
HVAC Maintenance Strategy for Techs to Prevent Failures without Gauging with John Anderson Part 2
About this episode
In this episode of the HVAC Know It All Podcast, host Gary McCreadie talks with John Anderson, Senior Regional HVAC Technical Trainer at Sila Services and former Service Manager and Technician at Burns & McBride Home Comfort, about practical HVAC maintenance and system checks. In Part 2, they discuss how technicians can use observation, temperature measurements, and airflow checks to evaluate a system before connecting gauges. John explains simple ways to estimate evaporator performance using return air temperature and suction line temperature. Gary and John also cover electrical inspections, including checking contactors and testing coils for shorts. The conversation ends with a discussion about preventative maintenance ideas, such as scheduled capacitor replacement and the importance of keeping coils clean.
Gary and John discuss practical HVAC maintenance checks and how technicians can assess system performance before connecting gauges. They explain how observing airflow, temperature differences, condensate flow, and suction line conditions can help confirm that a system is operating properly. John shares a simple method to estimate evaporator performance using return air temperature and suction line temperature. The conversation also covers electrical inspections such as checking contactors, testing coils for shorts, and spotting common issues. They finish by talking about preventative maintenance, including cleaning condenser coils and considering scheduled capacitor replacement to reduce breakdowns.
Expect to Learn:
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How technicians can evaluate system performance using temperature and airflow checks.
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A simple way to estimate evaporator coil performance using return air temperature.
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Why visual inspection and system cleanliness are key parts of HVAC maintenance.
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How to check contactors and coils to find electrical issues before they cause failures.
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Why cleaning condenser coils and planning capacitor replacement can help prevent breakdowns.
Episode Highlights:
[00:00] - CMPX Show Announcement
[00:34] - Intro to John Anderson in Part 02
[02:15] - How load calc fixes static pressure
[03:02] - Non-invasive checks vs. always using gauges
[07:59] - Electrical inspections: Contactors & coils
[12:08] - Real story: Bad contactor coil diagnosis
[14:09] - Preventive capacitor replacement to avoid callbacks
[18:28] - Importance of cleaning outdoor condenser coils
[20:21] - Wrap-up
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Follow the Guest John Anderson on:
LinkedIn: https://www.linkedin.com/in/john-anderson-188093251/
Sila Services - LinkedIn: https://www.linkedin.com/company/silaservices/
Sila Services - Website: http://www.silaservices.com
Burns & McBride Home Comfort: https://www.linkedin.com/company/burns-&-mcbride-home-comfort/
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LinkedIn: https://www.linkedin.com/in/gary-mccreadie-38217a77/
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HVAC Know It All Podcast — HVAC Maintenance Strategy for Techs to Prevent Failures without Gauging with John Anderson Part 2. Machine-transcribed; use the interactive transcript above to jump the player to any line.
CMPX Show is upon us. It's March 25th, 26th and 27th in Toronto at the Metro Toronto Convention Center. I mean, the trade changes so quickly. We're going to see all the modernizations, in equipment and tools and methods. We have the social hub, activations, all three days of tool demos and compressor tear downs, and there's going to be a full-on 18 van, which is going to be pretty cool guys. So if you use code, know what all. That's K-N-O-W-I-T-A-L-L. When you go to the CMPX website and register, you get a free pass for all three days. Come check us out. I mean, today's world, it's hard to find good talent and keep them retained within your company. So little perks and stuff could help with that. So Sintas, they provide high-quality professional grade options like car heart to show the team how much you value them. They also get free laundry and weekly delivery, giving time back to them so they can get out and do their job, do the things they love doing. What we want to do here is check out Sintas.com forward slash HVAC, know what all,
to check them out. And when we do that, it's spelled C-I-N-T-A-S, that's Sintas.com forward slash HVAC, know what all. What's up guys? Welcome back to the podcast. Now, I put it a podcast not too long ago about changing capacitors on a regular basis rather than waiting for them to fail. And I bring that up in this conversation with John, as we talk about our spring maintenance, as if we have this conversation. And John and I kind of go deeper on the subject. I explain why and he kind of agrees after we have the chat that yeah, maybe it could be part of a maintenance schedule to change a capacitor every three years or five years, whatever it may be on a schedule depending on where you live and how hot it is and how often they fail. So that is going to be part of this conversation here. This is the HVAC, know what all podcasts and I'm your host, Gary McCree. Welcome to the HVAC, know what all podcasts. Recorded from a basement somewhere in Toronto, Canada. Your host and HVAC tech, Gary McCree,
will take you on a deep dive into the industry discussing all things HVAC. From storytelling to technical discussion, enjoy the show. I don't want to spend the whole podcast on that, but I do want to state one thing. I found that when you do the proper load calc and you take out like someone's 80,000 BTU furnace and now you put the right size in, maybe you put a 50 in, maybe it's a 60 or whatever it is, I found that it almost instantly fixes your static pressure issues, right? Because now, you're putting the equipment in that size for the home and it wasn't the duck work that was undersized at all. It was the equipment that was oversized trying to push too much air into the duck, ballooning it out and creating that higher pressure. As soon as you reduce the equipment size, you have the right air flow, then your static pressure falls in line and the house is a lot more comfortable. When I hear that big boom, every time the unit starts up or stops, huh?
Let's leave the whole static pressure thing alone for now. We're continuing this discussion about maintenance. So, cleanliness, visual inspections, listening, using all your senses, HVAC, and air flow before gauging up. Let's talk about the refrigeration side of it because we've talked about like we'll change the filter, we'll clean the coils, we'll clean the drain, we'll do all that kind of stuff when we're on our maintenance. On the refrigeration side, a lot of guys will gauge up on every maintenance and some of the guys are gauging up, not because they want to, it's because their company enforces it. It's policy to write down the pressures every single PM. Now, I know you're a big measure, quick guy, but not everybody uses it or has it. We need to, we need to incorporate other ways to check a system to ensure it's running properly without putting a probe or a gauge on it. Maybe let's talk about that for a second. Yeah, so I mean, there's, in order to get into that, you get into design, temperature difference of the coil. I can nerd out on this for a little bit, but essentially what
it is is the return air temperature versus the saturation temperature of the evaporator coil. You can do a bunch of math, but what it really boils down to is if I look at the return air temperature, my suction line should be about 20 degrees below that. There's a 35 degree temperature design temperature difference. So if I had 75 degree return air, then I should have about a 40 degree saturated coil in the evaporator coil. Sounds normal, right? Sort of 40 degree saturation. I add 15 degrees of super heat to that. That means I'm back up to, you know, I went from 40. Now it should be about 55. That'd be 55 degrees. Plus or minus five degrees is what my suction line should be. That's how you can do a non-invasive without having pretty much anything. I can eliminate that whole 15 degrees of super heat thing just by saying return air minus 20 degrees. And that's about what your suction line temperature should be. It's kind of like going back to beer can cold, but just with the actual data behind it. Now, what bugs me is I've been on PMs with people. It's the hottest week of the summer. The space is satisfied. It's comfortable. There is all kinds of water running
out of the drain, all kinds of condensate running out of the drain. The suction line is cold and sweating. There's all kinds of heat coming off the top of the condenser. And I'll see people throwing their gauges on. I'm like, dude, this thing's running perfectly. It's comfortable inside. The stat it's the hottest day of the year, guys. Remember that it's like thermostat satisfied. It's comfortable indoors. We've got all kinds of heat coming off the top of the condenser. Our drain is pouring out water. We're doing some good work here. Our suction line is nice and cold and sweating. Yeah, beer can cold stuff. But if all of those things are happening on the hottest day of the year, the space being satisfied. One of the biggest ones is like, this thing is running at peak performance. There's no need to throw your gauges on this. There really is no need for it. I mean, yes, maybe once in a while there is. But I think after you have enough experience using your visuals and senses and common sense, you'll come to the conclusion that if my system is clean, my coils are clean. My filter is clean. My drain is clean. My blower wheel is clean. It's moving the correct amount of air. My static is not too high. And everything checks out on the other side. Like your
temp drop across the coil and all the other things I just mentioned. Why in the world am I putting gauges on a system just for fun to write down the number? It doesn't make any sense to me whatsoever. I completely agree with that, especially whenever you get towards the end of the summer, I guess you'd say, or even if you're doing in heater manises, if you're doing, and you know, after it's already been cold, you know, I would always tell my techs like, guys, they've made it through the hardest part of this summer already or hardest part of this winter. You don't need to go in there and try to make a billion changes on here. It's obviously doing the thing it needs to be doing. So I completely agree with that. I mean, we're able to assess and say, hey, the system's working. Let's let it keep going. Our main job, like we've talked about before, make sure that it is dirt free. We need to make sure that we're getting as much dirt and removed and that that system is running cleanly. Now, we can get into another debate on here on a 20 degree delta T. 20 degrees is not the delta T that we're all looking for. You mentioned that it was removing a lot of water. People were comfortable in the house, but, you know, I could have a 10 degree delta T and still be moving the exact amount of air and refrigeration charge
and everything to be fine. Depends on that latent load. How much humidity is in the air? You know, it's probably not a big, you know, I can't imagine, I don't know, never been there, but not a bit, humidity might not be a big issue in your neck of the woods up there. But, you know, I'm originally from Tennessee and there's quite a bit of a humidity down there, right? So if I'm removing a huge latent load out of a home, I could see a 15 degree delta T and that's perfectly fine. You know, I keep going back to it, but that's what I know. If I'm using something like magic, it'll show me what the sensible capacity that I'm removing and as well as the latent capacity, you know, that hidden heat, that latent heat, it's actually being able to show it through the enthalpy that you're using with your psychometers. We've got to the point where all of this information is really good and we can utilize it quickly and get a lot of information that is going to put us down the right tracker. Is there a problem? Is there not a problem? And we can do this with a strategy knowing that what we're using, like these apps that have all got the calculations
in the background, it prevents human error, user error, if you've got the probes in the right spot. So what I wanted to move on to next was the electrical section of a system. Now, I will open up the electrical panel on a commercial. Sometimes the panels are, there's panels where I've actually needed a ladder to get up and get to the contactors that are literally like eight inches high. I think we're building contactors and stuff. We just throw them away when we get that. Sometimes, yeah, a contactor gets rebuilt in the field if it's a big enough one. Now, visual inspection of these things is really important. So I take all the covers off of my contactors. I look for pitting and I will push the contactor with the power off, push the contactor and making sure like it's not stuck or caught because a lot of times, especially on like a startup, you can push the contactor and it won't budge, it won't move. Or sometimes you go to push it in
and it's already in, it's already stuck and welded. So these are things that you need to find on a PM and rectify it. The other thing that I'm a big proponent of is checking for dust and carbon in a commercial setting, even in residential, I've seen this too, where the dust and carbon that's resting on the top of the line side of the contactor, any type of moisture in the air will embed inside of that that dust or carbon and it will track back to the panel to ground and it will blow a fuse and or pop a breaker and when the person shows up on the dry day, yeah, and then when the person shows up on the dry day, they change the fuse or reset the breaker, everything runs and then the next time it rains or snows, it goes pop again and are like, what's going on here? Look at the top of those contactors and see if you can pick up a track back to ground because let's face it, let's say even light commercial residential contactors cheap, it protects the compressor
from failing prematurely if we're finding contactors that are pitted and have these issues and we get them replaced because a $20 contactor can take out a $4 or $5,000 compressor just like that, it's amazing, but you got to look for this kind of stuff, right? It can cause all kinds of other issues too, I mean, you know, a couple of things I always make sure that and the technicians are aware of whenever they're going on that pertains to contactors, I don't know if it's as big a deal in the commercial world, but these 24 volt coils that they have on contactors are just made like crap nowadays, they used to never have a problem, you never had issues, we're finding shorts all the time, you know, internal shorts, the fuses blown inside and we're searching for a short all around come to find out it's the coil outside on the contactor, you know, so I have them start to actually owe them out these contactors whenever they're the contactor coil whenever they're on a regular maintenance and they should be looking for that 12 to 18 ohms on that on that contactor coil.
If they don't have that, then it's it's probably going to fail if it hasn't already and it's going to cause that short that's going to you're going to be there for hours looking for it. You talk about pitting and things like that, we can we can also eliminate the you know, the guesswork on pitting, we can we can push in the contacts manually while the power is off and we can ohm out across, we should see zero ohms or while the unit is live, we could look for a voltage drop across, you know, if I see a voltage drop, yeah, it's pitted and it makes a good contact, if I'm seeing any any for any more resistance, then then zero, then that means it's probably pitted, right? So just a mechanical way of looking at this and actually like measuring it stuff, but yeah, nothing beats the eyes you can look at it and say, hey, it's all burned up pitted and discussing, so just different ways of looking at it. For sure, there was a call that I went on in the summer, just in my neighborhood, somebody walked by my house, seen my van, they're like, hey, we put our our own thermostat on, it's not working. And I get this all the time, people are buying their own
thermostats and installing them themselves and I've gone to about five to six calls in my own neighborhood for this exact reason over the last year and most of the time they've wired it wrong. So I'm I'm thinking, hey, they probably wired this wrong, but the guy actually wired it right, but what was that? Because they were having issues with the previous thermostat. He's like, oh, I'll just change it. Same issues, cooling, not working. And what I saw in front of me, I think it was, I think they bought an ECOB, I think it was. So when it would go to cool, it would you'd see it go to cool and then about five to 10 seconds later, it would shut off and turn back on the thermostat. So what it ended up being is what you were describing. It was a short in the contactor coil. So it would try to pull in, it would buzz. And I guess it would overamp the thermostat somehow protected itself, shut down, stop the call from happening. And then it would come back on it, it would just keep
going through the same cycle over and over and over again. Right. And then I used, I had a sure switch in my van, you know, the Emerson, or not Emerson, the Copeland sure switch. So I had one of those in my van. And all I did was take the coil wires off of the contactor, put them into the sure switch, just the coil wires, nothing else. And I went through the same thing, the same, the thermostat didn't go blank. It didn't reset. It just stayed on cooling. I'm like, okay, so the coil and this thing is bad. Took it out, ohm did out. And it was like one or two ohms. So you got, you got, I don't know what it is with these newer thermostats. Maybe they have a way to protect themselves. I have, I have pretty that far yet. But no, that's awesome. Instead of going through like an instant death from a short in a unit. But yeah, that's, that's what it was. So you're right. Check these contactor coils for shorts. The other thing that I'm going to say here, and I did a podcast on it a few months ago, just me solo, just kind of talking about it, is
in certain applications, certain times, I think it's, it's warranted to just change a capacitor just because it's been in a, in service for so long. Because I've been beat up on this before, where I'll go to a call, a capacitor or a contactor capacitor, okay, or even both. But here's, here's my, here's my justification on that. So I'll go to a call, I'll get it going, everything's fine, whatever, whatever, and I check the capacitor, it's good. And then like three months later, I'm back as the capacitors filled. You know what I mean? I, I, now I'm under the, now I'm under, especially in residential, now I'm under the, the mindset, as if you're going on a call, the capacitor is five, six years old. You know what I mean? What's the harm in replacing it and avoiding a potential issue that same summer or the summer after or even two years down the line? And now you're good for another bunch of years because it, it could look bad on you that you were there. Even though you checked the capacitor while you were there, and it, and it resorts back to
a call three months later, like it happened to me. And the, the guy is, the guy was my friends, so he didn't, he wasn't like, he was just bugging me. He's just like, you know, it bullshit with me. Ah, you didn't check that when you, I said, yeah, I did. You're supposed to know it all. Yeah. So I am under the mindset that you could probably change these things on a schedule, depending on where you live. If you have a pattern, okay, I live in a hot, hot place every three years, I'm changing the capacitor on these units. Why not put it into a schedule to change it every two and a half years on a PM and avoid the service call? I'm under that impression now. I think that works great in the, in the commercial world. It would all, you know, go ahead. Capacitors are one of those things that in the residential world, that's where, that's where used, there's a lot of profitability in capacitors. We're going to just say that. A lot of the companies when you look at it, that's, that's what they're, when you sell one, it's, it's, it's marked up to, to compensate for all the other time that we, time wasting that we have throughout other
times. It all balances out. But, you know, giving those things away free, I don't know if that's, if that's just what you're talking about as far as the maintenance every few years, is, no, no, not for, not for, not for free at all. Yeah, and I've noticed it. I think if you, you could work into like a contract, if you to differentiate yourself from some of the other contractors out there that said that, you know, part of our regular maintenance is every three years, we're going to go ahead and change out your, your, your capacitor, right? And it's just built, the price is built in, spread out across that point in time, across those three years or whatnot, can build some loyalty to, to the contract as well. Maybe it's, you know, hey, you know, I'm going to stick with these guys for at least three years because, you know, I'm going to get another capacitor out of the deal. I don't know. Yeah, that, that's a, that's an interesting point to kind of schedule these as a, as a, as a time thing, right? I honestly don't see this pattern in commercial. That's also the commercial equipment I work on. The compressors are three phase. Yeah, yeah, they're not single phase, right? And it's usually just the fans that maybe that
condenser fan will take a capacitor on some of these three phase units. It's, it's weird they do it that way, but I've noticed this pattern in residential specifically, I mean, it also has a lot to do with the main, again, when we talk about the manufacturing of contact or coils, but the manufacturers of capacitors are awful. If they're not coming from this half of the world, then they're usually even worse than what that, you know what I'm saying? A good capacitor should last you at least five years, but we're seeing them that are bad a year later. And that is just unacceptable. And that just, that has nothing to do with anything other than manufacturing I'm going to assume, unless you had just loose contacts on there, on your stacons, keeping on there, that's, I just can't understand why in the world is happening. I even started cutting some in half to try to see what in the world is going on, a bunch of goo and, you know, silver tape looking stuff. That's that that's like, well, I guess there's not much to it. Anyway, I just thought I'd bring that up because just a pattern I noticed and I'd be a big proponent of it. If I was running a large residential business, it would be something that I would try to push on a customer because there is value there.
Especially the value they may not see it until you go there. This happens all the time. Remember my story about the motor dying and then changing it into Blizzard. Yep. So now that customer when I recommend something, he'll be like, we should probably do it, right? Sometimes it takes that to happen. And sometimes it takes, okay, it's May. I'm at the unit. I think I should change the capacitor because I notice it's about five years old. It's got some corrosion on it and the homeowner be like, no, it's okay. It's working right now. And then on their son's birthday party, when they have 30 people over in the AC goes out and nobody can get there. The next day someone shows up, hey, it's the capacitor. Remember I told you to change this three months ago? It would avoid it all of your problems. And that's when people start to go, okay, maybe he's onto something here. Maybe does actually know what he's talking. I got to run in a few minutes. But last thoughts on, we touched on cleanliness. We touched on refrigeration side, electrical side. Is there anything else that we didn't touch on or you feel is important to end this conversation? All the companies that I've worked
for we cleaned condenser coils. We pulled the top, cleaned actual condenser coil. I'm not sure if everybody does that or not across, you know, I'm sure not everybody does it. But I think that's a very, you know, if we're adding value to our maintenance and actually doing a good job, I think cleaning that outdoor condenser coil is easy thing that we can do to try to build value and it's going to help that's just to be able to breathe better and work better. That's one of the big things out there. Again, we're looking for dirt and cleaning everything out. I know in my neck that was here in just a couple of weeks, there's going to be all kinds of pollen and everything going everywhere and that's going to be sucked into every single one of these units. And you might not even be able to see it. So just wash off that outdoor coil. Let's get those things clean so that they can breathe and they can, uh, systems can run a little bit better. All right. John, again, I really appreciate this man and we'll probably do another one of these before the summers out, I would imagine. Maybe we can pick a different topic, but it's always good chatting with you because you are passionate, you're knowledgeable. I mean, it's just two guys talking shop and that's what I love. All right, brother. I appreciate it. All right, brother. So much. I look forward to the next time. Yeah. Thank you. All right. Thanks a lot.
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