Tales from the trenches, stories forged in the fires of experience.
This episode recorded live at the 2024 National HVACR Education Conference.
Learn more about the education conference at escogroup.org.
All right, everybody.
Thank you so much for joining us once again on Did You Know the ESCO?
HVAC Podcast.
So we're spending time here at the National HVACR Education Conference, and we are going
to spend a little bit of time diving into some ECM troubleshooting, and we're going
to set you up for a class that we're going to have with Chris Mahali here.
Yay.
And I encourage everyone to hop in and take a look at it.
We'll, we'll, we'll cue you in for some pre-recorded classes that we had that Chris
and I did covering a variety of ECM topics and the evolution.
But we wanted to spend a little bit of time just bringing some awareness to changes that
we've seen in the industry.
So welcome, guys.
Glad to have you all introduce yourselves as we go through and let's dive on in.
My name's Dirk Nauman.
I'm with HVAC Simulator and enjoying the HVAC excellence.
Hey, I'm Jim Foltz with Copeland Light Rogers.
Great show.
Appreciate everything Clifton and the team's putting on here.
Chris Mahali with Regal Rexnard supporting the brand Genta Motors.
All right, guys.
So a question got brought up amongst yourselves and let's dive a little bit deeper and kind
of explore some of the interests you had.
All right.
Well, I'll start.
Just a little bit of a history behind how the three of us are together here at a podcast.
About a year and a half ago, White Rogers created a universal board that would do both
PSC motors as well as ECMXs or X13s.
And it's been a really good board.
Was sharing it with Dirk and saying, hey, that would be a great addition to the HVAC
Simulator.
Absolutely.
Yeah.
And so we got together and I sent him a board and I'm going to pass the mic over to him
to let him share what happened next.
Yeah.
So in the creation of the HVAC Simulator with the universal board, I put the board on, wrote
the program and then it doesn't work.
So I'm sitting there with my meter trying to figure it out and I'm like, this board
does not work.
I send an email to Jim and I say, Jim, what'd you send me here?
Did you send me a lemon?
What is this?
And so I can't figure this out.
So then I sent it to Jim and he talked to his engineers and said, hey, it's not working.
The engineer said, did you put it on a real furnace?
And I'm like, all right, here we go.
And the answer was no.
I put it on the real furnace and it worked.
I'm just like, all right, what's going on here?
I found out that ECM motors, X13 constant torque ECM motors, they accept a 10 volt DC.
My meter was set to 24 volt AC because my mindset was the control signal is always 24
volt AC.
So the logic here is if you don't know how something works, you cannot fix it.
So I wasn't able to fix it.
So I'm going to pass it to Chris.
Actually before that.
So I got the ECM motor out or I pulled out the the GenTech tech guide and I'm started
looking and there's a one liner in there that says accepts 10 volts DC.
Yes.
So yeah, Chris, well, I'm just going to clean up a couple of things because this is not
I mean, when you're recording, but some people might be listening.
So when we say X13, we haven't made X13 for a little while.
The names have changed, but we're talking about constant torque ECM motors, most identifiable,
identifiable by the nine pin plug usually says CLGN across the top of the plug.
One, two, three, four, five across the bottom.
It'll make it easier for everyone to associate that motor.
We're also not the only ones that make it, you know, so but but everyone's using that
same identifiable nine pin plug.
So that's the motor we're talking about.
And as you said, traditionally, it's been built and still today is most widely built
with 24 volt speed taps for 24 volts of taps one through five motor changes speeds based
on how the manufacturer programed it.
So here's some of the hiccups.
One the outside of the motor has not changed.
Nothing about the way the motor looks has changed.
So we've offered it in PWM mode.
We now offer it in what's called a nine speed mode.
And both of those modes of operation use DC voltage to energize the taps one one through
five or just tap one for PWM.
Now again, so if the technician is just looking at the motor, there's nothing identifiable
about the motor.
In your case, you were you got kind of set up on this.
In your case, you were just given a motor.
There's all that programming change happens inside the motor and the microprocessor.
There's no way for you to know what that motor is looking to accept.
But another another challenge and this is kind of a great topic because I'm talking
about it today.
Right.
And we just recorded it, like you said.
But you know, technicians think that these motors don't change.
Right.
They learn one thing and OK, I'll just apply.
I know this plug.
I know what this is.
I'm going to apply that forever.
And I do want to I don't want to I don't want to.
Oh, my God.
The simplest motor just changed.
Now the world's coming to an end.
So I would say 75 to 80 percent of these motors that are still being used by OEMs today are
still used with 24 volt speed taps.
It's a 24 volts AC speed tap.
So it is a small amount of OEMs that have chosen to use the PWM or the nine speed motor.
And they're doing that so that they can reduce skews.
Right.
And they're using a wider breadth of operating range so they can handle a wider unit range
with it.
But so really what happened is five, ten years ago, we started offering PWM first and PWM
signal is based off of a DC voltage creating a square wave.
Which stands for?
Pulse width modulation.
Thank you very much.
So and three years ago, we started offering nine speed mode and that uses all five pins,
but it's using DC voltage as well.
So here's the easiest way and I think this is probably of the most value for the people
that are listening, the technicians in the field.
If you see the constant torque motor wired back to the board and at the board those wires
are landing on heat, cool and fan, it's almost 100 percent going to be a 24 volt AC controlled
motor with multiple speed taps programmed into the motor.
If you see that all five of those taps on the motor brought back to the OEM board plug
to plug, there's no heat cool fan taps, that's your clue.
Something's going on here.
Better get in the book.
Find out if we're using DC voltage.
For PWM, so we only do PWM on pin one.
That's numbered number one right on the motor.
So if you see one wire in pin one, again, going straight back to the board with plug
to plug, no heat cool fan.
Absolutely.
PWM DC voltage.
PWM, right.
And I'll just say one more thing because I've been talking too long and somebody else should
get in.
In PWM mode, we also do where the OEM can get some feedback information.
So even though they're only using pin one to operate the motor, there may be two other
pins powered on our motors, likely four and five, where they're powering four and five
is sending some information back to their board.
And so one last thing I know I said, so now these constant torque motors operate and they
adjust as far as airflow adjustments, very similar to the variable speed motors, which
have been around forever and most contractors are familiar with, right?
So I'm going to make no adjustments on these DC controlled motors at the motor.
I'm going to be adjusting dip switches and I'm going to need to go into the manual to
find out the diagnostic values, which will typically be DC at the motor.
Based on the OEM programming, because it could be a variety of different voltage positions
or ranges depending on where it was designed at.
It actually could be, it could be a nine volt value or an 18 volt value.
It could be somewhere in between because we give the manufacturers, engineers, engineering
latitude to choose how they want to control the motor.
Yeah, makes complete sense.
So we can back up here a little bit to where I think both Dirk and I were.
And that was when we were teaching the constant torque motor, we was saying, okay, we have
120 going in, which is actually going to be converted to DC three phase back to AC three
phase for the motor.
And the motor itself is just a three phase AC motor.
And for the ECMAC or constant torque, that motor to, for me to get my mind around it,
I was like, it's no different than an air conditioning condenser.
You have 220 going to the condenser, but it takes 24 volts to pull the contactor down
for that compressor and fan motor to run.
And that's exactly what's happening with a constant torque motor.
You have the 110 going in, which is going to be converted through that head, but you
have a low voltage.
And historically it was 24 volts going into this thing.
And depending on which tap you, you sent that 24 volts in that contactor pulled in in the
motor and chose that speed.
And so this was a revelation, I think to all of us that, Hey, we, we have different voltages
here.
And especially for us after we've created a universal board and the technicians are
like, Hey, I don't have 24 volts here.
Something's not right.
Yeah.
Well, so even if it only has three taps being powered on the motor, if they're using some
boards like our aftermarket board, they're still not going to get that 24 volts off of
it.
So we had a DC signal and that range, I would agree with you for the testing that we done.
It was like, Hey, there's a range here that we can be in.
It's not just 10 volt DC.
It can be above and below that.
So it's not a unified standard.
Correct.
So, so let's, let's get the dirt back in here to finish how he's summed things up.
Yeah.
So as a technician and a technical trainer for the Habager corporation, ECM Motors is
the kind of like the topic that draws people into training because they don't understand
them.
Again, I want to stress the importance.
If you do not know how something works, you cannot diagnose it.
It's that simple.
And I met Chris, I don't know if you remember this, in Tucson, Arizona at the RSES convention
in 2010.
And with that, Chris talked about the ECM Motors and they were out for a while, but that's
when about around the 2010 era is when you started seeing more and more of them.
And Chris had a three part series ECM one, two, and three.
With RSES.
Yes, with RSES and the same manuals.
And then with that, I want to put a plug in for the website and the website, the name's
like this long.
I have it copied into my training for people to click, but ECM University, but if you-
Motormaster University?
Motor, thank you.
But if technicians would go there and they would spend one hour watching these videos,
they would be the expert in their company on ECM Motors.
So I'm putting a plug in.
Chris, do you know that website?
As regalmmu.com and it is called the Motormaster University.
Thank you, Clifton.
Absolutely.
I'm turning it over to you, Clifton.
Yeah, no, this is great.
And you're going to see some videos, some podcasts with Chris and I on that exact same
site where we dive deeper into this and we actually do some visual representation of
it.
We have a little fun.
We really, we have a lot of fun.
We have a lot of fun.
I mean, are you kidding?
I mean, this is a fun group right here.
You're getting top of the industry talking about things that are happening in this world.
And so we just, we try to encourage you all to understand the things that we work with
on a daily basis to be able to look at things and see that sometimes things change and we
may not be aware of it.
And it's up to us to continually educate ourselves.
We have 1200 of us here that are all for the same reason, to educate ourselves, to make
sure that we're delivering the proper content back to our classrooms, back to our technicians
and just getting better at the things that we do.
You bet.
Cool.
So the takeaway that I'd like to summarize for myself here is when you're troubleshooting
a constant torque motor, don't count on a 24 volt signal from the board to the motor.
It may be there.
It may not be there depending on the manufacturer, depending on what board it is.
And if you're not getting 24 volts, switch your meter to DC, check it in DC, see if you're
getting somewhere to 9 to 18 volts somewhere in there and check it that way because it
may be the signal that's communicating is now a DC signal and not an AC.
And if you're not checking that as well as what we would have traditionally known as
a 24 volt AC signal, you may be missing what actually is going on with the equipment.
Can I get an RTFM please?
What's that saying for?
I missed it.
Read the fantastic manual.
This is the fun manual.
It's not full?
It's a fantastic fun full manual.
I think that's what I heard.
Maybe what I don't.
It's a fun manual.
Absolutely, read your installation manual, clarify what those signals actually are being
used for.
You got it.
Cool.
All right, guys.
Thanks for joining me.
Thank you.
DCComm2 here.