Welcome to the Windshield Chronicles, a mental sequence of operation.
This episode brought to you by EWC Controls, Incorporated.
Excellence without compromise is dedicated to bringing state of the art controls to the
HVACR industry.
Learn more at EWCControls.com.
Well welcome everyone.
Thank you all for joining Did You Know?, the ESCO HVAC show.
Let me ask you a question.
Has anyone ever explained to you how communicating HVAC systems work?
What principle they come from?
It's a very important topic that we really don't talk about a whole lot in the industry.
And that's what we're here today to do is discuss how communicating systems work
and get a better understanding of what that communicating thermostat does in relationship
to the entire system.
If we look at communicating systems in general, they really do have their roots in the same
technology.
I'm not going to say that they all talk the same way.
We'll just say that they talk on the same network and they may speak slightly different
languages but they all have their roots in the same type of communicating system.
If we look at this reference from Eaton, Eaton will tell us that the RS-485 system has been
around for a very long time, really developed back in the 1980s.
And it's based on a 5 volt DC two wire principle, two wire communicating system.
It could be up to four.
Most of the time we're using two wires to develop that 5 volt DC signal but it is in
reference to a ground or a common landed ground.
And we have a positive signal that is in reference to ground and a negative signal that is in
reference to ground.
So how do we get to that point?
Well, it's really not that complicated.
It's very ingenious but not incredibly complicated.
We take our AC power source starting at the furnace or air handler, our indoor unit, which
is where our power source originates typically, right?
That's where the power supply is.
So we take our AC signal, we run that through some bridge rectification, we run it through
diodes, we get that rectified into a DC signal, a reduced DC signal at about 5 volts DC.
Then we will add a grounded reference point to it.
And the network that we're going to talk about today, which is the climate talk network,
which I would say that many manufacturers use this principle, we land that ground not
exactly in the center of that 5 volt DC span.
Remember, it's 5 volt DC, the height distance of our sine wave.
We landed off center so that it is not directly in the middle of our reference point.
So what we end up with in those two points is a 5 volt DC signal that is partially positive
in reference to ground and partially negative in reference to ground.
So now we have a place that we can start.
Well, when we talk on that, we're not going to be able to listen in on what's being said
on that but we can verify if our network is working properly so that we can start looking
for issues, right?
So if we reflect back on this RS485 platform and we can see here that it is a two wire
data function, primarily this one is going to call it data plus and data negative.
And then we might have our common and our ground, which is for our communication cable.
But the work is really being done on those two terminals.
Now let's look at a couple of different manufacturers and we'll try not to use names on these.
If you are a technician that reads your service and installation manuals, these wiring diagrams
will look different.
They're coming from different manufacturers.
This particular one is actually the one that we'll talk about the most today.
But let's hone in on what that communicating looks like from this manufacturer.
We are going to have a data line one, a data line two, then we're going to use two additional
wires for 24 volts hot.
Well what are we doing that for?
Well our 24 volts hot R and C is the amount of current, the higher amount of current,
the power that we're going to use to run that big fancy colored LED screen.
It's also going to give us our capabilities of running Bluetooth and Wi-Fi and any type
of a load that is on our controller.
Data one and data two are going to be our five volt DC signals that we are going to
use to communicate.
That is our parallel communicating network.
Well let's look at another manufacturer.
I go, my goodness.
I have another positive and negative signal and I'm using a common, so a ground reference
point.
So this particular manufacturer is using three wires.
It is using common, which is a grounded common.
So that is our ground reference point.
It has a positive signal on A in reference to ground and a negative signal on B in reference
to ground.
If we look at this manufacturer, they are also using a four wire connection.
We're using common and 24 volts AC for the load that is on the controller and we're using
data A and data B. It just happens to be our DC communicating signal.
We look at this other manufacturer, we'll see that we have our common and our R, our
24 volt AC load and then now we have, this one is labeling it as I negative and I positive.
Looky there.
We have a negative reference and we have a positive reference once again.
If we look at this one, we're going to see a four wire connection, two of those 24 volts
AC and two of those labeled as a positive DC and a negative DC.
So we look at this manufacturer, another reference of the exact same thing.
So I'm not saying that all manufacturers use the exact same cause I have seen some variations
of it, but I will say that the philosophy, the technology behind it all comes from a
similar design.
If we look back into the early technology of communicating systems, we will find this
reference to the Climate Talk Alliance.
The Climate Talk Alliance was a group of manufacturers that knew that technology was coming, 1990s,
late 80s, early 90s.
They knew that we were going to have more communicating systems in the industry, not
just in the HVAC, but in the HVAC refrigeration and appliance sector.
So many manufacturers got together and decided, hey, maybe we should have an open protocol
going forward so that we can all talk on these same channels and so we don't all get mixed
up along the way and technicians can have an easier opportunity to know how things function
in this new communicating platform.
Well, it happened for a few years, a couple of decades or so, and then it slowly started
fizzling out as many manufacturers started creating their own coding used on their network.
But the network itself is why we're here to talk about.
The network is something that we can understand and we should understand.
I got my first opportunity to dive into this communicating network back in my distributor
days when I was doing teaching on a particular brand of communicating equipment.
And I ended up with this amazing controller called the EWC, Excellence Without Compromise,
UT3000 or the Ultra Talk 3000.
And it is the only communicating zone control system that works with the Deakin communicating
systems, particularly like the Deakin Fit.
So I got to know my good friend, John Brown, in that time.
John Brown is the chief engineer for EWC and he helped me understand this entire communicating
network and how it all really comes back to understanding these DC communicating voltages
and the things that can affect the path of our DC communicating voltage.
And this really cool thing that just kind of blew my mind.
The fact that that communicating thermostat doesn't necessarily have to be the brain,
the control center of the equipment.
One of the general philosophies in the field is that that communicating thermostat is the
one and only component of that network that does the actual work, right?
That we replaced our legacy thermostats that just had switches that did the work with a
communicating thermostat that did the work for us.
And you really helped me understand it's not that way.
That it is a functional network.
And in some instances, you don't even have to have a thermostat connected to a communicating
system for it to be able to function properly.
So I would like you all to meet my good friend, John Brown.
And John is going to walk us through a little bit of technology in the communicating world.
Welcome John.
Thank you very much Clifton.
Thank you very much.
Really appreciate you allowing us to provide this information and increase the contractors
knowledge base.
Tech service managers, educators.
This is going to be some important information.
So we've got a lot to go on.
So let's get started.
Okay.
Now this graphic you're looking at in front of you, of course, is a hybrid RS45 communicating
network specifically for the Dakin communicating line of equipment.
On the left, you see the outdoor inverter.
This could be the FIT inverter or the original cube inverter.
Notice in the middle, the indoor evaporator coil is no longer a TXV.
It's an electronic expansion valve that also has a communicating circuit board.
There's the communicating air handler and or furnace as part of the indoor package.
And then on the lower right is the communicating block on the UT3000 zone controller.
Think of this block like if that was the communicating thermostat.
The UT3000 is essentially emulating the Dakin 1 communicating thermostat in that regard.
Of course, above it, we do include the standard legacy output as well because there are some
guys who might want to hook up a hot water coil instead of electric backup heat, various
ancillary devices that we can accommodate and incorporate into the communicating network.
Now what Clifton was talking about, extremely important here about these RS45 networks,
they are all roughly basically the same.
What varies, the baud rate with the data is moving on these networks as well as the hierarchy
of these networks.
That is, who's in charge?
Who's really in charge?
As Clifton pointed out, it's not necessarily the thermostat.
In this case, it's not even necessarily the zone controller.
In this scenario right here, take the zone controller out of the equation, put a Dakin
1 right there on the lower right.
The Dakin 1 thermostat is actually considered to be a subordinate entity on this network.
The actual coordinator or the boss of this network, believe it or not, is the electronic
expansion valve.
I know, blows my mind to think about that, not even the indoor unit.
If you think about it, think about what an important role a thermostat expansion valve
plays in a standard HVAC system.
It made sense that Dakin decided to make the electronic expansion valve the boss or the
coordinator of this network.
It knows what the superheat is, the subcooling.
It knows what's going on and is coordinating all of this data with the outdoor unit, the
furnace, the blower, the air handler, as well as the thermostat.
The thermostat doesn't command and say, give me cooling.
The thermostat says, can I get a chance to talk?
Exactly.
Can I get a chance to talk?
I'd like to have 75% cooling, please.
And the EEV takes it from there.
It's really astonishing.
It really is.
And that's the thing to point out about that electronic expansion valve, that not everyone
realizes that we are moving to electronic expansion valves to replace standard thermostatic
expansion valves.
But they are absolutely to our asset if we understand how they function.
If we take this electronic expansion valve, I know this particular one, it has two temperature
thermistors, one on the inlet evaporator, one on the outlet evaporator.
And now we can start using a pressure transducer, a suction pressure transducer.
And technicians go, oh my gosh, all that technology.
And I go, what are you doing when you put your digital gauges on a piece of equipment?
You are using a, by the way, a five volt DC pressure transducer to calculate the pressure
of your suction so that your gauges have a number to work with.
And we're also using a five volt DC potential temperature reading that we're going to measure
the suction line.
And now we have two mathematical numbers that we can calculate superheat with.
Exactly.
Well, doesn't it make sense just to put it at the electronic expansion valve and let
the process begin at the component that does the metering?
So if we know what the system is doing, if the system is functioning properly, we can
read superheat without even putting a set of gauges on.
Exactly.
The fit inverter, when you place it into charge mode, which we're going to show you later
on how to use the UT 3000 rather than the thermostat to place the equipment into system
test and charge mode, it will actually tell you whether the subcooling is proper or not
and whether you need to remove refrigerant or add refrigerant from the system itself.
So it's really quite interesting.
You saw the connections going from the zone control to each respective piece of equipment,
parallel wiring and daisy chain and daisy chain configuration.
We really would like for you to stick to that.
Everything is in a row.
You have a beginning to the network and an end to the network, but not everybody wires
in this fashion.
Quite often the data one and the data two wires from the outdoor unit, guys are just
used to the old way of doing things and they bring them over to the air handler or the
furnace.
Now, this is actually a star configuration.
It's not a daisy chain or series configuration.
Sure.
But just try to remember why are everything in a row and if you have different conductor
types, that is you have stranded going outside, solid inside, you can't put these two different
conductors into a single terminal block because the cage is not going to capture both of them
properly.
So the image you see in front of you is a best practice.
You got a stranded unit coming from a stranded wire coming from the outdoor unit, a solid
wire from the thermostat or the zone control.
Fit everything on it.
Make sure you don't twist too much and break one of those wires and make a single point
connection to the terminal block.
Remember low resistance connections is the key to keeping this network stable.
So that's very important.
It is John.
One of the things that I had encountered with this exact same scenario is many a times with
original solid conductor control arcs.
We know with the application allows technicians are going to flush a line set.
They're going to reuse to the original conductors and it is acceptable if things are installed
properly.
One of the things we have to understand is with that solid wire conductor that it might
have passed current through properly on an AC load because remember our legacy thermostats
had a switch and we were applying a load through that conductor for our thermostat wire.
Now when we get to work with our communicating systems where we're talking about a different
impedance and we're talking about a low amount of current passing through the wire, if we
have a lot of corrosion on that wire, it is not going to make a solid connection.
So I always recommend for technicians on all communicating systems, if we have existing
wire, especially if there's existing wire nuts anywhere, cut them off, re strip down
to fresh clean copper, put the wire nut on and then I always recommend to insulate those
wire nuts with dielectric grease or with silicone.
So we make sure we don't get any moisture in there to create oxidation, which can cause
future issues.
You're exactly right, Clifton.
I ran into this on a job.
Believe it or not, I got a call from Hawaii.
Well, this guy's splice connection from the indoor to the outdoor was so corroded, it
simply would not communicate with the outdoor unit.
It took him a while to find it, but he did, he cleaned it up and it worked like a charm.
Thanks for pointing that out.
Yeah, I always told guys if they have an issue with the outdoor unit not pulling up onto
the network and the reusing wire, find the closest window or door, grab you a spool of
fresh conductor wire, throw it outside and run you a fresh one.
We've actually done that.
Absolutely have done that.
That's a quick way to find out.
Okay, so, you know, installing a zone communicating system is challenging.
You know, there's no why circuits to test.
You can't use your meter to test C to W and stuff like that.
It can be a bit challenging.
But the most important thing with this is this equipment needs to be commissioned.
It needs to be commissioned properly.
And you initiate the commission process, typically through the thermostat.
But we've seen some confusion in this and that, you know, sometimes the network doesn't
configure, the thermostats can't find the equipment, the equipment, the zone control
did but the stats didn't or nobody can find the equipment.
And we've also seen some issues where the commission process can be affected because
the contractor doesn't have thermostats turned off.
Remember, commissioning that is equipment test and charging mode are commissioned functions.
They're not cooling operations.
So once these commands are sent to the equipment, they're forgotten about.
If a thermostat in grandma's room is set to heat, the zone control is going to try to
activate that.
And you're suddenly you've got some dampers open and some dampers closed, which could
inadvertently affect you the outcome of your equipment test or your charging mode in your
sub cooling values.
Sure.
You're low across evaporator.
Right.
So what we've done is we've devised a way for the zone control to perform these functions
for you without using the thermostats.
Not even connected, not even connected, Clifton, right?
The thermostats won't even be connected until the third part of the commission process.
Now, of course, you got to install the equipment first, right?
So you want to install your day can system indoor and outdoor components following the
specific Diken guideline and guidance.
You want to include all required mechanical aspects, structural support, properly sized
duct, a condensate removal system, a flu vent piping system as applicable for, you know,
the efficiency of your of your furnace, perhaps complete the refrigerant line set connections
per Daken guidance and industry standards.
Make sure you put in a liquid line filter dryer close to the EEV, not outside anymore,
right?
Close to the EEV to protect that component.
Oil traps are important.
Don't forget them.
Connect your manifold gauges, evacuate the line set and the evaporator coil.
When all the non condensables have been removed, the line set and the coil are leak free.
Open the service per Diken I instructions.
You're going to install the UT 3000 zone controller.
Go ahead and mount the dampers.
Do all the wiring for that.
Following the tech bulletin guidance from UT from EWC controls.
Don't mount the thermostats.
You've ran the wire, the plates are on the wall, but leave the thermostat right there
on the table.
Don't mount the thermostats just yet.
Go ahead route and connect all your electrical wiring.
Just don't connect the stats.
Sure.
Energize, power up, power up the equipment.
Yep.
Power it up.
Typical wait time is about five to seven minutes for the entire network to configure.
It varies.
It can be three minutes.
It can be five, six, seven minutes.
That's the typical wait time.
What you want to look for, don't cover up the EEV circuit board.
Leave the cover off.
Exactly.
Leave that off.
This is the boss of the network.
Remember, it's going to tell you if something's wrong.
Okay.
So don't cover up the EEV circuit board.
Also pay attention to the LCD screen on the UT 3000.
If the EEV board displays E77, the network has not configured.
If the UT 3000 does not display a valid outdoor temperature, it says the outdoor air sensor
is bad.
Guess what?
The sensor is not bad.
It simply can't fly.
It's just not there yet.
Yeah.
I can't see the outdoor unit.
So some troubleshooting is going to be required.
Not much, a little bit.
E77 meaning I can't configure the network.
I can't talk to the outdoor unit.
I don't see a complete system.
Exactly.
This is a clue.
The zone board might see the air handler.
It might see the furnace, but it can't see the outdoor unit if it displays OAS bad.
Now believe it or not, I've had guys tell John, I replaced the sensor.
It's still, it's not the sensor.
It's the sensor.
It's the data wires going outside.
The network has not configured.
So as Clifton pointed out, these voltages by equipment combinations and manufacturers
can vary.
The key is knowing what these voltages are supposed to be when all of your wiring is
correct.
Yes.
Okay.
No matter which manufacturer you're working on, if you know what the voltages are supposed
to be, and if you know what the Delta between these data lines are supposed to be, you can
create a good highway and a stable highway for the data to move on and your system will
function.
John Brown, EWC, excellent without compromise.
Once again, thank you.
You're welcome, Clifton.
Thank you very much.
Thank you everybody.
Everyone have a wonderful evening.
We'll see you again next week on Did You Know?
The Esco H-Faction.