July 14, 2025 • 32 mins
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In this episode, we cover the basics electrical troubleshooting for refrigeration systems. We explain how to read electrical wiring diagrams, how to use meters to diagnose issues and give a step-by-step process to assess power and ensure system functionality. We also cover new technologies, natural refrigerants and tips for finding and using manuals to improve troubleshooting skills.
In this episode, we discuss:
-Basic refrigeration lectrical troubleshooting
-Electrical diagrams
-Tips for safe electrical troubleshooting
-Step-by-step electrical troubleshooting guide
-Advanced troubleshooting techniques
-Continuous learning resources
Helpful links & resources:
Episode 12. You Need To Know About Refrigeration Compressor Electrical Issues
Episode 259. CO2 Experts Live: Electrical Troubleshooting with Rusty Walker
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker (00:00):
Welcome to the Refrigeration Mentor Podcast. So glad you're here. Always joining, learning, growing. This is what I love about refrigeration is that we continue to learn. There's so much to learn and grow from. And every day I am learning something new. I'm reading more refrigeration books, more on.
(00:01):
Getting better at electrical troubleshooting is gonna make your life easier. And I'm training a lot of technicians from all around the world, and I asked them, one of the things that I asked them is. How's your electrical trouble school shooting skills? What is your confidence level at that? Now? I go from zero to 10 and, the, the, the average is probably between five and seven.
Understanding how to read and troubleshoot using electrical wire diagrams. And I get probably 90% people say, NI don't do any 10%, five, 7% probably say that. I watch you did not probably, but they say I watch YouTube videos or some electrical troubleshooting videos, which is great. And then some other people say that I, that I'm doing some research.
How do you, where do you put them, test them first. Safety is our number one priority. If you get hurt, you can't work and make money for your family. You can't do the things that you want. Okay, so understanding right off the bat is what is the voltage you're using? Okay, this is important. A lot of times you get in the manuals, they'll, they'll give like tons of different wiring diagrams, just like this one.
You would have to go to a wholesaler or you would have to go back to the office and they would have to make a few phone calls and they would get like a fax of it, or they would get maybe an email message with a PDF. And I don't even remember honestly getting, getting those back in 2005, 2006.
The first thing you gotta know is that when you're looking at it, the power is off. So any switch that is closed and the contacted coil gets energized, that will open up. Some relays and contactors. So you wanna understand that you always want to test across loads. That is so, so important. If you test across a switch and there's power to it, you're gonna get zero.
They could have shut off that, that. Breaker, but their power could be somewhere else. So this, this technician was showing that this connects off. He was still getting 450 or four 60 volts. uh, across that, at that system when the disconnect was off, the main disconnect. So you want to use ground for safety and you want to go across, always go across.
So this is coming from grid Power. We got L one and we got L two. Okay. So on each of those lines, we have approximately. If it's two 30 volts, we'll approximately have 115 and 115, we'll say 120. 120. So it'll get us really close in that range. So what the first step, and I, I do this in tons of my, my train supermarket trainings, like I said, or any, any really, even my compressor trains I talk about when we're doing electrical troubleshooting.
Electrical you're trouble. It could be an air handler of carrier or whoever it is, , and they, they have a bit more complex wiring diagrams. There's a bit more going on sometimes be, besides this basic one that we have here. So if I took, we take our meter, and this is one thing that, I picked up from a few different people with the last training I did with one I did with Rusty Walker, who works with the N-S-A-R-C, either training director, super cool dude, super smart on electrical.
I just, there, there it is. I'll go and I'll put it in as a, with a alligator clip or I'll screw it in. I'll, I'll get it and I'll place it in there so it stays. So I now can troubleshoot this system with one lead, keeping one hand off, and now I got one. I can go and start troubleshooting everything, but what I, what I get people to do in all like a lot of my courses is have one of these drawings printed off just like this.
We connect we put it on L one now. Now it should say, we'll say for an example, two 30 volts. Okay. And from there we can go down to the next one right here. Two 30 volts. So we're going down to the fuses on the upstream size of the fuse, two 30 downstream, which is the next so we check, oh, I got two 30 there.
they'll probably get 1, 1 15. Right. But if this is closed, you will get your two 30 volts. ' cause remember we got one 15 on this one and we got one 15 on this one. So now upstream of the contactor, so L one right here. So if we put it on the upstream side, we should get two 30. Understanding everything that's on your map.
We have the crank case heater running on that compressor because we always want that to be running. So that we don't get any migration into the oil of that compressor. So the con a compressor contactor is open at this point. Well, how does it even start up? Well, really, we don't have the evaporator on here, but as we see the L one L two coming off the upstream side, we go to our compressor safety circuit.
'cause we're still, that lead is still in L two, so I should get two 30 here. If I go down to this one, this terminal block, I should get two 30 there. And then if I go. On this side, I should have two 30 here. So 'cause that crank case heater, at this point, what we're looking at, that should be actually running that crank case heater if we don't have this low pressure switch name.
It will close that thermostat. When it close, that thermostat will send power to a, usually a normally closed solenoid opening up, sending that. That refrigerant through the liquid, down the liquid line, through the evaporator coil, down to the suction line in as a vapor. And then that will start to rise the pressure, which will close this low pressure control, which is, which is very important.
'cause you in some systems like this, must be at anti shortt cyclone. Trip most likely. So if the compressor, if it starts up and it shuts down, it has to wait two to three minutes. I'll have to double check that in the manual. If power's going through there to terminal four, then we got a core sense module in here.
The way rusty said he in multiple electrical troubleshooting train we did. The way he likes to do it is he likes to break it down in half. So instead of the way I just showed you is going step by step through it, which I highly recommend doing because you're gonna be writing what the voltage is the whole time.
And you need enough voltage, I'm sure in the manual it's gonna say like maybe it's 20%. If you have less than 10 or 20% that it's not enough to pull into contact request. So if you ever heard a contact request could pull in and, and out, in and out, in and out. You might not have enough voltage as a voltage drop.
You put your pro break there upstream and put it downstream. If that switch has voltage going through it, and you put it on one side and the other side, you will get zero volts. If that switch is opened, you will get. Two 30 volts on this one here, you'll get one 15 volts because we don't have any power coming through the the contactor.
I go L one to ground one 15. I go L two to ground. Oh, I got one 15. I got power everywhere. But nothing's working well. It needs two 30 volts to work, so usually something is open. So, so important. I know this was a quick. Episode talking about electrical troubleshooting. I think the best thing to do is get out there and start re having the manuals with you looking at them at home or in the truck while you're on lunch or coffee break.
Great. And what's great about most of the new stuff, it's all terminal blocks. You don't have to pull covers off. Does it take time? Yes. Writing this stuff down, take time. Yes. But getting a good understanding on how all that works. And then in the notes, there's so much in the notes and a lot of the electrical wiring diagrams like you see if the oil switch, if oil switch not required.
I didn't work at it. I didn't try a lot, , I avoided a lot of electrical stuff, like, come on, I, I did get so many, fix so many things with electrical, 'cause refrigeration's, like 90% electrical stuff, but I avoided as much of like a fan out. , A fan's out, , that's basic. You condense a family or you can see it's out.
(00:22):
And there, this stuff is real, real important. And then looking at the notes, finding out what's in those notes. , Is it factory wiring? Is it field wiring by you? This is something important. And then getting into the manual. For those that are watching this, I'll pull the, pull the manual over, because I just pull this right of the, one of the keep Right manuals.
So you, you have the standard 1, 2, 3, 4, and x and the timer. Old school time clocks. You should actually be using digital one most man. Most systems now will have more of the digital ones on there you'll see like D Excel or Corell, or. LE Well, whoever it is, depending on where you're at in the world, they, they have defrost clocks in inside them built in.
But walking through that stuff as well, understanding this stuff, understanding what you're, you're looking at, and look, this is an 80 page manual. Okay? 80 pages might, some of it, it used to take me, it would take me weeks to read 80 pages. Now I could go through this in a, in an hour or two. I could go through this whole probably two hours.
And that's the big thing is in like, I'm doing these trainings with all these technicians from everywhere and a lot, most of the time it's like, I want a bit more confident. And I ask them, if you started reading a bit more manuals, if you started working off the electrical wiring diagrams, if you started reading the sequence of operations, if you started, , putting a little bit of effort outside of your workday.
You'll be the person people wanna call and you're gonna just. Fast track yourself. You're gonna be solving harder problems than other people. And this is a basic, like I just went through. These are basic troubleshooting skills and I talk with the, the team at Keep, right? And they get tens of thousands of calls a, a year for these basic troubleshooting wire diagrams and all different things as well.
If you get into the Supermarket Academy, I keep saying, you learn how to test this now go test it in the field. The same with these electrical wiring diagrams. Get the, get your meter out and safely start to go through. Okay? When I, you get this defrost time clock, , and you, as you spin, if it's a spin one, so you spin it around, have your meter on there before it switches.
I want you to be better. I want you to be better so you have more confidence. And this is why we do all these trains. We're doing this, like this is a basic electrical, troubleshooting scenario or, or walkthrough. But I really want you to take the time and I'd love to hear from you. This is like, send me a message, reach out hit me up on LinkedIn, Instagram, it doesn't really matter, one of the social media platforms and say, Hey, I've tried this.
I have lots of people that come into the trainings like this is the first time I've been outta training or since apprenticeship school, or first time I've been outta training since school, which was seven years ago, or 10 years ago, or 15 years ago, or I've never been to school before. And afterwards they're like, I should have done this before.
This one's a, like I said, this is a key bright one. Go to whatever manufacturer you're working on, get that manual and start learning. Start reading it, understanding. If you don't understand this, like call the manufacturer. Say, Hey, I haven't been at the site. But I'm walking through this manual and I don't understand exactly what to decide.
How much do you want to know? Do you want to be the best or do you wanna just be average? And then it's up to you. It has nothing to do with me or anybody else. Do you wanna spend the time to feel confident, crush your day when you out there ser on service calls and solve problems? Other people can't.
Take a screenshot of it. Well. What you're looking at right now, if it's on Apple or Spotify and share that, tag me, tag me in it, and I will definitely follow up, comment on it too. So make sure you tag me in those.
Welcome to the Refrigeration Mentor Podcast. So glad you're here. Always joining, learning, growing. This is what I love about refrigeration is that we continue to learn. There's so much to learn and grow from. And every day I am learning something new. I'm reading more refrigeration books, more on.
(00:01):
Getting better at electrical troubleshooting is gonna make your life easier. And I'm training a lot of technicians from all around the world, and I asked them, one of the things that I asked them is. How's your electrical trouble school shooting skills? What is your confidence level at that? Now? I go from zero to 10 and, the, the, the average is probably between five and seven.
Understanding how to read and troubleshoot using electrical wire diagrams. And I get probably 90% people say, NI don't do any 10%, five, 7% probably say that. I watch you did not probably, but they say I watch YouTube videos or some electrical troubleshooting videos, which is great. And then some other people say that I, that I'm doing some research.
How do you, where do you put them, test them first. Safety is our number one priority. If you get hurt, you can't work and make money for your family. You can't do the things that you want. Okay, so understanding right off the bat is what is the voltage you're using? Okay, this is important. A lot of times you get in the manuals, they'll, they'll give like tons of different wiring diagrams, just like this one.
You would have to go to a wholesaler or you would have to go back to the office and they would have to make a few phone calls and they would get like a fax of it, or they would get maybe an email message with a PDF. And I don't even remember honestly getting, getting those back in 2005, 2006.
The first thing you gotta know is that when you're looking at it, the power is off. So any switch that is closed and the contacted coil gets energized, that will open up. Some relays and contactors. So you wanna understand that you always want to test across loads. That is so, so important. If you test across a switch and there's power to it, you're gonna get zero.
They could have shut off that, that. Breaker, but their power could be somewhere else. So this, this technician was showing that this connects off. He was still getting 450 or four 60 volts. uh, across that, at that system when the disconnect was off, the main disconnect. So you want to use ground for safety and you want to go across, always go across.
So this is coming from grid Power. We got L one and we got L two. Okay. So on each of those lines, we have approximately. If it's two 30 volts, we'll approximately have 115 and 115, we'll say 120. 120. So it'll get us really close in that range. So what the first step, and I, I do this in tons of my, my train supermarket trainings, like I said, or any, any really, even my compressor trains I talk about when we're doing electrical troubleshooting.
Electrical you're trouble. It could be an air handler of carrier or whoever it is, , and they, they have a bit more complex wiring diagrams. There's a bit more going on sometimes be, besides this basic one that we have here. So if I took, we take our meter, and this is one thing that, I picked up from a few different people with the last training I did with one I did with Rusty Walker, who works with the N-S-A-R-C, either training director, super cool dude, super smart on electrical.
I just, there, there it is. I'll go and I'll put it in as a, with a alligator clip or I'll screw it in. I'll, I'll get it and I'll place it in there so it stays. So I now can troubleshoot this system with one lead, keeping one hand off, and now I got one. I can go and start troubleshooting everything, but what I, what I get people to do in all like a lot of my courses is have one of these drawings printed off just like this.
We connect we put it on L one now. Now it should say, we'll say for an example, two 30 volts. Okay. And from there we can go down to the next one right here. Two 30 volts. So we're going down to the fuses on the upstream size of the fuse, two 30 downstream, which is the next so we check, oh, I got two 30 there.
they'll probably get 1, 1 15. Right. But if this is closed, you will get your two 30 volts. ' cause remember we got one 15 on this one and we got one 15 on this one. So now upstream of the contactor, so L one right here. So if we put it on the upstream side, we should get two 30. Understanding everything that's on your map.
We have the crank case heater running on that compressor because we always want that to be running. So that we don't get any migration into the oil of that compressor. So the con a compressor contactor is open at this point. Well, how does it even start up? Well, really, we don't have the evaporator on here, but as we see the L one L two coming off the upstream side, we go to our compressor safety circuit.
'cause we're still, that lead is still in L two, so I should get two 30 here. If I go down to this one, this terminal block, I should get two 30 there. And then if I go. On this side, I should have two 30 here. So 'cause that crank case heater, at this point, what we're looking at, that should be actually running that crank case heater if we don't have this low pressure switch name.
It will close that thermostat. When it close, that thermostat will send power to a, usually a normally closed solenoid opening up, sending that. That refrigerant through the liquid, down the liquid line, through the evaporator coil, down to the suction line in as a vapor. And then that will start to rise the pressure, which will close this low pressure control, which is, which is very important.
'cause you in some systems like this, must be at anti shortt cyclone. Trip most likely. So if the compressor, if it starts up and it shuts down, it has to wait two to three minutes. I'll have to double check that in the manual. If power's going through there to terminal four, then we got a core sense module in here.
The way rusty said he in multiple electrical troubleshooting train we did. The way he likes to do it is he likes to break it down in half. So instead of the way I just showed you is going step by step through it, which I highly recommend doing because you're gonna be writing what the voltage is the whole time.
And you need enough voltage, I'm sure in the manual it's gonna say like maybe it's 20%. If you have less than 10 or 20% that it's not enough to pull into contact request. So if you ever heard a contact request could pull in and, and out, in and out, in and out. You might not have enough voltage as a voltage drop.
You put your pro break there upstream and put it downstream. If that switch has voltage going through it, and you put it on one side and the other side, you will get zero volts. If that switch is opened, you will get. Two 30 volts on this one here, you'll get one 15 volts because we don't have any power coming through the the contactor.
I go L one to ground one 15. I go L two to ground. Oh, I got one 15. I got power everywhere. But nothing's working well. It needs two 30 volts to work, so usually something is open. So, so important. I know this was a quick. Episode talking about electrical troubleshooting. I think the best thing to do is get out there and start re having the manuals with you looking at them at home or in the truck while you're on lunch or coffee break.
Great. And what's great about most of the new stuff, it's all terminal blocks. You don't have to pull covers off. Does it take time? Yes. Writing this stuff down, take time. Yes. But getting a good understanding on how all that works. And then in the notes, there's so much in the notes and a lot of the electrical wiring diagrams like you see if the oil switch, if oil switch not required.
I didn't work at it. I didn't try a lot, , I avoided a lot of electrical stuff, like, come on, I, I did get so many, fix so many things with electrical, 'cause refrigeration's, like 90% electrical stuff, but I avoided as much of like a fan out. , A fan's out, , that's basic. You condense a family or you can see it's out.
(00:22):
And there, this stuff is real, real important. And then looking at the notes, finding out what's in those notes. , Is it factory wiring? Is it field wiring by you? This is something important. And then getting into the manual. For those that are watching this, I'll pull the, pull the manual over, because I just pull this right of the, one of the keep Right manuals.
So you, you have the standard 1, 2, 3, 4, and x and the timer. Old school time clocks. You should actually be using digital one most man. Most systems now will have more of the digital ones on there you'll see like D Excel or Corell, or. LE Well, whoever it is, depending on where you're at in the world, they, they have defrost clocks in inside them built in.
But walking through that stuff as well, understanding this stuff, understanding what you're, you're looking at, and look, this is an 80 page manual. Okay? 80 pages might, some of it, it used to take me, it would take me weeks to read 80 pages. Now I could go through this in a, in an hour or two. I could go through this whole probably two hours.
And that's the big thing is in like, I'm doing these trainings with all these technicians from everywhere and a lot, most of the time it's like, I want a bit more confident. And I ask them, if you started reading a bit more manuals, if you started working off the electrical wiring diagrams, if you started reading the sequence of operations, if you started, , putting a little bit of effort outside of your workday.
You'll be the person people wanna call and you're gonna just. Fast track yourself. You're gonna be solving harder problems than other people. And this is a basic, like I just went through. These are basic troubleshooting skills and I talk with the, the team at Keep, right? And they get tens of thousands of calls a, a year for these basic troubleshooting wire diagrams and all different things as well.
If you get into the Supermarket Academy, I keep saying, you learn how to test this now go test it in the field. The same with these electrical wiring diagrams. Get the, get your meter out and safely start to go through. Okay? When I, you get this defrost time clock, , and you, as you spin, if it's a spin one, so you spin it around, have your meter on there before it switches.
I want you to be better. I want you to be better so you have more confidence. And this is why we do all these trains. We're doing this, like this is a basic electrical, troubleshooting scenario or, or walkthrough. But I really want you to take the time and I'd love to hear from you. This is like, send me a message, reach out hit me up on LinkedIn, Instagram, it doesn't really matter, one of the social media platforms and say, Hey, I've tried this.
I have lots of people that come into the trainings like this is the first time I've been outta training or since apprenticeship school, or first time I've been outta training since school, which was seven years ago, or 10 years ago, or 15 years ago, or I've never been to school before. And afterwards they're like, I should have done this before.
This one's a, like I said, this is a key bright one. Go to whatever manufacturer you're working on, get that manual and start learning. Start reading it, understanding. If you don't understand this, like call the manufacturer. Say, Hey, I haven't been at the site. But I'm walking through this manual and I don't understand exactly what to decide.
How much do you want to know? Do you want to be the best or do you wanna just be average? And then it's up to you. It has nothing to do with me or anybody else. Do you wanna spend the time to feel confident, crush your day when you out there ser on service calls and solve problems? Other people can't.
Take a screenshot of it. Well. What you're looking at right now, if it's on Apple or Spotify and share that, tag me, tag me in it, and I will definitely follow up, comment on it too. So make sure you tag me in those.
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