PLC Chiller Control Series Introduction – Process Chiller Pro Podcast

PLC Chiller Control Series Introduction – Process Chiller Pro Podcast

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Show notes

This episode introduces a multi-part series covering programmable logic controllers (also known as PLCs).

These episodes covering PLCs will help technicians who work on process chillers, rooftop package HVACR gear to residential furnaces, and everything in between.

Like most technicians, you probably service multiple types and brands of chillers and other equipment each week, so understanding PLC work will dramatically speed troubleshooting without needing to lean hard on the equipment manufacturers.

Learning how PLC’s work and troubleshooting more accurately and faster will make you more valuable as a technician to your customers and employer.

The topic covered in this episode of the PCP podcast is a foundational component of my skilled trade’s success process that you see here.  

We have a sign-up for a free five-day Mini-Course (coming soon) where I will share the four key elements of a success process that makes it possible (and I would argue likely) for you to become a millionaire working in skilled trades. 


Episode Transcript

Martin King 0:08
I want to start out this week’s episode with a scenario that may have happened to you. It’s Friday afternoon. By the way, these things always happen on Friday afternoon, and you get a call from one of your clients and their process. Chiller is not working. And you talk to the client, they’re definitely worked up because they were planning on working the weekend. But they can’t do that. Now, because the chillers not working and they have no cold water, so they can’t run their process, you find the chiller you open up the electrical compartment. As a side note, you’ve never really been to the site before. And you see that this chiller is controlled by a programmable logic controller or PLC. Now I know that you guys work on a variety of different chillers, different mechanical equipment, whether it be a rooftop package units doesn’t matter these days. PLCs are part of our lives, that’s just a fact. And in this scenario, you have to get it fixed. But you don’t have the resource of a manufacturer to back you up. And even if you did, the customers can get really stressed out because the manufacturers get backed up and you may be on hold for two and a half, three hours, you just don’t know. So what I’ve done about this scenario is I’m creating a series that’s covering PLCs. I’m going to be talking about the actual PLC itself, we’re going to talk about the different types of PLCs that are out there that you’ll see in the market. I’m going to talk about inputs outputs, a little bit about programming. So you kind of understand the craziness that can go into these PLCs and how they’re the software was designed because I actually did that for a while. And I’m going to give you a troubleshooting process that you can go through. So in this type of a scenario like I’ve described, you’ll be able to at least hit the ground running. And I’m going to give you some assurance that most PLCs they’re pretty darn reliable these days. So if you understand the inputs and the outputs, what should be happening versus what’s not happening, I think you’re going to be well on your way to solving a problem, an important problem for your customer. In doing so by if you’re a technician, and you’re able to understand PLCs and at least get the customers running faster, you’re going to be a rock star when it comes to the customer most important, as well as your employer, if you happen to be an HVAC refrigeration contractor, whether you work on chillers or not. This information will help you train your people. And by doing that, you are also going to turn into a customer magnet. If you understand PLCs in this world, you’re going to have customers that are going to be attracted to you because you solve the problems quicker for them. Before we get started, I wanted to just do a quick safety announcement. The content that process chiller pro podcast provides is really designed for experienced technicians only. So if any of the tasks that I described in any one of my videos are making you feel uncomfortable, unsafe, you’re not comfortable and know how to be safe with electricity, refrigeration plumbing, I suggest that you stop and find somebody with more experience to supervise you or help you do some of the tasks that I’m describing. I want you to be safe out there. So please don’t take any chances that can get you hurt. Hey guys, I have an exciting announcement. We just recently made some updates to our three most popular online courses at process Tiller If you’re a technician that’s looking to improve your skills a little bit, maybe get some specialized training to be of more value to your customers and your employer. Or if you are an employer, a contractor that is looking to augment your existing in house training with online training that can be accessible from any device. This is a really great opportunity. Just go to process chiller Academy comm just scroll down on the homepage and you will see the course area. If you go into the course page, you will see that we are currently for limited time. We have a promo code of chiller Pro that will save you 25% on any one of these courses. So I hope you check it out. And I’m looking forward to seeing you in class. As I touched on in the intro to this series, my goal is to provide the HVAC technician the diagnostic techniques in order to quickly determine what’s going on on a PLC equipped piece of equipment. Now this is not limited to just process chillers. You’re going to find PLCs or printed circuit boards on many types of equipment out of the market. This could be rooftop packaged units, it could be residential furnaces, and everything in between.

Here’s a list of topics that I’ll be covering in this multi episode series on PLCs. We’ll be covering some of the basics On the information that you always should collect from your dispatcher, when you’re on your way out to a service call and why you need that information how to perform a preliminary inspection of the chillers control architecture to determine if you do indeed have a PLC controlled machine. Assuming you do have a PLC control machine, we’re going to cover these items identifying and inspecting the PLCs inputs and outputs are what I refer to as I O how to verify if a machine is safe to run test. In order for you to do more diagnostics on the PLC control how to safely perform a run test to determine the operating condition of the machine how to check the HMI that’s the human interface. Or if your machine happens to have a PLC that has indicator light sequences, how to look at that information and determine what the PLC is trying to tell you how to identify how the PLC is measuring temperature. This is typically a thermistor. So we’ll get into what those do and how they operate in the series, we’re going to look at pressure transducers in figure out how they work and how to read the data that’s coming from them when to get the manufacturer involved in your diagnostic process. And I want to throw out an invitation to you if you happen to regularly work on machines with PLCs. And the list of items that I just described doesn’t cover some of the things you’re interested in, send me a message on LinkedIn or send me an email at M King at process tour Academy comm one of the benefits of having a multi episode series is we have the ability to make adjustments as we go along the way. So if you let me know soon, I can go ahead and look at other requests that are coming in and perhaps interject those subjects in this series as well. So I hope you consider doing that. Are you a contractor or facilities manager or maybe even an end user that has to use process chillers as part of your business. And maybe you’re having some short term issues like reliability or energy efficiency issues, or maybe longer term, you’re trying to put together a quality maintenance program that makes your machines run more reliably? Well process chiller Academy offers consulting services. And right now we offer a free 30 minute consultation, we’ll talk with one of our engineers, and we’ll help line you up with either short term or long term solutions. To make your equipment run more reliably and keep your processes running. All you have to do is go to the process chiller website and you’ll see on the homepage, there’s a link for consulting services. And right on that services page, you will also see how to schedule your FREE 30 minute consultation. So don’t wait, check it out. And we’re looking forward to helping you as soon as we possibly can. So let’s get to the mail. This question comes in from Stan Baxter of San Antonio, Texas. How you doing there? Stan? Nice to meet you out. Let’s get into your question here.

Stan wants to know, why are OEM replacement boards PLC is so expensive. Well, Stan, it’s the supply and demand. It’s that’s just how it works. It’s always been this way, it’s gotten worse lately, we’ll talk explain in a minute. Basically, when manufacturers decide to put a PLC or a board into their machines, there’s a specific form factor, meaning they have to fit into a certain space. They want special programming to do special things maybe that their customers are asking for. And that board is specific to that machine or that manufacturer. Because of that whenever you have to buy a replacement board from a manufacturer, it’s just going to be more expensive. Now my personal preference is if you are buying a machine, if you happen to have a higher end machine that has modular PLCs, which I’m a big fan of, I like those a lot better, the parts can be expensive, but you don’t have to replace the entire board, you can replace just the I O or a portion of the PLC that has is not working anymore. Now a good example of supply chain issues. When I recorded this episode, it was in January of 2022. We’re just sort of recovering from the pandemic. And the automotive industry has gotten themselves into kind of a pickle because the parts that go on the boards for their PLCs or computers that run the automobiles, they can’t get them. The manufacturers have went out of production for a while because of COVID. And we literally have 1000s of vehicles that are lined up that can’t be produced because they’re so reliant on these computers to make cars run nowadays. They can’t produce them quick enough. So I’m sure that the board manufacturers once they go back into production, they’re going to be aware that there’s a shortage so most likely supply and demand again, the prices of those boards are going to go up, which I’m sure the automobile manufacturers will quickly pass those additional costs on to the consumer. That’s just kind of how it works out. So, Stan, hope that answers your question. That was a great question. I really appreciate that. The next question comes in from Don clean out of Denver, Colorado, Don wants to know if we can remove a PLC from a machine. In other words, take the OEM board out and replace it with less expensive, more available parts. Okay. Short answer is yes. However, there’s some qualifiers here. So Don, if you do that, and that machine is under warranty, you can bet that all bets are off as far as getting any manufacturer warranty or manufacturer support, just the way it is. I know, that’s probably overstating the obvious. But that is the big caveat. So you have to make sure that if you have an emergency situation, and you got a customer that has to have that machine running and the manufacturer is not being cooperative, or is out of out of the park that you need, you’re just gonna have to make sure that you get it in writing that the customers are aware that their voided warranty has happened. So that’s something to keep in mind. The other caveat is that you can do it, I’ve got customers that have done it, where they’ve taken another brand PLC or in some cases replaced the PLC with some analog components, there’s a few tricks that you have to be aware of there. And I’m giving you an example, if you happen to have a variable frequency drive on a pump or compressor or something like that. Sometimes there’s a board on those major components, compressors, pumps, fans, that requires to get feedback from the PLC to operate. If that’s the case, you could find yourself in a bit of a pickle. So you’ll buy the new control architecture, whatever that is. And then you put it in there and you find out that the pump won’t run or the compressor won’t run, because its internal programming is waiting for some type of an input or enable signal from the old PLC, or board. So that is something that you have to really pay attention to. And again, it’s just a tough situation because you want to get your customer taken care of. But then you may end up with more problems. So you’re just gonna have to be smart in how you go about that. So hope that answers your question. So that was a great email segment. And if you’d like to have your questions read on the podcast, make sure you send me a message on LinkedIn or M King at process chiller Academy comm make sure you give me your name and town and let me know if it is not okay to put your question on the show. If you are not comfortable with that, I’d be happy to respond to you just one on one. But make sure you do that and keep the questions coming in.

So it’s time for this week’s words, terms and quotes. Last few weeks I’ve been doing quotes I’m going to switch over to do a term this week’s term is di D C. and that stands for direct digital control. So the whole concept of PLCs or programmable logic controllers can also be described as a DDC controller. So hopefully that’s helpful to you. Well, this episode of the process children Pro is a wrap as they say. Thanks so much for joining me today. I’m very much looking forward to developing relationship with you and seeing if I can help you in your career path as much as I possibly can. I’m looking forward to hearing from you on LinkedIn where I’m at most of the time I’m also on all the social networks. You can also send me emails at M King at process chiller. and I will see you next week for our next installment of the process. Chiller pro podcast. You have a great week and go get them out there. I’ll talk to you soon.