So earlier we learned about superheat and subcooling using our gauge set. This is our manual regular gauge set. I grew up learning and working with this manual gauge set. It's made me a lot of money over the years. You have a lot of people that love these and a lot of people that love digital.
This would be a great set to start out with. Pretty much any brand of digital gauges you go with, or gauges that you go with, you have to take care of them. You have to make sure that when you hang this in the truck it's not bouncing around. that it's not throwing tools on it, that you be sure and take the pressure out of it, you don't get dirt in your hoses, all of those same things retrue. And I've had many brands of gauges over the years, they've all treated me very well.
You don't wanna get the cheapest manifold gauge set because they do have have one particular store around that sells them that are very inaccurate but as far as everything we do in HVAC all the brands and supply houses you got a ton of different names they'll really treat you well if you take care of them the problem with the analog gauge set like this is is seeing the numbers as we deal with higher pressure refrigerants these numbers get more and more difficult to see the thickness of that needle and where it's pointing to we have a hard time seeing exactly what number it's pointing at So we end up just rounding it off. And then we convert that to a saturated temperature with our app, and it's usually between a number, so we end up rounding it off again. As we round those numbers off, we really don't know exactly how accurate we are anymore.
And then also, depending on the calibration of your digital thermometer, that number could be off even more. So one of the solutions for that is the digital gauge set. Now, a lot of the older people in HVAC that you're going to be working with are completely... anti-digital and I was too when I first got in it and first started working with these. I could do superheat and sub cooling.
It's simply the actual suction line temperature minus the suction saturated superheat and it's a liquid saturated minus the actual liquid line equals sub cooling. I didn't need a digital gauge set for that. However, I went to it because of the accuracy.
So the accuracy is why I went to digital gauge sets and while I went to them for the accuracy, I fell in love with them because of the speed. So I'm going to show you a little bit about a couple of different gauge sets. There's a ton of different. digital gauges out there and digital equipment out there and really it comes down to just personal preference it's kind of like ford chevy dodge toyota etc you're going to meet people that this one's the greatest there was and the other one's not there's not a one set that's perfect there's the one set that's perfect for you and so that's what you need to remember and no matter what you tool you buy there's going to be somebody out there that says one's better than the other and there's going to be that argument so this is one of my two gauge sets i have uh i have several i've had several over the time other these are my two favorites.
So I'll start with this one first. On this one I have set up with ball valves. So over here we have the low loss fittings. Now I can get regular low loss fittings for this gauge set. I just prefer these ball valves because they don't restrict the flow.
So whereas this valve, as soon as I take this off, it closes it off. This one, I have to manually close this valve off. I have to remember to, when I want refrigerant to flow through here, open it. When I don't want it to flow, I turn it to the side so it stops. And also with this, I like to have shorter hoses.
The shorter hoses means there's the least amount of loss. So I'm gonna go ahead and turn this gauge set on, power it up, and just so it'll zero out. And what I'm gonna do is, just like I did before, I'm going to leave this off though, and I'm gonna thread this on to the high side.
I take my ports, my extra valve cap, I'm gonna put it on where this hose went. Now this one, the extra hose mounts in the front, but like we discussed earlier, the one coming straight down, that's the one that always stays on the manifold set. So I'm going to use two fingers. I'm going to thread this on, and I got to do this as quickly as possible. If you saw, my set's a little bit older, and you saw that little spray coming out, it's okay because I only had two fingers going.
I'm going to open this valve. We'll see that it's showing pressure, and I can actually turn the little light on here. Oh, sorry. Turned it off.
Turned it off. We'll press the button and it turns a little backlight on. I'm going to do the same thing for the suction side.
Take this valve port off. This cover, I'm going to put it on the front so I don't lose it. Make sure all these are closed, I don't need anything open.
Thread this on, two fingers. Open my valve. And it wasn't tight.
Open my valve and now I'm reading my suction pressure. And my head pressure. My suction pressure right now I'm reading 177.5 psi gauge.
My head pressure is reading 340.6 psi gauge. So I immediately have my pressures and look how accurate that is. 340.2, 340.3, it's extremely accurate. Let's go a little step further.
I also have it to where I hooked it up on my liquid side. I have a temperature probe I can put on my liquid line and on my suction side. I have a temperature probe I can put on my actual suction line. So what's great about this, it will also, on the same screen, it will tell me my suction line temperature.
So my suction line temperature here is 85, and my liquid line temperature is 101.2. Pretty accurate. But one of the things I really love is the speed. Remember before how I got my pressures and converted it to a saturated temperature? It gives me my vapor saturated, my suction vapor.
saturated which is 62.4 that's what I really need with those two numbers we can put that in our app or into our formula so here I have my actual suction line temperature which was 84.6 and our liquid saturated temperature which is 62.4 and that gives me a superheat of 22.3 and actually just to let you know I didn't do that math my gauge manifold did that math it tells me what my superheat is and it tells me as it goes now it's down to 22.1 22.2 it's extremely accurate so i don't even need this formula anymore i don't need my conversion app anymore because my gauge set does it already i have to set it for what refrigerant it is and it automatically tells me my saturated temperature my line temperature my pressure and most importantly it's giving me my super heat right there instantly same thing for sub cooling it's got my pressure I have my liquid saturated temperature, my actual liquid line temperature. So if I wanted to do the math I could. My liquid line temperature is 102.3. My liquid saturated temperature is 104.6.
And it tells me my sub cooling is 2.1. So it does that math on here automatically. So I went to it initially because of the accuracy of it. I fell in love with it because the speed.
And when I'm on a job site, I can get those numbers very quickly, move on to the next job. It's extremely important. Superheat switch.
22.1, sub cooling is 2.2. Now, we still need more information to know if that number's good or bad, but look how fast that was. I can just simply look at it, let's see what happens.
See if it changed. 22.1 superheat, 2.1 sub cooling, boom, done. done.
That's why another reason why I really love these digital gauges. And I've heard a lot of people say they've got their gauge set and they, these, they don't like them because they break. I've seen a video where they throw these off a roof. I've had these, I've never thrown them off a roof, nor would I want to. But what I do is I keep this in its protective case.
So, and I also keep it very well protected. I keep it good. I've had this set for several years now. I don't use it just on any units. I use it in all the units I want them to run good and be accurate.
If I get an old, dirty. system's been pieced together. I'm just going to use my old gauge set. It's not going to matter. But when I'm doing digital stuff, new stuff, where accuracy is important, I love this and I love the speed behind it.
I can do a lot more service calls with this, especially preventative maintenance. I got a roof of rooftop units. I get my numbers very quickly and also accurately.
I really, really like that. This is just one of the brands that I like. I have another one.
These are my two favorites, personal favorites. Like I say, it's all about what works best for you. And it really is the same thing. This one's a little bit smaller. I have to change it to hit the buttons.
I get all the same information, but I can change screens. Has all the same ports. It's got temperature clamps. Some people like these better because they're a thermistor type temperature sensor to whereas this one is a type key thermocouple. Some people like this one better because you can see all your information on one screen without changing screens.
There's advantages and disadvantages to both. I personally don't like how these are on the side. because they're getting loose over time. But then again, I haven't had any problems with it. I don't like how this one's on the front, but I haven't had any problems with that one either.
They're both really great manifold gauge sets. If you take care of them and treat them well, it's gonna work well. I have friends with multiple other ones.
And both of these are also Bluetooth. I can send all this information to my phone as well as do a lot more with it. The other great thing about sending that to your phone is you can log this information and you can't cheat the numbers. that way.
They're set that way. But that's superheat and sub cooling with the digital manifold gauge set. I do really do like them.
It's not going to eliminate that set, but I still want to have both of them. for the accuracy. Plugs fall out. But that's just some of my preferences.
And when you're taking the gauges off, same way. I just want to shut this valve off first. I can bleed this de minimis low pressure vapor out.
I put this back on the front. My liquid side is what I want to be careful with. I'm going to put these clamps out of the way.
This one's what I want to be careful with. I want to take this valve, I want to close it off. Two fingers, I want to do this as quickly as possible. I don't want to just wait around and let refrigerant spread. I want to do it fast.
Two fingers fast. We saw that my hose was a little bit older. I probably need to put new O-rings in there.
Leaked a little bit out, but it's okay because I did two fingers. It shot out the back and the front. Not a problem.
Now I'm going to put this liquid refrigerant back into the system. So what we're going to do is put two fingers here, thread it onto the suction side. I'm going to open this valve.
That high pressure liquid refrigerant bleeds back into the system. I just kind of raise my hose up to make sure all that liquid goes in. Liquid refrigerant's in the system.
I shut this valve off. De minimis. And then I take my caps.
I check for the rubber o-ring. I put it on. Don't put your caps on without that rubber o-ring.
Same thing here, rubber o-ring, we're good. And I thread this on. Put my manifold gauge set back like so.
Done.