This video is brought to you by spore'ln quality, integrity and tradition, so this is a Sunday morning service call at a local sports bar their banquet room. The air conditioner is not working when I went in there, it feels like it's 90 degrees in that room. The thermostat is interesting because the thermostat says 73 degrees, but I come up onto the roof and the unit is not running at all. No condenser fan motors and what's even more alarming, is no safety alarms.

This is a York predator unit. You know how these work. You look up in that top left corner and, if there's a safety limit that the board has stopped the unit on it will flash red and then blink so many times to tell you what the error code is. You can usually look down here right down here.

It tells you the flash goes all that stuff, but regardless we're not getting a flash code. So the first thing that we're going to do is we're going to check 24 volts to the board to see if we're getting a 24 volt call. The thermostat was indicating that it was calling for cooling, so that's what we're gon na check. Okay.

So what we're gon na do here. I set my meter up right here, so we can see it. Okay and I'm gon na go up here to the board and I'm gon na jump from C, which is a little difficult to see which is common to our and we get 24 volts. Sita are okay! That's good! Now I'm gon na jump over to see to G.

We get 24 volts or 22 volts, okay and now I'm gon na jump over from C to y 1. We get nothing and I'm gon na jump from C 2 y 2. We get nothing so, according to this board, the thermostat is not calling. So that's interesting now.

Another thing that I will point out and we will correct before we leave, is my transformer is tapped for 230 volts. I do not think that we have 230 volts coming to this transformer here in Southern California. It's pretty typical if you've got a restaurant, you're gon na have 208 volts coming to the unit. We tend to see that in shopping malls, you'll see 240 volts or you'll see 240 volts in residential neighborhoods, where there's like a gas station, or something like that.

That's just something common to my area. That does not mean that's going to be the same way for the rest of the country. Okay, so we it's just very uncommon for me to see a 230 volt supply going to a unit in my area so that just catch me off guard. So before I leave, I will correct that that's an installer issue, funny thing is: is they haven't ran into a problem in this units, probably twelve years old, so go figure, but they must not, where you really start to see that becoming a problem is when you Have low voltage which, where I'm at right now, this is out in the Coachella Valley, we don't have low voltage problems in this area, but when we had more inland to where my shop is at in the Inland Empire of California, we have a lot of low Voltage problems where, in the summer time, the voltage will drop down to 180 190 volts and that's when the incorrectly tap transformers will really stand out, because when you've got a hundred and eighty or 100 90 volts come into the building and your tap for to 230.

That transformer more than likely, is all going to be putting out 16 to 17 volts and then you'll see issues with you know: contactors not pulling in and whatnot so okay. So at this point I do not have 24 volts coming up here. So it's looking like it's a thermostat problem in all actuality, so what I'm gon na do is I'm gon na kind of look? I think this is the thermostat mess right here. I'm gon na look into where the thermostat wires are coming from and we're going to make sure that we're not losing voltage anywhere.

So here's my thermostat, it's not loose from the wall, things good yeah, that's interesting, look like it might be about thermostat. I want to go make sure, there's no twists timers that are in line with so there's some interesting stuff going on here. Let's see if I can show you guys, this is a very peculiar. So when I check from common to our first off, I retyped that transformer.

So now you notice we're getting actual 26 volts instead of like twenty one, twenty two holes: okay, that's the difference too! So I tapped the transformer to the 208 volts. I just moved the tap over okay and we're getting better control voltage. Okay, so this is our to see all right now, I'm gon na go see to y1 and I get nothing and I'm gon na go c2 y2, and I get nothing. Okay now watch this.

If I disconnect y1 and y2 and I go from C or common to y1, I get voltage and the same thing why I get voltage. So something is robbing the voltage, so the thermostat is working from the looks of it, but when it goes into the board it gets lost. So it's very interesting. It could be something robbing the voltage meaning to contact your coil.

That's bad or something like that or a board. That's bad or it could be a bad thermostat. That's not making a good switch. It's looking like a bad thermostat, because what I did was i jumpered from r2 y1 directly, and I got my delay light coming on.

So it's gon na call right now see it just turned on, so it's almost like the thermostat isn't making a good switch and it's just not sending enough hole to jump like it's a bad contact in the thermostat, because when I jump it out, it runs so Yeah and it's either way y1 or y2, so it's gon na be a bad thunderstorm, but you guys understanding what I'm doing there. So when I have the thermostat wire hooked up to the board, you go ahead and disconnect this, and I have the thermostat wire hooked up to the board and I test it from common to y1. I got nothing and common why I got nothing, but if I disconnected the wires y1 and y2 and I tested from common to y1, I got 22 volts common. Why I got 22 bullets, but it wouldn't pull in anything on the board.

When I took a jumper and went directly from R to y1 on the board, it immediately turned on. So that tells me that we were sending power downstairs, but we're not getting a good connection at the thermostat coming back upstairs talk about confusing, so I diagnosed it as a bad thermostat and it still is about thermostat. But look at what I found, I disconnected power. So that I could change the thermostat and I jumped out the unit B notice, how this one that's labeled, AC, 6 turned off, and this one that's labeled, AC 3 is on so see someone has mislabeled these thermostats they're, not labeled correctly, so we still have a Bad thermostat, which is this one, but it's um, it's mislabeled all right, so just got the thermostat change down, set it up automatically turn on and off, so we're good to go so the whole time I was changing the thermostat I had this unit jumped out, so It was running and it cooled down that room really well.

So now I came back up and mind you. What I did was I disconnected all the control voltage, this control wire. So that way, I could change the thermostat without worrying about tripping out a transformer and right where the control voltage connects up on that terminal board. I had jumper wires.

Just you know: thermostat wires, jumping from R to G to y1 to y2. So that way all stages were running. It was cooling down that room and then that way I could do the thermostat change. The sensor get all that seven program at while the unit was cooling.

You know to get the room down to ten. It's currently about a hundred and oh my thermometer, I hear, but it's probably about a hundred and eight hundred and seven, and it's probably about I'd, say fifty fifty five percent relative humidity right now. It's pretty warm out here, pretty humid. So I wanted to cool that room down, so I didn't have to wait too long so, like I showed you guys in the video thermostat was mislabeled I'll get into something in the recap to that that led to, but for now I just went ahead and connected The thermostat back in I'm gon na watch this unit operate, make sure it turns all stages back on its currently in the delay mode.

So it'll be a second and then it'll turn on and then we'll go from there. So I've just been letting the unit run for about. I don't know a half hour now, just let it cool down the room in there and I just went to go check delta T across the coils, and this is what I come up with, and this is rather alarming. We're gon na 96 degree return air and a 60 degree supplier all right, so I had some more footage, but actually my camera overheated and cut out it does that when he gets above 100 degrees, we tend to have problems with the camera, doing that but anyways.

So initially we had a service call on their banquet room, not working okay. So when I arrived, the banquet room was damn near a hundred degrees and mind you, it's part of the same building. Okay, just it has open doors, and but it was still like a hundred degrees in that room, which was trippy found that the unit had a call. Well, it did not yeah.

It was acting like it had a call for cooling, because when I pulled the wires off, we had 24 volts, but when I put him back on it wouldn't engage anything okay. So there was something going on there. That led me downstairs to look at the thermostat and I diagnosed a bad thermostat, because the thermostat indicated that it was calling for cooling when I went to go, replace the thermostat. That's when I realized that they had them: mislabeled, okay, and this actually what it? What I kind of alluded to and the thing was, it opened up another thing and it totally makes sense.

Now previously we had a service call where we had, and I hadn't changed it. Yet at the time of this filming we had diagnosed a bad zone sensor for another thermostat I'll come to find out. They had several thermostats that were mislabeled okay, so I ended up going back out there. So let me let me finish up the video okay.

So when I went ahead and changed the thermostat and then the unit was working, fine changed the correct thermostat, but then I found that we had a 96 degree return air temp. That was where the camera cut off. What was actually happening was the economizer damper. Has a minimum outside air position and the minimum outside air position was doing what it was supposed to be doing.

It opens the dampers like 10 %, 12 % whatever it is and allows for the minimum outside air for fresh air requirements for the building. Okay. Well, because it was doing that and the unit had a call for fan the indoor fan, because it was in an occupied mode. That's the way it's set up.

We were blowing in 110 degree air into that room, and that's why it was over 100. When I got there, okay, so what they just weren't, getting a call for cooling, so the compressors weren't. Turning on this just shows you. You know why, and unfortunately we don't do it enough, but why we need to temper our makeup air for our buildings, meaning that we need to condition whether it be cool or heat our makeup air here in Southern California.

It's very very common for us to use the arts, you units or the air conditioning package units minimum outside air positions on the economizers as our fresh air for the building. Now this restaurant does have a make-up air unit too. Okay, but the are we using some outside air from the air conditioning units or the rtu units also, and so this is a great example to show you how hard that unit is working when it's just trying to cool the building. You know when there's customers in there, because it's still trying to cool that that minimum outside air that it's bringing into so it's really working overdrive, especially when we get above 100 degrees, so anyways.

So what I was alluding to a minute ago was we also found. I had previously diagnosed a bad zone sensor for another thermostat, we'll come to find out. They had several thermostats that were mislabeled. I ended up going back out.

This was a Sunday that I filmed this video. I ended up going back out. The next week took another service technician out with me and we went through every thermostat and relabeled them and actually didn't need to change the zone sensor after all, because once we figured out that all the thermostats were mislabeled, we got them all dialed back in and You know this kind of stuff happens. You really have to pay attention before you start diving into things and verifying, and luckily these are the de Vence Tower thermostats.

You know they lose power when you de energize the unit most thermostats. Don't if you do that, like a Honeywell, the one that I put in the vision, Perot or 8000, whatever it is, it has a battery backup, so it doesn't lose power so on some of these vents Darwin. So I don't care for the Vince star thermostats, but that's one cool feature about them is: if you want to know which a C's which just go shut it off, the thermostat will go blank. So I really appreciate you guys taking the time to watch this video.

I know there was a few things in the video. You know. I realized, as I was watching it. I didn't show the the thermos that it ended up being I didn't show that it was actually calling, but it even on that thermostat it was doing the same thing.

It was showing that it was calling for cooling and we weren't getting anything okay but anyways. I really appreciate you guys taking the time to watch these videos. Leave me some feedback down in the comments, send me an email to hvac our videos at gmail.com and pay attention. I do live streams every Monday, typically so long as there's no problems with work at a 5:00 p.m.

Pacific time, and I usually answer all the questions that you guys send me. I try to pick out some good ones, more common questions that I think everybody will benefit from and I try to answer those live on. The live stream so feel free to shoot me a question and all I'll definitely answer it, and if you, if you want me to mention your name who you are when you send me a question, tell me in the email or the comment just say: hey mention My name, I'm whatever and I'll, give you guys a shout out too so alright really appreciate it, and we will see you guys on the next one.