Don't Trust AI On HVAC Startups!

This video is brought to you in part by True Tech Tools. Quality Tools essential support. All right, guys. So, we're doing a startup today and we have seven units to do. Building's not done and the duck work's not completely tied in yet. We've got runs that are not completely filled in. We've got zoning on some of it. We've got an exhaust system start up. Got, like I said, seven split systems. And they're wanting this done so that they can get the ceiling tiles in. They're worried that they'll have condensation and stuff. We are at 63°. We've got lines ran all over. Now, one nice thing is the installer is on top of his game. He completely measured the line sets and he does a really nice job labeling things, which is awesome and greatly appreciated. This building's pretty good size. All the lines come down through here. Most of it's all hard piped and clamped. And then the mini splits. There's two mini splits that we got to do. Most everything in here is 410A. Only one of them's a 454. Uh they started this project over a year and something ago and so the equipment was available. Uh so we went with Fortna. So this area out here is going to be done within floor radiant heat which we got radiant heat coming down through there. And up here is our room for our mechanical. We have a welding department. They welded in this header here for the boilers. So they did a loop, primary loop right there with that. And these guys actually weld this stuff up at our shop. I didn't bring it in. I don't know how they do it. If I had to do this, I'd probably get my measurements all screwed up, but as you can see, it all goes across to there. Then we got some makeup air units. We've got three splits here. Then we've got four of them here. So, the unit I'm starting up is right here. Because the line set, like this one here, is at 90 ft. We have solenoids in there. So, I've got a magnet on it for right now. And I've got my supply and return. I've already went through double checked my static pressure, which is pretty low. It's only 38 right now. Uh filter's not in there. So, at least I know my basics are handled. I got my other probe up here at the top. I've got fresh intake here, which goes to a CO sensor or CO2 probably. And that will open up whenever the CO2 gets too high. That's what I'm working with today. These startups that I'm doing are eating into my repairs. It's going to make it very difficult to make videos if I ain't got repairs. Um, I can show the right way to start stuff, but let's go downstairs. That's RBI. Never worked on one before. Have to figure that out. Uh, a lot of times architect specs everything, including the design, and then you just do it the way they want. You got to do it the way they want it or you don't get paid. So, let's go downstairs. As you can see, a lot of the stuff is not quite ready yet, but here's my spot I'm at. So, I calculated it up. He said we had a total of 90 foot, which we've got that written in there. This is a Infinity system that we're using as a two-stage unit. And so we're not going to be doing that much more than that. What I ended up doing was calculating since the liquid line is uh 3/8 38 liquid and they didn't require it to be upsided upsized, but the suction line was uh it's inch and eighth, which is big. and they wanted some monstrous 1- in insulation on there. So, what I ended up doing, I figured it was 10T, end up double checking online, it's actually 15T. So, theoretically, I took my ounces, which is 6 oz for each additional foot, and took that time the feet of the line set, which I came in at 3 lb originally. So now the vapor density depending on what it is according to AI cuz sometimes you've got the sheets sometimes you don't set it to need an extra pound. Well right now we are right at 19.5 subcooling took a little while. Super heat's right at 10. If we look at our chart right here we've got 16 anywhere from about 16 maybe 15 at 65°. And like I said, we're right in that area. So, I might have went one degree or one degree or so over, which I'm going to watch it for a bit. I may have to take that extra pound back out that the suction uh I added for the suction, which was something that AI did, which is another reason why you can't trust AI. It makes mistakes so much. It's It's just ridiculous how many mistakes it makes. Now, this unit here, we are going to only run it in two- stage. Uh, as far as traps and stuff like that, 20 foot is what they wanted. Didn't say much more after that. Um, our temperature drop right now going with the factory speeds is right at 13, but the problem is that's going to change when we get the ducks on there. And then some of the stuff zoned. Right now, all the zones are open. By default, they're honey wells. And like I said, indoor return 67°. We're just barely, you know, in the range where we need to be at. Unfortunately, sometimes the weather doesn't always cooperate. Last week it was hot. This week it's not. So, let's just say 16. So, 17, 18, 19. Yeah, we may have to yank that pound back out. Now, look at that. You think I was going to actually use my recovery bucket? Of course not. I'm all about protecting the environment and people's pockets. We required somewhere right in there between 15.8. We're right at 15.5. I only took out about 9 ounces. I didn't go the full pound, but you know, according to this, and it's measuring temperature right here, we're 68 degrees out here. We're probably pretty good right now. So, what I'm going to do, I'm going mark that inside there that I added 3 12 lbs to this to the factory charge. And so if anybody comes back and say a line's busted or whatever and they need to make a repair, they look at the outside of the unit and it says, "Okay, we need a total of 8.3 lb." But you're like, "Oh my gosh, what do I need here?" They don't have to think. They just know 8.3 + 3.5. Boom. I have what I need. I can make my repair and I can go home. Also, the guy even labeled everything. He put it on the door, which I mentioned sometimes these doors can get mixed up. So, they are marked inside of the box, the electrical box, and I went ahead and marked it here. That way, if the cover does get messed up, those are some things that you may want to look out for. Of course, one of the things I'm doing is I'm, like I mentioned before, I'm going through and I'm double checking the tightness of all of my conductors. Uh, whether it be low voltage, high voltage, whatever. I did that with power off. Same thing over there on the disconnects. And then I'll do the same thing up there at the furnace and stuff. So, those are some of the things that I do on the startup. Startups can be pretty easy, but they're really important. If you don't do it right, you could cost a lot of money later for callbacks. I like doing things right. So, I don't get in a humongo hurry. It's one of them things where it's kind of important to me to make sure you document everything, double check everything, and that way there's no real excuses of why you didn't do it right. There's really never a good excuse unless, you know, it's lightning out and the boat was sinking and you only had 15 minutes to do it. So, I suppose if you're not on a sinking boat and you only have 15 minutes to do it, then you should probably just do it right. So, I've got my factory charge mount there cuz sometimes those stickers get damaged. I've got my outdoor temperatures, my date, the unit number, the date it was started, subcooling superheat numbers along with my low and high side pressure. All those things combined can help you out massively later if you're doing a repair. So, those are some of the things that I'm doing. Now I want to check my temperature drop. I went with the default settings. Told it was five tons. So according to this, we're in the green. The supply dry bulbs 53. Ideal range 48 to 54. Target 51. So if I wanted 51, I'd do what? Slow it down. As you can see there, we're just jumping it out for right now because the stats ain't mounted yet. Still under construction. And like I said, they got pushed pushed pushed to get this done quicker. Yeah. So, we got 15 degree split. I mean, we could drop it one speed, but that could change with the duck work. So, I'm going to double check with the person, the project manager, see if he wants me to mess with that right now. Otherwise, we're in range. It just ain't perfect. I like to be in the middle. You can see what we got there. And that is with me going off of the trunk line there. You can see it's off the radiant side there. So, when I do the furnace startup, which I can't do yet because they don't have gas to the building. They just got permanent power just uh within the week. So, there is no gas just yet. Yeah. Here's one of those honey wells. I've done these. They're pretty common, basic. Nothing super fancy. I mean, it's pretty simplistic. Nothing like an Infinity or something like that. Also, the solenoid here is not for pump down. It's just to stop the flow so you don't migrate the refrigerant back to the compressor on shutdown. So like I said, I don't know if I mentioned it earlier, they are going to have that wired on with and they already do with uh wide in common. Boom, boom, boom, and boom. And we'll stop the flow like that. And the fan is I lowered it down to 30 seconds of continuous run after the fact. Um that uh transformer there is for the uh zones. So that's what that's separate for. Anyhow, that's the first one down. We're doing the next one here. Checking static pressure and not a whole lot of anything to brag about because we have no back pressure from the supply side. So let's go ahead and already programmed it and so on and so on. Same thing again. 90 ft subtract 15 75 75.6 six divide it by uh that comes up to 45 oz got 2.8 lb. When you divide the 45 oz, which is how many feet we got, 2.8 and8 * 16 gives you 12 oz. So 2 lb 12 oz. We're going to go exactly like they said originally with just the liquid line only and let it stabilize and see where we're at. Temperature probes right here. Making it really easy. See our temperature drop. Taking a quick brief look here. We're at 6 of cooling. Not very exciting. We'll give her a minute like I said and we'll see how she does. Okay, this one here is at 115 ft. And so supposedly Carrier said they only needed the solenoids on the 5-tonon units. I don't know. Migration's migration. But for whatever reason, whatever, whatever. Just kind of like writing that on the inside so we can find it for later. Outdoor temperature 65. It's really cool. We're in September. Today's September, Monday, September the 21st. So we want to take 15 minus the 100 or let's just go 100 foot. the 100 *6 going to be about 60 oz. So*6 60 oz divide that by 16 that's 3.75 lbs. We got almost as much refrigerant in this unit as we do uh in the line set as we do in the other half. Another 10° sub cooling. Again, this kind of makes it braid and dead. I mean, we're basically just going to add, like I said, 3 lb 12 oz to it. Just do it over and over. So, if this in the middle of the winter, this is the way that they recommend doing it. Uh makes it really simple. um get you dog on close and theoretically it should be dead on but that's assuming that they've charged it exactly properly like they're supposed to do. We're just slowly adding I mean we ain't going 100 mph but you know we're not flooding our compressor. Subco is going to fluctuate. We just kicked it on. We'll slowly get it in there. As long as I don't hear the compressor chugging away we're kind of like you know slowly giving it to it. For those out there that don't really understand sub superheating and sub cooling very well or the way the the chart works. Look where our liquid line temperature is right now. We're at 73.9. We're undercharged. We have no sub cooling. That liquid line temperature will start to drop when it's on the right side of the curve. So, as you're adding, that temperature is going to start going up and eventually it's going to come down. When you're subtracting your liquid line temperature minus your saturated temperature on your liquid gauge, that's when you go to the number that they're giving you. That was something I didn't catch right away. We'll just keep an eyeball on that. 75.5 70. So, look, see the temperature's going up. If you add some refrigerant to it and temperature continues to go up, you're on the wrong side of it. Convenience of the wireless scale showing right up here. We've got the convenience of the probes. I've been really happy with the way these have been. I mean, I think these are day and night difference compared to what they used to be. Since we just added that refrigerant, we'll go ahead and start the stopwatch. Kind of give it some time to to run for a bit. Like we're at 78, so that temperature has gone up. Subcooling's jack. This sucker will eventually change. Just the thing I've always hated about 410A took forever. I haven't noticed if 454 is quite the same or not. Like I said, eventually this sucker is going to start to drop. That's going to start going up and we'll have the 10° subcooling that we need. It's all right. So, we're at 13 minutes. Hasn't changed a lot. Still only at8 for the sub cooling. Temperature hasn't dropped much. This is about where I ended up adding some, which I'm about ready to add some anyway. Then we went a little bit over. still holding in there just to wait for the whole 15 minutes just to kind of see see if it changes cuz they kind of did it at the very last minute. Okay, we're at 17 minutes. This ain't getting it. Obviously, it wasn't most the most accurate thing is like not uncommon. We're dog on close. We got 16° superheat. Obviously, we got work getting done our temperature here. We're just neck and neck here. So, let's go ahead and add maybe 4 ounces. See what we get. Okay. See what happens at temperature 79.1. Eventually, it'll start to go up and it'll start to drop. You can keep track of as I'm adding here. I'm stopping and starting the camera. There's that temperature coming down like I said it would. As that's coming down, your pressure will tend to build, which means that temperature is going up, which they're getting a separation away from each other. And that's your sub cooling. It's hehauling around because the super heats being screwed with with the TXV inside. If you look up here, you can see we've added some refrigerant right at 11. It's rated for 10, one degree, one and a half degrees, even two. Not horribly worried about it. Look at that temperature there. 72.3. Remember we was at 80 and then 79 and then 78. That came down. This temperature went up. There you go. The difference between this temperature and that temperature. This is the actual temperature of the liquid line. This is the saturated temperature of the liquid line. That's the conversion temperature. Subtract it from it. Boom. 10. That's your subcooling you need right there. 10. Now, what bothers me? 4 lb factory charge and I had to add 5 lb 7 ounces to it. That kind of worries me. I think if there's any of them that needs a a selenoid would be this one. I could see us having problems. I'm going to say something to the estimator. They should probably consider putting one on it. There's no way I can pump it down. I tell you that. No way that's going to hold it. Not at all. Like I said, the line set should have been right at that, but I screwed up. So, anyhow, 4 lb factory, 5 lb, 7 oz, total, 9 lb, 7 oz. It's written in there, double scratched. That way, they know what we're doing. Kind of looks a little crappy, but you know what? Nobody's going to look inside the cover. Uh, like I said, we marked this number five, and uh, this one started today. So, that one's going to be finished, and we're good to go on this one. So, here's the one we're working on. And we have a 19.5° split at the factory recommended speed. Our uh supply dry bulb is 48 and our return is 68. So we're in the colder side. But uh when you look at our design drop boom calculate 17, we got 19. So that's it for that. I don't think the the job link does that. Yeah. So you just don't have nothing. So anyhow, all right guys, that wraps it up. Till next time, we'll catch you on the next one. Thanks for watching. Later.