever. Whatever you prefer to use I think will make us a little better because I think sometimes we literally don't check because we don't have a mirror and we don't have a flashlight so it's like oh, I can't really see under there but I'm sure it's fine. and oddly enough, if you actually use a torque wrench, it's not because you'll over tighten down with the crescent wrench. Yeah, is a little bit less and you'll be surprised how much less it is. Yeah, a good point, especially on the smaller tubing. On bigger tubing, sometimes you'll be surprised how hard you have to do it, but on the smaller line. Um, you're going to be surprised how little you're supposed to actually torque that over torque it? Yeah, overtorquing is really common on the Quarter every time the player slips out vibration and problems. So over tightening is one of the main reasons it leaks. Yep, and again. then this is where people will say, well, that's Nylog. no if you're using a when, if you're using a torque wrench and we're torquing it to kind of the middle or low end of that spec, we don't have those problems. We have the problems when we don't use it and uh, and we really over tighten it all right. Thanks Y'all Have a great week! 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! Thank you Foreign.

7 thoughts on “Flaring and preventing leaks on ductless systems”
  1. Avataaar/Circle Created with python_avatars Ryan Malin says:

    If the flare connection is going to be inside a wall, I cut out the flare and solder it. This way I know its not gonna leak

  2. Avataaar/Circle Created with python_avatars Tim Kirkpatrick says:

    3/8 or 1/4in torque wrench with flare crows foot. Service area Barrhaven??

  3. Avataaar/Circle Created with python_avatars Sean Stinebuck says:

    AHAHAHAHA!! Definitely done it 3 times in a row before!!

  4. Avataaar/Circle Created with python_avatars Andre Contois says:

    Three times in a row???!! Omfg haha! I don't flare too often but when I do I almost forget the nut most times….

  5. Avataaar/Circle Created with python_avatars Jason Johnson says:

    Just had to do some leak repairs on a Daikin VRF. Had 10 different flares to repair and some leaks on the ref-net wyes. Torqued all flares,24 hour standing pressure test proved i got all the leaks. Vacuum down to 250 microns…only rose to 293 microns….added 52lbs of refrigerant and she's purring like a kitten.

    For those that don't know….on a VRF….you have to put the equipment in recovery/Vacuum mode. It opens all the stop valves, EXV's and allows you access via pressure and Vacuum to the whole system and its piping.

  6. Avataaar/Circle Created with python_avatars dealecrabr says:

    crows foot flair nut kit is the only way to go, all other wrenchs deform the brass nut by making 2 point contact,,,,, crows foot alows for use of the torque wrench which i do after using the regular flair wrench to snug up,, but im old and wore out,,,cant do much anymore

  7. Avataaar/Circle Created with python_avatars π—¦π—˜π—«π—–π—›π—”π—§πŸ²πŸ΅.π—¦π—œπ—§π—˜ says:

    πŸ‘† – FREE VIRT GIRLS CHAT IN YOU CITY πŸ’ŒπŸ’ŒvπŸ‘©

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