So to start out with we're going to have our hook and we're going to hook this on the unit. A lot of people just throw the hook in but the problem is the back side of this hook damages those fins. So you want to make sure that your hook goes in around and then back out. That way it doesn't cause any damage to the fins.
Some people also prefer to put the hook around the very top side. However it is we want to make sure you don't damage the paint or damage the aluminum fins. Now there's other types of hooks. We have this wider hook here we can put this in swivel it and bring it around as well. Now we're hooked on the unit we're not going to worry about our gauges falling we can see it and we're not damaging the fence so we're going to hook up our gauges on the suction side first notice the unit's not running it really doesn't matter if the unit's running or not if the unit's running i like to keep it running if it's off i want to put my gauges on before i start it i want to make sure that there is some refrigerant before i start the system up we're going to start by taking off this valve cap make sure there's a rubber o-ring in there i want to take my hose off the manifold gauge set this is very important i'm going to put this cap Right here, so it doesn't get lost.
I see a lot of texts It'll take and put them on the ground They'll vibrate over or get dirt stuck in there and then when you put it back on you get dirt into the valve core and it Causes problems or for the next guy gauges also I've seen people where they put it on top of the unit the problem is that they'll vibrate over into the fan and the Family that shoot it out damage the fan blade lose the cap or in the worst case scenario actually bust out a customer's kitchen window And yes that happened with the helper of mine, so we're gonna put it right here where it's protected. It's clean It's out of the way Now we're going to take our low loss fitting and we're going to put it on this port. And I'm going to touch it with only two fingers, front and back, side to side, either way with two fingers because if refrigerant shoots out it's going to come out the front or the very back.
This way I'm protected. Now while we're doing this some people prefer to use gloves. If you use gloves you have to use refrigerant rated butylene lined gloves. You can't just simply use gloves like this because they're made of a cloth type material. The problem with this is liquid refrigerant soaks into this material as it boils from a liquid vapor it literally freezes your hand to the glove and it causes more damage so i prefer not to use gloves at all but i am not an osha instructor two fingers critical we put it on with the two finger method Now this is low pressure vapor, so it's going to be the easy one to put on.
If you notice there, hardly any sound at all. Now I want to tighten this up. A lot of people stop prematurely when they're working, when they're new to the field.
So what we're going to do is make sure that we tighten it. And I'll actually move the hose this way, tighten it some more, move the hose this way, tighten it some more, until I get it on there nice and tight. I want to make sure it's actually showing pressure.
I've had a lot of students before, they get in the class, they just put it on to where it just starts to get snug, and then they stop, and they wonder why there's no pressure showing. So this way we're now firmly on the connection. We didn't lose any refrigerant whatsoever.
Now we're going to do the same thing on the high side. Now here's a trick. On this high side gauge, this is the one that's more likely to cause an issue.
This is going to be high pressure liquid refrigerant. It's going to be changing state from a liquid to vapor. This is the one we have to be careful about. I'm going to do this the same way, but you're going to see the refrigerant shoot out because this fitting needs to be rebuilt. I'm still going to use the two finger method front and back and we're going to start tightening this up.
Now you can see that liquid refrigerant shot out both ends. It shot out this way and that way. But because my fingers are right here in the center it wasn't an issue.
So you can see the liquid refrigerant actually boiling off and there's actually oil in there as well and that refrigerant is boiling out of the oil. We want to make sure we clean this up before we leave the job site. So now we have pressure in this gauge. Also important to note, when it started spraying, I didn't stop.
When it starts spraying, you either go all the way on or all the way off. You can't just let it sit there and spray. Now, if it's getting liquid refrigerant on your hands, your safety is more important than the unit. But you think if you put it all the way on, you have your two fingers in the middle. It's usually not an issue.
I've never had a problem with it. However, I have seen people before. that are new to the trade and it starts leaking and they try to stop it with their hands never stop liquid refrigerant from shooting out with your hands it will cause horrible horrible disgusting frostbite but don't be afraid of it starts hissing put it all the way on take it all the way off just like this one now this one needs to be rebuilt if it was rebuilt it would not be doing that We have our system off and our pressures are fairly equal.
Our suction pressure and our head pressure are the same. Remember head pressure is the high pressure side, red. That's the liquid line. And then the suction pressure, the vapor pressure, low side, it's the insulated line, the suction line.
They are pretty well equal because it's equal as the compressor is not running. Now we're going to turn the system on. Now we hear the compressor turn on and we see the pressure in the high side start to go up and the pressure in the low side starts to come down.
The compressor is sucking in low pressure vapor pumping out high pressure vapor. On this side it's the liquid only because it's after the condensing coil. So you see we have the high side and the low side. What's more important about the pressure is the saturated temperature. So the saturated temperature in my high side right now is 80 and climbing.
the saturated temperature inside at the evaporator coil is 44 and dropping. Ideally, you let the system run for about 15 minutes before you get a real solid baseline that has time for the refrigerant to equalize with the system, to balance out before you get an accurate reading. But in this case, that's not our purpose. We want to take the gauges on and off.
Now when the system is running, that's when I want to take the gauges off. I don't want to take it off with it sitting off. So let's start our process of taking the gauges off. I'm going to start with the suction side.
It's the least one we have to worry about. It's just vapor. It's not going to hurt me. Still, I'm going to use a two-finger method.
Two fingers, unscrew this. Now, the refrigerant is held inside of this line. If we look at our manifold gauge set we can see that it's holding the suction pressure in there now what I'm going to do is loosen this it's only vapor low pressure vapor it's called the minimus so we're just going to bleed that little bit of vapor out the minimus charge right only vapor no big deal now I'm going to take my valve cap off I'm going to hang on to it and I'm going to put the hose, I'm going to put the hose end back on this. I never want to let this hit the ground.
There's a little bit of oil in here. When that hits the ground, the oil sticks in there, causes these things to go bad. So I'm going to put it on the manifold set to where it's hold it, it's clean, everything's ready to go.
So we have zero psi, we're pretty close on our suction side. We're going to screw that back in. Now we're going to do the high side. So I do the high side. It's going to be those same steps, except this has a bad high side fitting.
So when I take this fitting loose, it's going to spray some out, but it's going to be okay because I'm only using two fingers. So let's go. And we're going to do it quickly.
The faster we do it, the better it's going to be. So I take the pressure out of the high side. We lost a little bit of gas.
We still have liquid inside of this hose. Now I cannot bleed it out of this hose because that's going to be liquid refrigerant. That's going to be an EPA violation.
So we're going to put the refrigerant back in. We're going to have to put it in through the suction side while the system is running. So the valve cap on the suction side that I was holding, I'm going to go ahead and put it on the high side.
But I'm going to make sure that we have that rubber O-ring in there. As you can see, we do have a little rubber o-ring. So that's what we want to make sure.
We never want to put it on without the rubber. So we're going to thread that on. Now we have the refrigerant that's in the high side. We're going to put this refrigerant back into the system. We cannot vent the refrigerant.
It would be a waste of refrigerant we took from the customer's unit. And also it would be an EPA violation. So we've got to put the refrigerant somewhere. And we're going to put the refrigerant back into the system.
Da-da-da-da-da. System ever down? No? Okay, moving on. So I'm going to hold this where you can see the pressure gauge.
And you can see what happens when I put the hose onto the suction side. So here we go, we're going to try this together. So I'm still going to use two fingers.
We have the pressure in here, we'll turn the light on. Now you can see the pressure start to drop because the high side of the refrigerant from the high side hose is now being opened into the low side. I'm also going to raise this up so that if there's any liquid refrigerant in this hose, it'll all drain back into the system. That's all it takes. Now, a key point is this will not zero out.
It's only going to go down to whatever the suction pressure was. It's not going to go down to zero. It's going to equalize what it was.
The key is all of my liquid refrigerant is back into the system. So we're going to unscrew this now. A little bit of vapor came out, no big deal. Now I have this vapor in here.
I don't want to leave this vapor in the hose. If I put this vapor in the hose, I put this in the truck, the temperature of the truck gets high, sun shines on it, the pressure is going to go up, it's going to push on my sensors, it can bust my gauge. So I'm going to use a de minimis release.
Saw a little bit of oil come out, but it's just vapor. Now we're at zero psi gauge. I'm going to take my other valve cap. I'm going to look to make sure there's an o-ring in there and there is a rubber o-ring in there and we're going to put this back on.
In the next video we're going to talk about these valve caps. There's a lot we need to know about these valve caps and I do not like these plastic caps.