Episode 327. Electrical Troubleshooting Strategy

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In this episode, we’re going over electrical troubleshooting - one of the more common challenges refrigeration technicians face in the field. We cover understanding controls and electrical systems, creating and using wiring diagrams and having a systematic process for electrical troubleshooting. We’ll also talk about safety precautions and the value of investing in quality tools - altogether will help refrigeration technicians diagnose and repair systems more efficiently.

In this episode, we discuss:

-Electrical troubleshooting basics

-Wiring diagrams

-Sequence of electrical checks

-Advanced electrical troubleshooting techniques

-Safety precautions

-Practical tips for field technicians

-Benefits of high quality equipment 

Helpful Links & Resources:

Episode 323. Electrical Troubleshooting 101

Episode 12. You Need To Know About Refrigeration Compressor Electrical Issues

Episode 259. CO2 Experts Live: Electrical Troubleshooting with Rusty Walker

Episode Transcript

Speaker (00:00):
Hey, what's up everyone? Trevor Matthews here from Refrigeration Men's, and once again, I wanna thank you for taking the time to listen to the Refrigeration Men Podcast. I want to dive into some troubleshooting, some refrigeration, troubleshooting. I have a lot of technicians coming into. Our programs from all over the world, experts, new people to the industry.

(00:01):
A lot of people say, oh, it takes 5, 10, 15 years to become a good, a great refrigeration technician. I don't believe that it took me that long because my thought process when I first started out as well as access to information. Google wasn't the way it was. YouTube wasn't the way it was back in 2005, 2006, 7, 8, 9, where it is today.
Setting up high pressure valves in CO2 system. Properly setting up TX valves, what you need to look for, what you need to do. This is why I have tons and tons of videos on the YouTube channel on this podcast to share with you to hopefully that you can learn one or two things that you can go apply out in the field.
You still can draw that stuff out. Does it take time? Yes. But do you wanna learn that system over time? If it's your store and you're gonna be working on it for the next 2, 3, 4 years potentially. Why don't you start drawing that out? Then every time you come back, you, if you draw a little bit more, it's gonna make it easier for you.
You have to be qualified to use this stuff and someone teach you. A lot of people don't understand how to use a meter. They know volts and amps, but actually, what is it doing? It's, it's testing some the re. Or testing the the voltage of it. What, what's the difference? What's that differential? So that's what you're checking for.
From the source power. So you gotta check that. So if it's 2 0 8, 2 33 64, 85, 75, 4 60, whatever it is, it doesn't matter to me. What's that source power coming in? And you want to check the label on that equipment. So if it's a rack, is the condensing you look on the outside of the condensing unit, what is actually the power that it should be?
Is the wires loose? Who we don't know yet, are they tight? Right? So you don't want to touch anything with your hands. 'cause this is a high voltage. You can actually die if you electrocute yourself. So be safe. One of the big, the most dangerous things about refrigeration, a lot of people in the CO2 program, they're like, oh, I'm worried about high pressure.
There should be no percentage. It should be zero volt. If you have six volts, eight volts, 10 volts, there's something going on with that disconnect, because I've seen videos where disconnects was, were off. And there's voltage going through the disconnect. 'cause the disconnect is damaged. Okay? And so if someone didn't use their voltage, mean just shut it off and went and grabbed wires, you could get electrocuted.
It took me a while to save up, to buy different meters, but you get the meters with all the, all the things you need on it, ? So the different things, , a capacitor, capacitance tester, because we got capacitors we need to test on there. Sometimes if you're getting more in controls, you might need a DIO tester.
Maybe it's one 20 control voltage or maybe even 24 volt control voltage where we're taking off one leg. Of the 2 0 8, 2 30, we take off one leg and now we power a transformer. So now you gotta take your vol, your meter and check, am I getting one 20 to that transformer? Or it could be 2 0 8 voltage, right?
It wasn't me. Going to check. The breaker was locked out, the disconnect was locked out. And honestly, be safe out there. Does it take longer and you wanna fit a job quicker? It's Friday. You wanna get home to the friends, the family, or it's a kid's ball, your kid's ball game or a hockey game, whatever it is, soccer game, and you can get complacent.
If it's one 20, do we have power on there? Yes. Okay. We got power on there. So then we check the, the secondary side. So the primary side would be that one 20 or 2 0 8 of that transformer. The secondary side would be that 24 volts. Okay, so do I get 24 volts out on that transformer? There's gonna be a VA rate of voltage amps.
Maybe it's a defrost or something else. relays that are connected to it that don't run while you're there and all of a sudden, oh, I get 24 volts, it's good. But whenever all the loads run, it might pull it back down to 16 and then over time you're gonna fail that transformer as well.
So on our line size of our disconnect, we get 2 0 8, 2 0 8, 2 0 8, or 2 10, 2 10, 2 10 depending on that. That incoming voltage, if the wires are sized properly, if they're undersized by a little bit, they'll start to overheat. So this is what's great about a thermal imaging gun. You can go right into a panel and see if any wires are overheating or not.
And that's actually how you test if the, you get a failed fuse or not too. If all of a sudden you have power on the upstream side, so the line side, and you don't have any on one of them on the downstream sides, you probably have a blown fuse. Why did that fuse blow? Do not put the, the a different, a higher amperage fuse or a time delay versus a slow blow versus a fast blow because the manufacturers select these for a purpose because they have tested it, at most manufacturers anyway, did their, there's mistakes made out there for sure, but most manufacturers, especially large ones, they're sell hundreds of thousands, millions of these products.
'cause it could be, there's a, a wire touching, one single strand of wire touching another thing that's causing it to blow. Or it could be a burnt out coil or a contact or a relay that's causing these fuses to burn out. So you just wanna make sure that maybe you have that circuit tripper. So you use that to test your problem.
The, the low pressure switch, or maybe it's the solenoid, I apologize. It, it energizes the solenoid so that solenoid gets energized because of the thermostat. So it sends a voltage through there. So you need to check all of these. 'cause that thermostat, if it's open, if it's not calling, 'cause it's cool in the walk-in box, you go across it, you're gonna have that voltage.
We get zero. Now we go to the solenoid coil, we go across that liquid line solenoid coil, and you use your meter and all of a sudden, oh, I got one 20 across it. It is energized. Okay? As long as that all the safeties are closed down the line. Okay, so maybe you got a low pressure switch, a high pressure switch in line with your safety circuit.
Just remember that is a wire. That just means there's a safety or something is open along the line, and that's why the coil is not pulling in. So when you go across that, that coil and you get one 20 A across it. Not 0 1 20 across it, it energizes that that stator inside there and it pulls up the armature and now it starts to let refrigerant through.
You gotta be writing all this down. And I know this takes work, but if you do this 20, 30, 40, 50 times. You're gonna be like, you're gonna understand that system inside and out. And then you can take this from one manufacturer to say it's a keep right? Or a, then you can go do the same thing on a, on a Tecumseh one, a Copeland one, Heatcraft one.
They get an evaporator there and it comes back to the compressor. So each one of those is just one circuit is one. One condensing unit. When you break it up like that, when you open up a massive panel and you have hundreds of wires, it's not overwhelm as as overwhelming. So start on the condensing units because you can transfer that knowledge over to racks.
So they gotta come up and start from scratch. Where if you have this process and all your pieces of equipment, you can start electrically troubleshooting a lot faster than guys, the people that have been doing it for a long, long time. 'cause I've seen this and you gotta put the work in, you gotta print off that electrical wiring diagram before you get to site.

(00:22):
Do that, have your meter in your hand. Put it on the paper. What should I be getting here? And then write all those numbers down. And then when you get to site, when you get to site, actually try it and write down what the actual number is. And holy smokes thing is gonna change in your career. You're gonna start troubleshooting way faster than ever before.
Because this is how we get better. This is how we uplift the industry together. This is how we get better as technicians in the field to support the industry, support the other people out there because this industry. The technology continues to advance and if we're not advancing with it, we're falling behind and I want to help you stay ahead of that curve.
Why you ask me? Don't talk to those people anymore. Reach out to us in the community of refrigeration mentor community. We got people in there like Andrew and Aiden and Chad, and all these people who want to help, and they, we don't always have all the answers, but we're there to support you to get to the next level, you know, , head to refrigeration mentor.com/hub and you'll get into the the hub.