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May 29, 2025 58 mins

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This month marks the 3 year anniversary of the Refrigeration Mentor Podcast! To mark the milestone, we're re-releasing some of our top downloaded podcasts from the past 3 years, and we’ve reached number one. Originally released in May 2023, this episode remains one of our most popular ever, and I’ve received a ton of feedback from technicians about how this one really helped explain and clarify compressors. Thanks to all of you listening, learning and making an impact on the people you serve. Also, thanks for all your reviews and comments, which help people discover the podcast on all our platforms. The top episode on our countdown is Episode 115. “Understanding Compressors: What You Need To Know.” Video link and links to our entire top 5 countdown below.

In this episode, we cover:

-Types of mechanical issues

-Contamination

-Overheat

-Flooded starts

-Floodback prevention

-Slugging

-Scrolls & semis 

-Preventing repeat failures

-Oil loss

-Compressor check points

-Mobile apps

-Educational resources

Helpful Links & Resources:

Video of this webinar: https://youtu.be/QyK_3oNBZnk 

Episode 310. 3rd Anniversary Listener Favourite Countdown #2 (Episode 135. 15 Tips To Become a Great Service Technician)

Episode 309. 3rd Anniversary Listener Favourite Countdown #3 (Episode 203. Supermarket Refrigeration Service Tech Tips with Andrew Freeburg)

Episode 308. 3rd Anniversary Listener Favourite Countdown #4 (Episode 188. Compressor Secrets I Wish I Knew When I Started My Refrigeration Career)

Episode 307. 3rd Anniversary Listener Favourite Countdown #5 (Episode 113. 5 Tips on Developing a Growth Mindset)

Emerson Bulletins

Bitzer Spot App

Danfoss Ref Tools

Copeland Mobile

HVAC School

 

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Transcript

Episode Transcript

Available transcripts are automatically generated. Complete accuracy is not guaranteed.
(00:00):
What's up everyone? Welcome back to the Refrigeration Mentor Podcast. I'm your host, Trevor Matthews, and I am so pumped up this week. This week marks the three year anniversary of the Refrigeration Mentor Podcast, and that is huge. It is mind blowing when the team told me it's three years, and I'm like, wow, this is amazing.

(00:01):
We're gonna re-release. Some of the top listen to podcasts, some of the ones that were, that you shared with me, say, Hey Trevor, this was a game changer for my career. This was a game changer for my life, and it set me on this new journey, this new refrigeration path, and I am so pumped up.
Uplift you. Get you to that next level in your refrigeration career. And I would really wanna, personally thank you and all of you who are bringing yourself to that next level, being better tomorrow than today, like we always do because of your passion, your support, your real, your commitment to investing in refrigeration.
That you can go and try and implement them in the field. Share this knowledge with others, but then go out and try some of it for yourself so you get a better understanding of how refrigeration works. 'cause this is your career. It's all you and you are the one that can take yourself to that next level.
I've worked with some of the top manufacturer, top experts for years now, and I feel like every day I'm still learning something new. I'm trying to gain and grasp new knowledge, and I feel like I forget a lot of the stuff along the way, so I have to go back and do some more research and follow up because there's so much to know.
We got a flood, va flood back video I wanna show you. And this is something that you can test in the field or look at it in the field for flood back to, for signs of it. This is important. This is why I do all these trainings and I, I'm, I'm sharing a lot of knowledge with people I. But at the end of the day, it's up to you to go out in the field and implement some of these practices and always do it safely.
Talk about them, use 'em on a consistent basis. I got a special announcement for all those who are here live on the session today, which I'm super excited about. And then I'm gonna talk about some educational resources where you can go and, and learn more. It's all about investing in yourself, learning a little bit each day.
It's liquid, it's liquid's. Liquid. Yeah, could be liquid, but how did that liquid get in there? There are specific ways that liquid causes compressors to become damaged. Maybe it doesn't reach to a failure, maybe it reduces efficiency. And this is the thing that we need to talk about because anytime a refrigeration compressor takes liquid, it's damaging it.
Think about the ways that we can contaminate a system, because when I started
You won't have any refrigerant left in that system. But what you need to understand, if you go to a job that has mineral oil. Or even POE oil, but it was a bad electrical failure, what we call a bad burnout. And you have all that in your hoses and then all of a sudden you just go to your next job, you fix that, you get it up and running, you go to the next job, or not even the next job.
They explain what they are looking for. And I know we're rush on jobs sometimes we don't, you know, have a lot of times to maybe get the proper evacuation pull down. But there is new. If you know how to do it right, you can do it a lot faster. Maybe that's where you potentially could be struggling.
Brian who? Brian Orr. Jim Bergman. He has some good vi videos. Jim Bergman, go look 'em up on YouTube and find out how he does it. But you remove the cores. You have the biggest hoses as possible. You have a va vac pump that worked, probably clean oil. All these things that you're saying in there is very, very important.
So now we pull the system down, we evacuate it. We don't do the greatest job we'll say, and then we charge it with gas. We get it up and running, and the system works. The system evaporator starts to cool. Might take a little bit longer, but it starts to cool and so, oh, well, I got it up and running. You set your superheat, whatever, do your processes to make it running.
What is that called? When you look at that, what does it look like to you?
I. When I get to the site, I, I had what my instructions on what to do is, okay, you gotta get this, just make sure there's pressure in the system. Maybe Eva evacuated, I think gotta charge it up again. So it was just a bit of a process. But I was told that it was, it was all isolated. When I got there, the valves were open, so it was open for months.
That's how hydroscopic it is. So it's something that you need to think about. And you need to make sure that you properly get all contaminants out, right? Because it, maybe it's not moisture, maybe it's nitrogen. I've seen this before as well. Someone put nitrogen to pressure tests. Ball valve's not holding properly, and you get nitrogen in the system, or there's nitrogen in the system.
CO2. When it came back to me, I'm like, okay, I've got a training coming up. Let's charge it up. So put in some liquid CO2, charge it up. All of a sudden, bam, off on high head, bam, off on high head. Looking at the gauge, and I'm just bouncing like this. I'm like, what is going on? It's been like 15, 20 minutes, just like, what is happening here?
And I know I've done a ton of it, especially in the supermarket side of things. Like I've put a lot of contaminants in a system, not real realizing and understanding that I was causing this stuff. So you could be reaming, copper could get into it, you could be sanding. You get little filings of it because what'll happen now, they start to move through the system.
Because of us. So this contamination is something that we don't talk enough about, and it's something that's a little more difficult to find unless you look. This is what's so important for us as technicians, is to look inside and see what is going on in that compressor. If a compressor's failed, you need to look inside it.
The customers warm, the products, warming, whatever it is you need to get them up and running. But the big thing is, is that you figure out what caused that issue. There's lots more on contamination, but we gotta keep going. Overheat. Overheat is another one that you really wanna. Be aware of. It's easy to say, oh, well I can tell.
I think pretty, I'll have to ask around again, but I still think it's overheat. And then, yes, high compression ratio. That's one of the, that's probably the biggest one. High compression ratio. And it could be for many different things. A lot of it comes back to what we are doing. As professionals out there, are we properly doing the maintenances or are the customers allowing you to do the maintenance one or the other?
So all these little different things that we need to understand and sometimes we, we can't always rectify it without a big cost potentially. If you're the service technician who come from a come to a customer to help them out, somebody else installed a job in the wrong location the wrong way. You gotta be honest with them to show them and talk to them what needs to be done and why this is happening.

(00:22):
So I like that one. Gas change over retrofit. That's a huge one. Paul, thank you. That is a huge one that most people don't know. Well, this, this rack's been running. With 4 0 4 refrigerant for 10 years, it's been doing great, but now we just did a retrofit with 4 4 8 4 4 9. This gas runs hotter. It doesn't run as hot as our 22, but it runs hotter than 4 0 4 or 5 0 7, but it breaks the peak point where you now may need head cooling, fans, demand cooling, refrigerant, injection, liquid injection, whatever you want to call it doesn't matter.
Yeah,
This was one of the key things that Copeland drove into me for their smaller compressors is you got to measure that oil and then all of a sudden, if you don't have any oil in it, you gotta think, where is that oil? Did you have a leak? Is it in the evaporator? Is your piping proper? There's so many, so many different things, so many different things to think about for loss of oil is a trap, right?
I can troubleshoot systems even if I had never worked on a system before. It doesn't matter the brand. I got a good idea of where to start, get the manual and then I can start walking myself through the engineering drawings, the piping drawings, electrical drawings, and work together, work all that together and get my systematic approach to start troubleshooting.
You can't just say it's liquid. You need to use these terms so when you're talking to someone else, they understand it. And these are kind of key terms. I don't know if it's globally, I, I train a lot of people around the world globally, but I'm, I'm talking this way. And a lot of people have similar conversations, but this is what I call it, flood of starts.
So this is why it's important, depending on the compressor. And then if it's a high pressure scroll, flood back causes a slug and an air a refrigerant cooled scroll or low pressure scroll. Flooded starts cause a slug. So these are the different things you need to know about these different compressors, different manufacturers, because that's something I didn't know and it's something that I'm continuing to learn.
So I could say liquid for flood. It starts liquid for slugging, liquid for flood back. But there's signs in the compressors that you need to look for. Or a crankshaft. If you look for an, in Copeland, say three cylinder, four, six cylinder compressor, if you see progressive wear across the crankshaft until that main bearing is is failed, that there would be flood back.
And that rotor drag leads to electrical failure and that electrical failure, you come up and, oh, it's the burnout. It's electrical failure. You need a new compressor. But actually it was the mechanical issue that caused that failure. I. And it could be anything airflow. It could be dirty evaporator, it could be a TX valve.
If there's not a probe there, you have to check it because if you don't do your measurements, you don't know what is happening. This is where the good technicians, the good professionals, separate themselves from the average. Tho those technicians are going in and checking this, and depending on the compressor, manufacturer's gonna have different numbers.
So if you hit 2 25, say plus 75, if that's the case, that's 300 degrees. What happens to your oil with 300 degrees Fahrenheit? Starts to lose lubrication, it starts to break down. But then you go to another compressor manufacturer, say Bitzer for an example,
I'm trying to get better at my unit conversion, but it then, if you look at their CO2 compressors. 284 degrees Fahrenheit. So this is why it's so important to understand the different compressors you're working on. There's lots of different Copeland scroll compressors where they say it's two 40 max, two 60 max, six inches away.
Prevention of overheating. Here's a few tips.
So if you don't have that link, I will put it in the chat. But these are the key things you need to understand. All compressor manufacturers have these, you need to make sure that. You are inside these envelopes. When you're outside them, that's when you start getting the overheat. That's when you start to get damage happening, and you'll see on, on this one here.
You need to understand this stuff. Your compressor may be failing because you have the wrong motor. You get the wrong compressor motor for that. These are a few of the little tips and tricks that you need to understand. Don't let suction pressure drop below design. That's a big one. We, we talk about compression ratio a lot.
of you thinking bubbles in the cycl glass. That's right. If you see a lot of bubbles in the cycl glass, you see it's starting to foam up and all of a sudden you see the oil level dropping. You get a lot of flood back happening right away and washing out. You are really washing out that that oil.
But afterwards, I've opened hundreds at least, and I've learned so much each time. While I was there. So I highly recommend E even if the compressor, you know why it failed, but you never looked inside. One, do it safely. And it's important to understand those failures. Okay, so we got liquid return and we got no super.
depends. It depends on the compressor manufacturer, what their recommendation. It depends on the manufacturer of the equipment. 'cause the compressor manufacturers sometimes have different different numbers than the OEM of it, the manufacturer of the equipment. So they could be different compressor and the OEM.
Because you could still get galling. From other things, not only from flood back, but flood back. Your oil comes up here through this crankshaft, and then it feeds through this bushing and bearing, and then all this thrust surface would get it. But if you don't have any oil, that lubrication that is needed, that film of oil that you need in all compressors except like magnetic or oil-less compressors, you're gonna cause damage if there you don't have that film there.
Frozen up coil blocked, honeycombs. There's so many different things that you need to take a look at. And does this take time? Yes, it does take time to learn all this, and sometimes you have 10 calls holding you need to get to another site. There's tips and tricks to really figure this out. The big thing is, is to have yourself your own service checklist.
Didn't defrost the, the coil. The coil caused the no boiling that liquid refrigerant made back to the compressor, washed out and shut it off on the TRO decor sense or the pen or Danfoss oil failure control. Just as an example, I got a video I think coming up here. Let's check it out.
Correct. Down again and then up again. Why this happens. Because CO2 is a great detergent is a great cleaner, so it flashes away the oil fill within the compressor, and therefore the oil pump is no longer able to develop a correct pressure.

(00:43):
Most controllers, they'll kick out at, I think, seven to nine PSID, which is like a 0.8 bar I think. So this is important to take a look at and understand that when are you getting flood back? You can actually see it. You can measure it by temperature, you can see it through the site class, and you can measure it through pressure.
Eat at the compressor 'cause it may be way too high. So flood back prevention. Let's talk about it. Ensure you have the correct inadequate refrigerant charge. That's a big one depending on your system, but all systems, you're gonna have high superheat if you don't have any refrigerant in there. And always set the the valve if it's a mechanical valve
So you wanna make sure that you have the proper super. I got a document there. This is liquid refrigerant controlling liquid refrigerant in refrigerant air conditioned applications for CO from Koblin. I've read this one dozens and dozens of times. I've even done a podcast with Brian or on this years ago.
Okay. Okay. Mobile apps. Got a few, few questions. Is that due to a bad TXV Ev over flooded? Yeah, it it for sure. That could be when, when we were watching that video and that gauge was bouncing back and forth, it could be due to a bad TXVI. Something that's overfeeding. It could be to an EEV that's hunting not set up properly.
Minus 40 Celsius is the same, but you have to get into the software and look at the compressors to see how far they'll, they will pull down. Because at minus 42, that compression ratio is extremely high. And when we talked about high compression ratio, talk about a lot of heat on that, Charles. Okay.
HVAC School for Text. By text. Brian or once again, he does a lot of trading education for the HVAC and refrigeration industry. There's a, there's a. Dozen other apps that I usually have on here. This is an older slide, but you know, TESI ha has, it has a, a great app for single phase compressors. What else do I have?
It'll spit out something. It'll kind of give you an idea of where to start. Danfoss Ref Tools, it has a whole troubleshooting section. You go in and you can troubleshoot so many different things. It's such a good learning app. It's such a good learning app,
But this is great for people in central time or Pacific time. I. As well as in New Zealand or in Australia. This is why I do trainings at a lot of different times. A lot of people say, well, Trevor, I can't make this training. Why would you do a training at this time? I'm trying to do trainings for people globally and try to help as many professionals out there as possible, so I.
This is gonna expire so you have till Friday to use this discount code. But if you click on that link and go to the checkout page you'll get a, a $50 US discount on this course. And what this course all about is it's about you getting to you to where you want. Why I don't have all these on-demand courses at this point is because I like.
Yeah, you are the professional. You're the one that's already spent years in the field working on this stuff. I'm just trying to get that confidence, that confidence up a little bit. So when you get out there, you can do it and feel confident. Do it yourself. All this stuff you need to do, do safely and and just take your time.
'cause I've seen it, I've seen that 30, 40% come back to the manufacturer. There's nothing wrong with it. Or that compressor, multiple compressors come back from the same site. So important. So if this is not something that you're interested, I got a, like I said, I got a huge schedule of trainings coming up.
There's a lot of other resources out there. I've got a lot of friends and industries sharing knowledge, and I want you to go and learn from them. You gotta learn from a lot of different people. 'cause I ha I look at the refrigeration in one way. Somebody else looks at refrigeration in a different way.
Spend the time to learn this stuff. Advanced Refrigeration Podcast. If you haven't heard of them, go check out their podcast. I don't think, give a ton of great knowledge for a technician in the field there. Lots of great stuff there. Hvac know it all. If you, you wanna learn about commercial refriger hvac, sorry.
He is got a book coming out, but just cares about the industry and helping others out. So check out these other educational resources. Finally refrigeration Mentor has a ton of platforms. We're on, we're on Facebook, Instagram. LinkedIn, a huge one there. YouTube, ton of YouTube videos we have. We got the podcast going.
We'll talk about Trev valves. We'll talk about liquid injection. We'll talk about demand cooling. We'll talk about operation envelopes and why it's important. We brushed on it today, but this is the great picture here of this one's from Sporin, but this is their DTC valve. Copeland uses a lot of these DDTC valves and they got a lot of information on there.
I wanna thank you for taking the time to hang out with me at the Refrigeration Mentor Podcast. I hope you learned a thing or two, and anything that you learned today, please share it with someone else. More importantly, anything that you've learned. Try to implement it in your role, if you can. That is gonna be the best key to your learning is implementing some of these strategies that we talked about.
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