Welcome to Did You Know, the ESCO HVAC podcast,
the show where we explore the cool, the hot,
and the everything in between of the HVACR industry.
Each week, we dig into the innovations, the insights,
and the inspiring stories that power our trade
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As well as AGAS, together we can. Whether you're
just getting started or you've been turning wrenches
for decades like myself, there's always something
new for us to learn. I'm Clifton Beck and this
is Did You Know? The ESCO HVAC Podcast. podcast.
Let's dive in. Well, hello, everyone. Thank you
for joining us once again on Did You Know, the
ESCO HVAC podcast. We are spending some time
today talking about invasive diagnostics with
our good friend, Joey Henderson, otherwise known
as JoJo, the HVAC man. How are you? I'm doing
great, Clifton. How about yourself? I'm doing
wonderful, hanging out in the new studio and
getting everything fine -tuned. We actually took
it out on the road to Hudson Technologies. I
was over there Monday and Tuesday shooting a
behind -the -scenes video of the life cycle of
a recovery cylinder. So just talking about the
journey from the time it leaves Hudson. Goes
out to the field. We shot field of a contractor
recovering. I mean, it was amazing. You know,
when it comes back to the facility and we split
and send the refrigerant one direction, send
the cylinder the other direction. And it was
really cool because while I was there, they were
telling us that they work with about 40 different
refrigerants there at that facility. Wow. You
know, it brings up one of the topics that's near
and dear to both of us. When we're talking about
refrigerants. A lot of people go, oh, these new
A2Ls or these new A3s. What's the pressure run
on those things? And as technicians who have
been out in the field for a while, we both really
got a passion for knowing what the temperature
is. And the refrigerant is almost irrelevant
until you're ready to convert it to pressure
because our systems run on temperature. And people
don't understand that. That's right. Yeah, you
know, it's funny because, you know, when I got
in it. uh it would join the navy in 88 and so
when i got in it was uh r12 and r22 was still
out there with a couple other 500 refrigerants
but you know when i stepped out of the navy i
stepped right into the world of change 1991 and
so we were converting you know from 22 to 410a
from r12 to 134a and everybody was going berserk
I became 410A certified in 1995. Wow. And in
98 or 99, somewhere around there, I sold my company
and got hired on to Carrier as a tech rep while
I was doing all the training for 410A across
the state. And everybody was just freaking out
on what the pressures are going to be, what the
pressures are going to be. And then I talked
to them. an old timer before my time. And he
goes, yeah, we were all freaking out when we
went from R12 to R22 because the pressures were
so much higher. He said, we had R12 in our air
conditioners. And I remember I actually came
across a couple of ACs that had R12 in them.
And so these systems are designed for whatever
pressure they hold, but there's no magic pressure.
Pressures are related to temperature. the more
and more i dug into that and the more i started
embracing that it made my life a lot easier because
boy in the refrigeration market it was nuts you
think going from part two to 14 oh my gosh refrigeration
was great so many different choices of you know
refrigerants so i've got to where i finally understood
and zeroed in on it's not about the pressures
it's about the saturation temperatures And so
it doesn't really matter what flavor of ice cream
is in that system. If we know what saturation
temperatures we're looking for, then we're fine
because they're going to change again. I'm sure
they will. There's going to be more refrigerants?
Absolutely. The application determines the saturation
temperature, which determines the pressure. There
you go. You know, walk -in coolers have a colder
evaporator than walk -in freezers. And air conditioners
have a warmer evaporator, obviously, than coolers
and freezers. But what should the temperature
be? And if we know that, it doesn't matter what
refrigerant we got. We just convert the saturation
temperature to the saturation or to the pressure
of whatever refrigerant and you're golden. So
no need to worry about like back in the day,
R22, everybody said 70 on the suction. 225 on
the head and we're good right that's all they
did you know but what they didn't know is that
that actually related to design conditions very
specific condition very specific conditions and
if you now know what the conditions you're in
you'll know what those should be oh yeah so i
love to talk about it because i think it alleviates
a lot of uh no pun intended, a lot of pressure.
You're right. Absolutely. And so you don't have
to worry, you know, what pressure do I need to
be? Don't, don't worry about that at all. I'll
tell you today, it'll let you and I already know
what saturation temperatures are when it's running
right clean. And, and then you, you can even,
even. be able to get an idea of what the subcooled
superheat is without throwing any gauges whatsoever
on the equipment. I love it. Let's break it down
and let's go through some examples to kind of
show people because it kind of really is based
on the performance design. You know, if it was
a earlier 10 sear or when we went to 13 sear
and then 14 sear too. So it really, there is
a difference in the system designs, but once
you understand what that is, any general, any.
Any piece of equipment in that generation is
going to be operating very, very similarly on
temperature if we have proper airflow indoor
as well as outdoor. It all starts with proper
airflow. So let's assume, I hate assuming because
you know what it's going to do to you and me.
Let's assume we've cleaned the blower. Huh? Yeah.
It's mainly technicians listening. They know
where this was going. So let's assume we've cleaned
the blower wheel. If it was a gas furnace, we've
cleaned the secondary heat exchanger. We've cleaned
the evaporator. We've got our airflow set to
the proper CFM for the size that we have. We
verified we don't have excessive duct pressure,
which would reduce our airflow. We've cleaned
the outdoor coil. We've made sure that the system
is ready to run. Properly, right? As designed.
We fire this up. We've got proper airflow. It's
not good. No such thing as good. Good's a determination
made by false expectations. That's right. So
we have proper airflow indoors. We have proper
airflow outdoors. We can now actually analyze
how this system is running. based on temperature
alone without putting a set of gauges on this
thing. That's right. That's right. There's quite
a bit that we can do, which it really blows my
mind. So going back to what you said, you know,
a lot of guys miss that. And so, you know, be
sure you got the right airflow. Now, if you've
got a constant CFM system, you know, a true variable
speed motor, you're probably going to be pretty
good there. but don't forget it does have a limit.
And also if you got a constant torque, we're
pretty darn good there too as well. Just remember
that if you're pushing that constant torque,
you will blow the capacitors eventually. Unlike
a variable speed motor has a limiter on it, constant
torque, they just keep drawing from the capacitor
to the coil. That's why a lot of them blow these
days, by the way. And then a PSC motor. You know,
just remember one of the things you can do is
pull an amp and draw on a PSC motor. If it's
pulling less than its rated amps, it's moving
less air. Amperage are a direct relationship
to how much air it's moving. So if you've got
a PSC motor and it's pulling full load amps,
that means it's fully loaded, which is a good
thing. All right. Now, don't forget one last
thing. Not only clean evaporator coils, not only
clean condenser, but clean blower wheel. That
means both sides, everybody. Both sides. So,
you know, I've had to pull many of blower wheel
housings out, tear them apart, clean them, put
them all back together to get good airflow. Don't
forget that part. And don't forget those double
row condensers. Split them open and clean in
between them. That will get you every time. All
right. So I do my little spill there. I love
it. Properly cleaned. All right. So now we got
all the proper, proper, proper. Right. All right.
So now. So what a big thing to change in the
efficiency. A lot of people think about the meter
device, which is true. But all of us old timers
out there that worked on 10 sear and then changed
them out even to 12 sear. We rolled out a unit
that could be three feet tall and three feet
wide. And we rolled in one that was four feet
tall. OK, you can literally slide the old condenser
inside the new condenser. And what it was is
we had these big, big coils. bigger surface area
on the outdoors. And so a lot of the efficiency
changed with the outdoor coil as it got bigger
and needed more surface area. Not only that,
but they were also reducing the compression ratio.
So they were reducing how high pressure to get
the right saturation temperature, the compressor
needed to go from low suction to high suction.
And the less, the lower we could change that,
then the more efficient the system was. All right.
Okay. So the old units, the way they designed
them, and we're going to look at design conditions,
95 degree outside with 75 degree inside. Okay.
We're not going to be looking at humidity. We're
not going to look at wet bulb because we're just
looking at. return air dry bulb temperature.
Dry bulb temps. Which everybody loves looking
at dry bulb. We can talk about wet bubble. Right.
So that's another invasive check, right? So one
thing you need to know is that, and there's a,
by the way, Brian Oro, his website has got a
very good chart that has all this listed on what
the air over condenser temperature ought to be.
I know it's also built with some apps out there
as well, but. The older units, the 8 SEER and
the 10 SEER units, they were designed so that
they had to bring the saturation temperature
of the refrigerant in the condenser 30 degrees
hotter than the outdoor air coming into it. That
way it would reject the heat out of the refrigerator.
Because remember, heat goes from hot. to cold
so we had to get that heat to move out of the
refrigerator into the air well think about it
you know we're trying to cool something off 95
degrees i don't know about you but if i take
a 95 degree shower i'm not going to be so cool
all right so but if i was 130 degrees then that
would feel really cool to me right so they designed
them so that it's saturation temperature we're
not worried about the pressure We want to know
what should the saturation temperature be? Well,
if it's a 10 -serie unit, 8 to 10, on average,
they designed them that they had to jack that
saturation temperature up to 30 degrees above
ambient. Okay. And it didn't matter the refrigerator.
We're not talking about whatever refrigerator
is in the system. So if you took a 10 -serie
unit, and if it was 95 degrees outside, I would
add 30. That would give me 125 degree target
saturation. Okay. I like it. And then following
there, you would just look at your PT chart.
You know, the old days we had them in our pockets.
Unfold it. And then one day somebody pointed
out that it was on my gauges as well. I just
ignored. I took without one big fat number. Yeah,
yeah, yeah. What's inside? That's actually saturation
temperature related to the pressure, right? So,
you know, you can get on your gauge and look
for the green circle, right, for R22. And that
pressure would be related to that saturation
temperature. And so now you know that in the
course of most of your 8 or 10 series are going
to be R22, right? So you would take, even if
it was a lower temperature, it doesn't matter.
You just add 30 to whatever the air temperature
is coming into that condenser. And be sure that
you measure the air temperature coming in. Careful,
you know, and I made these mistakes. I would
lay my thermometer or clip it to the grill. But
that grill and the coil can actually radiate
heat. Right out the middle. Never thought about
that. So I started holding it away from the condenser.
You know, you don't want to sit there and hold
it, you know, prop it up on your refrigerator
bottle or something, you know, just, you know,
keep it so that it's reading air temperature.
And don't go to the web, your phone, because
that's the weather station's temperature. You
know, that, you know, it's on the roof. We want
to know what it is on the roof. Add 30, and that's
where you are. So it doesn't matter. So any of
these older units, add 30 to the ambient. That's
what your saturation temperature ought to be.
And then it's as simple as converting that to
the pressure of whatever refrigerant is in that
unit, okay? Okay. So now let's look at the more
efficient units. Well, the more efficient they
got, the least amount of air over ambient they
need to make that saturation. Okay. So because
they're more efficient, right? So now we're reducing
the load of the compressor, which means they
can put smaller compressors in these units now.
And that's why the units got cheaper. Part of
it, yeah. So they would be able to get in there
with a smaller compressor, bigger coil, and get
the efficiency down. So now what we do is we're
going to take like a 14 SEER unit on average,
and even 14 SEER II would run around 20 degrees
above ambient, 20 degrees above ambient. And
if you took the ambient air and added 20, that's
what your new saturation temperature ought to
be. And at this case, if it was 95, it'd be 95
plus 20. So now your saturation temperature should
be 115, unlike the old one, which was 125. And
now you take that 115, you convert to head pressure.
Well, our new 14 CR2s have got R54B in them or
R32. And everybody wants to know, well, now what
should my new pressures be? You don't have to
worry about that. The question is, what should
my saturation temperature be? The same as it's
always been. Exactly. You're going to add 20
to 95, and that's on average where you ought
to be. And so 410A was that way, 454B is that
way, R32 is going to be that way. And whatever
other flavor of ice cream they stick in that
system. Nope. Who knows what it is? It's an application
issue, not a refrigeration. Exactly. Right. Now.
I've got a 20 sear. It runs 10 above ambient.
Okay. So the higher the efficiency, the narrower
that gap is, right? So now I've come across some
older 12 sear that were probably more like 13,
I would think. When I was installing 410A equipment
back in 97, 98, 99, to this day, on average,
I see them running around. 335, 340 head pressure.
Well, that actually comes out to be about usually
around 15 to 20 above ambient, but sometimes
15 above ambient. So what I look at is 20 is
the average, right? For a 14 to 15, 16 sear.
But if you're running a little bit lower than
that and your sub coolant's right, your superheat's
right according to your TXV, then you're just
running a little bit more efficient and that's
okay. You just don't want to see it more than
that. You don't want to see it more than 20 degrees
above ambient on these higher efficient units.
Well, let's think about that then for a minute.
So we've already got a saturation temperature
without putting our gauges on it. Could we measure
sub cooling based on the same principle? Absolutely.
So now we're getting into the magic that I love
about this. So if we know we've got everything
cleaned, everything's properly running right.
Then, yeah. So let's just go look at a newer
unit, 14 -0, 14 -0 -2. Again, doesn't matter
what figure's in that system. If you know in
our 95 -degree outdoor example, we add 20, we
know that our saturation should be 115. Well,
subcooling, let's say the unit's calling for
an average of a 10 -degree subcooling. The definition
of subcooling is any degree below saturated temperature.
That's right. And that way we know it's a liquid.
So one reason for subcooling is to make sure
it's a liquid. The second reason for subcooling
is to make sure we got the right quantity of
refrigerant in the system. So now if our required
subcooling is 10, then you go and measure the
liquid line and it should be 10 degrees cooler
than our saturated temperature. So if we have
105 degree liquid line, then that would be a
10 degree subcooling. You didn't even put any
gauges on it. So this is a good check on startup.
Oh, yeah, yeah. The condenser's clean as it'll
ever be. The evaporator's clean as it'll ever
be. You're going to verify airflow because that's
not guaranteed until you check it. And as long
as all that's right, you've got the cleanest
blowwheel you'll ever have, boom, you should
be able to really do a subcooler check without
throwing any gauge on it because the last thing
I ever want to do is put gauges on the system.
That's the last thing I ever want to do. But
if you need to, if you have to, the next question
is, what should my pressure be? Well, now we
know. Take that saturation. Take that temperature.
So because a lot of guys I know for their commission,
they got all the bat gear hooked up to it, right?
They got the pressure pros. They got the temperature
pros. And they got to do all that reporting.
Well, no problem. Now you know. I was just talking
to a group today, and I asked about their commission.
I said, what do you do when you commission it?
They said, well, we fill out that sheet that's
in the back of the installation guide. I said,
okay, you fill out the data, but what are you
comparative to? They had no standard to compare
their numbers to. And I said, when you go in
and get your blood pressure checked, the assistant
comes in and does the numbers, but the doctor
comes and interprets them. But when you're the
commissioning guy, guess what? You are the doctor.
You have to have a standard to go by. Now you
have a standard. Now you know. You know what
your subcooling ought to be because that's on
the side of the unit. But now you know what your
pressure is ought to be too. That's what you're
looking for. But you can do all this without
seeing any gauges on it and be confident that
you've got a charge system. Yeah, absolutely.
You know, when I was doing commercial refrigeration,
you know, we also took care of all of the HVAC
for the buildings as well. So I think some of
your larger grocery stores, right? You never
put gauges on a unit unless your sub cooling
was off, right? We'd walk around. What's the
ambient temperature? What's the discharge temperature?
What's the liquid line temperature? Move on to
the next one, right? These are all package units.
If they got brand new clean filters after we
clean the condensers, these things. should be
running in that ballpark, right? So that was
what we did with every unit. If it was off, then
we could get our gauges out and go determine,
all right, what's happening on this thing? But
we can still, we can go further than the sub
cooling. We could use this same philosophy and
move to the evaporator side of the unit. That's
exactly right. You can. So if you take that same
principle. and apply it to evaporator, the nice
thing about evaporators is that the efficiency
did not affect the evaporator saturated temperature
change. So we're always looking at return air
temperature minus 35. The evaporated coal should
be running 35 degrees colder than whatever the
return air temperature coming in is. With one
exception, it should never be lower than we know,
32 degrees. freezing up right exactly um and
i would like to get it that close right but we
run it we run it fairly close in the sense that
if we got an example of 75 degree return here
you subtract 35 and you're going to have a 40
degree saturated evaporator cool and that's that
gives you a good leeway for uh you're not going
to be freezing up the coil exactly and you'll
be dehumidifying as well as now The older units
ran a little bit colder. So anybody out there
that's working on some old R22 system, whatever,
10 sear. Yes, they would run more like a 40 degree
colder evaporated coal. So they kind of inch
that down closer at 32 degree mark. And but that
was the only way they really could get a good
dehumidification out of the air. Right. But now
that we can control the fan speeds and all the
efficiency. did bump up the required saturation,
but with, with our airflow, um, correct, then
we'll be okay. So, and we'll talk about that
in a minute, how we can change, check that out
in a basic way, but now we'll take the return
air. If it's 75, you minus 35, that's what your
saturation ought to be. Now you can convert that
to pressure, no matter what the refrigerant is.
Now you know what the pressure ought to be. Now
you can know what suction, uh, because Well,
in this example, if it's 75 return here, we minus
35, we had a 40 saturation. And so TXVs on average
will hold between a five and a 15 degree superheat.
That's an average. And then this is why most
people gravitate between 10 and 12 degrees superheat.
Because in the middle of that is about 10 or
12. Exactly. So with an EEV. is more precise
and it's much more specific. A lot of them I've
seen hold a nine, sometimes a six. You got to
look at the manufacturer to find out what their
EEV is calling for, but it's going to be pretty
much dead on. Okay. And so find out what your
super heat out to be. If it's a TXV. You're looking
for about, let's just pick 10 as a good average.
That's easy. All right. If that's the case, then
you know your saturation should be 40 at 10.
So your suction line leaving the evaporator should
be 10. Not a deep outdoor unit though. That's
what we're here for. Right. We're measuring actual
superheat at the coil. So you don't want to be
right next to the coil. I like to get at least
8 to 10 inches away from the connection, but
you want to be close to the evaporator core.
And, you know, there is an allowance, you know,
for superheat gain. But, you know, most of the
time, everybody's taking them right there to
condenser. Yeah. Right. And if it's typically
within the allowed refrigerant line length and.
it is properly insulated all the way down, then
you shouldn't lose too much, and you shouldn't
be pretty darn close, all right? Even if you're
within two degrees, you're still okay. You're
all right. But if you ever are concerned, then,
you know, measure the pressure, align the evaporator,
and then measure at the unit, and you can take
a check. By the way, if you want to know if you
have a restricted liquid line, just to give you
a little heads up, another invasive check is
to measure the liquid line temperature leaving
the condenser and then the liquid line temperature
entering the evaporator. You should have no more
than a two degree temperature change there. If
you've got more than two degree temperature drop,
you've got an excessive restriction. And I've
killed compressors due to that. Typically, we're
going to tie into from a 3 -8 to a 7 -16 behind
the siding of the house. And then it went back
up to a 3 -8 when they got in the attic and they
were hoping that little 15 -foot line wouldn't
be a problem. But it did. I had a 7 -degree temperature
drop on that line. That was terrible. That was
crazy. So, one more basin. Do you want to talk
about that? Let's do that. We've got a few minutes
left. Sure. If you have good airflow, excuse
me, if you have... proper airflow. Yeah. And
you have clean coils. And you have clean coils.
And you are confident. All those are good. One
last check is you can measure the dry bulb and
wet bulb drop across the evaporator. We want
to check this as close to the evaporator as possible.
Okay. We don't want any other influences on it.
We want to know what is that evaporator actually
dealing with. Okay. And this is where a lot of
guys miss. As a tech rep, A lot of times a unit,
they, you know, thought the charge was off, everything
was off. Before we threw on gauges, we measured
wet bulb and dry bulb across the evaporator.
This is akin to the temperature rise across the
furnace, okay? And it told me almost everything.
Because if all this other stuff is in line, the
wet bulb and dry bulb is literally the total
amount of heat that system is removing. And if
it's removing the right amount of total heat,
then all the other stuff's in play, okay? This,
and I got this straight from a carry engineer,
and you can plot this on a chart. But if you
have, and it's a ratio, between 16 to 18 degree
dry bulb, along with a 10 degree wet bulb drop.
If you got those two in line, so it's not just
dry bulb, which everybody looks at. Of course,
they think the more the better. That's not true,
right? If you got a 16 to 18 dry bulb. With a
10 degree wet bulb, that ratio right there is
dead on. It doesn't matter whether it's a two
ton unit or a 20 ton or 200 ton. If it is an
air cooled air conditioning application, those
two ratios will be there. And you can do the
reverse if you check those first. Honestly, everything
else. Yeah, exactly. The other one you can check
is the temperature rise method, the sensible
heat method at the condenser. All right. You
can look up. It's an axial fan. Yep. You can
look up the CFMs of that fan in the data for
the outdoor unit. You can measure the temperature
coming in, temperature going out. Now, you're
going to have motor heat and compressor heat.
Understood. So you're going to be rejecting a
little bit more heat than it's rated at. But
you could actually use the same formula you do
for strip heat and use that across the condenser.
and get a pretty good idea if it's like a three
ton unit it should be protecting at least 36
000 and if you had compressor and motor in there
then you should be rejecting a little bit more
than 36 000. that's right but if it's reduced
if it's if it's reduced you know producing less
than that then you got a problem that's another
quick check too love it all innovatively using
temperatures alone joey where can we learn more
about uh you and your training Well, if you go
to Jojo the HVAC man, and it is J -O -E, J -O
-E, the HVAC man. If you do the other one, you're
going to get some turkey, and I'm just kidding.
I'm just kidding. But J -O -E, J -O -E, the HVAC
man. Go to my YouTube channel. I've got some
training there. You can go to my TikTok channel.
I've got a lot more training there that seems
to be a biggie these days. But also, I love doing
remote training. I travel all over the country
doing training on sites at conferences. And I
do a lot of webinars as well. I'd love to talk
to anybody that would love training. I love training.
I love helping other people. And just reach me
through there. You can also hit me up on jojothehpacman
at gmail .com. Awesome. I appreciate you joining
us today. Everybody have a great day. Thank you,
Clifton.