Latest / The Refrigeration Mentor Podcast / Episode 263. The Importance of Understanding Trend Graphs with Andrew Freeburg

Transcript

Episode 263. The Importance of Understanding Trend Graphs with Andrew Freeburg · The Refrigeration Mentor Podcast

• 0:00
  Speaker 4: Andrew, welcome to the refrigeration mentor podcast. How are you doing brother? Great Trevor. How are you?
• 0:01
  Andrew: Thank you for having me again. I appreciate it.
• 0:02
  Speaker 4: No, it's always fun having you love talking to passionate people who care and who, who wants to help share their knowledge.
• 0:03
  So I know you were mentioned, you want to talk about graphs and how it's important. You were working with some apprentices. And you guys were looking at a graph of different graphs and learning how to troubleshoot and teach it and the value of reading trend graphs. I think that's what we'll dive into today.
• 0:04
  Andrew: Yes, that's great. That incident that we're talking about. I was it was on a uh, 407a rack protocol and it was when I looked at The suction, it was all ice. So I knew something was flooding back on it. And my apprentice was like, well, how do you know that already? I'm like, well let's do, let's do some math here.
• 0:05
  So if we're reading, I can't remember the pressure, but we're our SST was 22 degrees and I go, when does ice form? He's like 32. And then I, you could see all of a sudden that light bulb clicked. And he's like, Oh, that's how you figured that out. So yeah, so just, you know, just being visual and looking at items that you see that you come across, that will really, really help you.
• 0:06
  So that's how we began it. And then we got on the graph. And then we started pulling up cases and, and temperatures right at the machine room. I didn't have to go out to the sales floors and check every case. You just go right out to your, your whatever controller. This was a Dan Foss, I think 800. I remember, right.
• 0:07
  If I remember the model anyways, it had the temperatures of the cases and I just started going down. And then one lineup was running at 35. 36, 34. And then the next case was all of a sudden just down to 30. I'm like, that's probably where, where our problem is. There's something going on with that.
• 0:08
  Speaker 4: So what was it would be the next steps then?
• 0:09
  Like if someone's going in and they're taking a look and you got these, you got the multiple cases with multiple temperature probes what, what would be your next step?
• 0:10
  Andrew: Yeah. My next step is go and actually see if that sensor is reading correctly. Okay. So because you don't want to just go off of it and say, oh, that's our problem.
• 0:11
  That's what's going on. You got to verify that it is so grab your fluke 52 Stick your meter right where that sensor's at and see if it's correlating to the right temperature. So yeah, double check. Of course, that's where I would start.
• 0:12
  Speaker 4: what other graphs have you, cause I know we've talked many, many times about trend graphs.
• 0:13
  What is why reading them is so, so important and learning how to read them. What are some of the top things you look for in it? For an example, a case controller. What do you, what are you looking at a graph? Cause a lot of times you got air in, you got air out, you got defrost, you got valve percentage, you got.
• 0:14
  A superheat. What are, when you're going to look at a case controller, for example, what are the ones that you're looking for and looking at to see if there's any anomalies?
• 0:15
  Andrew: Well, first I would say you got to know what is normal. If you don't know what is normal, then how do you know one is not working correctly?
• 0:16
  Right? So I highly recommend any of you that are starting to get into this field or, or just, you know, just looking at it or trying to understand it, know what it's supposed to do. And then you could figure out like, oh yeah, this is what's wrong with this unit. There's something funny here. I need to go investigate it.
• 0:17
  So definitely take the time, 15 minutes out of your service call, pull up a case controller, see one that's working correctly. Go through it, make sure you could see everything and just get familiarized with it. So that would be my very first tip. I guess you could, you could say for that. And then now when you know what it should be, go on the graph, pull a certain time and see what that graph is.
• 0:18
  You'll see spikes in temperature. And that's okay, because guess what that means? It went into defrost. So that, that is exactly perfect, but let's say, you know, you go a month behind, you see the graph where it comes right back down then as you go through and get today, you get that service call, hey my case is running warm, or it's taking a long time to pull down, pull that graph up.
• 0:19
  You'll see it spikes, it'll spike, come right back down. Then maybe you see it spike and then it takes a little longer and a little longer and a little longer to pull down. Well, then there's something going on. Very first thing I would say to go check as make sure that your SST is at the correct pressure.
• 0:20
  If it's at the correct pressure, don't trust the gauge. Don't trust the controller telling you verify it with your own gauges, make sure your gauges are reading that once that's done, verify airflow. Make sure you got perfect airflow. Then after that, then you start investigating even more getting deeper.
• 0:21
  It could be a plug screen. Or your, your power head is, is losing charge because it rusted out and you're losing that opening force on that TXV or whatever it may be. I guess that wouldn't be on the case controller, but that, that's the, the stuff that I would be checking.
• 0:22
  Speaker 4: Yeah, no, I think that's important because airflow is one of the things that a lot of people, Oh, well, I feel a little bit of error.
• 0:23
  It's good, but you've got to actually check it. Cause it could be a frozen coil. One fan could be out, could be dirty honeycombs, could be dirty baffles in the back. There's lots of different things that you need to check. Yeah. And just takes time and looking at these graphs will give you an idea of where it was to where it is right now in that service call.
• 0:24
  Andrew: Absolutely. And then that's one of the best things about these is you can actually see what happened during that time. And it, it makes your job as a technician a lot easier because depending on how it's set up, of course, you could go from case to case to case or you go to a lineup, it's just all, it's just all depend how it's set up, but it makes, diagnosing so much quicker and then set a walk in the store and check and see where it's at.
• 0:25
  So the graphs will tell the story, you just got to understand what it's telling you. Once you get, once you understand what the graphs are telling you, you're solid.
• 0:26
  Speaker 4: Yeah, I think, I think so too. I, for me, when I'm troubleshooting on case control is one of my main ones is looking at that Oprah percentage of the valve, because if that valve continually starts to open more and more and more and more and more trying to maintain temp, there's really something going on and why it's usually not, if it's slowly gradually open more, it's usually not like a failed transducer or temperature probe.
• 0:27
  Usually it's something mechanical happen. It's a plug screen, plug strainer. Dirty honeycombs if it's dropping down more potentially, but usually when I start to see that it's more on the mechanical side, not on the electro electronic side.
• 0:28
  Andrew: Yeah another thing to add to that, Trevor, what you just said was low on charge.
• 0:29
  If the system's starting to get low on charge, you're getting bubbles in the sight glass or whatever, plugged filter dryer. I mean, those, those will definitely tell you, tell the story. So we all know that we have to have a full head of liquid to the metering device. It doesn't have a full head. It don't work.
• 0:30
  Speaker 4: Yeah. Correctly.
• 0:31
  Andrew: It don't work correctly.
• 0:32
  Speaker 4: And that's, that's important because I've seen this many times on racks that have sub coolers and the sub cooler is not working properly. Now you start to run into issues at all the different cases. And the big thing is to understand how it works. Why do we have a sub cooler?
• 0:33
  Well, it's to make a system more efficient. So we have colder liquid going out to those metering devices. Now those metering devices are sized differently. If you have a subcooler versus a non subcooler, hopefully they're all balanced TX valves, so you get a bigger range on it. But these are the things that you need to take a, well, things that I went in and looked at a little bit deeper because if you're changing and adjusting something in any system, you really want to understand that.
• 0:34
  And this goes back to those trend graphs. If you're looking at a trend graph and you see something all of a sudden is drastically different, Potentially someone might've came in and change something. I really would always love to go read log books, but I hear more and more people. They don't have log books anymore as much as they used to.
• 0:35
  And some people don't want to write them. So you always go back into the tablet or last service call. And that's where you're probably getting most of your information.
• 0:36
  Andrew: Yep, I've done that too is is a follow up on a on a on another technician that was out there. Just make sure that you guys are not chasing each other, you know.
• 0:37
  So definitely go through the history on your mobile device or whatever you have. And verify that you guys are not fighting each other, so to speak on, on the service calls and just a system analysis. I mean, just getting out there and looking and knowing what is right. I can't stress that enough. No, what is right first, then you could diagnose what is wrong.
• 0:38
  Speaker 4: So getting, getting back into the, the trend graphs, what's really good about all the newer systems that are out there is that you're, we're seeing more and more of that, we're seeing more energy optimization where we're seeing more systems integrating trend graphs. Cause back like 10, 15 years ago, there was like, I worked on a lot of micro thermal and.
• 0:39
  And there was tons of, they had great graphs and you could overlay lots of different graphs where on E2, it wasn't so easy. You'd have to get into now. Ultrasight would have been a little bit easier, but you'd get graphs and you just couldn't lay overlay them. Well, I didn't know how to do that 15 years ago.
• 0:40
  What are your thoughts on the different manufacturers and the trend graphs? And like, if a technician is going to work on a Dan Foss, like you talked about earlier, what are some of the things that they need to go look into to see those trend graphs? Yeah, if you,
• 0:41
  Andrew: yeah, if you could overlay graphs, it just makes life so much easier.
• 0:42
  So you could see you could have where your case temperature or your suction pressure where it needs to be, or even your head pressure and see, and you could graph that and then to what it actually is. What is your actually case temperature? What is your actual you know, opening of the valve? I mean, it makes life so much easier when you know how, what you're looking at and how to diagnose, and all of a sudden you'll see something weird, like well, let's talk about some CO2 stuff right here.
• 0:43
  So if you had a an HPV wide open, and then, and then you see it bounce close and open, bounce close and open, right? You could see that on the graph, right? And then you have your fla flash tank, flash, flash, gas bypass valve. You have that and you see it where it's at 90%, a hundred percent open at the whole time.
• 0:44
  And you're running into an issue where it's high head. Well, I would be going checking out that valve, right? Make sure that make sure that valve is actually open. The HPV, sorry, is, is opening up all the way. Is it programmed right? Right? Is it have the number of steps that's needed for that valve? It could be someone accidentally put the wrong steps in that valve.
• 0:45
  And now it's way out of whack. So it's just stuff like that will get you to know like there, there's something wrong. Because we know that our HPV shouldn't be up at 90 percent or 100 percent open and same with the flash tank bypass valve. We know that it's not supposed to be at 100 percent open at all, all the time.
• 0:46
  you need to know what is right. Before, you know, what's wrong.
• 0:47
  Speaker 4: Yeah. Usually I've seen, I've seen a lot of sites, but not a lot of sites running. You see them between 40 and 60 percent open the valves. If we. You know, if they're running at 90 percent and it's cool out, like, why, why is it so wide open?
• 0:48
  And I've seen this many, many times where the strainers get plugged up. So the strainers before the high pressure valves, protecting them. And I've seen, I've seen it from my friend, Donald Cole, send me some pictures and on startup coming right from the manufacturer already, really plugged right up. So this is something that you need to look at when you're doing a startup or when you're going in three months later due to maintenance, going through and understand, looking at that PNID diagram, the piping instrumentation drawing, and then going in and looking at the trend graphs for all the different valves.
• 0:49
  And then that's how you fine tune it. If you didn't, it wouldn't be very easy to fine tune a system if you don't have trend graphs. Like you couldn't, you couldn't tell.
• 0:50
  Andrew: Yeah, yeah, exactly. And then you get, I mean, we all been there where the customer says, Hey, this, this case wasn't working. And then you show up.
• 0:51
  And guess what? It's pulled down to temp. Everything's rocking and rolling. Everything's just fine. So the graphs tell, like I said, tells the story of what happened. So you can go back into those graphs and said, Oh yeah, it was that three o'clock. Okay. So we get over there and we look in that three o'clock, guess what?
• 0:52
  Well, that unit went in defrost. You got a brand new manager. He doesn't know when the unit goes in defrost. So then you kind of, you just. It tells the story that you can educate them. It's really, really nice when you, when you can display what you have. And then there's the proof you could start taking pictures of it on the computer, say, Hey, well, I pulled up this graph that this time you're telling me this case was at this warmly.
• 0:53
  Absolutely. But also you lay over it to see the red line, or so to speak, that this was actually in deep frost during that time. So then you have the proof and everything. So it just makes life a lot easier. Yeah.
• 0:54
  Speaker 4: Yeah, I was with charlie conlef from micro thermal. So this guy's the training expert 40 years in the industry He knows micro thermal inside nuts.
• 0:55
  So we were at going through some co2 sites and we were fine tuning some of the case controllers going through some of the high pressure valve and flash gas bypass valve and it is an earth to fine tune it But you can't just all of a sudden after one week you can but you need some some time the run in time You Two months, three months to take a look at actually what happened over that.
• 0:56
  Was there anybody there changing anything? You got to get some runtime in. Some people say you don't need, you need a couple of weeks, but you get a good runtime like that, then you can go back and look, how is it running? Like we were trying to maintain this temperature and this temperature, well, it was kind of maintaining it.
• 0:57
  But it kept climbing up, or we were at the top end of the temperature range. If they put a differential and just say, you're looking for 36 and between 32 and 40, that's your, you want to stay in there, but it's running at 39 the whole time for the last three months. Well, what do you got to do? Well, that's going in and fine tuning that by looking at the graphs, changing the base set point, you know, maybe you don't need to go to a hundred percent after a defrost, or you don't have to run at a hundred percent at all.
• 0:58
  Maybe you only have to run it at. 70 percent or 60 percent of valve opening at all times or, or, or maximum opening. And this is, this is the difference. And depending on the controller, then it will depend on those limits you could put in there. Cause some, some will limit it after a defrost, some may not.
• 0:59
  And so it's important to get into those graphs as well.
• 1:00
  Andrew: Yeah, I would, I would second that. I had a a plate heat exchanger for A sub cooler for the, well, for a sub cooler and it would actually overshoot and undershoot. So it was constantly just bang and open, close, bang and open, close. So what I did went in there and programmed it.
• 1:01
  So it only opens up to 60 percent and only closes, you know, to like 20%. And then everything started to smooth out. Right. So again, you got to give it some time. So I come back a week later, that puppy was running so smooth. I mean, it did go up and down, but not bang on, bang off, bang on, bang off. Like it was.
• 1:02
  So I a hundred percent agree with that. Yeah.
• 1:03
  Speaker 4: Yeah. And so what I want, what I like about the electronics now is like a lot of people, TX files were here for 40, 50, 60 years, but the trends and the graphs weren't there, this is where a lot of technician did it by rule of thumbs and you know, that the way they were taught now, you can just go look at the data and data is key in, in refrigeration today.
• 1:04
  Cause we get so many data points. And we can troubleshoot remotely because of all these data points and all these data points go into trend graphs So one thing if you're working on e2s and things like that right now You may be able to go in and you say oh, I don't get any graphs How do you go into a base log set up a graph for that point you can do that So it'll, it'll go and it's not difficult to do, get into the e YouTube manual.
• 1:05
  It's 200 some pages, but you can go in and type go to a search or find on page and write trends I think it is, or graphs. I can't remember what I, I searched 'cause I've done it before. And it brings you right to that section on how to do base logs or maybe it's base logs as well. I had Brett Cheshire from Copeland walk me through a couple of times on how to do it on the E three and it's similar to on the E two.
• 1:06
  So if you want to add a probe to check something, you can do that stuff. You know, go in, add a probe so you can monitor remotely if you're running into issues on something and then you can check that trend after a week or something, run it for the weekend and see what it does with that probe that you add to the multiplex board.
• 1:07
  Andrew: Yeah, absolutely. I have actually done that,
• 1:08
  so I had an issue where I had an oil trip on a, on a rack, and I didn't, and I didn't know why. So you get there, you get over there, you check between l and m with your volt meter.
• 1:09
  You read 2 2 0 8, 2 40 or one 20 depending on what power supply you have to it. It, it read a voltage. So I know it tripped out on oil. So then I look at the sightglass. I have oil in it. So I'm like, okay, so I didn't like run out of oil. So this also had a current sensing relay. So I wouldn't randomly trip over a, you know, an overload that would pop open because it ran too hot.
• 1:10
  So nothing like that. So I hook up my gauge to it, to check net oil pressure and fire the system up and I have 40 pounds of net oil pressure. So I'm like, well, that's good. I mean, for Copeland, that is excellent. No complaints there. So I'm like, man, so I sat there and for about an hour trying to check things, I was checking temperatures on each of the circuits that are coming, coming down into the suction header and nothing was alarming me.
• 1:11
  So what I did was I added a board a sensor and I stuck it on the return on compressor number three. And then I let it, let it just start trending. So now I never did get a call back from this, but I ended up going back to see, okay, now I got, now I got some time involved so I can see, so I pulled that graph up and it went and, you know, we had about 40 degrees of system supereat and all of a sudden it just dropped and then it came right back up.
• 1:12
  So I knew something was going on at that moment in time. They did that. Probably like four or five times a day. It just all of a sudden drop come right back up drop come right back up So i'm like, okay, so something's happening during this time So now knowing that I start pulling up each circuit That's close to that compressor and start seeing what's coming right out of defrost at that time.
• 1:13
  This was a This was a hot gas system. So I started checking it and then, and then it was from my walk in grocery walk in freezer. When it come out of defrost, it would flood so hard. It would flood out the rack and then it would catch itself up and close. So I knew exactly what was going on because I added that and it would just happen to be that compressor because that's right where that suction header is, and it just drops right in.
• 1:14
  So knowing that. And having that sensor there just helped so much to diagnose what that, what was going on with it. So, I mean, those are the graphs that you need to do or what you need to know, because that really helps diagnose what's going on with with your rack system.
• 1:15
  Speaker 4: Yeah. So what, so, so what did you do to fix that?
• 1:16
  So, cause you found out, Oh man, cause after defrost. So what was your fix for that? For, for everyone to know?
• 1:17
  Andrew: Yeah. So I, I think I mentioned it earlier where I had to go in and close that valve down. It wasn't that incident, but that's what I did. I, I've, I've. It was on an EV and I, and I made it so it only opened up to 80%.
• 1:18
  Let it run again, checked it out. It was still flooding back just a smidge. I didn't like it. So I dropped that 80 percent to 70 percent and it just cruised. It never, never flooded out my rack out or anything. It was, it was perfect. So I just left it alone at that point.
• 1:19
  Speaker 4: Yeah. And this is why you need to go into, or this is why I would go in and check, depending on the controllers, does it have a different setting for the, the valve after a defrost, because some do not all do, you know, so maybe after a defrost, you limited the opening of it.
• 1:20
  Maybe you have maximum operating potential MOP settings inside there. So it doesn't open up so much, you know, so all these different New controllers that you may come across that you might not have seen before. There's a potential that there's settings inside there. So doing the trend graphs, looking at it, well, this doesn't make sense to me.
• 1:21
  What can I do to fix it? And so Andrew's one, like you said, Andrew, there was like, I, I just limit the opening of that valve because it probably didn't have to go that open anyway even during the running system. So that that's important to know. So that's awesome. Good on you.
• 1:22
  Andrew: Yeah, I mean, that's just just reading the graphs and understanding and how to put forward points or even move board points.
• 1:23
  I think that is really important for us as service technicians know how to do. And if you don't know, like, like you said, Trevor, get, get the manual, do the work. Understand and, and reach out to, there's plenty of manufacturers and even maybe some of your techs or mentors that will help you do that.
• 1:24
  They want to teach you. So I highly recommend just, just if you get to in that situation, you want to know how ask, you know, I'm not going to know what you're going to want to know. If you're like my apprentice, so ask, I, I'm just, that's where it begins. And, and you'll know right away if, if someone really knows and wants to teach you, because they'll be like, yes, let's go do this.
• 1:25
  And that's, and that's just, just as simple as just, hey, how does this work? And then that, that opens up that conversation.
• 1:26
  Speaker 4: And the big thing is, is that when you ask someone, you should ask lots of different people, a similar question to like, maybe not in your organization, but you know, usually when someone knows what they're talking about, they're not going to talk in circles.
• 1:27
  They're going to explain it in plain English, like a five year old would kind of understand it. You know what I mean? So that that's important to you. And then if. To get the confidence you want, you need to ask lots of questions and you ask different people. Cause I do, I work with people all around the world.
• 1:28
  I'll ask the same question to someone in Europe, in Australia, here in Canada, in the U S and just see their thoughts on it because it's different, different places we go, but refrigeration doesn't change. Thermodynamics is the same around the world. Andrew, how can people find out more about you? Get to know you, get in contact with you because you always love sharing.
• 1:29
  I see your great posts on LinkedIn and stuff. So how can people get ahold of you?
• 1:30
  Andrew: Yeah, I mean LinkedIn is the best place for me, for you guys to link up is on LinkedIn. I don't really post anywhere else. LinkedIn has, is very, I love it because it's professional and I want to help people and I appreciate it.
• 1:31
  Like like you said, Trevor, I, I just post a lot of these little training things that I come across. It might be electrical one day, it might be mechanical the next day. But usually, you know, that's, that's where I post and hopefully something reaches out to one person. That's all I really care about.
• 1:32
  That one person that figures something out, like aha moment or, or whatever light bulb turns on, it's like, okay, I know what he's talking about. I did my job.
• 1:33
  Speaker 4: It's awesome. Well, once again, Andrew, thank you so much for taking the time to come on the refrigeration mentor podcast. And we'll do this again.
• 1:34
  Andrew: Awesome.