This video is brought to you by sportlin quality, integrity and tradition. We've got a kitchen ac, that's not working properly today, so we're gon na dive into this guy and see what's going on um. While we were doing a preventative maintenance service, tech said that the unit wasn't coming on, they actually have a lot of units down this unit. Right here is actually iced up.

It's a split system for their kitchen, so i just disconnected the condensing unit. So that way, the air handler can continue to run we'll dive into that in a little while, but we're gon na jump on this guy, so we're gon na start by just doing the most common things belts filters check those and we'll open up the electrical section And troubleshoot further there, like i said i had a service tech, doing a maintenance, so the filters are brand new. They look great now this particular building has a energy management system or a building automation system and some of the uh thermostats or whatever you want to call them for the automation system, don't work. So i have several units that i've quoted many times, but we had to add a thermostat to get them by and then the customer just hasn't upgraded the ems system or had it repaired or anything.

So we have to verify what's actually controlling the unit. So in this case, this one has a thermostat, that's just temporarily again. This was like two years ago, dropped down into the duct, and the customer just hasn't done anything to fix it. Since uh belt looks fine like it should everything looks cool.

The blower assembly is a little bit dirty to clarify, though the customers on these things, when they have us do a preventative maintenance. All that they want us to do is change belts, change filters, rinse off the condenser cleaning. Evaporators isn't part of it. Splitting condensers isn't part of it.

Pulling blower assemblies like all we do is make recommendations to the customer, and then they approve repairs, but so the pm service - you know every pm might be different depending on the customer's wants and needs. You know most of the time dealing with restaurants. They just want you to come in clean and then let them know if there's a problem or if it needs extensive cleaning, then you know you, you have them, create a service ticket and you do it from there. The unit is powered on we're gon na check to make sure we have three-phase power coming to this unit.

Yes and then yes and then yes, so we have proper, three-phase power coming to it. Now, let's go over to the thermostat control voltage: okay, rnc 24. Volts. Now c and y1, nothing and then c and g and the indoor fan is running so we're good on that um.

We need to go over to that thermostat. On the other side. Like i said this, one has that thermostat we need to see if we have a call for cooling from the thermostat, so i had some incorrect information. It actually wasn't this unit.

That was problematic. It's the other kitchen unit on the other side over there right there. So um this guy's running it's working like it should be we're going to put this one back together and jump over to the other unit. All right, we've got a kitchen ac that is not working, uh, obviously, and uh.

We got ta figure out. What's going on so we're gon na open this guy up start with the basics, electrical section filters belts and then see what we can get into here, all right, just doing a visual indoor blowers. Okay, it's got grease in it, obviously, which happens in these kitchens. Um belt's tight, it's a little dirty in here, but i don't see anything jumping out at me.

We're just doing a visual okay. So we need to test to see if we have three phase coming into the unit, one to two two ten two to three two ten and then one to three to 12.. So voltage is right as far as main power coming in so uh we're going to go ahead and go over here to these thermostat wires now and see. If we have a call for cooling, okay, r to c we have 24 volts, that's correct y 1 to c we have nothing and then g to c.

We need to find fan g to c. We have nothing. So we do not have a call for cooling on this guy. We need to figure out uh down at the thermostat if it's actually calling or not so i'm going to take a trip down there.

So this is our thermostat right here uh. It's part of an automation system and we have a power light, but we have no occ um. I'm gon na bet i'm waiting for ems to call me back right now, but i'm gon na bet that we have another thermostat, that's gone bad, so we've got this one. That's bypassed this one! That's bypassed this one's, let's buys past and the customer just hasn't.

Apparently they don't want to use these anymore and they want to upgrade to a whole new system. But it's like a big process. So i don't know i just pass on the information, but i'm waiting for them to call me back, but i'm going to be pretty confident we're going to have a an issue with this guy. I'm sure it's got no communication, all right temporarily in air quotes.

I installed the thermostat in the return airstream right here it's set and programmed to turn on and off at normal times. It's just zip tied on here temporarily again, i don't get too involved in the politics with these energy management systems and stuff, because the customer purchases their own replacement, thermostats and stuff um. When it comes to the ems system so bottom line, i got to get the system operational and they're, okay with me, putting in a thermostat now the next question i get when i do this, why the heck did i use such an expensive thermostat? Okay, that's all that i stock in my truck and i'm out in the boonies right now out in the middle of you know where it's going to take me 45 minutes, if not longer, to get to a supply house. So i don't i'm trying to save the customer money.

That's what i keep in my truck. I keep one thermostat in my truck and all my trucks. We all keep this same commercial honeywell thermostat, even though it says home on it. That's just because of the whole residio honeywell thing, if you guys don't know, honeywell sold their thermostat their residential and light commercial, thermostat division, two residio, it's it's like a whole thing, but they still brand them with the honeywell home name.

It's kind of silly on these commercial stats, but anyways regardless. That's the thermostat that i use. That's what i keep in all my trucks. That's what they get, because it's going to cost them more for me to go drive to find the right thermostat.

To put it in there and that kind of stuff, okay, so we put that in there it'll last as long as the customer needs it to like i mentioned, i have a thermostat here, that's been in there for over two years like this, so it is what It is right all right, we're gon na put this back together and finish troubleshooting the unit make sure everything else on it works properly. All right our thermostat is calling - or at least on the thermostat. It says that it's uh in cooling mode, so we're going to check from y1 to c and we have a call for cooling 26 volts. Okay, uh, you guys can't see it, but the economizer module is not holding out the compressor uh.

It's it scrolls across and has a marquee it's hard to see, but it says that it's not the problem. So next thing we're gon na do is check our pressure controls. Okay. So we have a high pressure and a low pressure right here.

So if we go across high pressure, we have zero volts, which is a good sign. That means the control is not open, and then we go across the low pressure and we have 26 volts on the low pressure control, meaning that the switch is open all right. It's a pressure switch and if we look at our pressures in the system, it's a 410a system, we have 86 psi equalized out um when i did put the service gauges on the system. I thought that looked low for sure, but i also saw some oil in here and and on the compressor section.

There's a little remnants of oil too, so we're gon na have to get in and try to find a refrigerant leak. Uh, this guy's definitely low on charge. So this is all factory and it's weird, if you look at that, liquid line, filter, dryer coming out the filter, dryer, the liquid line, comes up right here and then goes into a flare nut. That is not a piston.

That's just a flare nut. That's then, going into it's all accurate or metering devices fixed, orifice, there's little dimples on the lines right there. That's bizarre, so we need to get the leak detector out and see if we can find the potential source. I definitely see something down here on the bottom of the dryer.

It's a little oily, so we'll get the leak detector out and try to pinpoint this guy make life easy. I pop the top off the unit. It doesn't take much and we're going to do a quick leak search. You can kind of see some more oil when we do this, because the whole bottom of this unit has a little bit of oil right on the bottom of the filter.

Dryer right in here, but i'm not seeing anything just kind of following the oil and there it is right there. Leak detector is going crazy. There's a rub! Spot right there, where the two lines rub together, we'll get some soap bubbles on it. Get some big blue micro leak detector.

I mean we already know it's there. This is just for to be able to see a little bit better, but it's bubbling like crazy right there. So we got to get in here repair this leak and change the liquid line. Filter dryer all right, it seems like i brought my entire van up onto the roof.

We're going to get recovering on this guy we're going to make a few repairs we're going to uh and if all goes well we're going to eliminate these high flow schrader things and put in normal schraders um yeah. So we're gon na get the recovery process started and then we'll start uh fixing it now. This guy barely has any gas left in it, but we still got to do our part and recover the gas. So, just working on that right now getting what's out of there we're starting to kind of sand up a little bit, get things ready.

I sent someone to go, get a dryer and uh yeah we're gon na try to clean this guy up a bit all right! I've got nitrogen flowing through the system. I went ahead and unsweat this high flow schrader core fitting. I pulled off the mechanical part and took that off because we're going to cut this out of the picture, and i wanted to be able to cut as close as possible without hitting the brass that would make it so the cut was longer. So i have a special tea: we're going to put there so we're going to cut it as close to the braised joints as possible, cut out a small section.

Then we'll put a t there with an access fitting. I stand corrected. This is a piston, but it's uh. It's weird, though, because it's really small, but you can still see i'll put it back in there, but you can still see the dimples from the fixed orifice metering devices in there.

So i'm curious what they're doing here. That's very interesting huh, but yeah, that is a piston, but it's not removable huh. It's really bizarre kind of doing this in stages, so we got that piece put back in there um. This is where our leak was at this little guy right here.

That was it just rubbing against the line so probably going to redo some stuff here. Okay, so it can't always be perfect. The nitrogen is not flowing through these braze joints right now, we're melting! Oh, so you can't always be perfect. Nitrogen is not flowing through this right now, but it'll be okay.

Oh no! Oh! It's not perfect, it's ugly, but it works. So i'm not perfect kind of looks a little bit ugly, but it's functional ain't! Nothing! Gon na! It's not gon na hurt anything. We don't get a lot of moisture here, so we don't need to worry about this. I mean you know it is what it is.

I did this part out because it's going to be hard, i didn't want to have to climb too crazy in the unit. So well my phone crapped out didn't like the heat but um. We only had like three more braze joints, so we got this guy soldered in or soldered in this guy, this guy, the dryer's in we got to find a way to secure the dryer. I was going to try to use the existing panduit strap and i got new panduits but they're too wide for it.

So it's not going to work but yeah. We just need to strap everything in and get the evacuation running on this guy and then hope that uh, oh, i need to put some nylon on this guy and tighten down that uh piston, i'm still tripping out on what that is, because the typical fixed orifice Metering device has a double orifice already, so i wonder if maybe they reused like an r22 evaporator and added a second restrictor. I i don't know, i don't understand it. So we did a pressure test.

Um it's been running for about five minutes. We've gone up 0.2 psi. It makes sense because we're sitting out in the sun there is a big misconception that nitrogen does not change pressure when the temperature changes, and that is completely false. You can actually see it right here, because i pulled the top off the unit.

The sun is now hitting the condenser and the evaporator. It's raising the system temperature via just the the sun hitting the surfaces of the coil, and my system went up 0.2 psi when it just had nitrogen in it now to be fair, we also very most likely have some refrigerant still boiling out of the oil in The compressor okay, because we were purging with nitrogen, the whole time, but you're still going to get off gassing from the oil okay. But the most important thing to understand is nitrogen: does change pressure with temperature? Okay, as the temperature drops, the nitrogen pressure will drop and as the temperature rises, the nitrogen pressure will rise. Okay, so it does not stay the same all the time.

I'm not scared by this we're going to go ahead and stop the pressure test and get the evacuation running. We're kind of all set up for that, so we'll get it running, then we'll start putting the top back on the unit. Remember this system never came in contact with atmosphere, really we were pushing nitrogen through it the whole time it never ran out of refrigerant, so really we're pulling the nitrogen out and the refrigerant out we're not really pulling any moisture or air out really because it really Didn't have an opportunity um, but yeah. It's it's coming down 880 right now, so give it some time all right, so uh pulled an evacuation and then left the core tools closed.

I guess i should have caught it on film, but left the core tools closed. Put the manifold hoses on there and then evacuated the manifold down below what the micron level of the system was. That way. We had a clean system, we're charging it up now we're at 12 pounds right now and i think it takes 14 and a half pounds.

If i remember right, let's go over here just about so it's 14.5 pounds so we're just about there. Let's see if it'll take any more, i don't know if it will and we'll probably have to turn it on and meter in the rest, we're looking pretty good we're right on the money on the pressures superheats right about where it should be. What's the target the target's about five degrees we're running 4.6? This is just weight in factory charge. I'll tell you.

The airflow is probably jacked up on this unit. I know the duct torque on almost every one of these is kind of low, but temp splits kind of high, but it's also pulling a little bit of outside air and the duct works jacked up. So i think this guy's doing everything that it can. I do want to show you guys something, though, about the uh pressure drop across the condenser.

There's been a lot of talk about whether or not there is pressure drop across the condenser, we're running about 377 psi, liquid line pressure and we're running 393 discharge line pressure and i've got liquid line port back here. Discharge line port up there, so you can't just stop at the first thing when we found the bad thermostat and we got it changed out, we don't just assume, that's it. We finished diagnosing going through the rest of the unit and then i found a refrigerant leak. Okay, i did make some system modifications adding a liquid line port.

I like that, because then you can get a true sub cooling and i also was able to get it on video, the actual pressure drop across the condenser. I know there's some people out there that think that there's not a pressure drop right, but there is um and it varies from manufacture to manufacturer. In my experience, and it also depends on the seer rating of the unit, the higher the seer rating. In my experience, the bigger the pressure drop but anyways, but it does exist uh and it's kind of a it's.

It's really hard to use a rule of thumb to to guesstimate what the pressure drop should be because, like i said, every manufacturer beats to the tune of their own drum when it comes to how they design their equipment. Okay, um! So really nothing too complicated on this one we did make. You know like there was a mistake when i was brazing in the liquid line. Filter dryer it opened up a hole, you know it's, it's not the end of the world.

We don't have to have the picture perfect, instagram install you know, i mean. Of course i strive to make my stuff look nice, but i'm also practical, like you know, i'm not going to re-bend that whole piece just because i i you know flared out a hole like boom solve it. You know um. I was a little intrigued by that extra piston that that's still kind of tripping me out.

I'm curious um because i've opened up these evaporators before and they have a fixed orifice metering device. I kind of showed where the little pinch points are on the distributor line or whatever coming out of the the liquid header um going into the evaporator and uh i've autopsied those before and there's actually two restrictors, and there are two pistons normally, but on this one. I'm wondering if they have one piston outside and one piston right there. I don't understand what they're doing with that extra restrictor.

Who knows, though, again these manufacturers beat to the tune of their own drum? I'm surprised, you know, with a 14 seer unit that this thing has a fixed, orifice metering device and not an expansion valve, but you know who knows we run into interesting stuff out in the field um, i you know given the opportunity. I pulled that thing out because i was curious what it was instead of just saying huh. I wonder why that's there. I mean it really wasn't that big of a deal for me to unsweat it real, quick and just kind of inspect and be like.

Oh, it is a piston. You know, of course, i'm not going to do that. If you know we're not doing repair work on it, but anyways you guys get the gist. Okay, i really appreciate you guys making it to the end of the video um.

It's the the support that i get from you guys is amazing. If you haven't already please check out my website hvacrvideos.com merchandise, available on there, you can help support the channel. There's links in the show notes for all the other different methods that you guys can support. The channel um this is my last video of 2021.

I'm recording this right now on 12, 29, 21. So happy new year to all you guys, uh, hopefully um! You know you guys. Uh have a great 2022 right. Um i'll see you guys, then, on the other side, we got all kinds of cool plans for 2022 all kinds of different places.

I'm going to be going. I will be at the ahr expo in las vegas here in the beginning of 2022, and i will also be teaching or i'm sorry uh, presenting at the hvacr training symposium, the hvac school training, symposium uh at the what is it the middle of february, all uh? I'm i'm 99.9 sure i'm going to be there in person, but there's a very small chance that i will be doing a virtual presentation, but more than likely i will be there in person. So if you guys any of you are going to either of those events. Definitely pay attention to my social media and i'll have times when everybody can hang out and do all that good stuff.

Okay, so i really appreciate you guys and again happy new year and we will catch you on the next one. Okay.