Latest / The Refrigeration Mentor Podcast / Episode 247. Oil Management with Patrick Gregory

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Episode 247. Oil Management with Patrick Gregory · The Refrigeration Mentor Podcast

• 0:00
  Trevor: Once again, bringing experts from around the world, learning about technical CO2 supermarket refrigeration, I have a returning guest, Patrick Gregory, on the call today, super excited for this conversation because Patrick's super technical.
• 0:01
  He's been in the industry six, seven years, but really, Understanding refrigeration now because he's diving deep. He's studying outside of work hours. He's getting the different calls. He's taking on harder calls because he wants to learn. And when he doesn't know something on site, he goes and researches and you know, and he's asking lots of great questions and I love having him on the podcast because we could dive into some deep technical conversation.
• 0:02
  Patrick, welcome to the refrigeration mentor podcast. How are you doing, brother?
• 0:03
  Patrick: Yeah, thanks. Thanks for having me again. Trevor. I'm doing good.
• 0:04
  Trevor: I know you were telling me that you're actually just replaced a CO2 low temp compressor.
• 0:05
  We'll dive into that today as well. But how did that replacement go?
• 0:06
  Patrick: It went well, all things considered, everything went according to plan, there were no surprises, anything like that, everyone, me and the guy I'm working with, we did it safely, efficiently, effectively, and got the system back online without any product loss or relocation or anything like that, so it went really well.
• 0:07
  Trevor: And it doesn't always go like that. You know what I mean? But in this case, I'm assuming, cause you were telling me it was low temp scroll. You got some Rotolocks on there. So you pumped it down.
• 0:08
  Patrick: Yeah, this was super easy. Just two Rotolocks. And then the, Oh, this one I'm an OMB, three simple wires, no core sense.
• 0:09
  very, very easy compressor replacement for sure. So
• 0:10
  Trevor: today we're going to talk about oil management. But oil management is something that. Man, it, I stumbled over it for years, years and years because I never really spent the time to learn really the engineering design behind them as well as nobody really talked about some of the things that we're going to talk about today because it just wasn't talked about, you know, for example, on these low oil pressure management systems, we'll start on a conventional rack, you know, you got a oil check valve and let's dive into what this oil differential check valve is on a low pressure system. So in, we always need a move. We need pressure to move oil. And if you don't have a pressure differential in refrigeration system, you need pressure differential everywhere, or you're not going to move the refrigerant or the oil. So in the low pressure oil systems, when you have the old mechanical pots, so those are a few that are watching it here on the side of a compressor, you could have the, Oh, well 60, you could have a Henry, there's lots of different designs out there, but these are just, they got a ball inside.
• 0:11
  They got a pin inside when they start, the oil starts to drop down, they open up and they fill up with oil, you know, if everything's running properly, but we know that discharge could be 200 PSI, 300 PSI, you know, 10, 20, 30 bar, whatever it is in the, in that oil separator or the oil reservoir, we can't be blown that into the, the compressor.
• 0:12
  So we have. differential check valve. I want to talk a little bit about your experience with it when you first started out, because when I first started out, I didn't know what an oil check for many years, honestly, for many years, we're doing supermarket because I didn't know what a OCCV was or an oil differential check valve.
• 0:13
  And I think it's a very important component to talk about.
• 0:14
  Patrick: Yeah, for sure. I do think it's one of the more critical and important components on your oil management system. Because like you were saying, it's sometimes, a forgotten component. Guys don't put a whole lot of thought into it because, you know, it's just that dirty brass valve on the top of your oil reservoir that maybe can't see all that well.
• 0:15
  But it's definitely a component that if it fails, generally two ways, open or closed all the way, you're definitely gonna start seeing two separate issues, depending on its, It's way of failure.
• 0:16
  Trevor: So let's talk about that. So how these ones were like, explain how they, they should work. What's the process of a oil differential check valve.
• 0:17
  Patrick: So the process of this, basically it takes your, reservoir pressure. And allows it to be, five, 1530. I think there's, three or four different ratings for them. so five, 1530 pounds above your suction pressure. So that way it allows your oil. to be low enough pressure. So it's not damaging your oil pots, but also high enough.
• 0:18
  So you can go high to low, you know, pressure goes high to low. So that allows that oil pressure to, get to the compressors and in a safe, effective manner.
• 0:19
  Trevor: And so many things can go wrong with that. If that line gets plugged up, if the, like you said, if it gets stuck up, what happens if it gets stuck open?
• 0:20
  Patrick: Usually when I see a stuck open OCV, I see, two or three balls up in the reservoir or however many site classes you have and some empty, empty compressors because, if we're open where our oil reservoir pressure is going to be pretty close to our true suction pressure and we're not gonna move in any oil.
• 0:21
  And it's very hard for oil to get from your reservoir. To all your compressors individually that way.
• 0:22
  Trevor: Yeah. And this is like any oil system. If you do not have a pressure differential, it's not going to move. And in CO2 systems, when we get into there, you need a higher differential than this 10 or 20 PSI differential or, you know, one or two bar differential.
• 0:23
  You're, you're looking at more of like a 60, 70, 80 PSI, depending on the system on a CO2 system, you might, you know, might need four bar, five bar differential to move that oil. But. Let's stick with this a little bit more. So if it's open, it's suction pressure. We're not going to move What other things could happen to the ocv you said if it's stuck closed what happens at that point?
• 0:24
  Patrick: If you're stuck close, you're going to be sending a lot of high pressure to your oil pods and, you might be when it's stuck close. It's a little different because you might see no oil in that reservoir because it's blowing all out of that reservoir and going, going somewhere. Hopefully it's not stacking to one compressor.
• 0:25
  You're putting all your, oil into one compressor that might have a, the level control on the oil pot open all the way. So you might see, the first compressor in line filled with oil and the rest, the rest less and stuff like that.
• 0:26
  Trevor: Yeah. And you definitely want to always look how the rack is piped up.
• 0:27
  All these systems are different. You know, it might be a Hussman rack, could be a ZeroZone, it could be a Hill rack. But even though it's the same model number, that could be piped a little bit different that day in that factory, because they're making so many, they try to make it exactly the same all the time, but the field piping could be different.
• 0:28
  You know, depending on the contractor who installs it. So you want to make sure, or something could have been changed in a rental over the years.
• 0:29
  Patrick: Yes. And I think it's important to recognize how many suction groups you have on this rack because, it's oftentimes you'll have three different suction groups with different, different pressures.
• 0:30
  So obviously you have to make sure that, you can get oil to all your suction groups at their different pressures.
• 0:31
  Trevor: And that, that's a, that's a huge thing because if you, I've, I've seen this before on rack. So even though you get a differential check valve, you have different amount of compressors or you got satellite compressors on there too.
• 0:32
  if it's not checked when all the compressors are running, when three of the compressors running, when only one compressor is running, there, there could lead to, to an issue. I've actually seen where you have multiple. Check valves in, in a system. Yes. And I had to reach out to actually, they were spor ones.
• 0:33
  I had to reach out to Sporin and find out well, for that because instead of a 20, they needed a 40, 40 PSI differential to move that, to get the, that oil into the compressor. The guys sent me the pictures and they're like, what is this? Back to back pressure differentials, but it needed that 40 pounds.
• 0:34
  And that's the way the guy did it. Have you ever seen that before?
• 0:35
  Patrick: I haven't seen any racks that have more than one, OCV. but, I, I have read about them, like you said, with, different requirements and different pressures that you need to move. So, I mean, it certainly does make sense that way.
• 0:36
  Trevor: And another one too, is when you're working with Carlisle's or compound, compressors, because you're looking at the slide now, if any of you are watching, or you're listening. You have that, like Patrick said, you have the line going from your oil reservoir to the, that your check valve to the suction header.
• 0:37
  But if you put it on a suction header of like a compound compressor where you have an interstage, which is a higher pressure, You're not going to be sent. You might send, sometimes the oil might get in there. If that, if that compressor is running in a certain, a certain time, certain position, but if you're not at that higher pressure, you may not get that oil in there.
• 0:38
  Patrick: Yes. You definitely have to recognize what type of compressors you're dealing with. And in that regard, whether it's a compound cooling or a standard recip and stuff like that, just make sure, cause stuff happens, there would be a rub through on a, on that line somewhere and someone relocates it, the access valve may be rusted shut.
• 0:39
  So some relocated it somewhere else and maybe they put it on the wrong suction group or the true suction versus the interstage suction. So, I mean, anything can happen when you've got different guys out there. So never really assumed basically.
• 0:40
  Trevor: Okay. Let's answer this. So I got three suction groups. I got one that's running at, 10 degrees.
• 0:41
  I got one at 20 degrees and I got one at 30 degrees. Okay. Different pressures, right? As they go up, it doesn't matter what the pressure is. Let's do it in temperature. Which one should they put that line on? If they have three suction groups?
• 0:42
  Patrick: I generally want that on the higher suction group. That way my oil pressure is going to be higher than my highest PSIG suctions so that I can still move oil to that suction group.
• 0:43
  Trevor: Yeah, exactly. Exactly. You want to always get that to the highest, highest pressure. So what happens, have you ever seen, oil check valves, differential check valves put on like a satellite compressor or put on to a different place than the suction hunter?
• 0:44
  Patrick: Yeah, I have seen the OCV ran what looks like to be original to a satellite.
• 0:45
  suction group and, under normal operation, you may not see any issues, but what happens when that sound like compressor control via liquid line, solid oil, suction stop, what have you has a failed pressure control and pumps down to a vacuum and now we're going to 30 inches of vacuum. So how, how well is our OCV going to work in that regard to still move oil to our other, you know, other compressors that are still running and still at.
• 0:46
  10, 15, 20 pound true suction. what happens is oil doesn't move very well because it's the, the OCV is, is trying all it can, so to speak, but it can't raise the pressure enough to, to move the oil to, the higher suction groups because it's still a 10, a five, 10 or 15 OCV. So it's still gonna try to maintain that difference.
• 0:47
  Trevor: Why don't you explain what a satellite compressor is for those that may not know what a satellite compressor is?
• 0:48
  Patrick: So a satellite compressor is usually still the common discharge, still parallel compression there, but it's gonna have its own suction group that's not in the domain suction header. And that's if usually like walk in freezers coolers or something like that additional load added later on perhaps is when is when you'll see that, and it's same discharge same liquid but it's just a different suction group.
• 0:49
  Trevor: So, so that's kind of, is there anything else we missed anything on the oil check? These do fail, you know what I mean? Yes, they
• 0:50
  Patrick: do. people say that, you know, they've been doing this for 40 years. They've, they've never seen it where, well, that's cool. Maybe that's true, but I've only been doing this seven and it's happened at least five times.
• 0:51
  So anything can happen for sure.
• 0:52
  Trevor: Why don't we tell everyone how you, how do you test them? Well, how do you go and I check, okay, is this a OCV or does oil differential check valve working properly? What's your process and your steps?
• 0:53
  Patrick: So, once I'm in the process where I'm suspecting an actual oil issue in regards to oil fail, not an electrical, which we'll get into later, I'm sure is I use, I use probes for my pressure readings.
• 0:54
  That way I'm not getting my gauges dirty and six, 60 inches of oil. So I will, at that point, You know, use my probes to go on to my oil reservoir, my, my outlet, which goes from your oil reservoir outlets, perhaps an oil filter, then your compressors, and then I will put my probe on the, the suction header where my OCV is headed and compare the pressures.
• 0:55
  And I want to make sure that my oil reservoir pressure is higher than that pressure. it can get a little tricky because sometimes all your oil pots may be open. So, it's constantly flowing pressure. So that that can sometimes throw you an oil if it's trying to kind of throw you off. So you have to be, be weary to see if all your oil pods are, you know, full, empty or, or, or stuff like that.
• 0:56
  Trevor: And that, just remember when you put it on the outlet, it's gonna be full oil on that. Yes. That outlet. So be prepared, have some rags, have some things to clean up your PPE on for sure. And then just like Patrick said, if they're all calling or if they're not calling, it's gonna make a difference. So you could, is you potentially could isolate some.
• 0:57
  And kind of see that. So you go in and isolate each one because this is just a test. and then what's next? What if you, you feel like, Oh man, it's supposed to be 20 and I'm getting. 17 and before you Patrick would do this. He would make sure that all the screens are clean He would make sure there's no pressure drop across the oil filter He you know what?
• 0:58
  I mean all the easiest to think before he's going to check this check valve
• 0:59
  Patrick: Yes, so like I guess it's key to note that I don't generally go on any calls looking for that OCV because, you know, we mentioned how earlier, how it's not exactly the most common thing. So, that's not necessarily the first thing that I'm looking for in an oil, an oil issue, but it's something that you can, you know, confirm along your troubleshooting process for sure.
• 1:00
  Trevor: And so another, and you can also test in a way. So if you, you isolate, the, the compressor pots, you isolate the suction header, you isolate the, the oil reservoir, you put some discharge gas in above. What it should be. So just say if it's, you're running your suction at say 45 PSI or three bar, you push it up to say a hundred PSI, you know, seven or eight bar, and then you open your suction header and see if it drops down and you're that you're, you're yes, too.
• 1:01
  So that's one other test that you could do. but the straight up easy one is like Patrick said, after you do all the easy tech outlet of the reservoir and the suction header. Yeah. If that's where yes,
• 1:02
  Patrick: yes, if that's where it's located, it's, it's key to put your second prober gauge, actually where your OCD is going, because if you put it to a different suction stage or somewhere else, you're obviously not getting the readings you're looking for.
• 1:03
  Trevor: Great point. So, so this is the way it was done. We're not seeing this as much on racks anymore because new devices came out. Old school oil positive still work. They still function great. You see lots of them out there But on a lot of the newer systems now, we're seeing more of the omb's track tracks oils are you one?
• 1:04
  Yeah, omcs all these different different devices but you have we have another way of doing we don't only have the ocvs that that have been out there. We have what we call the Pressure valve they kind of look like tx valves These are oil pressure regulating valves. the Y 1, 2, 3, 6 is a common one.
• 1:05
  And then one that was called, Y 3, 2, 8, 2, 5. I think it was a Y 8, 2, 5, valves. So there's two different types of valves. You want to dive into a little bit of both those valves?
• 1:06
  Patrick: Yeah. So this is a valve that, I actually have never seen fail. completely I've seen them get plugged up or dirty somewhere along the lines, but, they're generally pretty robust in my experience.
• 1:07
  So I've never had to replace one due to it failing, just, just, cleaning the screen somewhere along the way, or, or something like that. So, generally, the high pressure oil system is a little more robust, I think, than, the low pressure oil system for sure.
• 1:08
  Trevor: Yeah, and basically they work exactly the same except instead of having two feeds coming off your oil, your reservoir, you know, now you can have an oil separator reservoir.
• 1:09
  So now your separator does two purposes. The last one we talked about, you kind of have a separator. And then you have a separate reservoir, so you got two vessels versus now you can have one vessel, which reduce the cost on the rack, the components, and then now you can have that high, that higher pressure reservoir, oil separator reservoir, feeding right into the compressors with this device right here.
• 1:10
  and one, one thing is there's a different check. Like you said, you would check that screen on the, the inlet, right? You got to check that screen, but once again, isolated safely, close it down, close all the oil pots, as well as the suction line, and, outlet of that oil separator reservoir to check it.
• 1:11
  There's going to be oil. It's going to get messy. make sure you have rags, try to do as clean as possible job. Anything you want to add to, The Y 1236.
• 1:12
  Patrick: I think you pretty much covered all the bases. especially like the most important part is, like, like kind of rolling back on your initial service call is the first thing you want to do is just just look at the rack and distinguish what type of system you're dealing with.
• 1:13
  high pressure oil system versus a low pressure oil system and identifying the different components so you can continue to troubleshoot on the correct path. So, it's key to know what these components are and the differences just so, just so it helps you along the way a little bit, rather than just going in blind and then realize thinking you're working on a low pressure oil system, all of a sudden you see a wide valve on the corner of your eye to realize, Oh, this is a high pressure oil system
• 1:14
  Trevor: and understand what they were.
• 1:15
  I didn't know what they were for years. I've seen them on the rack and I avoided it. Honestly, when I first, the first four or five years, I kind of avoided those. I don't know it. Let's just go to what I know, but dive into that, be a bit more, bit more curious because a lot of times that you're having issues with oil.
• 1:16
  You know, you, this is an adjustable versus the OCV valve, the other check valves, right? This is adjustable. So you can go in and have an issue and you start changing this around. Don't go do that because you're, you're tripping off and you got too high of oil pressure. Maybe it could be something else. It could be liquid coming back.
• 1:17
  It could be plug screens. It could be some blow by on a compressor. You could have compressor blow by a float issue. You know, there's so many different things. Oil too hot. It's another one. You know what I mean? Yes. Which has nothing to do with your, oil pressure radiating valve.
• 1:18
  Patrick: And, one thing I want to add about the low pressure oil system and the oil pots, make sure that you confirm.
• 1:19
  An OCV failure versus an oil pot failure being, you know, stuck open, constantly calling for oil, like we're talking about distinguishing, your pressures versus oil pots calling or not, you want to make, want to make sure all your oil pots, maintain their set level with their adjustment screw, and any oil troubleshooting process, of course, but just want to make sure that, it actually is the OCV, which, we discussed the different troubleshooting steps you would to determine that.
• 1:20
  Trevor: The 100 percent that's what like we said isolate the pot so you that doesn't affect because if you have a failed pot and you're trying to check the OCV the, the problem, the problem could be is that you've got a failed pot, not an OCV you're getting. So that's why you do that test. You isolate and then you verify, that's a verification that that OCV or that oil differential valve works 100 percent and there's nothing, involved because just like you said, it could be the oil pot.
• 1:21
  That's the issue.
• 1:22
  Patrick: Yes. And it's a pretty similar with the high pressure oil system as well. You still want to make sure that your oil pots, if that's what they have, the same, so that's what kind of translates is you want to make sure the oil pot is still doing what's supposed to be doing, whether it's a higher pressure oil system or a low pressure oil system.
• 1:23
  Trevor: Yeah. So then we can dive into having the new, the new valve. So we're still talking about conventional racks here. So now we went from the, you know, having an OCV and oil pots having a Y one, two, three. Six or a Y 8 25. They just look like TX valves or pressure regulating valves, two oil pots. But now with the new, electronic oil level controls, you don't really need that device.
• 1:24
  You wanna dive in, to, the ones that you've worked on, I'm sure o OMCS, omb, wanna dive into a few of that.
• 1:25
  Patrick: Yeah, so I've seen the OMBs, OMCs, and then some track oil. We've kind of been replacing those and updating this OMCs. So those generally utilize, a 24 volt solenoid to open this. The oil valve, the OMC to allow oil to flow into the compressor on demand or need based on its, oil level that it's, it's, seen and then sending back to a relay to the rack, then close a board point to then allow that solenoid to open.
• 1:26
  So it's not a constant feed of oil or a fully mechanical, oil feed supply, basically.
• 1:27
  Trevor: Yeah, and these ones are super popular super popular out there now because it saves components it saves sometimes complexity to a system As you can see in this video for any any of you that are watching Is that we have our discharge going along here our discharge goes into this, oil separator So the turbo shed some people call it there's a bunch of different Devices and then we got our oil line going right to the oil You And then from the oil filter, we go right out to the head oil header, which is feeding every one of those OMBs.
• 1:28
  but depending on where you're at in the world, it could be a OM3 and OM5. It could be a CREWON one. There are so many different brands that I've seen around the world, but they do the exact same thing. it just monitoring that oil. What are some of the things that you, came across with, say the OMBs, OMCs or TRAX oils that you've seen in the field?
• 1:29
  So. So maybe some service issues or maybe some things that, that worked real well with for them. So
• 1:30
  Patrick: with these, they're pretty straightforward. I see a lot of, electrical related issues when, these are failing, whether it be, the, the, solar connections on the O and the oral control or, the wire nuts inside of the, inside of the connection there, or an OFL relay.
• 1:31
  Or something like that. and then the inlet screen, if, if it has one, I believe some styles do some dough
• 1:32
  Trevor: and make sure that and make sure that
• 1:33
  Patrick: make sure that's clean.
• 1:34
  Trevor: Yeah. The old ones had it. I know when I worked at Copeland, they were phasing that out. yes. Rogers. I don't know if it's still under white Roger.
• 1:35
  They started to go with the OMCs. They started with the screens and then they moved towards. No screens at all, inside them. And so that's the thing you need to sometimes, take these off and look at them because they could be dirty inside. You could have dirt from the system. You know, there's always times when we're piping, the last join or a couple of joints left without, purging.
• 1:36
  So you need a purge. 100 percent every time you're brazing, you need to be purging nitrogen through there. So you don't get all this carbon because those get stuck or plugged. and I seen voltage issues on lots of them, right? So getting the voltage, but, and the fill lights on, but it's not filling and you check the screens and you check the oil and you got oil in the reservoir and they're still not feeling.
• 1:37
  So sometimes you get dirt plugged inside those, those things and they can't open up or feed or the solenoid is not opening for some reason. So they do have to be replaced sometimes, but that's not the first thing you should do.
• 1:38
  Patrick: Yeah, definitely. definitely don't just go replacing, you know, any, any component really, without making sure that you, you know, cross your T's and such.
• 1:39
  And on these, a lot of these, the solenoid is actually replaceable on itself. So if that were a failure, you don't need to order a whole new, a whole new component.
• 1:40
  Trevor: And basically in, On them, you can just check, you take the coil off and you just do your normal resistance check across the coil and see if it's open or if it's grounded, detects the coil itself.
• 1:41
  And one good thing about this, they have alarm, alarm relays. So this is the difference between, you know, going from the mechanical up to this. Now these can, can have alarm contacts, which is real cool. So all of a sudden on that E2, Dan Foss, Microtherm, it doesn't matter, controls say, Oh, we got a, An oil failure alarm oil level control alarm on compressor four.
• 1:42
  So it gives you an idea where to start. It doesn't mean it's yeah for sure. That's the issue but It's a good starting point.
• 1:43
  Patrick: Yeah. The one thing when you start going to these controls, as you start getting more into electrical failures and possibilities, rather than like you were saying, the mechanical oil pot, there's, there's quite a bit more behind the scenes inside the rack that, could potentially fail before it's, actually that component itself.
• 1:44
  Trevor: And one thing that you really got to understand. So if anyone, you have ever taken them out of the box or look, there's going to be a tube in a lot of these OMBs, OMCs, anytime you have an adapter You're gonna have to put that little tube on. If it goes right up against the semi hermetic compressor, you don't need the tube on.
• 1:45
  But that tube is to reference what's the oil inside the compressor. So just remember that. And then when you're doing a low temp compressor, like a Zed F, a Copeland scroll, there's actually a special tube because a lot of those compressors have baffles in it. I don't know if you ever seen those Patrick, if he ever took off an OMB, off a scroll low temp, and all of a sudden there's like a plate in there with a little tiny hole.
• 1:46
  Yes. It's a special adapter that doesn't come out of the kit. So you've got to order that up. So you're going to have to call Copeland wholesalers. The half the time don't even have those part numbers. So you might have to call Copeland to get that part number up.
• 1:47
  Patrick: Yeah, yeah, that one, we did come across once where we didn't have that, at Adapter, so that was Some way to deal with, but, usually, when you get a new scroll, they send like, adapter kits for the OMB or MC that, either it's like a screw on or a bolt on or the extension, like you're saying.
• 1:48
  So they send, it feels like some of the parts, but not necessarily all of them for all the applications.
• 1:49
  Trevor: Well, that's good. I don't re remember them. They, they might have sent it in there, but you just remember it. It's a machine at the end and it got to fit in through that hole because if you don't have that, usually if you have a failed compressor, you can take it off and then you just put it right back on and it's going to fit in that little hole.
• 1:50
  but that's something that I never knew of because those low temp scroll compressors pump a lot of oil. And so in the early stages, this is what I was told. And in the early stages, when they were first doing them, getting the scrolls into low temp, cause these are high temp compressors. That's what they started off as.
• 1:51
  Right. And they got into medium temp and then to the low temp, they were pumping out a ton of oil. Cause scrolls are awesome compressors, right? You know, they're small compound. Compact and very efficient, but they pump a lot. They can pump a lot of oil So I guess that's why they put in the the baffle in there But it's a real hard if you need to take oil get oil out of it You know having that baffle in there.
• 1:52
  It's real difficult because I had some guys Go like how do I get this out trevor? Like how do I get oil out of there? It's like you get a little tube and you try you try to get it out Yes. anything else on the electronic oil level controls?
• 1:53
  Patrick: I think we covered most of them. yeah, they're pretty robust, generally don't see them fail, you know, very often, but it does happen just like everything else.
• 1:54
  It does happen.
• 1:55
  Trevor: Very easy to test them to close your oil line off. Let that compressor run. It's going to pump out all the oil out of that compressor over as long as it's running because every compressor has oil carryover. Some have more or less and you run it and all of a sudden you get lower and lower oil that should go off an alarm.
• 1:56
  Like it should at least try to feel five times. It's different depending on the manufacturers, but you know, you'll have a certain time limit to try to feel if it doesn't feel you get an alarm. If you get so many alarms in so much time, I think it's five times, in 30 minutes for the Copeland ones, but other manufacturers could be different.
• 1:57
  It'll lock out. So you just close the oil line to test it. That should be one of your maintenance tests. It takes time to do this, but you do one at a time. And then what you do is you open it back up and make sure it feels right back up. If it feels up when it's supposed to in a lot of time, you're good.
• 1:58
  Patrick: Yeah, definitely. I'm pretty straightforward. The test just by closing that inlet and making sure that, you know, and it opened it and then it fills in a, you know, a reasonable amount of time.
• 1:59
  Trevor: There's still many different oil systems out there, different racks. You're going to have, you're going to have different components.
• 2:00
  You're going to have oil filters that have a core in it. Some that are hermetic. There's lots of things that you're going to see out there.
• 2:01
  but now when we move from that conventional HFC, HFO, even a to L racks, and now we move into CO2 systems. Now we're starting to talk about, some of the same components and, but some different components.
• 2:02
  You let's dive into that. You want to dive into some CO2 oil systems.
• 2:03
  Patrick: Yeah, for sure. We can do that.
• 2:04
  Trevor: So you've worked on, we've talked to many times and, you've been into a CO2 course before with me, but you, you said that, you worked on lots of advancer ones so far. You've been seeing those ones out there.
• 2:05
  I got a screenshot of, of one of them, from the field. Cause I've been in many, many advancer, startups as well as, sites. And I've been at a lot of sites with contractors. So one's a good thing of what I like about them. It's very. Similar you work on one of their industrial systems versus one of their small flex.
• 2:06
  It's Yeah, they're
• 2:07
  Patrick: very similar. I have realized that. Yeah.
• 2:08
  Trevor: So it may, it always makes it easy for me when I go there. And I think most manufacturers try to do that, but, there's just a lot of experience behind them. So let's dive into some of the differences between a CO2 oil management system versus say.
• 2:09
  conventional rock oil system.
• 2:10
  Patrick: So, it's kind of the same theories as we want to move oil from our separator to our compressors. And it's just a matter of what components we need to add on CO2 to do that. obviously on CO2, transcritical, we might have 1, 400 pound discharge pressure. Well, we can't really send 1, 400 pounds of oil into our, low temp compressors or even our medium temp compressors.
• 2:11
  So there's different things we've got to do. From our separator, from there to our compressors, a lot of the same components, you'll see some sort of a filter, looks a little different than your 303T or your OFE1s you'll see on a conventional rack, but, you'll see a, generally a filter down to like, 10 microns, I think I've seen small ones, to filter out as much dirt as it can.
• 2:12
  They plug up,
• 2:13
  Trevor: Constantly,
• 2:14
  Patrick: yeah. Constantly, yeah. Kind of.
• 2:15
  Trevor: Some people don't, don't like them and they remove them or they change them, which is fair. But if they're plugging up constantly, you got a dirty system. Right. Yeah, I mean, it's, it's
• 2:16
  Patrick: not, it's not supposed to be dirty, right?
• 2:17
  Trevor: Yeah, so and that's the thing and then some technicians get frustrated is for sure Well, we just put a bigger one in then you know what I mean?
• 2:18
  They do work, but they do plug up very they're annoying for everyone You know what? I mean, but they're doing their job. So i've seen technicians put bigger bigger filters on it that can handle it so it does They kind of look some of them kind of look like a car filter. There are high locks Filters and stuff like that.
• 2:19
  So they're bigger depending on the manufacturer, some manufacturers don't use the, the small torpedo like, filters. So, okay. So what, what are the different ones that, that we can talk about? So there's, the sensor oil management. So you got a different, a couple of different sensors. You could have like, the oil level sensors.
• 2:20
  HSB
• 2:21
  Patrick: O2s, I believe, which is that, component you see at the bottom of that separator with, or reservoir with, the red lights on it. So, there's two different styles of those. there's the older style. if you look at it, there, there, there may be no lights on it, until it sees oil, whereas the newer ones.
• 2:22
  Kind of simplified it. So there's, there's always lights indicating what's happening. So, I just kind of recently found that out. I was looking at, a level indicator on a separator. I didn't see any lights. So I'm starting to think, okay, we've got an electrical issue with this connection or some issue there.
• 2:23
  And then I looked at the model number and found out that it was an older one that didn't have as, as many light displays for different, for different indications. So. you'll see that, on advanced racks, pretty much anywhere you want to see your level receipt, your, pressure vessel, reservoir, separator, and, On your, compressors as well.
• 2:24
  So that's, that's one difference.
• 2:25
  Trevor: And it all depends on the design, right? So this would be a sense. I call them a sensor design. So, HB2, when it says red, that means it's sensing level. There there's all, we talk about this in the CO2 program. You know, you're listening to this now, but you got to really dive in like Patrick into the manuals and understand how they work because there's a solid state, really inside some of them.
• 2:26
  There is, you know, contacts, you know, there's lots of to them and there's lots of different ones, but these ones, the HB ones that we're talking about when it's red, that means there's continuity. So that means there's some sort of liquid there. It doesn't, it doesn't matter what the liquid is. You think, well, we got something there, right?
• 2:27
  So that, that's important. And the other one that I call like for CO2 oil managers, time oil management. So now this is where you could have solenoids where they'll open up for a certain amount of time and then close for a certain amount of time to try to empty the separator. Cause what do we not want to happen with the separator, Patrick.
• 2:28
  Patrick: We don't want to fill up with oil. That's for sure. That's right. All the way
• 2:29
  Trevor: You know what? I mean that the whole point of that separator is to separate oil And then that's why that you'll see on some of the racks that you have A oil level indicator on the separator as well as an oil level indicator on the reservoir.
• 2:30
  Yes The big thing I I think a lot of technicians that i've trained over over the years as well see in the field is that It's not just It sees a, it sees a level and it should be feeding. There is a process to it. There could be relays. There could be contacts. There is a process in the oil management system.
• 2:31
  It's not, you know what I mean? So, and I think a lot of guys don't understand that enough. This is where you have to get into the PNID and you have to get into the wiring diagram for that, that section of the system. What are your thoughts on that?
• 2:32
  Patrick: Yeah. So it does get a little trickier because, it's not always as cut and dry as seal oil, move oil.
• 2:33
  and then there's different fail safes as well implemented. hopefully that, if the, your, if your controller doesn't, if the controller doesn't see a signal from your level control and your separator, we've seen a fail safe built in that it'll go into a fail safe mode. Well, it will. going to operation where it allows, it opens up a solenoid going from your separator to your reservoir to move oil, whether it's there or not.
• 2:34
  And it does that if it goes through a time period where, it hasn't seen, seen oil in there to prevent, you know, that catastrophic failure of no oil going to your compressors. So there's a few different nuances that can be involved.
• 2:35
  Trevor: And then, and then there are some where you'll have, like you said earlier, you might have.
• 2:36
  these oil level indicators on the compressor, you could have them on the oil separator and you could have them on the oil reservoir and they all have to work together and then plus solenoids involved as well because if all of a sudden the compressor has a low oil level indicator on their sensing, there's no oil.
• 2:37
  So then now you need a pulse open, the solenoid valve, but that solenoid valve only pulses open if this is already made, or if this is already, so it's not like, like you said, so you gotta understand that. And this takes time. This does take time to learn these ones.
• 2:38
  Patrick: Yeah, it's, it's one thing to understand the components in the system, but then you have to make sure that you understand the why behind it and how it's configured and operation and stuff like that.
• 2:39
  But it definitely helps to get a firm foundation to know what this level switch does, what this solenoid does and stuff like that, to really help move along the process.
• 2:40
  Trevor: Yeah, what are some, troubleshooting tips on, the ones that you worked on for CO2? We know we already talked about it early. We need a hot, we need a differential.
• 2:41
  So we need to have that flash tank pressure. If it, if the oil management comes from the flash tank, you know what I mean? We got to make sure that flash tank pressure is higher than that medium temp suction pressure or the interstage pressure depending on if you got a parallel compressing compressor in there, but let's just talk about the medium temp compressors.
• 2:42
  We need a higher, we need a High differential, we got zero, we got no flow, like, like anything we got 20, it's probably not enough flow either. But what are some of the service things that you've come across when working on a co2 oil management system?
• 2:43
  Patrick: a lot of things I look for is, I start by just looking, I see, is there a ball up there in my reservoir?
• 2:44
  Does my level indicator tell me that? does my separator level indicator indicate that there's oil in there? And, And stuff like that. So I try to start off just by looking at things and getting a graph of things before I start diving in and head first and, and going from there. And then that's when I, that's what I want to determine if my level indicator, which style it is, is it, is it supposed to have lights on all the time or is it, is it not?
• 2:45
  And are lights on only when this, this, and this happens and what does those, what do those lights mean? So, That's kind of how I, I look, I go into it originally. And then, and then there's certain, steps I go to see if there's, if I have a clogged separator filter, if I'm not separating oil in the first place.
• 2:46
  And that's why I don't see any oil on my, on my level indicator.
• 2:47
  Trevor: Yeah, there's so so many different things like it might have nothing to do With the oil management system. Well, it separates part of it But if you're running too hot of dish and i've talked about this many times in the podcast But if you're running really hot discharge that oil that viscosity of the oil Will get thinner and you know and the problem there's daniel charts and all this stuff that I went through with dorin and all the manufacturers I would talk about on their compressors, but if that oil gets really Then now that separator only separates, you know, 90 percent of the oil out of the refrigerant and even 99 percent at certain temperatures and conditions.
• 2:48
  So we're running that oil really hot. It's not separating. We got no oil in the separator to send to the reservoir, which we need to send an oil from the reservoir to the oil level control to fill up that compressor. Now, all of a sudden you get trips and guys go in, they'll reset it. They'll add a pile of oil and all of a sudden, Oh, we've got the compressors they're working again.
• 2:49
  But the rack was off, everything's cold, you know? So you start it back up and you get the compressors running and everything's fine. You sit there and watch it for two hours and it's working fine. It's like, ah, it was a nuisance trip. I add some oil. It's good, but it's not good. That compressors run, the longer they run, they heat up a bit more.
• 2:50
  Then they start to do that to do oil thinning. Have you ever seen, come across anything like that before?
• 2:51
  Patrick: I haven't come across any of those scenarios because we kind of keep our racks running a little better where they don't necessarily. heat up the oil that much. but it definitely does make sense with viscosity and stuff like that.
• 2:52
  and that's when, so in CO2, I don't think I've seen any nuisance oil fail calls, there's always been, you know, an issue somewhere along the way. So like, like you were saying, a lot of guys want to just say, oh, it's just an oil fail, let's just reset it and move on. And conventional refrigeration, you could probably get away with that a little, a little more than, CO2.
• 2:53
  And CO2, I don't necessarily think that's, Because there's probably, there's probably a reason for it, in my experience anyway.
• 2:54
  Trevor: Definitely. And there's, there's other oil management systems that I see out there. It's like the oil depressurization ones. I see a lot of those. on system l and P racks. I've seen them on Hussman or, our, our neg racks as well, where they'll have, depressurization valve.
• 2:55
  So what does that really mean? Well, like Patrick said, starting out, it could be 1400 PSI, it could be a hundred bar. Going down your discharge. So that means your oil separator is running at 1, 400 PSI. We can't send 1, 400 PSI into a low temp compressor that is running, you know, 200 and 400 PSI, you know, like 14 or 28 bar can't be running that.
• 2:56
  So they have deep pressurization valve. So all it is is an oil regulator, a valve that you've got 1, 450 PSI or a underbar coming in. But it's always spitting out, you know, 600 PSI or 40, 40 bar all constant. have you ever come across those, systems yet?
• 2:57
  Patrick: The CO2 racks that we have just, when the, the oil dump valve, I call it going from the separate through reservoir opens, it opens up a solenoid to, send, excess, pressure to the pressure vessel.
• 2:58
  So, that's how they bring the oil pressure down to a, you know, Your pressure vessel. Basically and And that's how they get the, oil flow that way.
• 2:59
  Trevor: So there's lots of different ones. And I, there's even other ones out, out there, the way to do it. But you want to understand the system that you're working on.
• 3:00
  That's the most important thing. Don't just jump in and this is how it works because that's the way it worked on this other manufacturer. It may be different. It may be set up a bit different, than this one. And even one man, the same manufacturer, but it's a different rack could be, have different adjustment set points.
• 3:01
  So just,
• 3:02
  Patrick: yeah. Yeah, for sure. Like, even going back on, you know, conventional refrigeration, the, the oil filler you see there, that can be right off the separator, go into the reservoir, or it could be after, which will, obviously, show you different things if that's clogged. So, like you were saying, it's, it's key that just because you've seen it somewhere else on the same rack, it, it might be different at your next one.
• 3:03
  So, that's why I'm always saying just, just look. Just slow down and look and see, see what you're dealing with. Cause that could present different issues.
• 3:04
  Trevor: Yeah. So, so oil is still one of the hardest, hardest things out there. It doesn't matter. It just, because for me, where I got good is learning the really understanding the behind the scenes.
• 3:05
  And I think that's where, as, as, as when I started out, I didn't dive into the intricacies of oil. And this is where a lot of people run involved because oil is not only the system components at hand. It could be piping issues. It could be velocity issues. It, you know what I mean? If you don't have it, perhaps the proper traps, you don't have the proper slope back to the rack.
• 3:06
  These, this could be major issues.
• 3:07
  Patrick: Yeah. I mean, we've talked about a lot of different things and we haven't even discussed whether if, if it's a circuit store and by that, I mean, you got EPR is behind a rack, and hot gas defrost, what if there's an EPR getting stuck open and you're sending hot gas directly through your suction header and it's blowing out compressors.
• 3:08
  So like, in regards to oil fails in general, there's like, there's a, like you were saying, there's a lot of different intricacies to it that could present issues. So like that just runs back to recognizing what kind of system you're working on and the potential failures that that could represent.
• 3:09
  Trevor: Yeah.
• 3:10
  And that's a good one there on, on conventional racks. You, you know, you're, you have a sort valve, for example, something gets stuck in it, you're defrost and once again, you've got to understand the sequence of that defrost. Cause it's not just like, okay, it goes into a defrost and it turns everything up.
• 3:11
  There's a process. You've got to pump down that circuit, you've got a solenoid that closed, then you've got maybe a, hot gas supply line that opens up at that point. And then, or, and you get the suction, sorry, the suction stop closes and the hot gas line opens up. So there's a process. but if you've got something jammed in there, you could have that hot gas, just like Patrick had blown into that compressor.
• 3:12
  Be in the issue. And you're thinking oil issue, not let's add some oil. Don't do that.
• 3:13
  Patrick: Yeah. Cause usually when the hot gas valve is open and your stored EPR is stuck open, it might wash out your entire rack. All your compressors oil might just get blown out of there. And then you'll get there three hours later.
• 3:14
  And reset it and then that that circuit when it defrost is no longer defrost all your oil comes back all your pressure is good oil flows good and you think you're good to go so like, you know, there's that option there's flood back as we know is like a huge issue liquid refrigerant washing out compressors, and then, like, I just want to add one of the biggest things I see is actually electrical, like, About contact with pitted contacts, chattering on startup and shut off, presents oil fails.
• 3:15
  So it's not always mechanical or anything to do with the oil system. It could be, you know, electrical and some other components that result in oil fails. So there's, there's really a lot, a lot to unpack with them for sure.
• 3:16
  Trevor: Yeah, that's a huge one there. Just, the one that you, the electrical ones that you wouldn't think of, you know, a con how, well, how does a contact or trip my oil level control, you know, my oil failure controls and, but it can happen many, many times.
• 3:17
  So this goes back to the contact or check the contactor. What is the, is there a voltage drop across it? Open, you know, safely isolated, open it up. All this stuff that we're talking about here, you got to do it safe. PPE, doing it right, isolating stuff, lockout, tag out, you know, like, I know, I remember when I first started out, I was very complacent over the years.
• 3:18
  Okay, let's shut up. I'm just working in the rack room. But after I got shocked a few times with high voltage, I started to lock stuff out. You know, I went and bought breaker locks and I went and bought things to lock out these voltages because it only takes that once and you're going to get really hurt.
• 3:19
  Patrick: Yeah, for sure. It definitely makes you realize you have to really know what you're doing and, and like the different webs of what you're doing and different connections and stuff like that. Because, especially working on racks, you can be working on, you know, one isolated system, but then realize there's this pipe that goes somewhere.
• 3:20
  You don't know where it goes, perhaps. And then something happens and action, normal operation occurs. All of a sudden you got pressure on that pipe that you thought was isolated. So, it is the hazards there. And then, you know, even like an oil system, if you want to change an oil filler, you think it's as simple as shutting off, an oil net valve at the reservoir, then at the compressor, 12 feet away, well, there's going to be some pressure inside there and some oil.
• 3:21
  So if you just go to take the oil filler off, you're getting an oil bath. So, just one of the things like, slow and steady wins the race. And to make sure that you, you know, pump that oil line out, get the pressure out of there and, and do it safely and effectively for sure. Yeah,
• 3:22
  Trevor: and it is take your time, you know what I mean?
• 3:23
  You're going to be rushed people are going to be pushing and i've seen this for years I remember happening happening to me like just being rushed on getting getting stuff done
• 3:24
  so it's important to spend that time to understand these process. Take your time. Even if there's someone on your back, if it's a lead journeyman, your service manager, as long as you're doing your job or the customer, do it safe. Because what will happen, you do it right today. It might take you six hours.
• 3:25
  Next time you do it might take five hours and 50 minutes. Next time, five and a half hours, and you're going to learn is going to speed up. Okay. If I shut this, this, this, and this, and then I relieve the pressure out of, out of here, then, then that's it. And it's going to get faster and faster, but you've got to have the tools.
• 3:26
  You've got to plan. The big thing is planning. You're going to go do an oil change, or you're going to go do an oil, say maintenance. Have the gear there. Don't be like, Oh, you got the oil filter or I forgot the gaskets. I got to draw the bucket sailor and come back. You can't do that. That's wasting time.
• 3:27
  Patrick: Yeah, for sure. A lot of different things you have to keep in consideration is, be prepared for your plans, no matter how big or small the project for sure.
• 3:28
  Trevor: Yeah, and the big thing is, is that, especially on oil, like if you get gaskets in there and you're opening it up, you need new gaskets. That's it.
• 3:29
  They're going to, it's like any gasket in a refrigeration system. They're going to leak if you're opening them up. So make sure you prepare. And if you don't have one and you put it back, go and get one, get the system up and run, go get one, then come and put it back. Don't wait. Oh, well it's holding now just because it's holding out.
• 3:30
  It doesn't mean in two weeks time, it's going to be still holding.
• 3:31
  Patrick: Right. For sure.
• 3:32
  Trevor: And I definitely seen where, you know, on, on for CO2 for the high pressure valves, where guys show, send me pictures, they pull it out and all of a sudden the gas gets swollen and there's no fitting it back in. So, so it's a very important to think about that.
• 3:33
  So I love this. Any, any final thoughts on oil management? We covered a lot of stuff. In this short amount of time.
• 3:34
  Patrick: Yeah. And it's probably some more that we could go on some more of the deeper intricacies, but yeah, I think we, managed to cover a lot of the things that I wanted to make sure, guys were a little more aware of and, and stuff like that, because, you know, mistakes happen, all of us make mistakes, you know, I make them, we all make them.
• 3:35
  So it's just key to learn from them, and keep on and keep on going and just trying to learn and get better, which is what I'm doing now, talking to you, just trying to learn some more and learn some more things, talking to everyone else is just trying to learn more and get better.
• 3:36
  Trevor: Yeah, and that's how we do it in the industry and I really appreciate taking time because oil once again I said it's really difficult because You're not doing the engineering design.
• 3:37
  You know what I mean? You're not doing the pipe sizing You're you know, you're not doing the riser sizing. You're not doing the inverted trap or the lower trap How is that piped? You know what I mean? It could have been wrong for years, but they've been having intermittent problems every six months You know what I mean?
• 3:38
  Yeah, it works, but it doesn't work, you know, but, and then you don't have control of that, but if you know that and you can recognize that, that's where you're going to start to learn.
• 3:39
  Patrick: Right. And then I guess, I do want to add on conventional systems. If you have a, a clock separator filter, heavily enough and you get there and there's no oil in your reservoir, your compressors, you know, you figure out it's a filter, you change it.
• 3:40
  you don't always have to. Add, well, I should never really add all the oil back. It's still out in the system. So then you have to know how to get it back, whether it's pumping circuits down, pumping loops down to try to get your oil, it's already in the system. Back to where it's belong rather than just adding five new gallons of oil or something like that.
• 3:41
  Trevor: I love that. Let's talk about that, before we end off here, because I think that one's important because I had a call maybe early last year, one of the guys in the CO2 program had a compressor fail. The major issue pumped out all the, all the oil out of the rack into the store and the same thing. It took hours.
• 3:42
  Instead of he didn't want to pump in oil into it because he didn't know how much he was first time He's at the the store. He didn't want to pump any into it He was like it took him hours to get all the oil back because it was a low temp system Let's talk about getting oil back. If you if that happens you got a blown separator Blows all the oil out into the store on all the different circuits.
• 3:43
  What's some of your process to do, to get the oil back?
• 3:44
  Patrick: I just try to pump, use the rack, try to pump that circuit loop, whatever down, usually only a few times is what it takes until I start seeing oil come back. if the piping is correct and your traps where they should be, pumping it down allows, that velocity of the refrigerant when you restore it to kind of push oil back through the pipe, rather than just sitting there.
• 3:45
  Okay. So that, that generally gets the oil back to where you want it in, in your compressors and in your reservoir.
• 3:46
  Trevor: And it takes time. Sometimes it takes a while longer than others, but doing these processes and trying to stuff out, if you never pumped down a circuit before a rack, if there's someone there with you, ask them to show you, don't be afraid to say I've never put down a circuit before you might be in a one or two years in supermarket, but you did mostly construction or you did mostly maintenance and you never really pumped down a circuit yourself.
• 3:47
  Do ask them. Okay. Shut the liquid line. If there's hot gas you're gonna have to isolate the hot gas line There's so many things do and then you know, make sure it's all out and then shut the suction line So don't be afraid to ask and if that person that you're working with don't want to help you ask somebody else Because there's people just like patrick out there that want to help you.
• 3:48
  So love this conversation patrick. I appreciate your time I'm excited to have our next conversation
• 3:49
  Patrick: Thank you, Trevor. I appreciate your time.