Latest / The Refrigeration Mentor Podcast / Episode 287. CO2 Experts: Using Trend Graphs to Troubleshoot CO2 Systems with Andrew Freeburg

Transcript

Episode 287. CO2 Experts: Using Trend Graphs to Troubleshoot CO2 Systems with Andrew Freeburg · The Refrigeration Mentor Podcast

• 0:00
  Andrew: If you come across a valve like we showed you at the beginning of this, it was spiking all the way up and spiking down, that's like taking your van and all you got is full gas and full brake,? How long is that van going to last, right? So that's, that's kind of how I look at it. Just knowing what a good graph is, is going to be a game changer.
• 0:01
  Trevor: Welcome to another CO2 experts live. So excited here. I'm here at the 2025 AHR expo. Super cool. There's what's going on. There's more CO2 here than has ever been before. I did a CO2 talk yesterday on high ambient strategies for contractors and retailers to give them a better understanding of when they're designing a system, bringing a solution up to the, the, Retailer of the end user.
• 0:01
  So there's options and we have a CO2 design course. This is where I learned. I'm a technician in the background. You guys know that we're in the field, learning, troubleshooting stuff, but understanding the design is a game changer. Even Andrew has been taking the design course and you can see how he's learning and growing super fast and CO2 because he understands those, that the design, the engineering behind the system, and that really gives you what, really gives you the, how a system really works. But today we're going to be diving into trend graphs on CO2 systems, reading them. Andrew is out in the field, working on CO2 systems all the time. And I thought this would be a great episode to, to talk about. Andrew, how you doing brother?
• 0:02
  So there's options and we have a CO2 design course. This is where I learned. I'm a technician in the background. You guys know that we're in the field, learning, troubleshooting stuff, but understanding the design is a game changer. Even Andrew has been taking the design course and you can see how he's learning and growing super fast and CO2 because he understands those, that the design, the engineering behind the system, and that really gives you what, really gives you the, how a system really works. But today we're going to be diving into trend graphs on CO2 systems, reading them. Andrew is out in the field, working on CO2 systems all the time. And I thought this would be a great episode to, to talk about. Andrew, how you doing brother?
• 0:02
  Andrew: Great Trevor.
• 0:02
  Welcome everybody. I'm super excited to be here. I'm so excited to talk about some graphs here and reading and understanding them. So yeah, I'm, I'm ready for this. This is awesome.
• 0:02
  Trevor: Yeah, let's just dive right into it. So let's talk about this first one here.
• 0:02
  Andrew: Yeah, so this one here is actually on a not a transcritical, but a subcritical unit.
• 0:02
  And what you see in here is the valve that I adjusted. So this was actually my first adjustment. When I first arrived on site there was no issue with this unit as far as a service call, but I just like to look at an overview type of Just to I just really like to overview the system. So, looking at the system I noticed that this valve here was going from zero percent All the way up to a hundred to zero to a hundred I mean it just the whole thing just looked like a big old block of green, right?
• 0:03
  And what you see in here is the valve that I adjusted. So this was actually my first adjustment. When I first arrived on site there was no issue with this unit as far as a service call, but I just like to look at an overview type of Just to I just really like to overview the system. So, looking at the system I noticed that this valve here was going from zero percent All the way up to a hundred to zero to a hundred I mean it just the whole thing just looked like a big old block of green, right?
• 0:03
  It was just crazy. It was overshooting and undershooting just constantly. I was like, well, that ain't good so as you guys can see the opening only goes up to max at 60 But you can see where the majority of that cluster is running about, you know, 15 20 so right around there but we're still shutting all the way off and and That means it's overshooting and it's trying to correct itself so I let it run for Like a couple days there, and then I went back to the store.
• 0:03
  Unfortunately, the store was about two, two and a half hours from my home location. So, it's not like it was in my backyard. So, anyways, I made that adjustment, and it was just acting a whole lot better, but I knew I could do better. So I let that run and made another adjustment and then here's the second one.
• 0:03
  So as you can see, I just, I just take the max opening and I shut it down, right? So instead of opening up at 60%, now I'm forcing it to only open up at a max about 45, you could see there. And then it was really working really well for about 10, 11, 12, about an hour and a half. And then I made a slight adjustment there.
• 0:04
  So as you can see, I just, I just take the max opening and I shut it down, right? So instead of opening up at 60%, now I'm forcing it to only open up at a max about 45, you could see there. And then it was really working really well for about 10, 11, 12, about an hour and a half. And then I made a slight adjustment there.
• 0:04
  And it only,
• 0:04
  yeah, so that's where my, my second adjustment was, was right there. And, and then it was working really well. It dropped down once. So I was, I was pretty happy with that, but I know I can do better. Right. So then I restricted again a little bit more and then it was kind of going all out of control there a little bit, but with that, it actually learns itself, so you just, you got to be kind of patient.
• 0:04
  You can't just expect it to Worked the very first time so I let it I let it run for a longer period of time Like I said, it came back probably next week or something. So this was a progress of a probably a month's time. So Just because it like I said, it was two and a half ish hours away from my location.
• 0:05
  You can't just expect it to Worked the very first time so I let it I let it run for a longer period of time Like I said, it came back probably next week or something. So this was a progress of a probably a month's time. So Just because it like I said, it was two and a half ish hours away from my location.
• 0:05
  So Yeah, so but as you can see that graph is getting better and better and better So here is the last adjustment that I did as you can see, so I just let it run again. And then if you look, now I'm not even going down to zero anymore. So that, I restricted it no, what did I do? I actually slowed the valve to react at a slower pace.
• 0:05
  So it slowly will close the valve and then slowly open the valve. That's what I, I had to do is adjust that point. So that made it so it's not opening too fast and shutting too fast, right? So it was a combination of a couple things that I did to get this valve so it would settle down. One, I limited, limited, limited the opening.
• 0:05
  So instead of 100%, dropped it down to 60%. And then I slowed that valve down so it doesn't overshoot and undershoot. And here's the end result, this is the last adjustment that I, that I did. And as you guys could see there, it's just, does it shut off now? I mean, it is running so much smoother and that's, that's what we want.
• 0:06
  So instead of 100%, dropped it down to 60%. And then I slowed that valve down so it doesn't overshoot and undershoot. And here's the end result, this is the last adjustment that I, that I did. And as you guys could see there, it's just, does it shut off now? I mean, it is running so much smoother and that's, that's what we want.
• 0:06
  So, yeah.
• 0:06
  Trevor: This is what I have. I've talked with a lot of control people about fine tuning systems is that Speed is not, not what you're looking for with CO2. Everyone's like, I need it to react faster and faster and faster, but realistically, if you want to slow it down, and this is everybody I talked about EEVs and CO2 or high pressure valves, when they're working on it, and they're, they're adjusting the P and I's or the P and I's and D's is you want to slow that reaction time down which usually gets a better result.
• 0:06
  And I'm not saying that you don't want to speed it up in any situation. Maybe you do. The big thing is though, is that you make one adjustment. You let it run for a little while, make another adjustment and make it, let it run for a little while. So this is a pro a proactive rep approach, but it will take time to do it.
• 0:07
  And I'm not saying that you don't want to speed it up in any situation. Maybe you do. The big thing is though, is that you make one adjustment. You let it run for a little while, make another adjustment and make it, let it run for a little while. So this is a pro a proactive rep approach, but it will take time to do it.
• 0:07
  Andrew: Yes, it, it does take time and I like how the vow will actually start to learn itself and get, and get better and
• 0:07
  better. Like I said, like you said, it takes time. And P and ID loop, I saw a question pop up there. So,
• 0:07
  Trevor: yeah. And then, so which, which parameter do you actually change? You remember offhand?
• 0:07
  Was it the, was it the P?
• 0:07
  Andrew: I think it was the. The P and I, okay,
• 0:07
  Trevor: and we can, we can, you can dive into that, into the different one, but we just want to show you when you're, you're adjusting any set points in a valve that you want to make one adjustment. It's just like a TXL. If you don't make adjustment into two minutes later, you make another adjustment and two minutes later and make another adjustment because it's not there.
• 0:07
  You got to let it run. And you can see there's, there's a bit of time here of the runtime. Like there's 15, you know, probably right here, depending on exactly when you adjust it, could it have been even around here when it starts to, to, to wind out and start to, to fine tune. Awesome.
• 0:07
  Andrew: Yeah, so that that was the cascade.
• 0:08
  Andrew: Yeah, so that that was the cascade.
• 0:08
  So speaking of a cascade system where those EV controls on the, um, plate heat exchangers, those plate heat exchangers are designed for, um, vapor, so latent heat. So it If you are, if that condenser up on the roof or whatever that DUP heater is actually causing it to drop into a subcool state and it could actually mess up that those valves there.
• 0:08
  Trevor: Yeah. 'cause this is, this here had two different EVs on it. I'm pretty sure you were talking to me about, about it. Yeah. Two different circuit.
• 0:08
  Andrew: Yep. This one had two EAVs. And of course I did the same thing on the other valve. I'm just showing you one in these slides, but yeah both valves were banging on 100 shutting off to zero and then I got him to do do that on my last adjustment.
• 0:08
  So it was definitely a way better, happier CO2 unit. So, and imagine how much energy savings they are actually saving at this point just by adjusting these, these valves. So it's a huge game changer when you could read a. A graph and see that there's actually a problem, but it's not enough of a problem to send an alarm out saying that there is a problem, if that makes, if that makes sense,
• 0:09
  So it was definitely a way better, happier CO2 unit. So, and imagine how much energy savings they are actually saving at this point just by adjusting these, these valves. So it's a huge game changer when you could read a. A graph and see that there's actually a problem, but it's not enough of a problem to send an alarm out saying that there is a problem, if that makes, if that makes sense,
• 0:09
  Trevor: totally makes sense, because one of the things we and Andrew talked about that we didn't mention that he wasn't even here for this call.
• 0:09
  He was here to service something else at the store. And he just was taking a look and then he noticed these valves. This store has been not running very good for a long period of time. It seemed like, and he was just investigating and all of a sudden he seen that and he was like, this is not right. And so he was letting me know that this is what he sees a lot out there where You got to read these trend graphs.
• 0:09
  And if you're out there in the field and you're serving this stuff and you see this take a minute and take a look at it. If you've done it before, well, good. Maybe you can do one adjustment and come back to that store. But one of the big things is you got to, you got to make sure you make the time to make that adjustment and then make kind of.
• 0:10
  And if you're out there in the field and you're serving this stuff and you see this take a minute and take a look at it. If you've done it before, well, good. Maybe you can do one adjustment and come back to that store. But one of the big things is you got to, you got to make sure you make the time to make that adjustment and then make kind of.
• 0:10
  Follow back up, because if you make an adjustment and it's the wrong adult adjustment and it starts to flood out a compressor or flood out a rack because he didn't spend enough time watching it after a deep, this is for anybody, but after a defrost, as the curtains come down or whatever it is, you might not be there, that situation.
• 0:10
  You have to come back and look at that stuff because that one adjustment could cause more issues.
• 0:10
  Andrew: Yes. Yeah. Yeah, you got to understand what's happening inside that system. If you could put yourself inside of it man, you could really diagnose what's going on internally. What what that refrigerant and oil is doing.
• 0:10
  So it's, it's definitely important to understand all that information. But the key thing is here is understanding what is a good graph. And, and then, and then then you could say, Oh, man, there's a problem here. And that's how really I started here was I know, I know what is a good graph. And then when I come across it, something, an example this cascade system, it's like, Whoa, that ain't right.
• 0:11
  So it's, it's definitely important to understand all that information. But the key thing is here is understanding what is a good graph. And, and then, and then then you could say, Oh, man, there's a problem here. And that's how really I started here was I know, I know what is a good graph. And then when I come across it, something, an example this cascade system, it's like, Whoa, that ain't right.
• 0:11
  So it's, it's huge. It's huge. So we got to, we as technician need to know. What is good? And then from there, then that's when we could figure out what is actually causing it to be bad. So it's, it's huge. It's huge to know what is a good graph versus, oh, there's a graph, right?
• 0:11
  Trevor: Yeah. Yeah. So there was a question in the In the chat, just to elaborate how does the D superheater affect the cascade on an EEV plate heat exchanger?
• 0:11
  Did you mean the D superheater of the condenser or what was your, what did you mean when you mentioned D superheater? Just to elaborate.
• 0:11
  Andrew: Yeah, the D, the D superheater is, is a, a real small condenser. And all what you're trying to do is drop that, that discharge temperature down to a reasonable temperature.
• 0:11
  So we're not trying to take that discharge, which is what, 200 degrees, let's say, and then throwing it right into where the valve is, where the plate heat exchanger is. So what we're doing is taking the discharge, cooling the, the superheated vapor out of the discharge. And then it drops down, but not enough to condense, right?
• 0:12
  So we're not trying to take that discharge, which is what, 200 degrees, let's say, and then throwing it right into where the valve is, where the plate heat exchanger is. So what we're doing is taking the discharge, cooling the, the superheated vapor out of the discharge. And then it drops down, but not enough to condense, right?
• 0:12
  That's when the plate heat exchanger will start to do that. That's what it's designed to do.
• 0:12
  Trevor: And it's 200 degrees Fahrenheit, everyone, just, just to figure it out. Oh, yeah. Just so like, yeah, yeah. Yeah. Okay, let's dive into this next one.
• 0:12
  Andrew: Oh, yeah, this was a, this was a this was a good one. I know it says let's see.
• 0:12
  Oh, this was let me see. I got to look at it.
• 0:12
  Trevor: The defrost one.
• 0:12
  Andrew: Oh, defrost. Yeah. So this was happening defrost. It's not the condenser. I know it says rack the condenser up on top, but, uh. What's happening is, is on the top, it drops down and then it closes the valve and then it pops right back open on an EPR.
• 0:12
  And then if you look.
• 0:12
  Trevor: So we should just give some context to this. So you mentioned that you, you got a service call and then the cases were freezing up. They were continuing to freeze up. Is that right? I think you mentioned that to me. And then you were like, okay, well, let's figure out how and why.
• 0:13
  Trevor: So we should just give some context to this. So you mentioned that you, you got a service call and then the cases were freezing up. They were continuing to freeze up. Is that right? I think you mentioned that to me. And then you were like, okay, well, let's figure out how and why.
• 0:13
  They're frozen up again, because it wasn't the first time this happened. That Andrew mentioned to me. And then, so he said that anytime that happens on a hot gas, a defrost system, there's two two things that I like to check. I like to check the defrost temperature. I believe it is. And the EER EEPR percentage.
• 0:13
  So that, that was the first thing that you went in and you told me that you went to look at.
• 0:13
  Andrew: Correct. So yeah, background, this case they said every two weeks that they have to completely de ice it, and it's been going on like this for a while. So of course, when I hear that, I just pop off a graph because the graph tells the story.
• 0:13
  So when I look at this, is that when the graph on the very top drops down to zero, that means that valve completely shuts down. And then hot gas, it's reverse hot gas, so then it goes through. And then on the bottom is the temperature of the evaporator, so then that will go up and down. So what was happening here, is that the unit actually wasn't going into hot gas.
• 0:14
  So when I look at this, is that when the graph on the very top drops down to zero, that means that valve completely shuts down. And then hot gas, it's reverse hot gas, so then it goes through. And then on the bottom is the temperature of the evaporator, so then that will go up and down. So what was happening here, is that the unit actually wasn't going into hot gas.
• 0:14
  Sometimes, right? So anytime those things spike opposite, that means it actually goes into defrost, and then when the EPR shuts off. There's no spike. See that that That that means that it did not go into defrost during that time So it skips what is that one two three three defrost and then all of a sudden it works for one And then one two three three more defrost.
• 0:14
  It doesn't work and then all of a sudden starts working So that indicates, you know right there Why? So I know my valve is shutting off according to the graph, but why am I not getting any hot gas? So needless to say it was actually the hot gas line or a hot gas valve That was causing it not to turn on Or open up, it's just stuck.
• 0:15
  It doesn't work and then all of a sudden starts working So that indicates, you know right there Why? So I know my valve is shutting off according to the graph, but why am I not getting any hot gas? So needless to say it was actually the hot gas line or a hot gas valve That was causing it not to turn on Or open up, it's just stuck.
• 0:15
  So I ended up actually had our apprentice there. That was, he was a year one apprentice and I showed him how I found it. And then I showed him the process of you know, isolating the circuit, pulling down all the refrigerant, grabbing my recovery machine. And I don't take the gas out of that.
• 0:15
  And dump it into a tank. I actually throw that right back into the the suction of the the house the suction house and pull that down to about zero Negative one inches right there as long as the refrigerant's out Then I shut everything off and you're good to go. So I was showing him how to, how to do that too.
• 0:15
  So, yeah, he, he, it was a, it was a great experience for, for him. So that's what it's all about is sharing our knowledge. So, and that's why you guys are here.
• 0:15
  Trevor: Yeah. And I think that's, that's very important when you do it there, then we need more technicians out there showing the apprentices how to do that stuff.
• 0:16
  Trevor: Yeah. And I think that's, that's very important when you do it there, then we need more technicians out there showing the apprentices how to do that stuff.
• 0:16
  And, and just sharing a little bit of knowledge each time going forward. So this is another graph here that you send me that you were like, okay, Trevor, I'm on the roof, the high pressure valve bypass valve, we're working great. And then all of a sudden it went like this.
• 0:16
  Andrew: Yeah. So. You could see that, you know, right around when it's cooler, technically, outside.
• 0:16
  It was, they're pretty close to, together, which was
• 0:16
  awesome. That's kind of what you want. You don't want the crazy spikes. Then all of a sudden it goes haywire like this as you go through the day as the graph shows. This is an E2 and you could actually pull two graphs as you guys can see here.
• 0:16
  So, what I ended up finding was my condenser VFDs were ramping up real fast and slowing down. Ramping up and then basically shutting off, I should say, not slowing down. So it was just really inconsistent. So it was just all over the place. And knowing that we shouldn't have that, you have to slow things down, right?
• 0:17
  So, what I ended up finding was my condenser VFDs were ramping up real fast and slowing down. Ramping up and then basically shutting off, I should say, not slowing down. So it was just really inconsistent. So it was just all over the place. And knowing that we shouldn't have that, you have to slow things down, right?
• 0:17
  So that's all I did with the VFD is I slowed it down. I wish I took a picture afterwards, but I got it right back to the very first section of that piece there. So it's just knowing what's happening in that system and what's causing stuff to jump all over the place. We just want to get everything real smooth.
• 0:17
  So when it's, it's smoother, it's actually more energy efficient, which you're saving the customer customers the electricity bill on it.
• 0:17
  Trevor: Yeah.
• 0:17
  Andrew: Where that fine tuning comes into play with CO2. It's just, I mean, a lot of them, you could just shut, you know, just get it in and it's going to work. Right.
• 0:17
  But that's not for me. I feel like that's only part of it. That's. Right. So then we get a fine tune things and get everything in line. That's when those energy savings just right there comes into play.
• 0:17
  Trevor: Yeah. And so it's not even the energy savings come, but the big thing is, as you can see the green lines, the high pressure valve, the purple ones, the gas bypass valve.
• 0:18
  Trevor: Yeah. And so it's not even the energy savings come, but the big thing is, as you can see the green lines, the high pressure valve, the purple ones, the gas bypass valve.
• 0:18
  The big thing is, is that if you don't have those valves working, then your EEVs aren't going to be working. Right. Properly. And then if you have one flash gas, the flash gas bypass valve, not working probably, but the high pressure valve is working, but the EEVs, it won't work. You need them all to be working in sync for a really good really good running system.
• 0:18
  If you have the fans fighting the valves, you're going to have an inefficient system. Things are going to go all over the place. And in this example here, Andrew's talking about the, the VFD running into an issue. But he sorted it. What was the, what was the thing with the VFD and you might've sent it already and I missed it, but what do you do with the VFD to get it back up and running?
• 0:18
  Cause that was the issue. It was nothing, nothing to do with the valves or the controllers, correct? It was the VFD that was ramping up and shutting off.
• 0:18
  Andrew: Yeah, the VFD was the issue here and it was causing those fans to, like I said, go up to a hundred percent, drop down to zero and then it will bump up to a hundred percent.
• 0:18
  It was just all over the place. So really I adjusted, it was a. It was a five degree difference between the, the lowest set point of that HPV. So I, and so I moved it five degrees and then I slowed down the, the, I guess the quickness of how the, the BFD reacts to changes. So as soon as I slowed it down, it just.
• 0:19
  It was just all over the place. So really I adjusted, it was a. It was a five degree difference between the, the lowest set point of that HPV. So I, and so I moved it five degrees and then I slowed down the, the, I guess the quickness of how the, the BFD reacts to changes. So as soon as I slowed it down, it just.
• 0:19
  Got way smoother.
• 0:19
  Trevor: Yeah, and this was for the fan VFDs, correct? Correct. Yeah, yeah, because you have VFDs and compressors We just want to be clear on that. What what's what's working? So the fans are fighting the valve and this is no different than in supermarket applications I've seen this time and time again with an A8 fans and split condenser if you don't have the split condenser set up with the fans and with the A8 and A9 You're going to run into a similar issue.
• 0:19
  So just want to let you know, if you're working on supermarket applications right now CO2, a lot of the things are very, very similar. Very similar.
• 0:19
  Andrew: Okay. So this was a really cool it was actually my very first CO2 leak and I thought it was the neatest thing ever. So we had the store, I had to add 200 pounds of refrigerant in the middle of the night.
• 0:20
  Andrew: Okay. So this was a really cool it was actually my very first CO2 leak and I thought it was the neatest thing ever. So we had the store, I had to add 200 pounds of refrigerant in the middle of the night.
• 0:20
  Of CO2, I guess, yeah, CO2, and then I came back the next morning after I, I got it up and running, and I started a leak check. So, what's funny about, I feel like what's funny about leak checking with a CO2 sensor, is that we breathe out CO2, so, your, Meter actually will start going off and this is the first time like I said, I've I've worked with CO leak checks the co2 unit.
• 0:20
  I thought that was very interesting. I caught on to it really quick because I was experimenting with that. But I thought it was unique. So if there's a bunch of group of people sitting there talking. It actually goes a little up when you get close to that group and then it will fall down as far as your, you know, your parts per million.
• 0:20
  So anyways, I was a leak checking the whole store. And then this one was unique because it was on a meat case and I was going 40 feet of meat. And all of a sudden it will just spike up only like. So I was running about 100 parts per million, but this will spike up to about 350 in this one area, and then it will settle back down.
• 0:21
  So anyways, I was a leak checking the whole store. And then this one was unique because it was on a meat case and I was going 40 feet of meat. And all of a sudden it will just spike up only like. So I was running about 100 parts per million, but this will spike up to about 350 in this one area, and then it will settle back down.
• 0:21
  So I knew something was going on, but I didn't know what, right? So I leak checked the whole store, come back to this, and I pull it, pull all the, the product, and then I was hearing this tick, tick, tick, tick, tick, tick, tick, tick, tick sound. I go, what is that? That's weird. I go, it must be the fan hitting something.
• 0:21
  So I pull, pull the pan covers off. I look and I look and I could see dry ice dropping from the corner right where that red mark is for your, yeah, right, right. Full up more, but yeah, basically right there. It was crazy. So it was, it was at that triple point. And it was hitting the back of the. The air curtain and it was causing it to kick and, and you could see the dry ice ball.
• 0:22
  So I pull, pull the pan covers off. I look and I look and I could see dry ice dropping from the corner right where that red mark is for your, yeah, right, right. Full up more, but yeah, basically right there. It was crazy. So it was, it was at that triple point. And it was hitting the back of the. The air curtain and it was causing it to kick and, and you could see the dry ice ball.
• 0:22
  It was, it was gnarly. It was so gnarly. I only came across that once out of my whole career too, so it was cool.
• 0:22
  Trevor: But, but that's the thing, you're gonna, you're gonna find leaks and then The same thing he, he does the proper practices, you know, pump out the whole circuit, get all the CO2 out and then use your recovery unit, get the rest out and put it back into the system.
• 0:22
  If you can, some people will bleed it off, but once again, I talked about this before when you're bleeding off CO2, there's still oil POE oil and that stuff. So. That'll be out in the vapor. So you've got to try to save as much as possible and put it back in the system because this does cost money. And then the same thing, he doesn't just open up the liquid line.
• 0:22
  When, when he starts it back up, after he does a leak check, he opens the suction very slowly, get some more CO2, and then checks it with these either soap solution or leak detector again, to make sure he did fix the leak and then fully open the suction and then open up the liquid and do this in that safe process, which is super, super important.
• 0:23
  When, when he starts it back up, after he does a leak check, he opens the suction very slowly, get some more CO2, and then checks it with these either soap solution or leak detector again, to make sure he did fix the leak and then fully open the suction and then open up the liquid and do this in that safe process, which is super, super important.
• 0:23
  Let me and Andrew talk about this all the time so that's just following up a little bit more, more with that. Let's check out this, so Andrew sent me this video here, let's see if this video will work.
• 0:23
  So what's happening here Andrew?
• 0:23
  Andrew: Oh man, so, this was, we had we had a leak. As you can see it boiling up from the bottom of the cement there. And so, I was, this was actually a pretty good leak. We, it was about, I think I was adding 200 pounds of CO2 and a couple of days, right? So a hundred pound leak a day, it was gnarly.
• 0:23
  So there was a couple of people that went over there. They could not find this leak. This is actually underneath the case. You can't even see it. So this was me pulling the panel off just to give you guys a perspective of what happened here. So anyways, I was leak checking. And I couldn't, I didn't find it, and then I put my hand down and let the, the nose of the sensor go down to the floor, and then it just, it spiked up to 9999, I think it was, parts per million, and I go, holy moly, I found the leak.
• 0:24
  So there was a couple of people that went over there. They could not find this leak. This is actually underneath the case. You can't even see it. So this was me pulling the panel off just to give you guys a perspective of what happened here. So anyways, I was leak checking. And I couldn't, I didn't find it, and then I put my hand down and let the, the nose of the sensor go down to the floor, and then it just, it spiked up to 9999, I think it was, parts per million, and I go, holy moly, I found the leak.
• 0:24
  But there's no refrigeration near me. So I thought that was funny. So anyways, I started to pinpoint it and I could actually sit and Remind you there's a panel right in front of this so I cannot actually Physically see it and those pipes were all insulated at the time before I cut it so I could tell where it went into the ground and out of the ground and there were by leak checking it.
• 0:24
  It was that crazy of a leak. I mean 100 pounds It was a hundred pounds a day. So now we had to, you know, isolate the system and, and repipe it and then figure out what happened, right? That's the next thing because anytime you do any underground work, you always pressurize your, your circuits, right? Yeah, it's just it's just what you do.
• 0:25
  It was that crazy of a leak. I mean 100 pounds It was a hundred pounds a day. So now we had to, you know, isolate the system and, and repipe it and then figure out what happened, right? That's the next thing because anytime you do any underground work, you always pressurize your, your circuits, right? Yeah, it's just it's just what you do.
• 0:25
  That's normal operation. So we re piped it got everything up and running and then I I well, I didn't do the re pipe I had my Construction crew do it and then I came back and figure out what's going on So I had an apprentice at the time and what I love to do with Talking to apprentices or anybody new into co2 is give them a layout of what you expect Then i'll go into the machine room and point out all the valves and what's happening in these locations and then Then we'll start doing figuring out what's going on.
• 0:25
  So I had him hook up the gauges to the flash tank and The flash tank should have been running about 510, 520 pounds. And then I was at the E2 looking at all the, all the points check in pressures, whatever the temperatures what the. With the E2 and then I hear him yell my name and I look over, you know, and and to see what was going on He goes what's the pressure should be?
• 0:26
  So I had him hook up the gauges to the flash tank and The flash tank should have been running about 510, 520 pounds. And then I was at the E2 looking at all the, all the points check in pressures, whatever the temperatures what the. With the E2 and then I hear him yell my name and I look over, you know, and and to see what was going on He goes what's the pressure should be?
• 0:26
  I go it should be should be about five five ten five twenty something like that And then he freezes and just shakes his head. I Was like what's going on? And he goes it's 800 pounds. I go. There's no way it's 800 pounds So I ran over there looked at the gauge. It was at 800 pounds I go back to the E2 and pull up the graph.
• 0:26
  I was at 510 pounds. I was like, oh man, that transducer is way wrong. That's what's going on. So as we know, if you get bad information in, you get bad output, right? So I isolate that pressure transducer and I'm going to change it. And when I take it off, it was so full of oil. So that was causing bumper in there.
• 0:26
  So I got all the oil out. I routed the piping so it, it doesn't flow down. So it flows up. So gravity takes effect. So we don't get any oil in there. I put that pressure transducer in there and then the rack just calms way down and then I check the pressure transducer again to see make sure and it's reading correctly according to my gauges.
• 0:27
  So I got all the oil out. I routed the piping so it, it doesn't flow down. So it flows up. So gravity takes effect. So we don't get any oil in there. I put that pressure transducer in there and then the rack just calms way down and then I check the pressure transducer again to see make sure and it's reading correctly according to my gauges.
• 0:27
  So the next question becomes if I'm running at 800 pounds was one why which we figured out. But what else should have done? What else should have happened at 800 PSI? The PRVs, the pressure relief valves, should have blown about 650. So now, so now I'm questioning, why did not that not go, right? So all, if you know the process and you know what should happen, that's where you can start really diagnosing what's going on, right?
• 0:27
  So I go up to the PRVs and they were rated at 650. So, of course, I'm like, Oh, the PRV is bad, obviously, cause that should have blown, especially at 800 PSI. So I go and change out the PRVs. But yeah, that was the, one of the most craziest service calls that I've ever had come across with CO2.
• 0:28
  So I go up to the PRVs and they were rated at 650. So, of course, I'm like, Oh, the PRV is bad, obviously, cause that should have blown, especially at 800 PSI. So I go and change out the PRVs. But yeah, that was the, one of the most craziest service calls that I've ever had come across with CO2.
• 0:28
  Trevor: Wow.
• 0:28
  Yeah. Super interesting. But this is from, oh, there were, this was a video too.
• 0:28
  Andrew: Yeah, you can hear it. You just can't. But you can see the chunks, right?
• 0:28
  Trevor: I didn't even know it was a video. I should have played it. I can hear and see it.
• 0:28
  Andrew: Yeah. You can see the chunks flying down. It was just hitting the back. And like I said, it was ticking.
• 0:28
  It was the craziest, weirdest experience. Like I said, I've only came throughout my career with CO2 right now. That's the only time I've ever come across that triple point action. It was, it was pretty neat.
• 0:28
  Trevor: Yeah, I love it. So Andrew, what are a few tips that you'd like to give technicians who work on CO2 on about trend graphs and some of the things we talked about quite a few of them today already, but you want to rehash and some of the importance of reading trend graphs and understanding them.
• 0:28
  Andrew: Yeah, I would go to a system that, you know, that's operating right. And just pull up the valves that are there that actually you could see controls and see what it's actually doing and how it's reacting. If you come across a valve like we showed you at the beginning of this, it was spiking all the way up and spiking down, it just doesn't look like there's any control going on.
• 0:29
  Andrew: Yeah, I would go to a system that, you know, that's operating right. And just pull up the valves that are there that actually you could see controls and see what it's actually doing and how it's reacting. If you come across a valve like we showed you at the beginning of this, it was spiking all the way up and spiking down, it just doesn't look like there's any control going on.
• 0:29
  Those are the questions you should be asking. You should know, like, okay, there's no efficiency here, there's no rhyme or reason. That's like taking your van or your, or your vehicle, whatever you drive, and all you got is full gas and full brake, right? How long is that van going to last, right? So that's, that's kind of how I look at it.
• 0:29
  So just knowing what a good graph is, is going to be a game changer. Game changer. If, and then, and then you could actually go and look at other graphs or different valves. They should all be pretty, you know, linear. There shouldn't be a banging on and banging off type situation. Right. So. Yeah. My, my first advice is just getting in there and figuring out what is a good graph and then going from there.
• 0:30
  So just knowing what a good graph is, is going to be a game changer. Game changer. If, and then, and then you could actually go and look at other graphs or different valves. They should all be pretty, you know, linear. There shouldn't be a banging on and banging off type situation. Right. So. Yeah. My, my first advice is just getting in there and figuring out what is a good graph and then going from there.
• 0:30
  Trevor: I love it. I love it. Andrew, thank you so much for taking the time to show this. Cause this is important. Getting in there, doing these services, looking at the graph, fine tuning these systems, super excited to chat with you more on this stuff. And, and so once again share this, like this with. Anyone that interested in CO2, this is super important that we share this knowledge, you know, and try to help other people out there because once again, this is an evolving technology and it's going to continue to grow around the world.
• 0:30
  Andrew, thank you so much for this and let's get a conversation going. Everyone.
• 0:30
  Andrew: Thanks everyone.
• 0:31
  Andrew: Thanks everyone.