1 00:00:00,000 --> 00:00:07,000 Welcome to the Windshield Chronicles, a mental sequence of operation. 2 00:00:07,000 --> 00:00:15,000 The ESCO Institute is dedicated to bringing you quality HVACR training products and resources. 3 00:00:15,000 --> 00:00:19,000 Learn more at escogroup.org. 4 00:00:22,000 --> 00:00:26,000 Alright, so this is going to be an interesting conversation. 5 00:00:26,000 --> 00:00:31,000 I always like to talk about how far we are going down into the conversation. 6 00:00:31,000 --> 00:00:35,000 We're going to start at an overview, like a thousand foot, 7 00:00:35,000 --> 00:00:38,000 and then we're going to dive really deep into flame rectification 8 00:00:38,000 --> 00:00:41,000 and understand a little bit about what that is. 9 00:00:41,000 --> 00:00:46,000 So joining me today is author of our gas heating book, Jason Obrzut. How are you? 10 00:00:46,000 --> 00:00:49,000 Thank you, Clifton. I'm doing pretty well. How are you? 11 00:00:49,000 --> 00:00:52,000 I've got to be more professional. Every time I have you on here, I'm like, 12 00:00:52,000 --> 00:00:57,000 oh, there's my buddy Jason and I call him buddy. But it's so much fun when we get together. 13 00:00:57,000 --> 00:01:00,000 Because you and I see things from such a similar perspective 14 00:01:00,000 --> 00:01:03,000 and we always have a good time diving into these topics. 15 00:01:03,000 --> 00:01:08,000 And I have to say, for me personally, this was a topic that when I first started teaching, 16 00:01:08,000 --> 00:01:12,000 I really didn't understand. I thought I had a decent idea, 17 00:01:12,000 --> 00:01:17,000 but I didn't know what that entire rectification looked like. 18 00:01:17,000 --> 00:01:21,000 And so I got into diving a little deeper into it. 19 00:01:21,000 --> 00:01:23,000 And you cover it really well in our gas heat book. 20 00:01:23,000 --> 00:01:25,000 I want to make sure everyone is joining us. 21 00:01:25,000 --> 00:01:29,000 If you don't know what we're talking about, we have a really, really good 22 00:01:29,000 --> 00:01:32,000 instructor array of education on gas heating. 23 00:01:32,000 --> 00:01:37,000 So the book, the e-learning, we've got the entire digital copy of it. 24 00:01:37,000 --> 00:01:43,000 So the entire curriculum for teaching gas heat in our classrooms. 25 00:01:43,000 --> 00:01:45,000 And so let's talk about rectification a little bit. 26 00:01:45,000 --> 00:01:48,000 And I think to do that properly, we need to be able to go back 27 00:01:48,000 --> 00:01:50,000 and talk a little bit about how we got into flame rectification. 28 00:01:50,000 --> 00:01:53,000 I had a good understanding of this, but when I started teaching, 29 00:01:53,000 --> 00:01:59,000 what I understood didn't communicate to the students the way I understood it. 30 00:01:59,000 --> 00:02:03,000 So what you're going to show today, things like this are definitely beneficial. 31 00:02:03,000 --> 00:02:05,000 I could say, listen, this is how it happens. 32 00:02:05,000 --> 00:02:08,000 And they would all look at me like I had snakes coming out of my head. 33 00:02:08,000 --> 00:02:09,000 I'm like, wait, say that again. 34 00:02:09,000 --> 00:02:12,000 Wait, wait, wait, wait, wait. Hold on. Back up. What do you mean? 35 00:02:12,000 --> 00:02:15,000 Just because you understand it doesn't mean the others will. 36 00:02:15,000 --> 00:02:18,000 Exactly. And so when we're teaching this in class, 37 00:02:18,000 --> 00:02:25,000 it's very important to know how to teach rectification because it's really, 38 00:02:25,000 --> 00:02:29,000 for me, it wasn't exactly what I was expecting it to look like. 39 00:02:29,000 --> 00:02:32,000 So let's do a little history here so we understand the difference 40 00:02:32,000 --> 00:02:36,000 between voltage generation and flame rectification. 41 00:02:36,000 --> 00:02:38,000 And when we talk about our earlier furnaces, 42 00:02:38,000 --> 00:02:41,000 now I grew up working on thermocouple driven furnaces. 43 00:02:41,000 --> 00:02:44,000 Almost everything that I worked on had a thermocouple on it. 44 00:02:44,000 --> 00:02:47,000 So whether it was a gas fireplace, whether it was a gas furnace, 45 00:02:47,000 --> 00:02:51,000 whether it was a water heater, it all goes way back into the early 1800s 46 00:02:51,000 --> 00:02:55,000 when Thomas Johann Seebeck found this really interesting effect 47 00:02:55,000 --> 00:02:57,000 when he applied heat to dissimilar metals. 48 00:02:57,000 --> 00:03:00,000 It created a magnetic field. Right. 49 00:03:00,000 --> 00:03:02,000 And so when we start talking about electrically, 50 00:03:02,000 --> 00:03:06,000 well, magnetic field can turn into current when we utilize it properly. 51 00:03:06,000 --> 00:03:12,000 So we started experimenting with thermoelectric current as early as 1821. 52 00:03:12,000 --> 00:03:14,000 Well, what does that mean to us? 53 00:03:14,000 --> 00:03:19,000 Well, that's actually the technology that we put into play into thermocouples. 54 00:03:19,000 --> 00:03:22,000 And there are still thermocouple driven devices out there. 55 00:03:22,000 --> 00:03:27,000 But the difference between thermocouple and flame rectification is very different. 56 00:03:27,000 --> 00:03:30,000 So if you learn from someone who understands thermocouples 57 00:03:30,000 --> 00:03:36,000 and you move to flame rectification, you may not have gotten the full clarification. 58 00:03:38,000 --> 00:03:39,000 All right. So let's talk about this. Right. 59 00:03:39,000 --> 00:03:43,000 Thermocouple, two dissimilar metals fused together at one end. 60 00:03:43,000 --> 00:03:48,000 When a thermocouple is heated, it generates the actual DC voltage. 61 00:03:48,000 --> 00:03:52,000 We create voltage with a thermocouple. Right. 62 00:03:52,000 --> 00:03:54,000 So we have the difference in temperatures. 63 00:03:54,000 --> 00:03:56,000 We have the magnetic displacement. 64 00:03:56,000 --> 00:04:03,000 And so we actually generate DC voltage directly off from our thermocouple. 65 00:04:03,000 --> 00:04:05,000 So the more heat, the more voltage. 66 00:04:05,000 --> 00:04:07,000 And we have different types of thermocouples. 67 00:04:07,000 --> 00:04:10,000 Basically, depending on the construction of it, 68 00:04:10,000 --> 00:04:14,000 we can get different voltage ratings. Right. 69 00:04:14,000 --> 00:04:18,000 So we're talking about millivolts, very, very small amounts of voltage. 70 00:04:18,000 --> 00:04:21,000 So if we think about like a C type thermocouple, 71 00:04:21,000 --> 00:04:26,000 we know that at a certain heat range, we're going to get a certain voltage. 72 00:04:26,000 --> 00:04:31,000 So like on that C type thermocouple, if we are at around 3000 degrees Fahrenheit, 73 00:04:31,000 --> 00:04:36,000 we're going to generate around 30 millivolts DC voltage. 74 00:04:36,000 --> 00:04:45,000 So a common thermocouple is going to be in that range, 18 to 30 volts DC, millivolts DC. Right. 75 00:04:45,000 --> 00:04:50,000 And this is voltage being generated right out of nothing from being heated. 76 00:04:50,000 --> 00:04:54,000 Nothing is supplying anything to this other than the flame. Exactly. 77 00:04:54,000 --> 00:04:57,000 And we are going to do work with this. 78 00:04:57,000 --> 00:05:01,000 When we talk about K type thermocouples, like for our meters, well, same kind of thing. 79 00:05:01,000 --> 00:05:06,000 We're generating a voltage that our meter is going to read and interpret it as temperature. 80 00:05:06,000 --> 00:05:09,000 Well, that's all fine and dandy when we're talking about thermocouples. 81 00:05:09,000 --> 00:05:13,000 And maybe we need a little bit more because remember, we're going to do work with this. 82 00:05:13,000 --> 00:05:17,000 So on a residential light commercial gas furnace with a water heater or the fireplace, 83 00:05:17,000 --> 00:05:22,000 we're going to generate some voltage and we're actually going to do work with that voltage. 84 00:05:22,000 --> 00:05:24,000 Well, what if we need more? What if our valve is larger? 85 00:05:24,000 --> 00:05:29,000 And we're talking about a commercial gas valve or an industrial gas valve that's got a bigger diaphragm and a bigger solenoid. 86 00:05:29,000 --> 00:05:31,000 And we need more power. 87 00:05:31,000 --> 00:05:38,000 Well, we just take thermocouples and we put them into series and we create more voltage. 88 00:05:38,000 --> 00:05:40,000 That's all it is. 89 00:05:40,000 --> 00:05:48,000 So we're applying heat onto multiple thermocouples so that we get a common higher output voltage. 90 00:05:48,000 --> 00:05:52,000 Works great when we're talking about a larger gas valve. Right. 91 00:05:52,000 --> 00:05:58,000 So if we're typically working on a thermocouple, we can actually measure the voltage that's being output from that. 92 00:05:58,000 --> 00:06:02,000 And Jason covers this completely in our gas heating book. 93 00:06:02,000 --> 00:06:06,000 You can measure the voltage to see how good your thermocouple is working. 94 00:06:06,000 --> 00:06:11,000 A lot of time in the past, we just cleaned them. If it held good, if it didn't, we replaced it. 95 00:06:11,000 --> 00:06:13,000 Well, you can actually measure that. 96 00:06:13,000 --> 00:06:19,000 And so we can measure the voltage on a thermocouple as long as we have proper heat applied to that top half inch of the thermocouple, 97 00:06:19,000 --> 00:06:22,000 somewhere 10, 15, 30 millivolts DC. 98 00:06:22,000 --> 00:06:26,000 If we're talking about a thermal pile, well, now we are just generating more. 99 00:06:26,000 --> 00:06:28,000 So it depends on the size of the thermal pile. 100 00:06:28,000 --> 00:06:35,000 But typically in that, you know, 540, 750. So 5, 600, 700 millivolts is pretty common. 101 00:06:35,000 --> 00:06:40,000 So what this can do, it can tell you not just about your thermocouple or your thermal pile, 102 00:06:40,000 --> 00:06:42,000 but actually the quality of the flame being used to heat it. 103 00:06:42,000 --> 00:06:47,000 If you throw, if you have a brand new thermopile or a thermocouple and you're getting these low readings, 104 00:06:47,000 --> 00:06:51,000 it may be the the issue is the quality of that pilot flame. 105 00:06:51,000 --> 00:06:54,000 It might be a weak flame. It might be dirty. Right. 106 00:06:54,000 --> 00:06:58,000 So a lot of things you can do with it. That's super important on this conversation. 107 00:06:58,000 --> 00:07:10,000 So what we're saying is that with a thermocouple and a thermopile, heat is absolutely crucial to be able to use this safety device. 108 00:07:10,000 --> 00:07:15,000 The heat is the function of generation for voltage. 109 00:07:15,000 --> 00:07:17,000 That's what I was taught. 110 00:07:17,000 --> 00:07:24,000 Well, that was great until we moved into newer technology in the 80s and 90s with solid states. 111 00:07:24,000 --> 00:07:27,000 So let's talk just for a second. So we understand completely what we're doing. 112 00:07:27,000 --> 00:07:32,000 So if we have a say that we've got a pilot driven gas valve. 113 00:07:32,000 --> 00:07:38,000 So we're going to push down on our pilot button. We're going to supply fuel onto that pilot tube. 114 00:07:38,000 --> 00:07:45,000 We're going to light that with whatever device, whether it's a hand ignition, whether it's a direct spark, whatever that is. 115 00:07:45,000 --> 00:07:52,000 We're going to create a hot enough flame, hopefully 2000, 3000 degrees. 116 00:07:52,000 --> 00:07:59,000 We're going to get hot enough that we're going to generate voltage off from those dissimilar metals. 117 00:07:59,000 --> 00:08:03,000 And that voltage is going to be applied to a magnetic coil. 118 00:08:03,000 --> 00:08:11,000 And so we have an electromagnetic plunger, a plunger inside of electromagnetic field that's going to hold that plunger down. 119 00:08:11,000 --> 00:08:15,000 We generate enough voltage. We have enough magnetic field. It's going to draw it in. 120 00:08:15,000 --> 00:08:18,000 OK, so that's how those work. 121 00:08:18,000 --> 00:08:21,000 So we're heating up our thermocouple to generate voltage. 122 00:08:21,000 --> 00:08:24,000 And that's how all thermocouples and all thermopiles work. 123 00:08:24,000 --> 00:08:28,000 Here is the thing that we're not always instructed on. 124 00:08:28,000 --> 00:08:38,000 When we moved from thermocouple systems with manual ignition controls and we moved into electronic ignition that almost all went away. 125 00:08:38,000 --> 00:08:48,000 And we moved into the era of flame rectification that doesn't rely on heat at all. 126 00:08:48,000 --> 00:08:54,000 And that's where I got pointed out that the thermocouple itself was a safety. 127 00:08:54,000 --> 00:09:07,000 All right. So if the pilot went out, the thermocouple or thermopile would stop generating voltage and the valve wouldn't be able to open to let the gas out because there would be nothing on the other end of that valve to ignite that gas that we were letting out. 128 00:09:07,000 --> 00:09:09,000 So it was more like a safety device. 129 00:09:09,000 --> 00:09:15,000 And that function, if you will, the safety portion of it carried over to the flame rectification. 130 00:09:15,000 --> 00:09:18,000 But the principles did not. It's a completely different principle. 131 00:09:18,000 --> 00:09:24,000 Exactly. And that's where I got hung up the most because I was not explained this. 132 00:09:24,000 --> 00:09:27,000 And so once I learned it, then it's like, OK, how do I teach that? 133 00:09:27,000 --> 00:09:32,000 Well, like everything else, it comes down to understanding what's going on. 134 00:09:32,000 --> 00:09:34,000 And we're going to dive into this. 135 00:09:34,000 --> 00:09:41,000 And if you hang around, we're actually going to maybe even potentially construct one so we can show you what it looks like electrically. 136 00:09:41,000 --> 00:09:52,000 OK, let's clear our mind for a little bit and let's think about what's happening here so that you can completely get a new perspective if you don't understand it the way that we're going to show you. 137 00:09:52,000 --> 00:09:57,000 So with rectification, we absolutely are not relying on heat. 138 00:09:57,000 --> 00:10:01,000 Right. So there's a misconception that we need to break real quick. 139 00:10:01,000 --> 00:10:07,000 So with flame rectification, we are actually completing an electrical circuit. 140 00:10:07,000 --> 00:10:12,000 Right. So we are actually going to apply voltage onto a flame rod. 141 00:10:12,000 --> 00:10:23,000 We're going to pass through the flame. We're going to go through this process of rectification and will help you understand why that gets that name, what it's actually doing. 142 00:10:23,000 --> 00:10:27,000 And then we're going to return back on our ground. 143 00:10:27,000 --> 00:10:35,000 And so we have to stop for a minute and go, well, wait a minute, wait a minute. Maybe I wasn't explained that that's what happens with this flame sensor. 144 00:10:35,000 --> 00:10:42,000 And by the way, you'll see it called a flame sensor. It's really not. It's a rod. I'm going to show you what it's made of here in just a minute. 145 00:10:42,000 --> 00:10:49,000 It's just a conductor, right? That's it. That's all we're doing. It's a means of applying voltage into the path of the flame. 146 00:10:49,000 --> 00:10:55,000 All right. So let's think about this because we're going to come back to this here in a few minutes and it's really going to sink in. 147 00:10:55,000 --> 00:11:03,000 So what we're actually doing, we are completing a circuit. We're applying voltage onto the rod or probe or sensor. 148 00:11:03,000 --> 00:11:09,000 You'll see different names. It's just a rod. We are applying voltage, AC voltage onto that rod. 149 00:11:09,000 --> 00:11:23,000 It's passing through the flame. And because of the ionization, the combustion that's happening in that flame, we're actually going to put a load on the flame as it's making its way back to ground. 150 00:11:23,000 --> 00:11:31,000 And so we are creating an electrical loop through the fire. Now, flame does conduct electricity. 151 00:11:31,000 --> 00:11:35,000 It's not a good conductor, but flame will conduct electricity. Absolutely it does. 152 00:11:35,000 --> 00:11:42,000 The ground is one of the most important pieces of our circuit. And we'll show you here in just a second. 153 00:11:42,000 --> 00:11:46,000 So let's think about this electrically, right? Just so we can see what's going to happen. 154 00:11:46,000 --> 00:11:58,000 If we think about this electrically, that means we're applying an AC voltage. We are going to convert into a DC looking signal only because that's what happens in the ionization side. 155 00:11:58,000 --> 00:12:03,000 And so our meters can't read it as AC anymore. It's not a clear path to ground. Remember, we're jumping through flame. 156 00:12:03,000 --> 00:12:10,000 We're jumping across carbon molecules and carbon atoms, actually, carbon atoms and water molecules. 157 00:12:10,000 --> 00:12:16,000 And we're going through this effect of ionization that's in the flame. We don't have a straight path to ground. 158 00:12:16,000 --> 00:12:25,000 So our meter can't read AC. It reads it as DC. And we're putting a load on that flame, which is why we are reading in amps. 159 00:12:25,000 --> 00:12:31,000 So we're putting a very, very small amount of voltage through it. And we're putting a very, very small load on that flame. 160 00:12:31,000 --> 00:12:38,000 So we're reading it in micro amps and we're reading it in a DC voltage. 161 00:12:38,000 --> 00:12:45,000 OK, yes, it is basically half of the sine wave because the flame does have a very high resistance. 162 00:12:45,000 --> 00:12:53,000 The circuit board is usually only seeing about half that sine wave and on your meter, you're only going to see about half that sine wave, which is why it shows up in DC and not AC. 163 00:12:53,000 --> 00:13:00,000 Right. Exactly. But it is 100 percent AC voltage. I'll even show you on a wiring diagram. A lot of people have missed this. 164 00:13:00,000 --> 00:13:06,000 When you read your wiring diagram, it'll completely make sense and we'll actually show one for this particular model that I have right here. 165 00:13:06,000 --> 00:13:17,000 So let's think about this now that we if we approach it from an electrical perspective and we start using our electrical trained brain instead of our heat trained brain. 166 00:13:17,000 --> 00:13:29,000 This entire process will just make sense like a light bulb. So if we take a burner assembly, we are going to first thing we're going to do, we're going to apply an ignition source. 167 00:13:29,000 --> 00:13:37,000 So whether it's direct spark or it's hot surface ignition, we're going to apply the means for igniting our fuel, our A3 highly flammable fuel. 168 00:13:37,000 --> 00:13:54,000 Right. Once we introduce fuel into our circuit, our igniter is going to ignite the gases coming out of our burner because it is mixed with fuel and diluted to an area between its lower flammability limit and its higher flammability limit. 169 00:13:54,000 --> 00:14:03,000 Right. We're making combustion. It's going to pass across our burner assembly and it's going to light the rest of the burners. 170 00:14:03,000 --> 00:14:14,000 So we have a complete path of flame. Very important to verify that all of our burners are lit. And this is where our circuit comes into play. 171 00:14:14,000 --> 00:14:25,000 At the opposite end, we now have a dedicated wire going from the molex connector of our furnace board right over to the flame rod. 172 00:14:25,000 --> 00:14:36,000 And I will always call it a rod because it's just a rod. Right. And it's typically orange. So we're going to have a dedicated wire directly from the control board to the flame rod. 173 00:14:36,000 --> 00:14:54,000 Here's another thing that a lot of people miss. A lot of people don't recognize that we actually have not just a ground, but we have a dedicated ground going directly from the molex connector of our board straight to the burner box. 174 00:14:54,000 --> 00:15:02,000 And it is landed there by the manufacturer for this particular reason, because it is part of our complete circuit. 175 00:15:02,000 --> 00:15:10,000 The ground is as important as the rod itself, as well as the surface of those burner faces. 176 00:15:10,000 --> 00:15:17,000 Because remember, we are applying AC voltage and a lot of people are going, oh, that's crazy. We don't apply AC voltage. Well, let me show you. 177 00:15:17,000 --> 00:15:28,000 So let's take a look at the wiring diagram for this particular 80% Goodman furnace. If we look on here, this is where people just will just skip it. 178 00:15:28,000 --> 00:15:34,000 It wasn't until I looked at the wiring diagram myself and I went, oh, my gosh, it was right there in front of me the whole time. 179 00:15:34,000 --> 00:15:40,000 If we look at this wiring diagram, my flame sensor, the manufacturer is actually calling it a flame sensor. 180 00:15:40,000 --> 00:15:45,000 I'm going to call it a rod because it's not sensing anything. It's just a rod made of canthal. 181 00:15:45,000 --> 00:15:50,000 But if you look, it is on the high side of our transformer. 182 00:15:50,000 --> 00:15:57,000 It is on the same side of our transformer as our hot surface igniter, our induced draft blower and our circulating blower. 183 00:15:57,000 --> 00:16:04,000 The only difference is our voltage has been reduced to typically a lower, safer voltage rating for handling. 184 00:16:04,000 --> 00:16:10,000 But it's actually AC voltage. So in a classroom, here's the way that we want to show that. 185 00:16:10,000 --> 00:16:15,000 Or even if you're a technician and you want to verify it yourself, next time you're sitting in front of a gas furnace, here's what you do. 186 00:16:15,000 --> 00:16:20,000 So let's walk over to a meter. Let's put our meter on volts AC. 187 00:16:20,000 --> 00:16:28,000 My thermostat is not calling for heat, but I have power applied to my furnace, which means everything on my high side has the potential for voltage right now. 188 00:16:28,000 --> 00:16:35,000 So if I go from ground and I go directly over to my flame rod, I am actually producing right now. 189 00:16:35,000 --> 00:16:43,000 Forty three point four volts AC directly onto my sensor, my rod. 190 00:16:43,000 --> 00:16:52,000 OK, so that's step one to be able to see what we're doing. So we're going to apply AC voltage back onto that wiring diagram. 191 00:16:52,000 --> 00:16:55,000 Let's go over that wiring diagram and let's complete this path. 192 00:16:55,000 --> 00:17:04,000 So what we're going to do on that flame rod, we apply AC voltage that AC voltage comes out of our board and it's going to go to the rod. 193 00:17:04,000 --> 00:17:09,000 It's going to pass through the flame back onto that dedicated ground wire. 194 00:17:09,000 --> 00:17:21,000 It is such a dedicated ground wire that if we look at this separate burner assembly that I have here, Jason, this is something that we can never, never overlook on a gas furnace. 195 00:17:21,000 --> 00:17:32,000 Right. Our dedicated ground wire from that control board lands on the burner box so that we can get as close of a connection to our burners as possible. 196 00:17:32,000 --> 00:17:45,000 It is such an important wire that this particular one actually is a straight wire from here all the way back to the control board and is a component of the wiring harness of the furnace. 197 00:17:45,000 --> 00:17:52,000 It's not a separate wire. It cannot be relocated. It is there as a dedicated path. 198 00:17:52,000 --> 00:17:57,000 And so what we're going to do, we're going to talk about measuring this. What do you think, Jason? 199 00:17:57,000 --> 00:18:07,000 I think that's a great idea. Another thing to point out is just because that wire is present, if the furnace itself is not grounded upon installation, then we may have some. 200 00:18:07,000 --> 00:18:10,000 Yeah, that's where the question comes up. We got to have a really good ground. 201 00:18:10,000 --> 00:18:17,000 Yes. Well, you may have to depending on where the furnace is located and how you're running the electric to it. 202 00:18:17,000 --> 00:18:22,000 If they're using Romex and flexible gas line, then you may not have a reliable ground. 203 00:18:22,000 --> 00:18:31,000 You may have to run a wire from and typically there's a stake on on that gas valve somewhere where you can stake a wire on and run it to a water pipe or gas pipe or something of that nature. 204 00:18:31,000 --> 00:18:36,000 But that's where you run into some ground issues. The firm from the manufacturer, they've got a good connection there. 205 00:18:36,000 --> 00:18:46,000 They've got a solid wire, no breaks. But after I got after installation, you may not depending on the way it was installed and the materials that were used to install it. 206 00:18:46,000 --> 00:18:52,000 We may not have the best ground after installation and we may throw some intermittent flame sensor problems. 207 00:18:52,000 --> 00:19:00,000 Exactly. So what we're doing when we're teaching you to or we're teaching our students to measure the flame current, that's really what we're doing. 208 00:19:00,000 --> 00:19:05,000 We're validating. Are we making it back to ground? That's all that we're actually doing. 209 00:19:05,000 --> 00:19:12,000 So let's talk about this for a minute. If you've not been explained this, I'm going to very quickly just demonstrate what we're going to do. 210 00:19:12,000 --> 00:19:16,000 We're going to show you we're going to prove to you that it's actually electrical. 211 00:19:16,000 --> 00:19:29,000 So if we are measuring the actual microamps that's passing through there for measuring the load that is on that flame, what would we do if we're measuring any kind of a load? 212 00:19:29,000 --> 00:19:35,000 Right. We're going to put our meter in series with our load. 213 00:19:35,000 --> 00:19:42,000 So what we're going to do, we're going to disconnect our next, typically orange, we're going to disconnect it. We're going to put our meter in series now. 214 00:19:42,000 --> 00:19:51,000 So literally just disconnecting the wire, putting our meter in. So all we've done is we've completed that loop. 215 00:19:51,000 --> 00:19:56,000 So if we go back to that wiring diagram, we'll actually see exactly what I just did. 216 00:19:56,000 --> 00:20:06,000 So I took the orange wire off from the flame rod. I put my meter in series so that my meter is measuring the current that is passing through. 217 00:20:06,000 --> 00:20:13,000 Right. So if we're reading amps of any kind, we're reading the current. And that's actually what we're going to do. 218 00:20:13,000 --> 00:20:23,000 Now, here's the important thing. Manufacturers of control boards, electronic ignition control boards, set a range, an acceptable range for that microamp. 219 00:20:23,000 --> 00:20:32,000 It's typically around one microamp DC. So if we get less than that, the board has the potential for locking out. 220 00:20:32,000 --> 00:20:45,000 So this is why it's critical for us to measure what those microamps, just like Jason said, what if it's a flame that is just, you know, if our gas pressure is low and our burners are dirty, 221 00:20:45,000 --> 00:20:54,000 we may not be getting the proper current passing through so we can actually measure it to see what we have. I want to point something out real quick. 222 00:20:54,000 --> 00:21:01,000 Yes. When your meter is in that position, it allows voltage to pass through it. Right. 223 00:21:01,000 --> 00:21:07,000 So if you accidentally touch ground with either end of that, you're going to have some fireworks. 224 00:21:07,000 --> 00:21:15,000 So you have to be like you have the insulated clips on your alligator clips there. Don't let the meter touch the burner, touch the furnace. 225 00:21:15,000 --> 00:21:22,000 It's got to be firmly connected to the wire and to the flame sensor and nowhere can we introduce the ground or we're going to have some problems. 226 00:21:22,000 --> 00:21:30,000 So, Jason, let's let's do a quick middle sequence of operation. If I'm a gas fired furnace, what's my sequence? 227 00:21:30,000 --> 00:21:38,000 So number one, if I'm a circuit board, I'm sitting waiting for something to happen and that something is the thermostat asking me for heat. 228 00:21:38,000 --> 00:21:43,000 So the first thing I need is for the thermostat to ask for heat. All right. We'll go do that one. 229 00:21:43,000 --> 00:21:47,000 Now I have a little bit of background noise as the blower and stuff kicks on, but I'm going to try to keep close to the microphone. 230 00:21:47,000 --> 00:21:54,000 I'll try and keep up with the speed of the board there. Yeah. As a board, once I receive this input signal from the thermostat, 231 00:21:54,000 --> 00:22:02,000 my reaction as a board is I'm going to send an output signal to the inducer motor. All right. A combustion blower, power venter, whatever they want to call it. 232 00:22:02,000 --> 00:22:11,000 It has a million names. There goes one. There goes. And the purpose for that blower is to induce into the heat exchangers, the combustion air and the gases. 233 00:22:11,000 --> 00:22:17,000 But we also have a safety switch in there that needs to make sure that our flu is clear. 234 00:22:17,000 --> 00:22:21,000 We have the proper airflow through the heat exchangers and that's that safety, that pressure switch. 235 00:22:21,000 --> 00:22:25,000 So when that inducer comes on, the pressure switch is going to close. 236 00:22:25,000 --> 00:22:31,000 And as the board, I'm going to get a signal from that pressure switch to say, hey, everything's a goal. Move on to the next step. 237 00:22:31,000 --> 00:22:39,000 So when the board gets that signal in from the pressure switch, it's going to react by putting a signal out to the igniter. 238 00:22:39,000 --> 00:22:44,000 The igniter is going to have a warm up period, 30, 60 seconds, whatever it happens to be. 239 00:22:44,000 --> 00:22:53,000 And after that timer, it's then going to send 24 volts to the gas valve, which is going to let the gas out, hits the igniter and we get ignition. 240 00:22:53,000 --> 00:23:02,000 Once we get ignition across all those burners, that flame sensor rod, whatever we want to call it, there's going to be a path through there to let the board know, hey, we got ignition. 241 00:23:02,000 --> 00:23:09,000 We've got current through here. Once it sees that current, it's going to allow 30, 60, 90, 120 seconds and it's going to turn on the blower motor. 242 00:23:09,000 --> 00:23:14,000 So all it is is a series of inputs and outputs in a very specific order. That's it. 243 00:23:14,000 --> 00:23:27,000 So what we just did was in that sequence of operation, after the igniter comes on, after the gas valve comes on, we have a very short window of time that we have seconds. 244 00:23:27,000 --> 00:23:31,000 Yeah, that's right. We have to prove that there is actually flame there, but we're doing it electrically. 245 00:23:31,000 --> 00:23:44,000 So what we did was we created our little flame rectification circuit using a 10 mega ohm resistor in a parallel circuit along with a 2.2 mega ohm with a 404 diode in series. 246 00:23:44,000 --> 00:23:53,000 When we did that, we created a micro amp load across from ground to the flame rod. 247 00:23:53,000 --> 00:23:59,000 And so you'll actually see we are running right now. My board is as happy as can be. 248 00:23:59,000 --> 00:24:08,000 It timed on, brought the flame on, and I'm actually measuring about 1.9 micro amps DC. 249 00:24:08,000 --> 00:24:22,000 It has 1.9 micro amps DC current passing through the flame, creating the electrical circuit that we know as rectification. 250 00:24:22,000 --> 00:24:26,000 And that's really it. It's kind of complicated. 251 00:24:26,000 --> 00:24:34,000 A good way to explain this, when you start, if we start at that 30,000 foot level and say, listen, it's kind of like a switch that closes. 252 00:24:34,000 --> 00:24:41,000 All right. All you're doing is closing a circuit. That flame hits the rod, closes the circuit and allows current to flow. 253 00:24:41,000 --> 00:24:47,000 In the absence of the flame, the circuit is open, no current flows, and we get no ignition or we get no sequence. 254 00:24:47,000 --> 00:24:56,000 So when you're trying to explain this to somebody, students or colleagues or coworkers, say, listen, it's kind of like a switch. It's open or closed. 255 00:24:56,000 --> 00:25:00,000 That flame closes the circuit and absence of flame opens the circuit. 256 00:25:00,000 --> 00:25:04,000 And then you can take the deeper dive and say, well, actually, here's the current. Here's how it's going. 257 00:25:04,000 --> 00:25:07,000 The flame conducts electricity to the ground, that sort of thing. 258 00:25:07,000 --> 00:25:12,000 But when I started teaching and I started using the switch thing and the students started getting that. 259 00:25:12,000 --> 00:25:15,000 Yes. We're adding it into the electrical circuit. 260 00:25:15,000 --> 00:25:19,000 We are taking an electrical circuit and adding it into the rest of the electrical circuits. 261 00:25:19,000 --> 00:25:22,000 That's all we're doing. And that's in the very small current. 262 00:25:22,000 --> 00:25:26,000 I got me because the flame is not a great conductor. It does have high resistance. 263 00:25:26,000 --> 00:25:29,000 So it's a very small current going through there. 264 00:25:29,000 --> 00:25:34,000 We got to put our meter in series with it to see that current in DC micro amps. Exactly. 265 00:25:34,000 --> 00:25:45,000 We'll see you all in a couple of weeks on, did you know the ESCO H-Fact Show.