Latest / The Refrigeration Mentor Podcast / Episode 217. Compressor Inspections and Identifying Common Failures with Dean Steliga of Bitzer Canada

Transcript

Episode 217. Compressor Inspections and Identifying Common Failures with Dean Steliga of Bitzer Canada · The Refrigeration Mentor Podcast

• 0:00
  Trevor: We keep sharing knowledge and hopefully you're getting some of this and you're taking some of it away and you're going to utilize it in the field, in your daily life. We love that. We're always bringing the top experts from around the world.
• 0:01
  And this week we got a, a deep technical session with a friend of mine, Dean From Bitzer Canada. He's been a inspection doctor for over 20 years on compressors. And this is a game changer. When you understand how to tear a compressor part inspected, you're going to find a root cause of that failure almost every time.
• 0:02
  Every time. And you gotta know what to look for. And this is what we're going to be diving into, into this podcast, because it is a game changer when you know what to look for Dean, welcome to the refrigeration mentor podcast. How are you doing?
• 0:03
  Dean: Good morning, Trevor doing very well. Thank you. Thanks for having me on and thanks for everybody for listening.
• 0:04
  Trevor: Well, no, I was super excited when we talked back in March and you're like, yeah, I'd love to come on and have a conversation with you because you've been doing this for 20 years. You've been seeing the same mistakes happening over and over again, even though all the training you guys do and all the, you know, knowledge that you share, we still need to continue to put this out, talking about flood back, talking about overheat, talking about slugging, which we're going to talk about today and the things that you've seen over the years.
• 0:05
  But why don't you give a little bit of History about yourself in the refrigeration industry.
• 0:06
  Dean: Well, in the, in the industry, I've actually been in in the business since 1985. I started out designing equipment for manufacturers dehumidifiers and ground source heat pumps, and I moved into refrigeration with Bitzer in 1998.
• 0:07
  So I've been here, been here for a while and I've been, I've been involved in the forensic analysis and failure analysis of the compressors since well for about 20 years now.
• 0:08
  Trevor: Yeah. So you've seen it all this, this amount of time you've seen it all, all the different types of failures, all the different types of excuses you heard out there from people and you've seen it.
• 0:09
  Because I know I've been a part of that as well and learning. And that's how I got good is by opening up thousands of compressors, looking inside and figuring out. And not all technicians have the opportunity to do that on a daily basis, but every time you get the opportunity, you got to take it.
• 0:10
  That's what I tell them. So if the compressor is failed, you might not be able to do it at that point. Maybe you have to get that process up and running right away. You get the new compressor in and that afternoon you pull it apart or that evening at the wholesaler or at your shop, whatever you, but you got to pull it apart.
• 0:11
  What are your thoughts about over the last 20 years, technicians inspecting compressor you've seen more or less or the same over the last 20 years of looking and inspecting from the field side of it?
• 0:12
  Dean: I would, I would say that we're seeing a lot more recently, very recently, say within the last four or five years, we're seeing more guys jumping in and opening the compressors up and having a look at them.
• 0:13
  We seem to find more of that after a training session. So some of our people will go out and they'll do these great training sessions out on the, out in the field at the, at the wholesaler or at the, at the. customer themselves. And after these trainings, all of a sudden now we've got guys looking at them.
• 0:14
  And you know what I like to see when I'm, when I'm, when I get a compressor back and we're going to examine it. And you'll see on our reports, sometimes an observation that the, the heads have been have been opened up or the valve plates have been changed or something. I love to see that. That means the guys are actually taking the time to go and try and repair something before they just send the compressor back or pull it out.
• 0:15
  And let's face it. These compressors are not small. small dollar items or small money. This is a big chunk of change for the customer, the contractor, for everybody involved. So if you're opening it up and you're looking at it, you're trying to determine what's the cause is, you think you've got something easy to fix, you're repairing it, we'd love to see that.
• 0:16
  Trevor: Yeah. And that's, that's exactly right. And this I've talked to manufacturers from all around the world, and this is what they want, because you can't learn if you do not look inside, there are different rules for warranty and stuff from the manufacturer who put the compressor in as well, because there's, there's different things as a compressor manufacturer, you sell that to different manufacturers.
• 0:17
  So you've got to follow the policies of the manufacturer of the actual equipment. But. You as a compressor manufacturer, you love to see that because, you know, hopefully they learned something from that autopsy. Correct.
• 0:18
  Dean: Correct. It would be a little bit more helpful if they would tell us that when they're when they send us in the the request forms to do the to do the return and to send the compressor back.
• 0:19
  Don't be afraid to put down what you think you found on that compressor. Nobody's judging here. We love to see it. We love to try and get an idea. It helps us kind of look into the compressor and, and helps us with the overall analysis once we've done all our observations.
• 0:20
  Trevor: Yeah, because the thing is, you get a compressor back, you don't even know what refrigerant it is, the application it is, and any information will be great, because I remember when I worked at the compressor manufacturer, it would come a burnout.
• 0:21
  What does that, you know, burnout, what's a burnout really mean to you? You know, it's actually an electrical failure caused by this, this, and this, and that usually comes back to a mechanical failure, which we're going to dive in today.
• 0:22
  Dean: Right.
• 0:23
  Trevor: What are some of the things that you believe that will really.
• 0:24
  Help a technician or motivate them to inspect it a little bit more. Do you believe it is the training that you guys are providing when you go out there? Is it maybe a little bit more confidence in, in them pulling it apart? What are one or two tips that you've seen over the years that you help technician get to the point where they want to open that compressor up?
• 0:25
  Dean: Well, absolutely. Education, training. Get as much as you can on the compressor. Not just, not just one brand or another brand. Get as much as you can on every compressor you can get your hands on. Open them up. Don't be afraid to open them. I don't think there's a manufacturer anywhere that's going to give you a hard time about opening up the compressor and trying to solve an issue.
• 0:26
  Just don't be afraid.
• 0:27
  Trevor: I totally agree because like you said, these are high ticket items. And when a compressor is in the middle of a roof of a big warehouse and you need a 300 ton crane to pick that compressor up, put it on the roof, then you got four or five guys rolling it across the roof and then you get it.
• 0:28
  To the where it is, and then you find out it's the contactor that's the issue and not the compressor. Right? Right. And that happens out there. Stuff like that has happened to me in the past. So doing these inspections can save your back, save your customer's wallet, and just bring more value to everyone, value to the manufacturer, value to the end user.
• 0:29
  Value to your, the con the, your business that you're working for yourself.
• 0:30
  Dean: Well, absolutely. Absolutely. Right. Anytime that you can provide confidence to your customer about your, your skillset, you are going to be the man, let's face it, you know, and not only for them, you're going to be the man for anybody they talk to in their industry that has similar equipment.
• 0:31
  Yeah. So this is just 100 percent beneficial to everybody.
• 0:32
  Trevor: I love it. I love it. Okay. So let's, let's just dive into it. Let's dive into some technical points to really find out. We know, and we've talked about this on the podcast many, many times. There's like five or six main mechanical failures. And then like five or six different types of electrical failures, but let's dive into a few of the mechanical failure.
• 0:33
  What are the main mechanical failures that we could see out there? A technician could see in the field. Probably the
• 0:34
  Dean: biggest the biggest mechanical failure is lack of lubrication. Something has happened to the oil. And what causes lack of lubrication? It's liquid slugging, liquid flood back, anytime the refrigerant is mixing with the oil.
• 0:35
  Guys don't have enough heat in the oil to begin with. You know, this is the reason we have crankcase heaters in them. If they oil, minimum oil temperature should be like, About 95 degrees Fahrenheit. If you're below that, you got refrigerant in the oil, you're losing lubricity of your oil. It's affecting the viscosity of your oil.
• 0:36
  This is going to attack your bearings. This is going to attack your rings. It's going to attack everything. Some of the things that we look for when we're opening up a compressor or something like that is you might see you know, we'll check the cross hatching. When we get a valve plate off, we'll check to see if the cross hatching is still there.
• 0:37
  Cross hatching is not there. It's perfectly smooth. This is going to affect the film of oil that keeps the pistons and keeps everything rolling. It's going to cause wear. So that's a good sign, you know, that something's happening with refrigerant and oil or high temperatures even. So it's, it's very complicated because you need to look at all of these things too many times.
• 0:38
  Like you said, yourself, you see an electrical failure, a diagnosis, the motors grounded. I see this all the time. Motors grounded. We pull the heads off and there's no pistons in the cylinders. They're sitting in the bottom of the compressor.
• 0:39
  Trevor: So how's that really an electrical failure? The electric failure did happen, yes, but if the pistons are in the bottom, that motor was still running.
• 0:40
  Dean: This is why you have to have a look at the compressors, why you have to open it up. Your electrical failure might actually be a mechanical failure, something that you can prevent when you replace it.
• 0:41
  Trevor: I totally agree with that. Let's talk about, okay, that that's one of the main major issues, lack of lubrication.
• 0:42
  And you just said there's like four or five different ways you can lose that lubrication. And this is something as a detective, as the technician out there, you've got to figure out. Let's talk about before we dive into that, the process of doing an inspection. So what is your process? Because I know what you do in your lab is different than what a technician needs to do in the field.
• 0:43
  You know, we just need them to look at a few different things where you're doing a full blown analysis. You're looking at inspecting everything, but in the field, technicians don't really need to do that to get to the point. Why don't we talk about what did you do in your lab on an inspection and what a technician in the field should do before we get into these failures?
• 0:44
  Dean: Well, the first thing that we do when we started, when we started any inspection is we give it an overall look on the outside. We're looking for discoloration, you know, is one head darker than the others. That's going to give us a hint of what might have caused the failure. When we, the first thing we will open is the terminal box.
• 0:45
  You're going to look at the terminals. Are they dark? Are they overheated? Are you leak, is there, is there a leak at the terminals? Well, overheating terminals can cause refrigerant leaks. There's a good, there's something to look for if you're having low refrigerant charge. You know is, are they leaking around the terminals?
• 0:46
  Have I overheated them? What's causing that overheat? So we're looking at that first. We check for the color. If we see a discolored head, that's the first head we're going to open up, and we're going to look at the valve plate, and we're looking to see if there's valves are deformed or if there's any color on the valves.
• 0:47
  Right? So if you see rainbow color or a copper color or something, you've got high temperatures, high internal temperatures. This is giving us an idea of where to look for problems.
• 0:48
  Trevor: And that's so important, you know, getting into doing that. And the first one's the visual one. Right off the bat. That one's a pretty easy one visual.
• 0:49
  If you see it really hot. And these are tests with the new tools that we have out there today, like the flair and the in thermal imaging gun, you can see this stuff. Cause I know I've read so many Bitzer documents and they'd say if you're selling their temperatures, this and your one right beside it is like 30 degrees Celsius difference, or even Fahrenheit difference.
• 0:50
  There's an issue. Absolutely. But they should be pretty close together, but if you get this big difference and this is, could be even while it's running. So that visual inspection is probably the key to start with. Absolutely. If the
• 0:51
  Dean: compressor is running and you're still having, and you're having issues you know, obviously you're going to check your, your suction line superheat, but something that guys very rarely check is the discharge line.
• 0:52
  Superheat. This is so important because it is, it is reflective of the refrigerant you're using as well. There are differences there. So, you know, a minimum superheat of 20 degrees Celsius for most refrigerants, and 30 degrees Celsius, if you're talking 410A, 407, R22, CO2 is even higher than that. So you need to have those minimum discharge temperatures.
• 0:53
  If you don't have it, if you have, if you're below that minimum discharge superheat, you're going to be looking at flood back to the compressor. You're looking at poor oil distribution, oil breakdown. These are things that if your compressor is running, don't forget to check that.
• 0:54
  Trevor: Yeah. And I think that's, that's the thing that when I, I worked at Copeland, we always did the, I always trained a discharge temperature check, which is key.
• 0:55
  But when I started learning more about Bitzer and talking with Phil and the team there, they were like, you need to check discharge super, do you want to explain how technicians can check the discharge
• 0:56
  Dean: superheat? Well, the discharge superheat is going to be, you need to, you need to actually measure.
• 0:57
  The discharge line, we, we like to say, some people say six inches. We like to say within four inches of the valve. You want to measure the temperature of that line, and then you need to take the condensing pressure of of your system. Find out what your saturated condensing temperature is, and your discharge superheat is the difference between the two.
• 0:58
  Yeah. So you're looking for, you're looking for 20 degrees Kelvin, which is Celsius, the differential, or 36 Rankine for most. most refrigerants, 36 Fahrenheit for most refrigerants. R410A, 407C, 22, you need to be getting 30 degrees Kelvin or 54 Rankin. Okay. If you're below those, you need to start checking your suction, superheat, your suction, flood back issues.
• 0:59
  You need to check that.
• 1:00
  Trevor: And these are quick checks because these are main checks on any, any system. Absolutely. Just like you do suction, temperature, suction, pressure, discharge, temperature. Discharge pressure, sump temperature, if you can get it, you know, the oil temperature.
• 1:01
  Dean: Absolutely. For our compressors, you would take that right, right at the oil drain plug or the, you know, right, right at the at the bottom of the compressor, at the bottom of the sump, you want to take a temperature right there.
• 1:02
  You need a minimum of 95 degrees, but you need to keep it under, right. You need to keep it under what's our saying on there? I think 175.
• 1:03
  Trevor: Yeah. Yeah. So that, that's super important because if not, you could have, like you said earlier, refrigerant in that oil. Absolutely. If you got refrigerant in that oil, you're going to start losing that lubrication.
• 1:04
  It's not going to kill your compressor right away, but this is where the damage starts. And this is what I try to teach technicians. You may, it may not you know, fail that compressor that day, but if this happens over a period of time, It's going to rapidly decrease the efficiency of that compressor, which will lead to a quicker failure because your compressor should last 10, 15, 20 years if they're serviced, maintained and installed correctly.
• 1:05
  Dean: Oh, absolutely. Absolutely. Some of the condensing units that I designed in 1998 with the Bitzer compressors, they're still running. So, you know, good maintenance program, you should be checking these things and always check the oil heat. If you don't have adequate oil heat, do you have a crankcase heater installed?
• 1:06
  I've seen them come back where it was evident that there was no heater ever installed in the compressor. And the compressor failed because of liquid in the cylinders and bearing failure. We knew what happened. If the crankcase heater is installed, is it working right? Is it working properly? Is it working on the off time of the compressor?
• 1:07
  So are your controls working with that? Yeah. So this is all super important stuff to, to, to do before the failure happens. You know, this should be part of your maintenance program actually going in and just making sure all of that stuff is, is where it's supposed to be. And you can find, you know, you can find the information that you need for that from any of the compressor manufacturers, you know, Copeland, Bitzer, Carlisle, they all publish this information.
• 1:08
  So it's readily available.
• 1:09
  Trevor: Yeah, exactly. And it's, it's easy to find, find today. But once again, it's like we talked about earlier, it's about the repetition. You got to do it and do it and do it over and over again. One of the big things is that I work with a lot of supermarket technicians and contractors from around the world.
• 1:10
  And they rely a lot. On that PLC, that controller, the temperature. So, okay, well, the suction pressure is this, the discharge pressure is this, this is the SSTs, but that's for all six compressors running or all eight compressors running. Do you want to talk about when you're working on a multiple compressor application what the process is?
• 1:11
  Instead of just using the controller information, because that's where a lot of guys get tricked up because if I have 10 compressors and only one cylinder is gone, can you tell that from that header suction pressures?
• 1:12
  Dean: No, no, no. You need to examine the compressors. You need to go and look at them and you need to look at, you know, check this stuff individually, go through the rack, one compressor at a time.
• 1:13
  Look at your cylinder head temperatures is one cylinder on one compressor are hotter than the others by a lot. That would be my suspect right there. That's where I would go. You got to break it down. Don't rely on, on what the controller is telling you, you know, are the sensors still accurate on the controller?
• 1:14
  Trevor: Yeah.
• 1:15
  Dean: Is it reading the proper things? You need to question these things, you know, and, and. Always, always inspect them one compressor at a time. Check the temperatures one compressor at a time because you can have six compressors all running and the system is causing an issue where one compressor is seeing a lot of oil come back to it, maybe even through the suction line and the others are not.
• 1:16
  And what's You know, it's causing the problem on that compressor. One compressor is vibrating a lot more than another, you know, these should be pretty smooth, fairly smooth operating machines. If one of the compressors on the rack is shaking, I would be right away on that and having a look at it.
• 1:17
  Trevor: I totally agree.
• 1:18
  And this is what I tell the technician is not, it's not, you're just not measuring all, all of them all at once. You gotta, you gotta do it individually. It takes time to do this stuff. Individually each one and then you're gonna find a problem a lot faster. Does it take longer? Yes But this is a part of our job.
• 1:19
  And when we do it right the first time, we don't have to come back and do it a second time. Absolutely. Absolutely.
• 1:20
  Dean: And if you're talking about a rack that has six compressors and each compressor is worth thousands of dollars, it's worth your time, you know, and your customer is going to understand that it's worth your time.
• 1:21
  Yeah.
• 1:22
  Trevor: Another big one that I, I talk about it and a lot of people, when we get into the supermarket, they have trouble with oil management, oil systems. Do you want to talk a little bit about the different oil management systems you guys provide for your customers?
• 1:23
  Dean: Well, that's, that's getting a little bit out of the forensic analysis, but oil management systems We, we rely on we rely on, on aftermarket products, obviously.
• 1:24
  But mostly what we're looking for is something that can provide us a steady level of oil return back to your compressor. So a lot of times you know, these, these, these can cause some really interesting failures because the valve sticks, the oil is not coming compressor and you've got a lack of lubrication system or, or a situation.
• 1:25
  Right. So yeah. Yeah. Oil management, super critical. Always check your oil management, part of your maintenance program. Yeah, absolutely.
• 1:26
  Trevor: And, and sorry, I didn't ask that question correctly. The two different types of way you guys lubricate your compressor. So that, that's what I meant by the question.
• 1:27
  So that was my bad. Absolutely.
• 1:28
  Dean: Well, depending on the compressor that we're, that we're talking about, if we're talking reciprocating compressors, we lubricate two different ways. We have the the dynamic disc, which is a splasher type plate that picks oil up from the crank case and drops it into a receiver cup at the front of the compressor, which is drawn down the crankshaft through passages in the crankshaft, out to the bearings, and out to the rest of the system.
• 1:29
  For the smaller horsepower compressors, you know, the, the 10, 10 and 15 horsepower maximum sort of compressors in regular refrigerants or any of our CO2s that are four cylinder or smaller. This works fantastic. It's a great system. What we do on the bigger compressors, bigger recepts, they have a gear pump in the front.
• 1:30
  So it picks up the oil from the, from the crankcase through a dip tube and pumps it out into the, into the compressor through the crankcase through the crankshaft.
• 1:31
  Trevor: Yeah. And so on there, there's two different ports. You've got a positive and a negative. What should that be for when a technician is going to check that?
• 1:32
  Because we said earlier, lubrication is one of the biggest causes of failure. What should that look like? You
• 1:33
  Dean: like to see 45 pounds on across those two ports. You really do want to see that you want to see 45 PSI.
• 1:34
  Trevor: If you don't, if you don't see that, there could be many things that are happening. Like we'll get into flood back could be an issue.
• 1:35
  Oil could be that oil management control that we talked about a little bit earlier. It could be one of those things, but these, this is one maintenance check that you have to do on every pump. You don't just check one and all the pumps are good on all of them. You got to check each one individually.
• 1:36
  Dean: Correct. Correct. Absolutely.
• 1:37
  Trevor: I love that. I love that. Why don't we dive into a little bit of a flood back and, and we'll talk about what flood back is and how does it, how, what you would see when you are opening or looking inside a compressor for telltale signs of a flood back situation.
• 1:38
  Dean: Well, flood back is actually liquid droplets in the suction gas that's coming back into the compressor.
• 1:39
  So you might not. It might not provide a liquid slugging smash, like you would see if you have a cylinder full of liquid that's trying to compress itself. What you will see, though, is the liquid tends to dissolve in the oil. It loves to, they just love to get together. Refrigerant and oil, they adore each other.
• 1:40
  And when it does, It, it reduces the viscosity, it reduces the lubricity of the oil. So what you're seeing with liquid flood back is wear. And we see that in rear bearings, main bearings, you'll see that as I said in cross hatching. You can, you can get a good idea if you're, if you're getting liquid flood back, if the system's running again, check that discharge superheat.
• 1:41
  If the discharge superheat is too low, you've probably got liquid flood back coming in. You're going to have to get that suction superheat higher somehow. So we see that in where, that's what we're really looking at and see if I have something on that.
• 1:42
  Trevor: Yeah. And for those that are listening right now, we'll have the video of all the slides and stuff up on on the YouTube channel, just to check that out because it's important to visually see it.
• 1:43
  But once again, you've got to hear this, listen to this three or four times, Take notes while we're talking about this, because this is going to help you out in the field.
• 1:44
  Dean: Yes, sir. So, some of the things you're going to see when, with the wearers, we talked about this, the cross hatching. This is something you can check in the field when you take the head off and you're looking at the valve plates and that sort of thing.
• 1:45
  If you lift the valve plate, you can check those cylinders and see if the cross hatching is still intact. If it's not, you've got a situation where you have high oil carryover, you've got lack of lubricity, lack of lubricity, you may have liquid refrigerant in the oil. What temperature is the oil in the crankcase?
• 1:46
  Trevor: That's exactly right. And this could be caused by a faulty TX valve or electronic valve. It could be a frozen coil in your evaporator, all the fans out for some reason, some, something may be electrical could be causing these mechanical issues. And this is why you got to look inside because if it's super shiny in there, that's not good.
• 1:47
  Nope. That's right.
• 1:48
  Dean: That's right.
• 1:49
  Trevor: And if anyone worked on cars before, it's a similar thing in the engine to have that cross hatching inside there, this is for the lubrication to keep that and like Dean said, if that's war and it's shiny and as that compression pushes up, but it's all war there, all that discharge gas could be potentially starting to go inside the engine.
• 1:50
  The sump of that compressor, I want to talk a little bit about that. What this flood back situation where we think about, okay, TXV malfunction, or you had a frozen up coil. Now we flood back. Now we wear that cylinder a bit and now it's super shiny. And what would happen next? And we're pumping that discharge going into the crank.
• 1:51
  What, what is the signs at that point for a technician?
• 1:52
  Dean: So now you're, now you're not, you have no oil. You have no oil. creating that lubrication film for the piston, you could be seeing some blow by. You could be seeing some, some discharge gas, getting some hot gas, getting down into the crankcase. That will start bringing temperatures up again.
• 1:53
  So you could see, you could see that oil sump getting higher and higher in temperature. And as you get higher and higher in temperature, again, what happens to the oil? You lose viscosity. So there's two situations with the oil, where you're losing lubricity. Too much refrigerant in the oil, which is low temperatures, or too high temperatures, causing viscosity breakdown.
• 1:54
  And you're getting more blow by coming by, which is causing more wear. And as these things are turning at, you know, 1, 800 rpm, so those pistons are going up and down, you know, 1, 800 times a minute. You're going to wear out some, some bearings and you're going to wear out some cylinders and rings and, and, and cause the compressor to stop pumping gas or even seize.
• 1:55
  Yeah.
• 1:56
  Trevor: And we talked, we talked about that. Dean already talked about that. Check. You got to check that oil, some temperature. If it gets over that one 75 degree Fahrenheit, that's, that's an issue. And that's, could be a sign of potentially. And I always talk about in sequences. Cause it just, this doesn't happen.
• 1:57
  We had the fans go out, we froze up the coil. We had liquid returning as droplets. We wore to cell nurse. Now all of a sudden the discharge goes into the oil, increases the temperature of the oil, which maybe led to a seized compressor. But before that was still running, we're over we're 200 degrees Fahrenheit oil.
• 1:58
  There's an issue. What is it?
• 1:59
  Dean: Absolutely. So anytime you can check those things while you're running, you're going to, you're going to help prevent that compressor from failing.
• 2:00
  Trevor: What's a, what's a good way to check with, you know, without the tools, you know, we always need to put the gauges on and the temperature probes and the gauges, but what would be a good check?
• 2:01
  Cause I've, I've always told guys, if you see in the sight glass, it's full of foam and all of a sudden the oil starts to drop off, potentially that could be flood back, do you want to talk a little bit about a few things that could cause foaming in the oil?
• 2:02
  Dean: Well, absolutely. Foaming in the oil would be like, as you, as you mentioned, you've got liquid refrigerant coming back in.
• 2:03
  It could cause foaming in the oil. There are other reasons for foaming in the oil as well. It may not be a serious issue, but it should be a trigger to have you go and measure all these other temperatures and make sure that, you know, If everything's in the manufacturer's specification and you've still got foaming in the oil, then we'll have to look at maybe something else a little bit different.
• 2:04
  But generally speaking, foaming is a function of liquid flood back. Yes. The way you got liquid in the refrigerant.
• 2:05
  Trevor: Yep. And this is something you go up and you look in all the site classes that if you don't have any foam in, okay, you still want to check your suction superheat, your discharge superheat, your pump pressure, your oil sump temperature.
• 2:06
  These are checked and your amps and your volts all the time, because all that into place, because you take this information and you go back to the Bitzer software or the app, and then you plug that in for that specific compressor, and it will tell you if you're running efficiently or not.
• 2:07
  Dean: Absolutely.
• 2:08
  Absolutely. So what is the result of this lack of lubricity? In fact, you know, when, when this oil loses its lubricity, loses its viscosity, what can happen? You might end up with a little bit of extra oil carryover, which it means your oil is now leaving the compressor in excessive amounts into the system.
• 2:09
  There's no more oil in the crankcase. So what a lot of guys may want to do is, Pump a little more oil in there and see what's going on. Now you're causing oil slugging in the coils, in the condenser, in the evaporator, all this oil sitting in there, reducing your system's efficiency, creating capacity issues, and maybe causing further problems with overheat or out of, out of spec systems.
• 2:10
  So again, check these temperatures.
• 2:11
  Trevor: Yeah, and I totally agree with that. I have a lot of people that send me pictures with cylinders full of oil. They're like, Trevor, I just took the head off, but my cylinder is full of oil. Both cylinders are full of oil. Do you want to talk about some different ways that the cylinder, the top of the cylinder could be full of oil between the valve plate and the piston?
• 2:12
  Dean: Well, sure. This is a, again, this is another lubricity problem. Your oil has lost its viscosity. It becomes like water. It can get through the whole, it can go everywhere in the compressor. And most particularly, it ends up carrying forward into the, into the cylinders and into the valve plates and the discharge galleries.
• 2:13
  So you can get a lot of oil built up in a short period of time because of this. It can also cause a liquid slug. And you'll notice this right away when you open up the valve plate and you find, well, a couple of valves are missing or little chunks of metal in the discharge gallery. Or more commonly what we see actually is you'll see discharge valves actually bent, missing broken when you've got a slug happened from, from inside like that, when it's a carryover slug like that.
• 2:14
  So you'll see that sort of thing. If you're looking at a bent suction valves, that is probably liquid refrigerant coming back into the compressor, too low superheat.
• 2:15
  Trevor: And so that too low, and is it different on different compressors, like pump style versus your dynamic disc or a splasher feed? Style when flood back is happening.
• 2:16
  So you have a pump or you have the splasher when you have flood back happening. Does it look differently? Does it look exactly the same? Well, if
• 2:17
  Dean: the, the, the thing about having a liquid flood back or, or refrigerant in the oil in a pump system, of course, is the pump, the pump may cavitate a little bit.
• 2:18
  So you could see a little bit of wear inside these gear pumps. It's not really common, but you could see that the refrigerant gas will flash out of the oil at the pump as the pump increases pressure, the gas will actually flash out of the oil before it gets into the into the compression cycle of the pump, and you'll get a little bit of cavitation where it's with a splasher system.
• 2:19
  You won't see that.
• 2:20
  Trevor: Okay, well, well, that's kind of how we dove into, you know, flood back now. What's the difference when you get a flooded start? You know what I mean? Like what causes a flooded start and what does that look like when you're doing an inspection?
• 2:21
  Dean: What did start when you, when you get a flooded start in an inspection we're going to see blown head gasket.
• 2:22
  We're going to see broken suction valves bent suction valves. You're going to see smashed pistons rubble in the crank case at the bottom. When you lift it, when you lift the valve plate off and you know, if you can move the pistons up and down in the cylinders, you're okay. But if you push on one of those pistons and it goes right into the crank case, Yeah, you know, you've got an issue there.
• 2:23
  And, and liquid liquid starts flooded starts is probably one of the worst conditions that I think you can get because at this point, your cylinders are full of liquid refrigerant that have migrated there or oil that has actually been pumped up into there. And as the compressor, the gap between the top of the piston and the valve plate is very, very small.
• 2:24
  That's how we get our efficiency. When you're trying to compress, you know, even small amounts of liquid in that little gap you can't compress a liquid. So something has to go and it's always mechanical. And this is where you're going to see the damage to the valve plates. And pistons and connecting rods and
• 2:25
  Trevor: yeah, yeah, exactly.
• 2:26
  So I'd love to talk about the difference in, if there's a difference. And so we got a slide of liquid slugging showing deformed valve, blown gaskets, you know, damage valve plates, but could you tell a difference between flooded start sluggings and or flood back sluggings when you're doing an inspection?
• 2:27
  Dean: It's, it's very hard to do, although a flooded start, generally speaking, might not have the same amount of bearing wear and wear on components underneath at the bottom, whereas liquid flood back, you will definitely see where you'll see where to the we use a PTFE coating on the bearings. You'll see that worn right out.
• 2:28
  You'll see You might actually see rubble in the bottom of the compressor because, you know, the connecting rods have bearings in, in the connecting rods. And as those wear out, sometimes they don't seize, they just shatter into a bunch of little pieces there, you know? So you'll see that kind of thing.
• 2:29
  If you've got a lot of wear, a lot of excessive wear, you're probably looking at flood back. If you've got one cylinder that smashed a piston or broken the valves, and there's not a lot of wear, that cross hatching is still there. You probably got a flooded start situation.
• 2:30
  Trevor: And so you just got to remember to the different components in the system.
• 2:31
  If you have an accumulator in that system, it's going to protect help protect against the flood back, but does that protect against flooded starts?
• 2:32
  Dean: Oh, no, no, no, no. This is, this is this is something that flooded starts. If you get liquid migrating back down to the compressor over a long off cycle or something, then the liquid is migrated to the coolest part of the system, which at that point in time is the one compressor.
• 2:33
  This is where you're going to have issues with flooded starts.
• 2:34
  Trevor: I totally agree with that. Okay. There's one thing that I've been teaching for years when I've teached on coplan compressors for 460 Compressor if you have major flood back with their pump system The very furthest bearing is always going to get weird first because you have oil traveling and it gets less and less oil We've all, I've always taught shake hands with the crankshaft because that main bearing on the pump systems would be the first goal.
• 2:35
  So if there's a lot of up and down play on the crankshaft, that means that stator would drop and scrape. And then you usually get that where guys say it's a burnout, but actually it's a flooded back situation because the main bearings work. Drop the rotor, rotor drag, correct. That electrical failure.
• 2:36
  Would that be a similar test in in your guy, Bitzer compressors?
• 2:37
  Dean: Absolutely. Absolutely. We have, we have the rear bearing as well, but you'll see when we see rotor drag, we're going to see that very quickly when we open the back cover. You open that up, you're going to see right away, because the rotor itself has, has got definitive marks.
• 2:38
  You've got a black motor because the whole thing burns and it burns very, very quickly. It's not a slow burn like you would get with overheating or or, or liquid flood back. But you'll, you'll see that sort of that sort of situation. Yeah. See if I have a if I have something on that.
• 2:39
  Trevor: Yeah.
• 2:40
  But the thing is, though, we, we kind of got into in a how to inspect it. If you're going to take the back cover off, make sure the oil is out. So that would be the end bell. So you've got to make sure it's drained. A lot of the times when we're doing it, you're doing an inspection, you just have to safely isolate this compressor, lock it out, electrically, properly, get all the refrigerant out, safely recover that refrigerant out of there.
• 2:41
  So you're, you can safely work on it. When you loosen the bolts, don't pull them all off. Make sure there's still two in there and then you crack the head. So if there's any pressure, it doesn't blow up, blow on you. But if you're going any deeper than looking at the heads you want to pull that oil out.
• 2:42
  Even the pump, I think you could take the oil pump off maybe without having to drain the oil. Dean.
• 2:43
  Dean: I wouldn't do it. I would drain the oil. Anyways, you kind of want to do that anyways, because you want to have a look at the oil itself. And this is something you can actually do in the field. quite easily without opening the heads and everything.
• 2:44
  It's just take a little sample of the oil out of the compressor and take a look and see what's happening. If it's if it's black like tar, you need to get deeper. If it's really clean well now you have to look at maybe different things because if it's really, really clean, if you're getting any kind of bearing where you're going to see a little bit of coloration in that oil, you'll see it a little grayish.
• 2:45
  If it's crystal clean and yellow, I'm not talking about the bright, you know, leak detector yellow, but if it's, if it's crystal clean and clear then you're not, you, you probably don't have that much wear in, in the system. Again, you're going to do an analysis to see if there's any kind of acid or moisture and everything.
• 2:46
  And, and, you know, this is something I've said on, on on the on the bullet points is non condensibles. are a huge cause of compressor failures. Huge cause. You have oxygen in the system. Somebody's done a test and used the oxygen on their torch, whatever they want to do. It's it, it, or nitrogen in the system and they haven't pulled it out.
• 2:47
  You got a multiple compressor system feeding you know, your condensers, which could have multiple circuits and multiple control valves and everything. Did you open up all the valves is, you know, when you pulled the vacuum and this sort of thing. This causes, if you don't do this and you have non condensables in there, these can cause issues with your oil as well.
• 2:48
  Like these come back into the oil, they create acid. You can see that maybe some copper plating in, in in the bearings and things like that. You know, when you, when you get enough heat,
• 2:49
  Trevor: I want to just before we dive into this, these pictures here of lack of lubrication, what are your thoughts on testing oil?
• 2:50
  Because this is what I'm training heavily for maintenance. And how and why technicians need to be checking oil in their systems consistently, especially the supermarket ones. I'm not talking about the little one ton or two ton system, but talking about supermarket racks are larger systems that have.
• 2:51
  Multiple compressors on it. And what are your thoughts on the type of oil analysis they should be doing
• 2:52
  Dean: well for, you know, from, from a compressor standpoint, you need to be checking to see if you're Well, if it if it's got if you've got viscosity, it's a little difficult to check. You can test for that.
• 2:53
  Actually if you've got good viscosity, if the oil is clean and clear, really look at the color. Look at look at the look at the oil itself. If it's grayish. Looks smoky. You've got a, you've got a high temperature situation. You got bearing wear situation. If it's black and opaque, don't just change the oil.
• 2:54
  Now we have to dig in and check the motors, you know, check your motor, check your terminals, see if that engine, if the motor is still in good shape. You want to open up the heads. You want to check the pistons, make sure they're moving tightly. There's no slop or play between them, which might indicate bearing wear down below.
• 2:55
  You have to get deeper when you, when you've got black oil, some guys just drain it and change it.
• 2:56
  Trevor: Yeah.
• 2:57
  Dean: Shouldn't, should never do that. Should always check for it. Good idea to do an acid test. Because you don't know what's happened in there. If you've had some kind of an overheating issue, there was a little bit of moisture left in because of, like I say, evacuation, or, or whatever reason you got a bit of water in there, like water cooled condenser you know, had a busted a leak or a pipe broke.
• 2:58
  You don't know how you're going to get that in there. You want to check for acid because acid will eat the insulation off your motor. It will eat away all your bearing. It'll, it'll just do all kinds of damage to the compressor. If you've got acid in the oil, now you've got to get deeper into the system.
• 2:59
  You know, you, you can do the cleanouts and, you know, doing cleanouts is great, but make sure you understand where. Why is there acid in this system? There should be only two substances in any refrigeration, compressor, Trevor, oil, and refrigerant. That's it.
• 3:00
  Trevor: Exactly. And this is why it's not, not just going by the 50 oil, oil kit or acid test kits.
• 3:01
  You've got to send this out to like, cause if you've got a big system with. 20, 30, 40 gallons. You're going to send this to a lab. It's not that expensive either. Maybe a couple of hundred dollars, but an oil change could be tens of thousands of dollars, depending on the size of the system. Cause how expensive oil is.
• 3:02
  So send it out to a lab and actually get a test. I tell everyone, if you're on a big system once a year, that's part of your maintenance. And then it'll tell you, do you need to do an oil change or not?
• 3:03
  Dean: Or if you have an issue.
• 3:04
  Trevor: Or if you have an issue, if
• 3:05
  Dean: you have an issue,
• 3:06
  Trevor: I love that. I see what I see on here.
• 3:07
  So lack of lubrication. So those that are listening, there's, you got the rotor drag, you got the worn bearings you got the worn pistons because that's your journals off your crank, let's talk about the, the wrist pins, what are some tests for wrist pins and how you can get damaged wrist pins in a system?
• 3:08
  Dean: Damaged wrist pins is. Again, you get a bit of acid in the system. It's lubrication guys. It's oil. Okay. Lack of lubrication, overheating, which is caused by lack of lubrication or high temperatures you know, high return temperatures operate the compressor outside that's the manufacturer's envelope. We actually test our compressors guys.
• 3:09
  So that envelope is actually a proven envelope. And when you operate outside of that. that's where you get the oil breakdown. So you're going to see copper plating on the wrist pins. You're going to see scoring on the wrist pins. You could see wrist pins wearing an elliptical, you know, they, they fit into the pistons very fair, fairly tightly.
• 3:10
  And you'll see that opening in the pistons themselves. Turned into an oval as it wears itself through and your, your piston gets all sloppy and, and this is lack of lubrication, overheating, temperatures again.
• 3:11
  Trevor: And I love that because these are little things that you need to check consistently. So one way that I have always taught, you know, is that you.
• 3:12
  Get the piss in top dead center, turn a little bit, and you push down. If that just drops, you got risk and wear and that compressor. And cause I know that a lot of people can back in the day, everybody used to just fix the compressor, change a piston, you know, cause that's what they had to do today.
• 3:13
  It's not as common because there's more mistakes that can happen. But if you find that out and you see it's a risk and where you got to change, you got to replace that compressor. Absolutely. Absolutely. Because there, there's a lot of times if you get once again, it comes back to that process. What really happened?
• 3:14
  What was the story of the compressor? And this is what I kind of talk about. Well, a slug happened, the discharge valve smashed. So because of that slug, whatever caused that that, that slug, and now you got discharge pressure pushing in on the piston. So the piston is not coming up as far. Now it's starting to wear that, that wristband.
• 3:15
  And now you get that wristband. So just instead of. Replacing that valve plate, because that's a lot of money just to do the valve plate, do your customer a favor, because if you hear a knock in that compressor, maybe the compressor needs to be replaced, and just not the valve plate. Do you want to talk about some compressors that you've seen come back where they could have stayed in the field with a, with a quick, not a quick fix, but a repair instead of a replacement?
• 3:16
  Dean: Wow, we're talking probably 5 percent at least of the compressors that we see coming back. You don't even need to repair them. I get five percent of those compressors come back. They're spotless. They're brand new. There's absolutely no issue with these compressors. Something happened in a control or you know, miswired overload, something, something Outside of that compressor has happened.
• 3:17
  They've changed the compressor, many thousands of dollars, sent it back to us, and honestly, you could take that compressor, put it right back there, it's going to work fine. 5 percent of those are no, no issue at all. There's probably another, I would say another 10 percent that come back where a liquid slugged one cylinder, and it blew a gasket, or it blew the valves on the valve plate.
• 3:18
  Everything else is fine. You know, we've checked it, the pistons, there's no slop, there's no wear, there's no stiffness in the, in, in the mechanics, change the valve plate, and you could run it again. We can't do that here. When we do an analysis, we tear it right down to the very last bolt. Yeah. So. We've got brand new compressors torn down to the very last bolt sitting in the back of our shop.
• 3:19
  Trevor: Yeah. No. And I love that. And that's how you learn. I tell the technicians once, at least once you got to pull it down like that, pull everything apart. You don't have to do when you're doing it more and more inspections, you don't have to get that deep as the manufacturer does, but just do it once. So you can see all the, all the components.
• 3:20
  And I send so many people to the, I think it's a Bitzer E parts store. So they can go in and look at. Every component inside one of your compressors, because it's so important because just one of those components could fail in there that caused the issue from a system related issue. You know, a lot of people like, oh, you know, it's a, the manufacturer's issue.
• 3:21
  It's, it's a compressor issue, but it's a defect. Yeah. It's a defect
• 3:22
  Dean: 90.
• 3:23
  Trevor: There is a small percentage of all manufacturers that have, cause you're making millions of compressors, you know, but
• 3:24
  Dean: it's
• 3:25
  Trevor: like 5%, 2%. And we're talking millions of compressors. Cause you guys do have unbelievable quality control. You know, you're not letting compressors just go out.
• 3:26
  You're testing them, you're running them and you're making sure that they're good before they go. If you get it to site and someone's saying it's a DOA dead on arrival, there's something else going on. 98 percent of the time.
• 3:27
  Dean: Here's, here's a, something that we, that I do see a lot we'll get it, we'll get a claim back.
• 3:28
  We want to return the compressor. They're requesting the return. And the cause of failure was DOA and the compressor started on, you know, May 1st 2023, and it ran until October 10th 2023. So, guys, that's not DOA, you know. Yeah, exactly, that ran. It would be, it would have been a lot more helpful for us in helping, helping that particular customer and getting back to them with reports and even, even sending on site assistance, if they could have told us that, well, we're not really sure why it failed, but, you know, it was pulling off road ramps when we got to the site, you know, and it blew breakers.
• 3:29
  That's more helpful than DOA. Yeah. Yeah. Yeah. Or, or motor grounded.
• 3:30
  Trevor: Yeah. Yeah. That's another one. Motor. Well, what caused it? Once again, it's 80 percent of the time is that mechanical issue and what caused that mechanical issue or more, you know what I mean? Well, it's one of those system related issues, you know, low superheat fans gone out non condensibles into gas could be one of many things, but that grounded compressor was grounded.
• 3:31
  For a reason, what's the story? I keep telling them because you know, the story, that's what I love about talking with people that inspected and failure analysis, you know, the story doesn't matter, the refrigerant doesn't matter. The application, you can really pinpoint what that story is. And if you talk with that technician in the field, you could probably say, look at this, this, this, and this.
• 3:32
  And that's where your problem is. So when you put the next compressor in, we don't get one back in two weeks or six weeks or eight weeks or two years or six years, cause it should still run.
• 3:33
  Dean: Well, this is, this is the whole point. I mean, you don't want, you know, you're going to have to replace compressors.
• 3:34
  Yeah, we know that. You don't want to have to replace that second one. So you really need to go in and look and see, try to analyze what's happened. It's, I'll be honest, it's not always possible. Sometimes we get compressors back that are so badly destroyed and so badly burned. It's almost impossible to determine was this liquid flood back?
• 3:35
  Was this too high heat? What, what actually caused this? We try to do our best. You got to look and say, you know, everything here, this motor burned. Did the motor burn first? Well, if your parts are smashed in the crankcase, no. The motor was still turning because that's how the parts got smashed. Did the motor burn first?
• 3:36
  Everything's in impeccable shape on the other side of the on, on the mechanical side of the compressor. But it's covered in soot. Soot everywhere. Well, right through the whole compressor. That's evidence of a slow burn. That happened over a period of time. Could have been, you know, many seconds or minutes or hours, whatever.
• 3:37
  But it didn't happen like a fast burn in under one second. So when you see a lot of soot, you open that valve plate and it's covered in soot and, you know, it looks like your old chimney. You've got a slow burn. This is something to do with operating the compressor outside the envelope, too high heats going into the, you know, too high suction superheat.
• 3:38
  Maybe some valve damage causing discharge gas blowby. So now we're going to go look at those components to see if, if anything was found there.
• 3:39
  Trevor: So, yeah. And it's so important to take your time with this because I see a lot of technicians Kind of rushing they feel they feel that you know The stress of having to get to the next job putting out a fire here going to the next job You know, there's a lot of pressure on the technicians today in the field But I promise you if you take the time to inspect these compressors that fail And you figure that root cause out you're going to go so for so much further in this industry You You're going to be way more valuable for any organization, as well as those customers, because you're taking the time.
• 3:40
  If it takes you an extra hour and I know it doesn't take an hour to do an inspection to find out if the valves are busted or a piston is busted, if you can take 15 to 20 minutes to inspect that fail compressor, to find the root cause that's game changer for you and your business. In your company.
• 3:41
  Dean: Absolutely. Absolutely. And if I know, I know time is always an issue for everybody, but anyone that wants to take the time to, to take that old failed compressor back to the shop and you know, to do a complete, complete teardown, it's going to take you three, four, five hours. Okay, you gotta, you're gonna take time to do it.
• 3:42
  It's well worth the time, and especially if you've got more than one mechanic in there, get everybody involved, try and make a, you know, an afternoon barbecue or an evening barbecue out of it, and just go to town and have a look at this thing. It's going to give you so much knowledge as to what's going on in that compressor, and, and what happened in the system.
• 3:43
  And you kind of have to be a little bit of a clue CSI kind of geeky guy to get into that. But I promise you the knowledge is, is, is really impressive. You know, when, when you get in there, it's kind of fun too sometimes.
• 3:44
  Trevor: Yeah. And the more and more you do it, like when you started out, it took a long time to do an inspection.
• 3:45
  Now you could take a, I know you could take a compressor now, do even filling out your report and you can crush it. You know what I mean? You can crush it in less than a half an hour. You, and you could probably find a failure. So you do it so many times you can find a failure maybe within the first 15 minutes.
• 3:46
  Maybe the first 10, you pull off that first head and you can, you can do it, but it does take time and it takes that repeat of doing it. So if you're only doing it once in a while, you got to do more of a teardown, but over time you'll get faster and faster and faster doing these inspection and the tell tale signs, just like the pictures that Dean is showing right now, is that the lack of lubrication, when you see this stuff, you're going to be no, okay, that rotor drag could have been from this, this, or this.
• 3:47
  Okay. Now let's check when we get the new compressor in those that operation of that to find out what was the real true cause. Absolutely.
• 3:48
  Dean: Some of the other things that we see coming in as well, when we're inspecting we're looking at the motors, we want to see what happened. You know, is there a way for us to determine what happened?
• 3:49
  Some compressors come in and the mechanical side is fine and the motors burn. What's going on in there? We pull the end bell off. And what are we looking at? We're looking to see if there's any, anything that was abnormal electrically. So a lot of guys when they replace, a lot of people when they replace contactors, a lot of people when they design systems, they put in the contactor and the contactor isn't sized correctly.
• 3:50
  You know, and this can cause some major issues, the contacts bounce, they weld on one phase, some kind of thing, it can cause single phasing, it can cause you know, all kinds of issues, but it always causes a motor burn. So guys need to size the contactors correctly. You know, don't just, the compressor says my rated load amps on the compressor is 30 amps.
• 3:51
  I'm putting a 30 amp contactor, 575 volts in there. Nobody looks at the locked rotor amps. Okay. So
• 3:52
  Trevor: that's a good point. So why don't you explain how somebody should go about sizing sizing a contactor, because this is where you need to get into the. The Bitzer app and take a look at that specific compressor because each contactor is going to be different depending on the size of that motor.
• 3:53
  Dean: Absolutely. Let's have a look at an example. So we're going to take a direct online. That's most of the most applications really are direct online. There are a few part wine starts. So there's some considerations that have to be taken there. But for direct online contact compressor 575 volt. Our, our, one of this model, this particular model, the the MCC, which can be found on the rating plate, divided by 1.
• 3:54
  4 will give you your rated load amps, if you don't see your RLA on the, on the, on the plate. Some of them have it, some of them don't. So this particular compressor, 25. 7 amps, and the locked rotor amp on the compressor, right on that rating plate, 140 amps. So, when we're sizing the contactor, you want to give yourself 25 percent safety margin.
• 3:55
  Bigger contactor is less of a chance of failure. So, what we're looking for is something that can handle 25. 6 rated load amps and 175 amp locked rotor current. This particular contactor, a very common one when we look at 575 volt. We find that this is a 30 amp, 30 amp contactor, and that in 575 volt, the locked rotor amp rating is four times the full load amp rating of the contact, 120 amps.
• 3:56
  Wow. 120 amps is not even the no safety factor locked rotor current that you could experience with that compressor. This contactor
• 3:57
  Trevor: shouldn't be in place. Wow. That is so, so important. And and this is how actual electrical, true electrical failures happen. This is not a mechanical failure. This is a true electrical failure.
• 3:58
  What are a few other telltale signs? Because you got. Single phasing. Like you said, you can have a turn to turn short, could be contamination that caused that phase to phase short. What are a few of the other electrical issues that you could see? Let's look at this little guy here.
• 3:59
  Dean: So if we're looking for, if you open up that compressor end bell and you can see a defined pattern.
• 4:00
  So you've got clear copper, three windings, three, three turns of clear copper, six turns of. Jet black, three turns of clear copper, six turns of jet black. This is a single phased motor. So this is a motor where one point on the contactor failed, and that clear winding, that new winding, is the winding that did not get power.
• 4:01
  that's the one that where the phase dropped off the black windings or the other windings that tried to make up for you know that motor is going to turn got to turn 40 horsepower it's going to do it on two windings if one's not there pulls way more current through those windings burns them up like that i love that so this is a this is a great Clear example of single phasing.
• 4:02
  It's not always this obvious.
• 4:03
  Trevor: Yeah. Yeah.
• 4:04
  What are, what are a few other electrical failures technicians can look for, because I think that one, those ones are sometimes a bit harder. Then mechanical failures, but all of them, it takes experience in looking at them.
• 4:05
  Dean: How about let's see if we got, what's this one, this one.
• 4:06
  Anybody who's opened up a motor that's fully burned has seen something like this. This is a complete overload. So the compressor was operating outside its, its rated conditions outside its envelope, drew way too much current and every winding burned in the motor. This is assuming, of course, you don't have rubble in the crank case, which caused this to happen, right?
• 4:07
  Yeah, exactly.
• 4:08
  Trevor: Yeah. And what, and what could, what are a few things that could cause the overload?
• 4:09
  Dean: Oh if you're operating outside of you know, you have no motor cooling, no auxiliary no additional cooling in an area of the operating envelope where you need additional cooling that can cause an overload.
• 4:10
  If you've you could see overloads happen if you have an extended pull down condition where you haven't throttled back the suction valve. These are situations that can cause it. Again, temperatures, you got to measure those temperatures. Yeah. And see what's happening. If the compressor seems to be running too hot, you've got really high discharge temperatures.
• 4:11
  You're looking at overloads. Yep. So exactly. Did the overload protection device quit? You know, a lot of guys in, in our particular case, we have overload protection on our on our modules that have a little jumper on them. That little jumper prevents that over, that module from automatically resetting.
• 4:12
  And we get into the field and a lot of times we see the jumpers missing when the jumpers missing on our overload, that thing is resetting every time. So you have an overload condition. It's overheated. It's it's gone. It's got an electrical overload caused those thermistors in the, in the motor windings to send the, the resistance above 4.
• 4:13
  7 kilohms. The module says shut her down. And it drops below 2. 3 kilohms, which is the lower, the lower reset point, and the module says, okay, we're all good, the windings are good, start it up again. You haven't addressed what caused that motor overload. All you're doing is killing the compressor. You're, you're allowing it to run in a situation that needs to be diagnosed and fixed before it, it's allowed to run again.
• 4:14
  Trevor: Exactly. Cause this is the funniest thing too, is like, I've talked to so many technicians, even I did in the field, you know, you get that oil failure control and it tripped off in the middle of the night, you go in and you reset it. Oh, it's working. It's running fine. I sat and watched it for 20 minutes on, and it's totally fine.
• 4:15
  There's no such thing as nuisance trips. Something caused that to trip electrically or mechanically, but there is an issue just like that. If that tripped off your motor overload, open. Something caused it to open. It wasn't just all just happened once. It's not going to happen again.
• 4:16
  Dean: Absolutely. Absolutely.
• 4:17
  We need to get into that. You need to see, okay, it's running, get out the gauges, get out the, get out your, your temperature sensors, get everything on there and say, what happened? You know what's the oil level in the compressor? Why did this trip? What's going on here? Check that oil pressure. If it's a, if it's a pump compressor,
• 4:18
  Trevor: check that oil pressure.
• 4:19
  And sometimes you do have to sit on a bucket and watch, I've done it before, you know, you just got to sit there and wait. It doesn't happen that instance. Patience. Yeah. Patience is key. Patience is key. It could be a certain compressor turns on, it could be a certain system that goes on hot gas defrost. It could be a certain thing that comes out of defrost.
• 4:20
  It could, you know, it could be one of many things. And sometimes you're just going to take the time and, and sit there and that's part of our job.
• 4:21
  Dean: Right. Some of the other things we've seen this kind of a failure when I'm looking inside and I see a slot burn like this. This means that something has got in there, some kind of contamination.
• 4:22
  Or as it says here or you've got a voltage surge. Voltage surges, we don't see a lot of those failures. Now, are, are they coming back on, on inspection compressors? When we do inspections, they're mainly for warranty claims or a customer requests. you know, can you do an inspection on this? Tell me what happened so I can fix the problem.
• 4:23
  We'll do those. We do get a lot of salvage core returns that we don't inspect those unless we're specifically asked. So I don't know if, you know, I can't tell you if we've got voltage surges more voltage surges in there. But on the ones we do inspect, no, we don't see surges a lot. What we do see is a lot of contaminants.
• 4:24
  Yeah, it's, it's, it's crazy.
• 4:25
  Trevor: That's us as technicians doing it, you know, we can't blame anyone else because the manufacturers aren't sending out the compressors with full of dirt and, you know, copper, copper shavings inside them and stuff like that. Right. That's what we're doing. And when we're installing a system.
• 4:26
  Dean: Absolutely. Let me show you a great example right here. This is an this is a Silphos rod that we found in the motor cover of a compressor that we inspected. That's a, that's a six inch length of welding rod.
• 4:27
  Trevor: Yeah, and it made it through the screens and made it through the, the, some part of the system in the suction line, I'm assuming to get in there.
• 4:28
  Dean: We see many, many come back. There's no screen in the suction. The screen that we put in, in the factory is no longer in place.
• 4:29
  Trevor: And this is, this is why you need to understand every component inside that compressor you're working on. Go and look at all the Bitzer has all this information out there, go and take a look, investigate on that specific compressor because there are two cylinder compressor is going to be different than their six cylinder compressor or their eight cylinder compressor.
• 4:30
  So you've got to understand each one. So this takes time. You don't learn all of this overnight.
• 4:31
  Dean: No, no.
• 4:32
  Trevor: 20 years.
• 4:33
  Dean: It takes
• 4:34
  Trevor: 20 years, but you can fast track by. Going in and inspecting more instead of just pulling one out putting one in and going to the next shop Do that inspection and over time you'll learn more and more man dean.
• 4:35
  I love this conversation we're gonna have to do this again because I know there's so much more that we can talk about that I'd love to dive in in with you What would be a couple final thoughts for some technicians out there how that they could start fast tracking their knowledge really?
• 4:36
  Bringing more value to their customers, bringing more value to their businesses a couple of tips for them.
• 4:37
  Dean: Go go go talk with your with your wholesalers or talk with a Bitzer representative or a Copeland representative, whoever you want to work on, get them to give you the training, find out where their trainings are.
• 4:38
  Go and attend these trainings. Believe me, they're fantastic. The guys that do these trainings have been doing this for a long, long time. They're going to open your eyes to a lot of situations that you may not be aware of. So, educate yourself. Educate yourself. Go see Trevor. Go on. Take his, take his training programs.
• 4:39
  Learn about this stuff. Give us a call. You know, if you have a situation, you're, you're, you're questioning something, we offer services to help out with that. Site services occasionally, if you know, if it's warranted, you got a, a supermarket where you've lost six compressors on there. Well, we need to go in and help you find out what's going on.
• 4:40
  Give us a call, you know don't be afraid to learn about these things. Take that, take, take one of those old compressors home if you're, if you're inclined to you, you, you like mystery novels and clue novels and detective stories, take the thing apart, let's go, you know, don't be afraid of it. If, even if you're just thinking about replacing the compressor, look at it first, open the heads, do what you need to do.
• 4:41
  Open things up, look at them, say, is this, do I need to replace the compressor? You know, can I get away with a valve plate and a gasket? Is everything, everything else solid.
• 4:42
  Trevor: I love that.
• 4:43
  Dean: Guys, change your contactors when you change the compressor. Every time, don't even, don't even question it. Just if you're changing the compressor, go get a properly sized contactor, change that contactor.
• 4:44
  It'll save you tons of grief.
• 4:45
  Trevor: Yeah, I totally agree with that. And I like what you said that, and this is not only one training. Like you go to a Bitzer training two years down the road, go to another one or go to another, you know, just don't, you got to consistently do this because you're going to learn something different from somebody else who is teaching it.
• 4:46
  And even if it's the same person teaching it, you're going to learn something. These are more questions you can have. You have two more years of experience, maybe a different things you see and getting into these training sessions, like the manufacturers have, like I have that you can dive into this stuff.
• 4:47
  stuff. And this is what we talk about all the time. This is, we want you to get to your next level. We don't want the customers to have to pay more out of their pocket because you know, you didn't inspect it and it just takes time and inspect those compressors and take a look at them. Dean, how can people get ahold of you, your organization, if they want to learn more, if they want to try to dive into some more knowledge from you guys?
• 4:48
  Bitzer.
• 4:49
  Dean: ca. www. bitzer. ca or the Bitzer website. Get familiar with it eParts the selection software. There's everything, everything that, that you need is on that site. All the documentation is available on that site. You can get a hold of us here in here in Montreal, or you get a hold of us through, through your favorite wholesaler.
• 4:50
  Most of these guys, most of the the wholesalers now in Canada are offering www. bitzer. ca. BITS are, BITS are hosted training sessions in their branches. You know, if you hear of one sign up, go like, we'd love to see a, you know, Phil, Ron, Alex, and Kim, they'd love to see you. And you know, we'll, we'll, we give trainings on all of this stuff.
• 4:51
  So ask, give us a call, ask, we'll help, we'll help direct you in the right way.
• 4:52
  Trevor: Thank you so much for sharing your knowledge with us. I know we're going to do this again because you're a wealth of knowledge of 20 years doing this. And, and like Dean said, you gotta just continue to grow your knowledge, invest in yourself, the more you invest in yourself.
• 4:53
  The easier job is gonna be. 'cause you're gonna build your confidence, you're gonna try a little more, you're gonna try different things instead of doing the same thing, day in, day out. Pigeonholed right now. 'cause I know I talked to a lot of teachers. It's the same, you know? So get in and take these trainings.
• 4:54
  Be like, let's try this. Let's size a contactor. Maybe you never size a contactor before we just talked about it. Go to your next system today when you're driving to a system. Go and check the the nameplate of that compressor and then go size it yourself and check. Is that verify? Is that the right size?
• 4:55
  This is how you learn going out in the field and doing the stuff we're talking about. Dean, thank you so much for taking the time to come on the refrigeration mentor podcast and we'll see you at the next one.
• 4:56
  Dean: Thank you very much, Trevor.