Jim Fultz with Emerson discusses universal controls and how HVAC technicians can expect to use and interact with them. He specifically focuses on White-Rodgers aftermarket controls in heating equipment.
Universal components work across all systems, such as modern thermostats; you can see thermostats on gas furnaces, heat pumps, straight-cool A/Cs, and more, and they'll all serve the same purpose. The "Universal" identifier merely indicates a part that works across several systems regardless of OEM. Universal controls aim to be easy for technicians to use when OEM parts are too expensive or impractical to order; customers also appreciate being given alternatives.
On furnaces, a common burner component that can usually use a universal replacement is the gas valve. White-Rodgers aftermarket components can work for hot-surface or direct-spark ignition.
In the blower compartment, we have the 24v transformers, which are critical components that allow universal components to work on systems. The "control circuits" that a 24v transformer connects with are the thermostat circuit, limit circuit, pressure switch circuit, gas valve, and ECM Speed Tap selection circuit. The integrated furnace control (IFC) is another critical component, as it fully controls all furnace operations; each control has specially designed functions for one or two-stage equipment, various blower motor types, direct-spark or hot-surface ignition, and OEM or universal options.
Nowadays, universal kits typically have adapters to multiple furnaces, so they can work across several different manufacturers' models. You just have to verify the cross-reference of the voltage of the universal control to the IFC (such as via the WR Mobile app). After that, the installation instructions should tell you which harness you need for the conversion.
Whereas the IFC is the heart of furnace controls, the defrost control is the heart of a heat pump system's controls. The defrost control manages the condensing fan motor, contactor, reversing valve, and coil temperature. It may also operate and monitor the high-pressure switch, low-pressure switch, outdoor air temperature, and backup heat.
The defrost control may use one of two strategies: timed defrost or demand defrost. Of the two defrost strategies, demand defrost is favorable because it can result in longer equipment life, more cost savings ($200-400 annually), and offer better compression protection. White-Rodgers defrost controls can upgrade units from timed defrost to demand defrost with the Matrix LED by using thermostat and heat pump harnesses and thermistors.
Contactors are components that require frequent replacement nowadays, which is ironic because they used to be the most durable part of the system. Contactors may come in the 1-pole, 1.5-pole, and 2-pole varieties. Most manufacturers tend to use 1.5-pole contactors nowadays. The SureSwitch universal part is a 1.5-pole contactor that can replace all three types.
Contactors commonly have electrical arcing issues. Pitting and welding occur during arcing, which prevents contactors from opening or closing. Pitting and welding may also happen due to voltage drops or insect damage. The SureSwitch contacts are sealed, so it is an appealing replacement because bugs cannot access the contacts and cause welding or pitting. The SureSwitch also comes with protection against brownouts and short cycles; those benefits will lead to improved equipment longevity.
The SureSwitch also comes with coil voltage options. The red cap on the spade can allow the SureSwitch to work with 120v, 208v, or 240v applications.
Jim also discusses:
Common White-Rodgers applications
Furnace burner components
Furnace blower assembly and blower motors
Furnace operation sequence
IFC pins
Universal benefits
Universal component usage for Carrier/ICP air handler boards
Time defrost vs. demand defrost
Setup and programming options with the 47D01U-843
State requirements for heat pumps
Using auxiliary (backup) heat
47D01U-843 benefits on heat pump systems
The anatomy of arc damage
SureSwitch features
White-Rodgers product warranties
Future three-phase universal contactors
SureSwitch compatibility with refrigeration systems
Mounting the SureSwitch
How WR Mobile works
Visit the White-Rodgers website at www.whiterodgers.com.
Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.
Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.
Universal components work across all systems, such as modern thermostats; you can see thermostats on gas furnaces, heat pumps, straight-cool A/Cs, and more, and they'll all serve the same purpose. The "Universal" identifier merely indicates a part that works across several systems regardless of OEM. Universal controls aim to be easy for technicians to use when OEM parts are too expensive or impractical to order; customers also appreciate being given alternatives.
On furnaces, a common burner component that can usually use a universal replacement is the gas valve. White-Rodgers aftermarket components can work for hot-surface or direct-spark ignition.
In the blower compartment, we have the 24v transformers, which are critical components that allow universal components to work on systems. The "control circuits" that a 24v transformer connects with are the thermostat circuit, limit circuit, pressure switch circuit, gas valve, and ECM Speed Tap selection circuit. The integrated furnace control (IFC) is another critical component, as it fully controls all furnace operations; each control has specially designed functions for one or two-stage equipment, various blower motor types, direct-spark or hot-surface ignition, and OEM or universal options.
Nowadays, universal kits typically have adapters to multiple furnaces, so they can work across several different manufacturers' models. You just have to verify the cross-reference of the voltage of the universal control to the IFC (such as via the WR Mobile app). After that, the installation instructions should tell you which harness you need for the conversion.
Whereas the IFC is the heart of furnace controls, the defrost control is the heart of a heat pump system's controls. The defrost control manages the condensing fan motor, contactor, reversing valve, and coil temperature. It may also operate and monitor the high-pressure switch, low-pressure switch, outdoor air temperature, and backup heat.
The defrost control may use one of two strategies: timed defrost or demand defrost. Of the two defrost strategies, demand defrost is favorable because it can result in longer equipment life, more cost savings ($200-400 annually), and offer better compression protection. White-Rodgers defrost controls can upgrade units from timed defrost to demand defrost with the Matrix LED by using thermostat and heat pump harnesses and thermistors.
Contactors are components that require frequent replacement nowadays, which is ironic because they used to be the most durable part of the system. Contactors may come in the 1-pole, 1.5-pole, and 2-pole varieties. Most manufacturers tend to use 1.5-pole contactors nowadays. The SureSwitch universal part is a 1.5-pole contactor that can replace all three types.
Contactors commonly have electrical arcing issues. Pitting and welding occur during arcing, which prevents contactors from opening or closing. Pitting and welding may also happen due to voltage drops or insect damage. The SureSwitch contacts are sealed, so it is an appealing replacement because bugs cannot access the contacts and cause welding or pitting. The SureSwitch also comes with protection against brownouts and short cycles; those benefits will lead to improved equipment longevity.
The SureSwitch also comes with coil voltage options. The red cap on the spade can allow the SureSwitch to work with 120v, 208v, or 240v applications.
Jim also discusses:
Common White-Rodgers applications
Furnace burner components
Furnace blower assembly and blower motors
Furnace operation sequence
IFC pins
Universal benefits
Universal component usage for Carrier/ICP air handler boards
Time defrost vs. demand defrost
Setup and programming options with the 47D01U-843
State requirements for heat pumps
Using auxiliary (backup) heat
47D01U-843 benefits on heat pump systems
The anatomy of arc damage
SureSwitch features
White-Rodgers product warranties
Future three-phase universal contactors
SureSwitch compatibility with refrigeration systems
Mounting the SureSwitch
How WR Mobile works
Visit the White-Rodgers website at www.whiterodgers.com.
Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.
Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.
When you're talking in florida on universal parts, it's kind of hard to know exactly what to start with or or where to go, because my understanding is this: is heat pump territory and if you get down to miami, you might find a heat pump that don't even Have heat strips in the air handler is just a heat pump with a a plane box inside with a fan and a coil in it. So this has been tailored a little bit more to include furnace universal furnace controls, but in doing that in in this area, it's a pretty basic foundation for furnaces. A lot of you that already work on gas furnaces is going to consider this pretty simple. There may be a couple little gems in there as we go through it uh.
That may be something unique or different uh that that we can pull out so we're at 8 29. Are we going live feed here from what i understand? I'm live very good. Well, welcome everyone uh to the white rogers presentation here for universal controls for today's hvac technician and my name is jim fultz. I've been in the industry since 1988, back going to uh trade school learned a lot of uh the the book smart stuff and got a job as an installer and then as a service tech, uh, learning the the real world application and any of you that's went Through that knows there, there is a difference.
There's there's a good benefit of of the foundational uh school information that you can get, but there's nothing like the real world experience. So today, uh our game plan for today is going to go through. Why universal? Why how's something become a universal part and then we're going to cover furnace operations, defrost operations, contactor operations and finally, utilizing the wr mobile app and how to make it your best friend. So at any point, if there are questions, feel free to raise your hand - and let me know there will be opportunity at the end - we'd like to do a lot of the questions at the end as well.
But if you got something on your mind, sometimes you forget it by the time we get to the end, so i'm okay either way part one here. Why universal? How does something be get the universal title we're going to go through obstacles as well as understanding benefits? So how does something get a universal title and what is universal, universal merriam-webster just simply says it's adapted or adjustable to meet varied requirements and we're all familiar with the thermostat, with the ability for a thermostat to be what we would call universal. They they work on a multitude of furnaces. There are a few systems out there today.
That would be communicating thermostats that talk specifically with the board, but by and large our thermostats are really universal. They can go on any type of a system and universal just simply means in hvac. The control has the ability to work on a variety of original equipment. Manufacturer designs, thermostat's always been that way.
Well, here's an early thermostat - and actually i would have seen these 30 years ago - this would have been. Linux - was the last one to get on board. But can you imagine wiring a thermostat with letters like x, m, l, f, r, you know what what do they mean and and linux was trying to to keep their uniqueness at the time by having their own identifiers. It was still a universal from the fact that it had a fan: a circuit for heating, a circuit for cooling, a circuit for a heat pump, but they weren't universal in the fact that anybody that was working on any other system understood what this meant. Well. Standardizing that came about this is the same sub base. It's the same plastic, the same screw, design everything, but now we have a different label design, so the old sub base x now was identified as g. You know what g is this.
One still has a little bit of uniqueness from the fact that here yet we still didn't have c or our common circuit. It was labeled b uh and that would have been the common circuit. But what what you would have thought a down here - 24 volt hot - is what it was. It's the r terminal.
So now that you see what those labels mean, it makes it a lot simpler to understand, and that's really the goal of today is is to help for you to understand how a universal control will fit in and how you can make it work, because you only Have so many different variables that you're dealing with and it's really a short list back in 1990, i was in indianapolis indiana at an air conditioning service school for two weeks and during that time the instructor said we're going to go over air conditioning residential air conditioning Refrigeration and by the way, there's only 66 different things that can happen within a refrigeration cycle that that will cause it not to function well at the time that was kind of a revelation for me, because i would look at an air conditioner in the air conditioning System and think wow, this thing has endless things that can happen that will make it not work and in reality it wasn't endless, and once you know the the parameters of what you're working with it's a lot easier to get your mind around how much uh that That you're dealing with and and how easy it is to understand it same way with a wiring diagram. You look at a whole wiring diagram and you got a whole bunch of wires going everywhere and it looks like a spaghetti mess. But if you look at one wire and trace it from one spot to the other, you understand it. It would be no different if you took out a map of the united states that had all the interstates freeways country, roads, streets and everything else and said.
I'm going from this side to this side and you looked at every single road be kind of confusing. But when you pick out one route to go across, it's a lot easier to understand, and so a lot of times when we're dealing with universal obstacles, we're gravitating away from something that the word lack of familiarity. We have this fear of of how complex it is and we don't have the training and once we get the training once we understand what we're dealing with what happens is something that looks a little scary becomes a path that we're comfortable taking and that's our goal. Today is making understanding, bring ease of use, ease to be able to understand how to use a universal control. Why consider universal controls? Well, if a system fails you research only oem and - and i was in a uh parts house once contractor walks in and says hey. I got this model furnace and i need this control and and the parts man looked up the model furnace and says: oh yeah. We have uh that part available. It's at another branch.
We can have it here in two days. So, what's the contractor do what would you do as a contractor i'll, let you know you're going somewhere else to find something to take care of that customer that day and when you're looking for oem parts that can happen, you can go to multiple places, trying to Find your oem part when an aftermarket park would be readily available to save you all the time of the research, uh and, and the other factor of that is sometimes you think. Well, a a oem part is less expensive than the aftermarket park. There's there's both of those out there and from being in the industry, 30 years being a technician as well as a company owner.
I was familiar with with the pricing of different things and there are some components that have so many extra bells and whistles that that they cost more than than the plain jane model. However, there are some and - and one of the things we're going to talk about today - is control boards, where the oem control board has got a higher price tag than what the universal aftermarket board does. Even though that the universal board has a lot larger of a spectrum of what it can actually cover to replace, so so your two factors, if you're trying to get something to take care of a homeowner you're going to eat freight overnight, it's going to run the Cost up that either you're going to pass that on and the homeowner's going to to have a really expensive repair or you can consider an aftermarket part, that's going to be less expensive. You can pass that savings on or you can pocket that savings and make the job a more profitable job for you.
Customers appreciate that available alternative. They they're not interested in waiting a couple days for that part to come from somewhere else, so universal benefits - and these are some of the products that we have at white, rogers 77 of all single stage furnaces made within the last 15 years, can be serviced with One of five of our universal integrated furnace controls, 92 percent of of heat pumps, single-stage compressors, can be serviced with the universal defrost control, the d01u 843 and then 99 of contactors, and and these are numbers that that that we come up with internally on all these. We know that you know we could say well, it's a hundred percent. Well, there's always a few out there that have something a little unique and different, and so so we leave that margin of error in there that that the majority of your contactors can be replaced with the emerson, 49, m11 sure switch and and that's a standard single Phase contactor, so, let's, let's start and head through uh, the first section that we want to cover is these integrated furnace controls, and this is going to kind of be the furnace 101 that i mentioned a little bit ago of of the basic uh that we're we're Dealing with within furnaces uh, diving it down or taking it down to your common level. Here you got two efficiencies. You got the standard efficiency, which is an 80 efficient furnace, and then you got the high efficient furnace, which is 90 uh, 90 plus uh. Those are are our two furnaces that are out there on the market. Today, heat exchanger difference in the heat exchanger, your 80 percent efficient furnace is going to heat exchange, have a heat exchanger that this at this point, just an extruded tube is the way they're designed the second, the 90 plus furnaces will have a secondary uh heat exchanger.
Uh that heat exchanger is is based on the bottom of the furnace and and within that uh. What happens? Is the the burner burns into the top of the heat exchanger? That's the hottest part of the the flame at that point and as the air is coming up across that it's taking, that that heat and being able to put it in the house and as it goes through the tube it cools off. And then it gets to this coil at the end of the heat exchanger, that's got fins that allows that that burnt gas - that's still got heat in it, but now the heat's less to be able to be absorbed into that air and the air is actually coming From the bottom, so it's hitting that secondary coil, where the air is, is cooler inside, there's less heat in there. Picking that up before it goes through the primary heat, exchanger picking up the rest of the heat and taking it into the conditioned space and i'm going to run through these fairly fast.
So i think it's it's a lot of basics but, like i say, if you have any questions, don't hesitate to to ask the burner area we're going to go through the components in that and the first thing we talk about is the gas valve uh an older Furnace we're talking um the furnaces that would have had the standing pilot that that were eliminated here, uh by the epa and those furnaces there's still a few of them out there. But for the most part, most of our gas valves now are an hot surface ignition or a direct spark ignition and and the common uh universal valve that we would have, for that is the 36 j22 214. That valve can be used for both hot surface, as well as direct spark. The manifold and burners, as the gas valve would hook onto the the manifold comes down in shot.
Burners is one of the names of the burners. We used to call them jet burners, because when we went from the ribbon burners of the old standing pilot furnaces that came on and flowed gas really slow and quiet. Quiet like a gas grill would do and went to these. These sounded like miniature jets. Uh. There were, there were homeowners was saying this furnace is a lot louder than than what my old one was primarily because of the sound of the in-shop burner. The benefit of this is because it was an in-shop burner, and that was pushing that flame into the heat. Exchanger, it required an inducer to pull that air through the heat, exchanger and exhaust it.
What that did was prior when there were ribbon burners the fan would come on and if there was a crack in the heat exchanger, that fan would go past. That crack and have the ability to suck some of that carbon monoxide out into the air airstream and that's where you would get poison or carbon monoxide poisoning from a furnace. Today's furnaces with the inducer motor is constantly pulling a vacuum on that heat exchanger. It's pulling air through that heat exchanger.
So when the fan comes on and blows across the heat exchanger, it's not pulling air out of the heat exchanger into the air stream. That inducer is pulling air from the air stream into it. So the risk of carbon monoxide poisoning in today's furnaces is very, very negligible. It would have to be a a crack at a very specific location that the fan could push that air into that crack and force it around back out into the airstream.
So a lot safer with the inducer motors now either 80 or 90 percent. The way that the these furnaces would ignite is through either a hot surface igniter or a spark. Igniter manufacturers today, for the most part, are hot surface igniters, with the exception of riemann and rude manufacturing. They still are are using the spark ignition system uh and have continued to to use that the igniter, whatever type it would be, would be at one end of the burners and then at the complete other end of the burners would be what was called the flame Sensor that flame sensor, most flame sensors, will have 120 volts going into them, but the amperage or the current is not enough that if you stuck your finger in there and touched it, you might be able to feel it.
It might tingle. But it's a really low. Current draw and what's happening is as that flame goes across, that rod with that current the process of the flame, converting from natural gas or propane, mixing with oxygen and creating the flame. The flame process breaks the molecules, apart and in the process of breaking those molecules.
Apart turns into the carbon monoxide, but that process of breaking apart separates the positive ions and the negative ions and the positive ions actually carry that electricity to the burner itself, ground itself to the the burner and that's where to test a flame rod. You can test it with a meter reading, milliamps or millivolt. Excuse me it's it's a small amount of amperage that you're actually pulling through that that you're that you're going to read - and i think i was correct - i need to change that. It should be mil milliamps. It's the amp draw that that you're actually reading, and that confirms that that burner is on the reason that that is at the opposite. End of the igniter is to make sure that all the burners have came on all the way across. If this the flame sensor was right beside the igniter, then a couple of burners at the other end might not come on and you'd never know it so they're they're separated for that purpose. The inducer motor uh and and here's a little bit of of novel information on this, you can tell the difference between an 80 and 90 efficient furnace by the housing of the inducer motor, an 80 efficient furnace is going to have a metal housing.
It's going to take more heat, you got a higher temperature that that you're dealing with there versus the 90 percent. The ninety percent pulled that extra heat out during going through the secondary heat exchanger uh coil, and it's cool enough. That plastic can be used to be able to to take that heat and and send it on up. The flue pressure.
Switches are in place and a pressure switch starts out in an open position. The inducer comes on and it closes if the pressures, if there wasn't a pressure switch, you would never know if if the flu is blocked or not, and so a pressure switch is put in to be able to to close showing that there's suction on that pipe And and that the flue is not restricted and having a stuck pressure switch would be the same as not having one at all, because it would, it would be closed all the time, and so when a furnace starts up, it will look to see that that pressure Switch circuits open and then closes after the inducer comes on. That's a safety check of the pressure switch on top of the pressure switch being a safety to make sure that the flue is open, that the furnace can run on on the pressure switches. There's been some look into it at this point, the question was: is emerson going to have a universal pressure switch and - and at this point, there's there's nothing in the works that that we have right now.
Thank you. Next, we're going to go to the limit circuits and typically a furnace will have a couple different types of limit circuits. One is going to be a rollout limit, that's going to be really close to where the burners are it's designed, so that if the inducer was to fail and that heat wasn't being pulled through the heat, exchanger would come out the front on the plate right there By the burners heat up that plate and turn the gas valve off, there's a main limit that would be located on the heat exchanger wall on the main wall between the burner area and the heat exchanger. And then some furnaces would have a blower limit mounted by the furnace blower in case the blower motor failed, and you had heat going into that area. The the blower limits would probably be seen more on downflow furnaces, where the blower is above the heat exchanger and that heat would be rising up and if the blower wasn't coming on it would it would trip that limit as well and we're skipping some here. I'm sorry our computer's freezing up a little bit, i think we're getting there going from the burner area to the blower area. The blower area has primarily the blower assembly in it, which is the blower itself the motor inside and that blower this style blower. We call a squirrel cage and that squirrel cage has got a name and that's not working.
My animation is not working on that. If he's going to come out and do that, i think i can do it this way. There we go so a squirrel cage gets its name from a cage that a squirrel could run in these happen to be hamsters, and you really would want to be the front one, not the back one, because that's no fun to to try to be playing catch Up in a squirrel cage all the time, the the other type of fan that we would have is is a flat blade fan which we would have in a condensing unit. Circulator blower motors uh, three types, the psc motor, is a motor that, if you've been in the industry a couple years now, you realize that we just recently passed regulation across the country for blower motor wattage and most manufacturers at this point have went away from the Psc blower motor psc blower motor is something you would find in your air handlers as well.
In this area, psc stands for permanent split capacitor and the split part of that is defining the phase. We have a single phase motor here and this capacitor is taking the the voltage and it's changing where the phase goes, so that it's a different spot on the sine wave to be able to rotate that motor, an ecm x or an ecmv. Both of those motors are both motors that would typically be called a three-phase motor. They have three equal poles on them and they would function as a three-phase motor.
However, they have an electronic control on the end of them. That takes that ac voltage, converts it to dc and splits it out into the three legs to allow it to run. The the constant torque motor, more commonly known as uh x13 or an ecm x, is a motor that would keep the torque of the shaft constantly the same. With that constantly the same, you can still have a variation of airflow of how much cfm you've got going through a unit, the ecmv or the the ecm, the constant volume motor, which is what you're going to find in the the top end of furnaces and air Handlers is a motor that's going to keep that cfm as close to the exact cfm that it's designed for and it can fluctuate on how fast it's rotating, how much torque it has based on adjusting itself to keep the airflow constant through the entire operation. 24. Volt transformer uh is located uh in the blower area, and this this is part of, is uh important in understanding what we're going to talk about in universal in furnace controls, because you're you're looking at a transformer, that's running control, circuits and remember earlier, i said: there's 66 different things that can be wrong within a refrigeration system within a furnace. These are the circuits that you're going to deal with on the 24 volt side of things. It's not a list of a dozen or two dozen, it's it's down to primarily four and then a fifth one.
When you're dealing with a high efficient, uh blower motor, the the thermostat circuit, the 24 volts. That's going to that! There's one circuit in a furnace that that connects all the limits, one circuit that connects the pressure switches, those are typically two different circuits and then a circuit going to the gas valve to turn it on on the 24 volt side of things. And so knowing that when you're looking at a universal control, you know those are the four circuits that you're looking at in connecting with an integrated furnace control. There are manufacturer designs and the these would be the main differences when you're trying to determine what universal control is going to work for me, is it a single stage or a two-stage furnace? What type of blower motor does it have? Is it direct spark or hot surface, and then there are some manufacturer, specific options that you need to take into consideration and that's the biggest thing when you're crossing over a universal control is something that may be specific to the manufacturer.
And what am i talking about? In that, and that's primarily things like the plug-in, that's on the control could be a nine pin or a 12-pin or it could be inline. We have a question. The question is: do i talk on heat pumps with air handlers, the air handler purchasing, or am i just talking on gas and uh as i get through this? I have several a couple slides on the air handlers and then we're going to go into heat pump. The universal defrost control and some benefits and and the circuits that we're going to find within that as well, so with with looking at these options, those are going to be your options now.
Do you have to remember - and you have to know this furnace - is this and this these specific things? What for our answer today, you don't have to all you have to have. Is the white rogers mobile app, you take your old control and you punch the old model number in and it's going to tell you if we have a replacement control, what that control is, and so you're actually trying to dig in digging into this information. This is more along just simply sharing with you what you could be looking for in that, but actually knowing what to cross over, we take care of that that work for you there's also non-integrated uh controls. These are sometimes called modules, rather than controls, because they're only pieces, uh and - and this is what we would have had prior to somewhere around 1996, when a fully integrated control came out fully integrated means it controlled. Every aspect of the furnace. Prior to that there was a fan timer prior to the fan. Timer was a a metal spring, a bi-metal spring that went into the furnace. That would turn with the amount of heat that was on it close the switch and the fan would come on at this point.
We have a fan timer and this fan timer's been built into the board. This is one of the differences that you're going to find on universal controls, and this is probably going to be about the only setting that you really deal with, and that is the burner fan off delay when the burner shuts off. How many seconds do you have till the blower needs to shut off and that can vary with with furnace manufacture? Some some could be a minute. Some could be up to two minutes, so there's there's a variation there and those are typically changed in dip switch settings.
And so that's that's what you're primarily going to deal with uh when you're trying to set up a universal control on these? The fan timer would have had those dip switches for the different timers and then you'd had a module for direct spark or hot surface. So i've got a little slide here, just simply to go through that sequence of operation to to give a little bit of definition, of how that sequence is actually happening and we'll play that and that's about as simple as i can make a furnace operation. That's that's from start to finish. All that's going on.
You got four low voltage circuits. You got either a spark or a hot surface which is 120 volt circuit. You got 120 volt circuit running an inducer motor and you got 120 volt circuit running a blower motor. That's that's it.
That's the the extent of what you're dealing with within a gas furnace and and here's the list that we just went through of those parts. The first four 24 volts. Excuse me the first 324, the the flame sense uh, which uh is kind of a circle of itself, because it's not using a full voltage to operate something it's it's reading the micro amps, the igniter, inducer and blower on today's circuit boards. Most of them are 12 pin or 11 pin connectors on them, 11 pin, inline, 12 pin molex and those main pins, the 12 or 11 pin are going to be the 24 volt circuits in and out through the control.
Your 120 volt circuits are sometimes plugged directly in sometimes they're on a separate plug. Those plugs can be a two or a four pin plug, and this is where we start getting confusion of all the variations of different manufacturers throughout a large period of time. You could have started out originally with all of the circuits of spade connectors and you plug the individual wires on and as time progressed rather than individual wires. The plug-ins got larger and larger until we've got to the the 12-pin and 11-pin in line today, and and so looking at something like this as well. You know how am i ever going to know which matches up with with which i get a box, and i open it up, and i get a pile of wires like this. How in the world am i supposed to know what i'm supposed to hook up here, and this is where the lack of understanding the fear of the unknown catches, most people in dealing with furnace controls and and that universality of it so we're going to go through A couple quick steps here: first you're going to verify that cross reference you're gon na to go to the wr mobile app on the boxes. They have a lot of the listing of the cross references right on the boxes. So you can.
You can check with that. On this application, this is kind of our our most common psa psc single stage universal control, and this control would replace igniters that are 120 volt igniters, as well as a period from 96 to about 2001, when some manufacturers thought of a brilliant idea to use an 80 volt igniter for a while. That's since gone we're now 120 all the way across the board, but there's still some of those 80 volt igniters out there, and so, when you're going to replace the control board, you want to match the voltage of the control board with the voltage of the hot Surface igniter about seven. Eight years ago i went out to a home.
The homeowner had a company come out twice a year three or four years and replaced the hot surface igniter it kept burning up. I went out and i got the model number of the furnace and i looked it up and it said this is an 80 volt ignition system, and so it needs an 80 volt igniter. So my first thought was i'll, get an 80 volt igniter and put in here well, i turned around and looked at the control board and come to find out about four or five years. Prior, the control board itself had been replaced and whoever replaced the control board.
Put 120 volt igniter control board in but had failed to replace the igniter itself, so you're sending 120 volts to an 80 volt igniter, and it's not even going to last the whole heating season. It ignites fast. You bet, but but it's not going to to uh. Last and this homeowner was paying for a replacement igniter multiple times a year until they called us out, and it's like you're, not matching.
You either need to get a control board, that's 80 volt or we can put 120 volt igniter in and and which is what we did ran into the homeowner about a year and a half ago in a walmart parking lot, and he says, hey, says i've not Had a single call on that furnace since he said i don't know what you did, but it fixed, and so that's the key that i want to share here when you're replacing a universal control make sure the ignition igniter itself voltage matches the voltage of the control And on this particular model anytime that you're replacing an old 80 volt board, the model number of that 80 volt board is going to be shaded orange on the box so that you can look at the box and say hey. This original board would have had an 80 volt igniter in it. This kit actually comes with a 120 volt hot rod, igniter in it. So you have the new igniter to to go ahead and replace it at the same time, and you you uh, you want to do that both together. So that's that's the first thing cross reference verify your voltage now comes the scary part, and this scary part is something that i don't really want to open up the installation instructions. But i just asked you to open to two pages two pages only and within those two pages, every single one of these adapter harnesses that was in that pile is going to be listed. Not only that, but you're going to have brands with it. You got a goodman amana, icm furnace.
You got a nordyne rheem rood brand. The these two pages will be able to tell you exactly which harness you need, interestingly enough, on on this 50m 56u. This this universal board, 75 of the applications for this board, will not need a single one of these harnesses only about 25 you're going to need one of these harnesses and the rest of them spare jumper wires for you and and to be able to find which One we actually gave a class on this to a wholesale house and we had the counter people saying i can pull that out and hand it to the contractor and say here put these in your in your truck and do that for them. It's that easy! It's it's as simple as knowing which brand you have, and it's going to plug right in there's once you, you narrow that down.
That's that's where your biggest fear is going to come from of knowing where this is at two pages, in the installation instructions, and, and once you do it a couple times, uh you're you're good to go the nice part about this control. It replaces over 430 skus. So consider that 25 of that's going to need those harnesses over 300 of these skus are going to be able to be a direct plug and play without anything else on them. This would come with the hot rod igniter.
It's the the harnesses are easily identical identifiable. 25, the applications uh and so a lot of good features uh. They can be twinned together and - and you have another feature on these - there's actual pins on the controls of our universal boards. You don't have to have a microamp meter to be able to test for the flame sense.
The the control takes that flame sense and can feed it back through the board as a dc voltage. So you can turn your meter to dc volts. Put it on the two probes that are sticking off the board and one dc volt equals one microamp. You got a really easy conversion to be able to test and see if you got a strong flame if the flame senses is functioning properly, all right, let's switch to air handlers here for a little bit, and - and this is a situation where you have three different Air handler controls and they have different styles of of connectors on them, and now we have a universal control that can handle uh, multiple ones. This is also an example of two controls that we made and we could have made one because this control right here takes care of all three. Why didn't we just make one? Why did we make a second one well in making that one, the additional cost to have that one made to cover an ecm motor was enough that it wasn't competitive uh with the pricing with the boards. It was replacing on the psc side of things, so we made a psc only version so that it would be compatible and it would be affordable it would. We wouldn't be running into saying.
Okay, we got an aftermarket part, that's now more expensive than the oem, and even our psc covers two styles. So this is a carrier application where one control board would cover both a spade style of application and an inline pin application. Both the spades and the pins are on that control. The the difference between these two uh one is called a uh, 48 m.
55 751.. The other one uh is called a 48p 55 751. p stands for psc. Only im would be multiple motor speeds or multiple motor types, and, and that would be the the two differences uh within them.
When you're dealing with the m with multiple motor types, you do have the ability to switch between the two, and the next slide will give a little bit more detail of that. The fact that you have the ecmx relay and spade terminal on the multi-blower control, also in the old controls, go back slide here. Real quick. These controls had a little wire that you would cut as a jumper wire when you wanted the time delay with the wire on you had zero time delay, you cut the wire.
Now you had a 90 second time delay for the blower to go off after the air. Handler no longer has the call for cool, rather than put a jumper, we put a switch 90 second or zero. So it's not something that once you cut you're done in this application for a universal control, you actually have the ability. If you want to go back to zero, you can most the time when you're dealing with with efficiency and trying to get that last bit of of heat into the coil in the in the air conditioning mode for an air handler.
You want that blower to continue to run 90 seconds for that coil. That's still cold, to be able to absorb that last little bit of heat before the blower would shut off. So we are ready to to head on up here to uh defrost control operations and the main part of of what we want to cover here is primarily dealing with the actual time versus demand. Defrost and there's there's a good bit of difference in those that i'd really like to share.
First of all, we're going to we're going to skip the the basics. Hopefully you all understand what a compressor and a condenser fan, motor and and contactor all the basics. Within a heat pump are reversing valve and typically an outdoor coil temperature. Those are are your basic components that we're going to be discussing most your defrost controls are a single board back 30. Some years ago, when i started circuit boards, weren't a consideration in heat pumps. You would open up a heat pump and you would have a spaghetti set of wires with a timer, a mechanical timer and a hold relay and a contactor and multiple relays in there. Your job's a lot easier today, thanks to circuit boards, because this this takes all of the guesswork out of wearing all of those different parts. They're all put in internally in the board, made a lot easier to to operate with these boards.
There's two manufacturers carrier and goodman that are still utilizing time, defrost and and what i mean by time, defrost is it's defrosting, so many uh minutes it's going to kick into a defrost. Let's go into that a little bit more and understanding the difference. Uh between the the time and the i hit it twice: uh, let's catch this first here uh on the the time defrost, your timer is going to initiate the defrost mode, every 30 to 120 minutes, whether it needs it or not. It's kicking into the defrost mode.
You're reversing valve is switching over and it's checking the coil temperature sensor at that point to see hey is this coil cold enough for us to actually go a defrost into defrost? If it's warm enough, it init. It immediately goes back into the heating mode, but in the meantime, you've got all the electricity all of the energy of switching into defrost and switching back out, and this is happening typically, every half an hour to two hours, uh with with carrier and goodman uh, primarily The the users of this so in in running this see if we can get this this to run real, quick, the you go through a two hour cycle here and every 30 seconds you're going to hit a defrost mode. So, within a two hour period, you have now ran three defrost modes: you've had that reversing valve kick over and and you're starting and stopping the condenser fan motor you're using extra energy that you wouldn't have to use. If you was looking at the demand, defrost style, the demand defrost style is taking in the outdoor coil temperature and it's also taking into consideration the outdoor temperature and and with that temperature in that coil sensor.
It's determining when that coil gets frosted up when it gets cold enough and when it determines that there's frost on it, that's when it initiates. So you start running uh with demand defrost. It could go up to six hours without defrosting if it's warm enough outside. If you get some ice on it and it determines that it needs it, then it will kick into defrost, but you can have demand defrost initiating only when it's needed versus time you're going to consistently have that kick in uh on a regular basis.
So so, what's the benefits of of going with the man defrost type of an application? Well, you're, you're running more cycles. So if you want to extend the life of a heat pump, running less cycles in the defrost cycles is going to add additional life. Not have the wear and tear and you're going to have cost savings and and we've estimated somewhere between two to four hundred dollars a year in savings using demand, defrost versus time, defrost, uh and and then with demand, defrost uh, the the control that we offer. This with the universal control, it will run a defrost cycle every six hours. So it's not like you have a 24-hour period and you're never going to get a defrost. Why do you want to run it every six hours? Well, within the refrigeration circuit? You have the refrigerant and you have oil and that oil is circulating through the system and it's keeping the bearings and the compressor lubricated and what will happen when you're in the heat pump mode. You've now taken the evaporator that was inside and made the outdoor unit. The evaporator and you've taken the condenser that was outside and made it the hot condenser inside now you have that cold evaporator on the outside, and you have oil going with the refrigerant through this cold evaporator and as the oil goes through, the cold evaporator, the viscosity Of the oil slows down, it gets colder and it slows and that extra oil slowing down and getting stuck in the outdoor evaporator will keep that oil from being able to circulate back around and keep the compressor lubricated.
And so by going into a defrost cycle. Every six hours now you have that evaporator coil, the outdoor coil warming up warming, that oil up with with the coil and allowing that viscosity of that oil to continue to go around through the refrigeration circuit and keep that compressor from getting its bearings washed out. So it is, it is needful that you do continue to have that cycle question. I've wondered this before, especially after this on the podcast human right.
Why does carrier or goodman do that? Do you know at all? Is it cost, or i mean it seems obvious, so the question is: why do goodman and carrier continue to use time defrost rather than demand defrost and at this point not not having that relationship directly with them and understanding exactly what what they're looking at? I don't know that i could give you that answer of why they would choose to continue that we yeah you could ask them and then there's potential that that we could see them change to a demand. Uh defrost sometime down the road. It's maybe something! That's not been in their research and development uh up to this point uh and so, and it's interesting because carrier and goodman are leaders in in heat pump sales. They have the majority of the heat pump units out on the market in the united states.
So you, you have a a carrier unit or a goodman unit, and you go out and you're servicing this unit. This is something that you could on a unit. That's not even requiring upgrade the control board in that unit and replace it with our universal defrost control and configure it to be demand defrost. So you can take any carrier unit, any any goodman unit and convert it over and the slide before shows two to four hundred dollars a year savings you can, you can show that to a homeowner and say this board doesn't need to be updated, but if we Upgrade it to a demand, defrost board, it's going to the cost of doing that today is going to pay for itself and it's going to help your equipment last longer because it's not going to go through those cycles. So that's one of the benefits of this. This board is it can do that conversion for you within within our kit. You have the universal control board. There's two harnesses one hooks to the thermostat wires, which you would all be familiar with.
The other harness has four sets. What are those four sets? We got the reversing valve low and high pressure switches. What if you don't have low and high pressure switches in your heat pump? There is a setting within the control that i believe comes factory default off and you turn those on so that the control board recognizes it needs to see a circuit through there. If you don't turn them on, then it would ignore them.
It would have that circuit closed and and would not see that high or low pressure switch. So you have the ability uh to use those or not. Depending on your unit. You don't have to use those in the the uh, the pressure switches, a reversing valve uh and the final one is the the contactor running, the compressor uh and i say compressor only because your your outdoor fan motor is being ran by the the defrost control itself.
Uh with this also comes two temperature sensors, they're thermistors they're, not snapdisk, and again, a lot of your manufacturers are still using the the old-fashioned snapdisk, which is less accurate. The thermistors are, are reading a lot more accurate in their temperature readings. It would require the the unit to be taken apart for the coil thermistor to be replaced where the old coil temperature sensor is on the bottom of the condensing unit, probably the most complex part of of replacing a defrost control. If you're replacing, that sensor is opening up that unit and getting down to where that's at and then the outdoor air temperature sensor just hangs in the area there outside the unit where your low voltage wires coming in where your high voltage wires is, is coming in And we also do include uh little sticker labels so that when you're pulling your wires off your old one, you know exactly what you have yes, the question is: would you take your thermostat wires to this first and then to the control board? That's in the condenser! This control board would replace the control board in the condenser there when, when you're, when you're talking about multiple stage, two-stage compressors or variable, speed or or units that have there's some units that have an an ecmx or an x13 in the condensing unit uh, those would Not cross over to this that's this. This would. This would primarily be for your psc condenser fan motor single stage, compressor system yeah, once you're getting above that efficiency. There there's a lot more going into those yeah. Another question you can take the the question is: can you type uh information in on the app and see if it can convert over? The app is designed that you put in the the part number of the control you have and it will show the matches for that.
And so, if you have a defrost control, you put the defrost model number in whatever part number that is, and and it's cross-referenceable it will bring up this control and show that this is compatible with this. Yes, so set up with this uh is, is very easy as well. There's two buttons option and select when you power it up, it powers up powers up with a smiley face, uh, primarily because you've just hooked up somewhere around a dozen dozen, a half wires and you're. Probably looking at this thing, i need somebody to smile at me right now, so uh we we uh, i that was the humor of an engineer somewhere in st louis uh.
They gave us a smiley face to power up, but the first thing that you can do within that is change the display orientation. So if you was to mount this sideways or upside down, it doesn't matter which way you mount this. When you hit the the options button, the first time it's going to display, do display orientation and if you hit select, you can hit that four times and the do will will change rotate around four different directions. Till you get the direction where you can read it.
Uh in in regular english uh position, uh so and then another option is oe, which is original equipment and we'll get to that in the next slide, where again, a universal part. A lot of different perimeters with different manufacturers. We've taken eight basic parameters of different manufacturers and set all those those standard parameters up within those eight, so you're not having to go through and manually program every little option. You have the ability to at least start out with a base, and if you want to change them, then you can go in and change each individual one afterwards.
Those eight would be carrier goodman, linux, train, green york, nordyne and then what we would have a factory default set and you can see with each of those numbers - there's a whole bunch of settings that go with that with the carrier and goodman. You can see their time temperature defrost rather than demand. You can. If you have a carrier, a goodman, you can use one or two to do the default programming and then you can go back into the program and you can change the defrost type to demand. So you can have all the rest of your settings configured with with one one round the next round, you're going in and changing it and giving that demand option where the homeowner is going to get savings. Other other features are listed on here. The the defrost cycle cycle time the short cycle, time uh. If you have uh the reversing valve in orb, it's a matter of a configuration uh within here, uh reversing valve shift delay and what this does is.
It gives uh time uh for the reversing valve to shift and then the compressor to delay and come back on what that does is it makes a lot quieter restart. You don't have that high low pressure when the reversing valve's shifting and the compressor is trying to come back on at the same time and you've got the full load on that compressor. It can growl pretty loud and homeowners. You may get a call from that.
If you work on heat pumps of how loud it is, and it's it's smoking and growling outside and - and we don't know what's going on uh the the shift delay helps that abate - that noise uh some defrost time you can adjust as the defrost enable coil temperature And terminate temperature, so all of those features come preset in in configuring, one to eight additional features that come with the 47 d01u uh. Is you get energy savings? Uh? You can operate, the heat pump, extremely low temperatures uh and it can be less heat per ounce. Of the the backup source, so if you have electric heat within this control, you can set the control so that the electric heat won't come on until it's 30 or 35 or 40 degrees outside, and it requires the heat pump to do all of the work. Above that - and there are times that your backup heat could be more efficient than the heat pump itself.
You can shut the heat pump off and allow the backup heat to kick in at a specific temperature as well, and you could also have a situation where the heat pump is is not going to heat the home good. Once it gets down to a certain temperature and you need that backup to kick in, and so you can uh make that backup source kick in at a certain temperature to to help maintain the the comfort of the homeowner and then the third item on here is State requirements: in 2015, we had a new map drawn up uh from the epa and it divided three areas: uh, four requirements for energy savings, and these savings were the cooling side of and the heat pump side of things. What what we found is two states set up their own. There could be more if your state does i'd, be curious to know i'd like to add it to my list.
North carolina has a regulation that says that you're, you need a control that will prevent the supplementary heat to come on, uh to to meet that heat load, and it's supposed to lock out the lockout shall be set no lower than 35 and no higher than 40 Degrees, so they set the range at which that electric heat needs to be locked out to come on anything warmer than that california, title 24 would would be very similar to that. These are requiring what we would call an outdoor thermostat. That does not allow that backup heat to come on until the temperature gets below a certain point that thermostat that ability to do that is built into our universal control, and so you have the ability to set all of those adjustments. Those adjustments are set as you're going through the option option button that that 8x8 screen is going to read different letters. You go down through them and you're going to come up to it to an auxiliary heat lockout it's default to off, but you can set it anywhere from 0 to 40 degrees to keep that auxiliary heat from coming on until the temperature drops to that level, and Then the low uh temperature compressor cutout is going to turn the compressor off when the the temperature drops to a point where the backup heater auxiliary heat is more efficient than the compressor that number's pretty low. In most cases, i would say well below 32. Some people would would argue, depending on where they're at that number could be somewhere between 0 and 17 degrees that you're still getting enough heat out of a heat pump to justify operating it in question. It's going to it's gon na tie directly in with that thermostat.
There should be no difference within that thermostat, as so. The question is: is the thermostat going to have priority and priority over the way that so the is the thermostat going to have priority when the auxiliary heat comes on? The way that this would be wired would be, you would go through the thermostat and you could wire it. However, you wanted to, but you would go through the thermostat with your auxiliary heat and then run that out to the defrost control and then from the defrost control. It would go back, so the defrost control would basically have the last say of whether or not this is going to happen now you could wire it the other way you could.
You could take it off the thermostat and make it only that or or wired in conjunction. It would really depend on how you wanted to wire it uh of of what got the priority, but but basically, what we're dealing with here is a set of contacts within the defrost control. That's that's going to stay open for the backup or auxiliary heat until you reach that temperature and then it's going to close, and so, however, you want to configure that that normally open set of of contact points is is completely up to you. A summary of the defrost control and some of the benefits uh that we have here with with the uh 47 d01u, a universal sku, again 400 plus different models.
So you got one defrost control. You can stock to cover quite a large range you're you're, going to have less truck stock. That way it's pre-configured or you can adjust the settings. You have the defrost demand option.
My opinion is really a big key in being able to use this control. The reversing valve shift delay limits excessive noise. The the 8 by 8 matrix display, gives you a very easy way to program it uh. There is a test mode uh. Within that i didn't there's and there's lots of features. I could give a whole presentation just on all of the features of this, and this is kind of a a summary of that really in trying to to stick with the universal theme and the fact that how universal this really is for that there are short cycle. Random start time, delays couple different delays, auxiliary heat, lock, out low temperature, compressor lockout, which we we discussed. There is a 24 volt brown out protection, and why do we call that a 24 volt brownout protection? Well, the reason it's it's listed: 24 volts is it's actually looking at the low voltage to determine when a out event is occurring, so you may have 240 volts if it drops down to 180 volts, your 24 volt transformer is going to go from the 26 25 Volts that it's at down to maybe 18 volts and and so they're going to sync with each other.
When the high voltage drops the low voltage drops and this control is actually looking at the low voltage dropping below that 18 volt mark. Knowing that there's a brownout event occurring and shutting the system off so that it doesn't damage the motors high low pressure inputs are inputs that you can either turn on and off their their an ability, if you have them to use them to extend the life of.
Nice video, great knowledge and experience.
Thanks for sharing
Thank a lot HVAC School
Does the 47D01U-843 Timed Defrost to Demand board retain the user input option settings after a total power outage, if so, is there a time limit that it will keep them for… Excellent presentation, Thank You…
There is a lot of standing pilots out there, you can find H pilots also!
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Stay safe.
Retired (werk'n) keyboard super tech. Wear your safety glasses! Are you in Barrhaven ?
How long does it take before White Rodgers is allowed to supply a universal part versus an OEM?
Great class. Thank you Bryan.
Problem I see with the sureswitch is trying to pump a system down that has a low pressure switch in it. Without being able to hold a contact down and keep the machine running. Guess one would just have to wire around em or jump them out temporarily
Jim, is an expert at what he does and shared a lot of great knowledge in this discussion.
Thank you some awesome info going into heating season
Thanks Jim!excellent information Service area Orleans??