In this video and short presentation, we talk about pressure testing large jobs. So when you pressure test a standard residential system, we've talked about that a lot. but what happens when you've got a lot of copper lines and you need to make 100 sure that none of them are leaking in this video We talk a little bit about that. I Also want to add we didn't really talk a lot about the temperature compensation side of things and I always suggest when you pressurize something to log that temperature and then to look at the temperature again when you come back.

and we have a calculator for that in the HVAC school app that'll make that easy for you. But anyway, big thanks to Matthew Taylor for giving this class. I Think you'll get a lot out of it. Foreign.

First thing I Want to talk about is is now that we've done all this brazing right, we got all of our stuff done. What are we going to do next? We're going to pressure test it. We're going to make sure we don't have a leak. All right, These large commercial systems supermarkets.

We got a lot of joints, all right, So there's a definite possibility we've left a leak somewhere. We want to know that. So we're going to do that using our nitrogen that's free, grows on trees, right? All right. So we're going to use the nitrogen to do that.

Uh, in all seriousness, there's a couple reasons why we're going to use nitrogen. Nitrogen: Does it change pressure with temperature? Very much in the in the range we work. Now it does. You know, Technically, but it's pretty minor, right? Uh, it's very inexpensive.

We can pressurize the entire system and check all the little places we can't get to with a leak detector underground overhead inside the Armaflex. All those places. We check all that at one time, right? So so nitrogen is really, really useful for pressure testing. So we're going to talk about how to do that.

One thing Nathan Talked about is being very careful about a pressurized system that has refrigerant and adding nitrogen pressure, right? We're never going to do a pressure test with nitrogen on a system that is connected to a refrigerant system. You know, we're not going to count on a ball valve or a service valve or anything like that to separate those two, but we just can't trust that. Okay, when we're purging and and we're flowing because we're Lottery we're at much lower pressures than we're talking about for a pressure test. So if we're going to pressure test and and there is, you know we're pressure testing some circuits.

For instance, uh, on Iraq we're gonna. We're gonna physically cut those pipes and separate them from their act, right? We're never going to add pressure at this at this level to a live system that has has refrigerant on the other side. So so that's one of the key pieces there. All right.

Uh, so when we're thinking about this using our our brain, right, we could have some very different environments when we're doing. this. One may be a brand new store that there's no, there's no product in, it's not open. Uh, we're building.

It doesn't even have refrigerant charged yet. Well, that's that's an environment where we can leave that pressure on for a very long time and be very sure that we we have no leaks. Right on the service side, we've got a whole nother animal, right? A real common problem. Frozen food doors.

Uh, we got underlying underground pipes. the go out there to those circuits Leak Detectors Kind of going off near the pit. We think maybe one of those six pipes is leaking. Don't know which one, right? This is.

This is a real problem. Okay, we can use nitrogen to pressure test to isolate those pipes, get them off the rack, pump them up, and do a much faster test that will show us which one of those pipes is our problem, right? So so just two different ways to do that. Two completely different applications in in the install world and in the service side and we'll just combine those ideas as as the real world problems come up. So how do we do this? Well, once again, I'm going to go through all the steps, but the idea here is we're going to add a manifold, set some type of gauge that we're going to leave on the system.

All right, we like to use Electronics these days. Uh, they're They're pretty cool In this application. we may want to go old school and use an analog gauge. The reason Because we're going to leave this thing on there at least 24 hours, sometimes a month, right? We don't want to worry about losing our calibration.

We don't want to worry about who's got the right app to read the thing we don't want. You know, we want a nice gauge. We we can probably grease pencil that gauge and come back in a month. And if that thing has moved, we know we got a leak, right? So the other thing about this type of pressure test versus our Electronics our electronics are going to be very, very accurate.

They're going to show us tenths of a PSI. We really don't need to be that extreme with this. If we're within two or three pounds, we don't have a leak. If this thing is is leaking, we're going to lose 100 pounds we're going to.

You know, it's going to be pretty dramatic. So that analog gauge just tends to work a little better in that application. I Want to make a quick distinction though, which is that that's A. There's a big difference between a new store, a lot of pipe you're leaving it on for a long time versus if you're there for a service repair.

uh, and you still need to make sure everything's not leaking. That's where a digital comes in. really handy because now you may only have an hour to do a pressure test and so it's watching for that 10th or two tenths of a PSI drop. and using soap bubbles.

If you're the one who made the, you're the one who made the connection. So this is where application is so so key. Sorry to interrupt and and you just brought up the next piece I was going to talk about. And that's soap bubbles, right? right? So once we get this thing up to pressure, now is a perfect time to use our soap bubbles.

The nitrogen is is actually slightly smaller molecule may leak a little better than our regular refrigerants. It will definitely cause bubbles, right? So this is the time we're going to hit it. Hit all of our joints with our bubbles. Uh, before we start that vacuum process and everything else.

And as he said, if it's a small system particularly, we will see that change in pressure very quickly. Uh, we'll see that fall out on our very large systems. with armaflex and whatnot. we may not be.

It may not be practical right to soap all of our joints, so we will. So the ones we can, the ones we can get to all right then we're We're going to close off the system and we're going to give it its time. Okay, go ahead. so the the time that we do that, we've already kind of touched on.

uh, really, the longer, the better, the most practical uh timeline that we can go, the more obvious our leak is going to be I Mean it's just that simple. So if we're driving it down to an hour, we're going to see a very small change. If we're leaving it for 30 days and we've got a leak, it's going to be very off. So long before 30 days we're gonna.

we're gonna notice that right away. So you know, Just know that once again, being the circumstance is going to determine how long we actually leave this thing sitting for and there's our bubbles right there we go. I'm going to go ahead and pressurize a nitrogen rig and talk about that for a minute. So on my nitrogen rig, you might find it useful once again to use a core tool instead of my manifold set.

It's not as critical this time, but it's a good practice because once again, I've got one sealed valve instead of, you know, a four port manifold. I've got all kinds of gaskets and valves and shut offs and anti-leak fittings and all that stuff that could be a potential problem, right? Well, in the end, what I want to do is leave this system. As we talked about, 30 days is not uncommon, right? two weeks, right? So I don't want to leave my manifold set hanging either I Want to leave a system that is compact uh and and can take care of itself so to speak. That's why I brought that gauge up.

All right. This particular one. There's nothing special about it. In fact, it's a discharge gauge right off a manifold.

I Mean there literally is nothing special about it. It just has a short piece instead of a tube. a hose, right? Uh, you notice it's not sitting at zero? Okay, it's out of calibration, right? So what am I using this right? Because it really doesn't matter. That's the Re.

That's my point. Okay, I'm going to leave this attached to my system I'm gonna pressurize this until it reads something. I don't even care what, right? As long as it's in my range. I'm going to mark that pressure, write it on the pipe, and when I come back 30 days from now, it better be at the same place.

Even if it's out of calibration, it doesn't matter. I just don't want it to move right? Does that make sense Now when we talk about I did mention that temperature does affect pressure for for nitrogen. this is. this could be a whole hour long class.

Not gonna, you know, get get into that. But just know that the that here in Florida Particularly where we don't have these wild temperature swings. you know it's not going to minus 30 and then 70 in the afternoon, right? It's just not doing that. We're going to have maybe 20 30 degree swing.

Uh, two to three. PSI Max is what we're going to actually see in our outside conditions here. It's very minor. When I say it's minor, it's very two three pounds.

That's it, right? If I see a 50 pound drop, a 25 pound drop, that's what a leak is going to look like. Don't attribute that to the temperature aperture because it's 70 degrees and it was 90 when I hooked this thing up. It ain't that okay. One of the routines that we do is 24 hours, right? Or seven days.

Well, we tend to in that 24 hours at the same time of day as we started it right. So if it was 90 degrees at two o'clock in the afternoon, it's probably gonna be pretty close to 90 degrees two o'clock in the afternoon the next day, right? So I'm going to have very little temperature difference. That's another thing to remember. Now, if I'm holding this thing for 30 days, who knows? You know I may turn this thing on the middle of the night and I come you know, day 30.5 right? You know I'm there the next morning Might be different, but most of the time for the service work we're doing, it's going to be a very similar time of day.

Uh, that we're going to be checking that and there's going to be negligible effect. Okay So we talked about they're setting up, purging and all that over there. I've got that. those markings on my regulator.

I'm not going to pay any attention to that today because we're just pressurizing, right? So I'm going to turn on my pressure and I'm going to set my regulator to about the pressure that I want. Now, what pressure do I want depends on what I'm pressurizing and what it's rated to. Okay, Condensers typically good to 450 500 pounds, right? but my evaporators not so much. Uh, maybe 150.

We got to be careful on the evaporators. Austin 250 is a standard. Okay, so I'm going to set my gauge to that pressure. Whatever that maximum is that that can be allowed.

Okay, now once my gauge is is dialed in, I'm going to flow that into my pipe system and I'm going to see this gauge rise. now. What I was talking about earlier I don't know that I can trust that gauge, right? I mean that one's a little bit out of calibration I Don't really care. As long as my gauge is pretty close over here, it doesn't have to be 450.

it could be 437. that's okay, right? What I'm looking for is a reference I want to see it I don't want to see a change, right? Whatever. that gauge is showing me when I do that. Okay, all right, so we're going to go ahead and open that up.

Okay, and I've got, uh, my pressures coming up. I Set my gauge over here at about four and a quarter and it looks like it's coming up to around 450, so they don't really agree. Okay, is that okay? Yeah, that's fine. That's going to give me my pressure test.

now. if I've got a a specific Target that I have to hit for a customer, they want to see 250 right then I'm probably going to use an electronic gauge also on another service port and dial that in precisely right. But if I'm just doing my own pressure test and I want to run this somewhere around 450, I'm now 445. all right, I'm going to call that pretty good.

I'm going to isolate this guy after I do my fleet check right? So while I've got it pressurized before before, I isolate I may have a leak, right? This is my first pressure test after I've done all of my soldering. So if I've got a leak now is when I'm gonna find it right now. so every fitting that is accessible I'm going to go ahead and soap bubble up all right. And I'm going to include my fittings because I could have a leak there right now.

These as I was describing earlier will absolutely bubble up at least as well as your refrigerant. Probably even better, you're gonna get bubbles if you've got to leave, All right. So so I passed my my leak check now I'm going to isolate all right now that I've isolated I'm going to begin that check Okay, so when I do that we talked about I'm going to mark this somehow. We can record this any way you want.

But the way that I recommend is that you record it on the pipe near the gauge. Okay, why? Because that's where whoever's going to check is going to check may not be. You may be you. you may not remember, but you're gonna see the gauge and you're going to see that pressure.

Put your tape very close to the game so that the standing there you can see what's going on. All right. This guy is sitting here at 440. PSI you're gonna put the date and the time and I'm probably going to put my initials on there and the temperature 84.

I'm going to isolate my nitrogen and I'm gonna I'm gonna take it off. Okay, because I don't need it I can move this whole system now to something else, right? My nitrogen is free, the system's under pressure, and it's going to see in a month, right? Let's be realistic. I'm coming back tomorrow. If I've got a leak, I'm going to see that very dramatically.

Uh, very quickly. Okay, uh. that's when I'm going to stop. Go find my leak, repair it, start it again.