Welcome back to Teaching the Unteachables, where we dive into teaching and learning methodologies
for professionals like you.
This recording is from a portion of episode 73 of Did You Know the ESCO HVAC Show.
Learn more at escogroup.org as well as hvacredu.net.
Well hello everyone, thank you for joining Did You Know the ESCO HVAC Show.
We are joined this week by Todd Kler from hvacredu.net.
How's it going Todd?
Howdy.
I thought I was going to be running on this one solo because I've got Ty, I've got Daniel,
and I've got Eugene all down at the symposium, down at Brian Orr Symposium in Florida.
We had AHR last week, which was insane.
A lot of stuff going on.
So this kind of segues into what did we find at AHR, right?
We found lots and lots and lots of inverters, lots of A2L.
We've seen a lot of communicating equipment.
And I always preach about the communicating equipment.
And you and I, we have some fun conversations about what is happening in the automotive
industry, especially when we talk about communication stuff, right?
Indeed.
Yeah, automotive, there was a time when every different manufacturer had their own code
reader.
You had to plug in and see what was going on, on a 5 volt DC communicating network, by the
way.
Right.
And so when we get into talking about new technology, a lot of us are uncomfortable
with communicating equipment.
Now I'm going to break this into two different types of communicating equipment.
We're only going to cover one today.
Hopefully we'll get through all of it.
I've got a ton of stuff for us to talk about.
Today we're going to talk about unitary communicating, and we're going to talk about all of the different
manufacturers and how they really are on the same platform and how to test those platforms,
how to see when you have problems on a network.
And then on another episode, we're going to talk about our, let's call it ductless communicating,
our higher DC voltage communicating platform.
So Todd, you spent a lot of time in the BAS side of things, building automations, and
you guys have got a great course over at HVACR EDU.
And so BAS and our unitary communicating really are very similar.
The six one half does the other, right?
I mean, they're very similar the way they communicate.
It's going to be a DC voltage, right?
Usually a 5 volt DC.
Very, very, very similar to a pulse width modulation.
We may have heard that in the industry, right?
Absolutely.
So that communication, here we have a master slave type application, and this is very similar
to the RS85 cabling that we are used to.
Usually a four wire lead wire and usually two communication and two or one for voltage
for the power to the device usually.
Absolutely.
Maybe sometimes 24 depending on the device.
Exactly.
And then the common, right?
You got to make that complete circuit.
So when we look at that communicating platform, this is very important for people to understand
that we're going to look at all these different manufacturers and you're going to see a similarity.
You're going to see in a lot of these, a four wire system, two that we're going to communicate
on and two that we're going to supply power.
Now we do get into some differences in the way we communicate, but it was all very much
the same.
So if we look at this basic layout of what we call an RJ45 communication, so where we're
talking about like cat six cables or cab, what, when we're looking at communication
cables, a lot of different industries use a same or similar platform.
So even our ethernet cables, we're using a variable five volt DC.
It's typically it's a 0.25, but it's plus or minus.
And I'll show you what that looks like here in just a second, how we get to that.
But we've got some supply voltages and we got some communicating voltages.
And we're going to go through all of our manufacturers here and there are some that are better at
giving information into it.
And then some that are not.
So Todd, you want to break down just a little bit about some of the decoding.
Yeah.
So most of us, at least in the, in the residential or unitary type split systems are custom to
24 volt, right?
Our thermostat in a 24 volt system, we have a thermostat in a communicating system.
It's no longer a thermostat is now a control or controller, right?
And the 24 volt system, it's just a, or a deck thermostat is just a fancy switch and
it sins.
It's going to, it's going to be a light switch, right?
But in this case, 24 volts typically.
And in doing so we either tell the heat to come on to come on, or we tell the compressor
to come on sometimes in some cases to speed, right?
We have a two speed.
That's right.
So we're not communicating.
Okay.
But when we dive down that, that communicating, where usually we get that four wire to gating
and to, to, to, to other 24 volt or 12 volts depending on the manufacturer and a common,
right?
So there's your four that DC DC voltage is usually five ish volts and it'll pulse width.
Right?
So it'll, it'll on it exactly.
The voltage come on for a half a second, millisecond and go off and that language or how long it's,
how long it stays on or off is, is interpreted by a language and actually a protocol and
that protocol will speak to that, to that controller or module or the PC board that
is communicating with inputs outputs, right?
We're going to get those signals from thermistors, pressure transducers.
It's going to say, Hey, at this pressure, at this temperature, do this, or Hey, do this
when you get to these pressures or temperatures or whatever it might be.
And we do it in those pulses.
And that's the important part to understand.
Remember that AC was just a simple command 24 volt on or off.
Well, we're now going to do this in pulses that are going to be on or off, but the amount
of time that we are on and the amount of time that we're off are going to be the language
that we're speaking.
And many of our different manufacturers use different languages.
We're really just talking about different spacings within one relation, right?
And we can, yeah, it's all ones and zeros and we can actually read that.
Now we're not going to go this deep on it.
We we're not going to bring it on a oscilloscope, although maybe down the road we'll do this
so we can actually talk about it a little bit.
So if we were to put an oscilloscope on a communicating network, we're actually going
to see our ones and zeros, but we're also going to see those as a positive reference
to ground and as a negative reference to ground.
We're actually going to go both directions because they came from our AC sine wave.
So the important thing to remember is all of these DC communicating voltages started
with our 24 volt AC power supply.
So where do our DC circuits begin?
Typically it starts at our indoor unit for residential unitary split systems.
It starts at our furnace or our air handler where our original power supply was at.
So we'll take that AC voltage, we'll turn it into the DC voltage, and then we will start
pulsing that thing.
You may mention that, you know, we get that that transform or 24 volts from our indoor
unit.
Do keep in mind this is unitary, usually a split system.
Now when we go to when we do go and talk about ductless split system, then it's coming from
the outdoor unit.
So just keep that in mind.
Everyone's going to hey, time out that that comes from the outdoor unit.
Yeah.
And I'm ductless system.
Exactly.
So our inverters that have a power supply at the outdoor unit, they will typically have
their own as well.
And we'll show you a little bit on what that one is.
So for those that are comfortable with the Dyken platform or the earlier Goodman and
Manna stuff that was using the climate talk platform, let's let's look at this real quick.
Remember those four wires, Todd?
What we're going to use in this particular platform, we're actually going to use two
of those for 24 volt AC.
So that great big colorful screen that we have on our thermostat, right?
We still need to light up if we put batteries in it, we know what's going to happen that
we had seen that back in the early 2000s when you put batteries in the digital thermostat,
you burn them up.
So we're actually going to use two of those for 24 volts AC, R and C just like normal.
And that common is actually very important.
It is a reference to remember what we do with the 24 volt side of the transformer.
We ground it, right?
So we have to, we have to.
So on a grounded transformer, our common is actually connected to ground.
This is very important when we start looking at and testing the communication.
We look at this communication.
So we're going to run four wires from the thermostat to the indoor unit.
And depending if we're talking about like the fit system uses a electronic expansion
valve, we've got a board on that as well.
So we're going to use AC for powering our controls.
We're going to use our communicating the two wires.
They're going to do this on number one and number two.
And so they're going to supply two wires to the outdoor unit.
And when we're using a communicating outdoor unit, the board of the outdoor unit actually
has a power supply built on it.
So we're not going to be connecting R and C. We're just supplying the two wires.
But if we have a bad ground within the system, we can really have some issues.
And I'll talk about that here in a minute.
Once we get a little deeper into what's going on with these wires, it'll make so much more
sense.
So what are we actually doing to get those DC signals?
Well, with this particular platform and with many of them, when we take our AC sine wave,
we actually, because we have a grounded circuit, we have a reference point.
And so now we'll actually utilize the voltages that are above neutral or ground and the voltages
below.
So we're going to have one signal that's in positive reference to ground and one signal
that is in negative reference to ground.
And that is the number one and number two wires.
So when we use our circuit to be able to rectify our AC, we're going to get a DC looking signal
because it's going to be chopped off.
And now we're going to do these pulses within it.
Think about it as like SOS, you know, inside of that wavelength, right?
That's a great way to explain it is your Morse code, right?
All it is.
Our spacing, our timing is all we're actually doing.
And that zero voltage baseline.
I don't know if you all remember maybe in some of the furnaces you plug in.
And if you have a two prong and you don't have that ground and then all of a sudden
your PC to board doesn't work.
It doesn't like it.
This has no reference to ground.
No reference point for our voltage.
So those two wires have a reference to ground that number one and number two have a reference
to the ground.
And there's a difference between the two of them that we're going to call the bias.
So with this particular system, this climate talk system that we're using with Dyken and
some of the earlier Good Minimana stuff, we are going to be able to measure from ground
to number one and from ground to number two and get two different voltages.
And what a lot of people don't realize is that difference between them, that bias is
actually our bandwidth.
So about a year ago, I did a class with John Brown over EWC where we went really deep into
this.
Exactly.
So I'll talk about that on this finished edited video.
I'll make sure to put a reference to get back to that one so you can understand what that
entire bandwidth looks like, how to set the bias.
If your bandwidth's not good, how you adjust that.
But for today, we're not going to go that deep.
I just want you to understand when you're looking at that, we actually have those signals
above ground and below ground in reference, right?
So some positive, some that are actually negative.
So if we were having a problem on a communicating system on the climate talk network, we could
actually take our meter and we could measure from common over to number one.
And we should be reading a positive 2.8 volts DC.
There is a difference when we have an air handler.
It only uses three volts DC.
And we can actually talk about that if anyone's ever, if they're really interested, I can
show you the math on how to figure out the bias on an air handler that's using three
volts DC and five volts DC.
It's simple.
You take the two that are on number one, you add them divided by in half.
Take the two for number two, add them divided in half.
And so the difference between those should still be that 0.6 volts DC or greater.
Now if we took our meter and we went from common to number two, we're going to see that
we're going to have that 2.2 volts DC.
It's a negative, right?
So we have a positive and then a negative voltage gives us a bias of 0.6 volts.
Here's the thing.
If we do not have 0.6 volts DC bias or greater on the climate talk network, you're coming
back.
It's that simple.
It really is.
You can literally measure between number one and number two.
And if you have less than 0.6 volts DC on a climate talk network, you do not have a
stable bandwidth.
You have conductors that are corroded because a mouse has chewed on them.
You have conductors that have kinked or broken.
You have conductors that are not landed properly on the terminals.
You have wire nuts sitting outside from your existing solid wire that got water in them
that corroded and no longer allow the communicating voltage because we don't have the amount of
current that we had with AC.
It's very, very, very low current.
So it's super simple to check the bandwidth.
So if I'm an educator, I'm bringing in a new dyken communicating system, I'm connecting
it.
And I actually can now show my students how to make sure that my network is good and operating
properly.
If it's not, this is where you start.
You start on the bias voltages.
So if I am trying to isolate a system, say I've got all these components hooked up, this
particular one, I got my thermostat, I got my indoor furnace, I got my cased coil, and
I got my outdoor unit.
If I am struggling for communication, I just start it.
Where would I start, Todd?
Where does my DC voltage begin?
It's going to be at the ground.
You got to get a reference point.
You got to get a reference point of ground and power at our indoor unit.
So worst case scenario, disconnect all your wiring, check it, make sure we got our 2.8,
2.2 or 0.6 bias difference at our indoor unit.
It's going to be 1.9 and 1.3 on an air handler, but it's still a 0.6 difference.
And then start adding my parts.
When I add something on and my voltage bias changes, guess what?
0.6.
If it's not, I've just found my problem.
Now, I will talk about one really oddball one that I have found, and after I found it,
it made sense.
Look at that outdoor unit.
I've got two wires, right, going to the outdoor unit.
So I'm communicating my DC voltages.
So where is my reference point, Todd?
From the indoor to outdoor?
Yeah, there's no wire.
Where would my outdoor unit find as a reference to ground?
Well, it is connected to hopefully a disconnect.
That disconnect hopefully is grounded.
So back to the equipment ground, back to the panel.
So I had a technician that called me and said, hey, I've got good bias voltage at my indoor,
at my thermostat, and my EEV, my outdoor unit.
I've got some janky voltages and my bias is not right.
I'm like, well, that's really interesting.
Let's check your voltages to ground and check the voltages to ground.
And they were low at the outdoor unit.
So I had him disconnect the wires from the outdoor unit, check the wires going to the
outdoor unit.
The wires were good.
So as soon as we connected it to the outdoor unit, the voltage dropped.
And I thought, well, maybe it's a board or is there something else?
I thought, well, let's go check all of our ground.
And we found a corroded lug inside of the disconnect that had poor connection.
So the path could not make it back to the electrical panel to the indoor unit.
The reference point was bad.
Clean the wire.
I've seen on rare occasions, by a handful of times, maybe half a dozen times throughout
my career, the euphor, the residential or even commercial, the euphor, did that.
It got corroded, got water on it.
And that euphor, that reference ground, that rod that goes what, six, eight feet in the
ground was corroded.
Yeah, absolutely.
Remember on that AC system that was using 24 volts AC to run a contactor?
It didn't care.
It had enough AC voltage running to the compressor.
It may not have been the safest thing in the world, but it didn't affect the way that our
24 volts AC operated contactor, but could absolutely with the communicating system.
So I have had incidents where I had bad ground wiring that was not able to be reconnected
properly.
And so we would simply connect common from the indoor to common of the outdoor.
Cannot use R because we already have a power supply at the outdoor unit on those, but we
could use common as a backup.
Okay.
So that's an overview of our Dyken.
We learned a lot about what's going on in that one.
So let's look at the other networks and see how similar they are.
Now we'll see one in the JCI side.
A lot of times you'll see it referenced as echelon.
It really is their communicating system.
Yeah, I see two primary connections because they've had a couple different generations
of it, right?
So you'll see one that is labeled A, R, C, B, primarily using green, red, black, and
blue or white wires.
And then you can also see a variation of that that is just common B and A. And I like finding
this one in their service manuals.
Remember, almost all of this comes right out of the service manuals.
This is not like hidden stuff.
You have to read it to find it.
It's in there.
You have to read?
You have to read, right?
That ground rod is absolutely, and we've got places out West that don't have ground rods.
They have ground arrays where they have shallow wide grounding.
But it is absolutely in a dry condition and it becomes less of a conductor.
So it's very important to understand that that ground is part of our communicating network.
We didn't think about that before, but it is now.
So let's look at this JCI one and we'll see that either way you look at it, we've still
got a common.
We have A, which is our positive reference, and B, which is a negative reference.
If we go back to the other diagram, which is their newer design, we still have R. We
still have common.
It just had B on the end and A on the end.
You got what?
A positive and B negative.
Gee, I wonder which one those are without even referencing what A and B are.
Isn't it?
It's amazing when you look at this from the perspective, because remember, a lot of us,
I would say most of us educators, we're technicians out in the field, many of which never worked
on communicating systems.
And so sometimes we're a little leery to bring communicating systems into the classroom because
we don't completely understand them.
Well, you get done with this class, you're going to go, that's all?
Bring it on because I've got this, this, this all makes, everyone's really doing this and
they're just saying it's different.
Yeah.
Yeah, pretty much.
It's just a different, it just matters a different protocol, a different language.
Exactly.
It's being delivered to one piece or one controller, the outdoor, the unitary devices in a, in
the same way, just a different language.
Different language.
Now I will say that I cannot speak for the bias voltage between one and two for the rest
of the manufacturers.
I know the climate talk pretty well and there's a lot of training material for that.
So if there's anyone out there that has tested the bias voltages and know more about the
bias voltages between different manufacturers, I'd love for you to hop on because that's
a piece that not every manufacturer likes for you.
To disclose either.
To disclose, right.
So I'm curious myself, but I mean, I've got my own ideas.
So let's talk about how do you check these?
Okay.
So if we're talking about this particular network, so with this particular one, so if,
if you think there's a communication issue, you're being told in the service manual to
isolate A plus and B negative, right.
And then measure the A plus and B terminals to common.
Back to our reference point of common once again.
And so this particular one has done a little bit different because they are utilizing voltages
at each different part.
And so they're saying, all right, let's just make sure that we're going from A to C isolated
that we're going to have 3.2 volts and B to C is going to be less than a volt DC.
Right.
Really communicating positive from A to common at the indoor unit, we're checking A to common.
We're checking B to common outdoor unit, A to common and B to common.
And if you look at it, it's simply stating we've got a three volt DC power supply on
these instead of a five volt DC power supply.
And each manufacturer will be different.
That's right.
But goes back to that protocol language.
It does.
How do we check them?
We simply open up the service manual and verify the voltage.
You're going to find that some of these look really similar to each other.
All right.
So let's take a look at the infinity line.
Most people are comfortable with infinity.
You know, have a lot of people go, man, I really struggle with my communication line,
especially if I get into zone systems.
I'm like, well, let's just understand what we're doing on that zone system.
Let's look at the entire system.
What is infinity?
It's four wires.
Okay.
And they are going to be labeled A, B, C and D. Now, if I were just a guessing guy, Todd,
and I didn't, if I didn't go into the next slide, we're getting ready to look at, I might
look at that and go, hmm, I got two wires going to my outdoor unit.
I wonder what's on those two wires.
Gee, I wonder.
If it's the outdoor unit, it probably has its own, if it's communicating, it probably
has its own transformer.
Well, we aren't going to have, we usually don't have common hooked up.
Right.
Rarely ever.
Unless you have a problem like you described.
Exactly.
Not going to have R hooked up.
Right.
So, if you have two wires there, and this takes green and yellow, one's got to be a
positive DC and one's got to be a negative DC.
All right.
And then from my indoor unit to my thermostat or whatever I've got, I've got four wires.
So let's take a look and see what those actually are.
Well, looky there.
So you got to break it down a little bit different from this manufacturer, but let's start at
the very bottom.
Either one.
Let's just start at the top.
And if we go from C to D, well, that looks awfully hot to me.
That looks awfully familiar.
That looks like an R to me.
And they're all in reference.
A, B, and C are in reference to C. A and B are both in reference to C, and D is in reference
to C. So C must be common.
So C is actually common, and D is actually 24 volts hot.
And A to common, I'm going to have a three volt DC signal.
And B to common, I'm going to have that 0.1, 0.3 volts DC.
And of course, that little tilde is approximately three volts, approximately 0.01 volts.
Exactly.
And they are showing you to reference it a little bit differently.
They're saying, hey, on the top reading with a board power applied, so I've got power going
to the board, but no connected.
This is the voltage you're going to see coming from the indoor unit.
And then once I connect things, I'm going to see a change in voltage.
And I'm going to see it moving between 2.5 and 3.9 volts DC.
And so that is how you test that communicating network on our Infinity system.
Let's just keep going.
And anything outside those parameters, we got a problem.
You got a problem between them.
And it's usually, typically, you're wiring.
Absolutely.
It's usually not the controller.
It's usually not the board.
Yep.
The only thing that I don't see in many of these, except for the very first one, is measured
between A and B, which that would be our bias voltage.
So I need to round up some is what I need to do.
I need to get in some of my friends' labs and go, all right, what's the bias voltage
on every one of these manufacturers?
Because I've got a feeling they all operate under the same principle that if I have a
certain bias, then if it's below this, I can't communicate well.
So what are we looking at here?
All right.
Let's take a look at Linux iComfort system, right?
Woo.
I like those.
Good pieces of equipment.
What do they do?
Wow.
They get kind of crazy with the wiring diagrams.
Let's stare at this for a minute and go, man, am I really going to work on this thing?
Yeah.
Yeah, you are.
Let's break it down a little bit simpler.
We can look at this one or we can look at the one after it from another piece.
And it sometimes makes it a little easier to understand what those four are doing.
All right.
Let's start at the indoor unit, Todd.
All right.
Let's start at the indoor unit.
And interesting that everything is tied back to the indoor unit on these unitary.
Yeah.
It'll be completely the opposite when we get to the duckless.
The duckless.
Absolutely.
But all of our unitary, our primary DC voltage is coming from that indoor control board.
So let's look at this indoor control board.
This one's using a smart hub because it's connecting another component to it.
But we can even talk about the smart hub if we needed to.
But what do you see at that indoor unit?
What are you seeing wires?
Yeah, I do.
I got an R, a forget.
I don't see it at a common.
So the are in common, I imagine, be 24 volts and the one in the two in the middle.
I see a negative and a positive.
I can't read what they are.
I they call it I but it's I I negative.
So there you go.
And I wonder which what those are.
Right.
So as elusive as these may seem, they're really not.
One difference that we do see with this particular brand is we may not be using that that 24
volt AC all the time.
We might have a 12 volt DC.
So if we hop over to the smart hub up here, when we get to our smart hub, we originated
with 24 volts AC and are to communicating when we go out of our smart hub, we're actually
going to now start using a DC voltage to work with, but we still have a positive.
So let's jump over to some of our ICP products.
Right.
I wonder if this is going to be similar to carrier kind of looks a little similar.
Now they've had two different generations to though.
So you're going to see observer.
You want to see Ion.
And I'm going to show you a couple of different wiring diagrams, but let's break it down.
All right.
Let's put it into perspective.
Looks pretty similar.
What do you see there, Todd?
D X positive D or DX negative.
I wonder which ones are data.
Right.
And our indoor unit, it might call them ABC and D, but then all we've got to do is we've
got to look at the wall controller.
We look at the outdoor unit and we see exactly what those things are.
So I see 24 volt hot between common and D or R. And then I see a negative communicating
signal on B or DX native and a positive on a looks pretty dang familiar.
If we can check this one.
Well, why not?
So doesn't it look similar to go their way?
We named her.
I wonder why.
I well, we're just saying that they're they're training material on their slides.
Look similar.
That's all we'll say.
So, yes.
DX negative common that that is common.
Commodore 24 volts.
So we're just on three volt DC.
We're going to see three volts on both of them.
And if we don't, we've got to disconnect and we've got to start seeing where we're losing
it.
So the best way on any communicating system, disconnected control wires start at that indoor
unit, verify you got good voltage coming from it and then start adding them one at a time.
Let's look at comfort sink.
All right.
I think this might look similar to Linux.
I'm seeing common.
I'm seeing our I'm seeing positive and I'm seeing negative again.
And look at our pseudo shulid cable with our typical 18 gauge whatever.
Yeah.
So if it's a non communicating wire, we got communicating existing wires.
Oh, we're going to tie those together.
And then we're going to check our voltages.
Right.
So it's the service instructions are a tad bit different.
They're a bit different.
But you know, this is because of the communicating platform that they're using.
What we're checking changes how we check it never actually changes.
So we know that it's a five volt DC system.
Right.
So we can now check the pin one to pin two.
We should have four point five to five point five volts DC when it's not communicating.
So when it's sitting there idle pin three to pin two should read four point five to
five point five when it's not communicating.
And then pin two to pin four should read four point five to five point five volts DC.
Geez, they all look like four and a half to five and a half.
I'm telling you.
That's why I like doing this class.
Because when you go through it all and you go, oh, really?
Oh, I'll make sense now.
When one last thing I'll put in there is that communication systems are here to stay.
They are.
And we're going to be not going.
But we're going to be talking about it more and more and more.
And hopefully we'll end up persuading a common common language, common common protocol.
All right.
So once again, always fun hanging out with you my friend.
I just I love these conversations and know it's just about bringing quality education
to the industry.
So yeah.
And one final as we say goodbye.
Happy birthday to my best friend Clifton.
I know I was I had people say what what what kind of day and I was like, I don't want to
do this the whole time.
But how come you don't have your your your get up from from from HR?
We just picked it up from the dry cleaner.
So here's where you go.
All right, everyone.
Thank you so much for joining us once again.
We'll see you all next week on Did You Know the Esco H5 show.
Bye.
Bye now.