HVAC Trade Program — Week 18
Gauges, Temperatures & Don’t Touch the White Walls
Saturday, August 22, 2026
Welcome to Week 18 of the Klein Cooling HVAC Trade Program.
If you’re one of our students, you already know how this works.
If you’re thinking about joining a future class — or you’re one of our customers wondering what exactly goes on around here every Saturday — come sit in on class with us.
This isn’t meant to be a textbook.
It’s a look inside what we’re actually teaching, what we’re working on and what we’ve learned from another week of doing HVAC for real customers.
Because we’re not just trying to teach somebody how to work on an air conditioner.
We’re trying to teach them how to become a good HVAC technician.
There’s a difference.
This Week in the Field
We start every class by talking about what happened during the week.
Real service calls.
Real installations.
Real customers.
Real mistakes.
Real victories.
Sometimes we found something weird.
Sometimes another technician taught us something.
Sometimes we got something wrong.
Sometimes a customer asked a really good question.
Sometimes the lesson has absolutely nothing to do with HVAC equipment.
That’s intentional.
Because sometimes Tuesday’s service call teaches Saturday’s lesson.
We want our students hearing these stories now — while they have a room full of people to talk through them with — instead of encountering everything for the first time when they’re standing alone in someone’s garage.
What Are We Doing This Week?
This week we split the class up for hands-on work.
One group worked on brazing copper.
The other group worked on an outdoor condenser, where they:
- Replaced a capacitor
- Replaced a contactor
- Removed old spade connectors
- Installed and crimped new spade connectors
- Inspected their electrical connections and workmanship
Then we came back together for this week’s classroom topics:
Analog Refrigerant Gauges
Low-Loss Fittings
Airflow Temperatures
None of this sounds particularly glamorous.
That’s okay.
The fundamentals aren’t supposed to be glamorous.
They’re supposed to keep you from doing dumb stuff later.
Analog Gauges: Learn What You’re Actually Looking At
Digital refrigerant gauges are awesome.
We use them.
Modern digital tools can calculate things for us, display multiple measurements and make diagnosing equipment considerably easier.
But we’re learning analog gauges too.
Why?
Because I want our students to understand what they’re actually looking at instead of just reading numbers off a screen.
Which gauge is the low side?
Which is the high side?
Why is the low-side gauge called a compound gauge?
What do all those numbers mean?
Why are there different refrigerant scales?
What is saturation temperature?
What happens to saturation temperature when pressure changes?
And eventually:
How do those measurements help us understand what is happening inside the refrigeration system?
Most importantly:
Pressure alone does not diagnose an air conditioner.
We’re going to say that one a lot.
Gauges give us information.
A technician still has to understand what that information means.
Low-Loss Fittings: Keep the Refrigerant in the System
We’re also talking about low-loss fittings.
If you’ve ever disconnected a refrigerant hose incorrectly and received an unexpected blast of refrigerant, congratulations.
You now understand why we’re discussing this.
Connecting gauges isn’t a race.
Neither is disconnecting them.
Know what you’re connecting.
Know what you’re opening.
Know what you’re closing.
Understand what’s under pressure.
Take your time.
Use the proper equipment.
We’re trying to measure the refrigerant.
We’re not trying to wear it.
Your fingers will appreciate this lesson.
Airflow Temperatures: Start With the Basics
We’re also working with one of the simplest diagnostic tools an HVAC technician owns:
A thermometer.
What’s the temperature of the air entering the equipment?
That’s our return-air temperature.
What’s the temperature of the conditioned air leaving the equipment?
That’s our supply-air temperature.
The difference between those measurements gives us our temperature split, commonly called Delta T (ΔT).
Simple measurement.
Very useful information.
But there’s an important word there:
Information.
A temperature split isn’t automatically a diagnosis.
A certain Delta T doesn’t mean:
“Yep. Everything’s perfect.”
And a strange Delta T doesn’t automatically mean:
“Needs refrigerant.”
We’re collecting clues.
Temperatures tell us something.
Pressures tell us something.
Superheat and subcooling tell us something.
Airflow measurements tell us something.
Electrical readings tell us something.
The technician’s job is learning how those pieces fit together.
That’s troubleshooting.
Hands-On: Brazing
You can watch someone braze.
You can read about brazing.
You can watch 400 YouTube videos about brazing.
Eventually…
You have to light the torch.
There’s really only one way to get comfortable brazing copper:
Do it.
Then do it again.
Make an ugly joint.
Look at it.
Figure out why it sucks.
Do another one.
Eventually your hands start understanding what your brain has been trying to tell them.
That’s why this program isn’t just classroom instruction.
Repetitions matter.
Hands-On: Capacitors, Contactors & Spade Connectors
Our other group worked on an outdoor condenser.
They replaced a capacitor and a contactor — two components an HVAC service technician is going to encounter constantly.
But we also had them replace the spade connectors on the wiring.
That might seem like the least important part of the exercise.
It isn’t.
We’re not teaching:
“Put the wire back.”
We’re teaching:
Make the connection correctly.
Use the proper connector.
Make a good crimp.
Pull on it.
Inspect it.
Route the wire properly.
And when you’re finished, make it look like somebody who gives a crap worked on it.
Because someday another technician is going to open that panel.
They’ll know.
Stuff That Isn’t in the Manual
This is another part of class every week.
There isn’t necessarily a chapter for it.
There won’t be a test on it.
But it matters.
You can be fantastic with a meter and still be a terrible service technician.
So we talk about the other stuff too.
Use a drop cloth.
You’re in somebody else’s home.
Treat it that way.
Clean your fingerprints off the wall.
Yes.
We actually have to discuss this.
If you’ve been working on an air handler and your hands are filthy, perhaps the customer’s white wall isn’t the ideal place to put them.
And if you do?
Clean it.
Clean up after yourself.
The homeowner shouldn’t have to clean up after the technician they just paid.
Talk to customers like normal human beings.
You don’t need a ridiculous sales script.
Explain what you found.
Show them when you can.
Give them their options.
Answer their questions.
Don’t pretend you know something you don’t.
There is absolutely nothing wrong with saying:
“I don’t know. Let me find out.”
That’s infinitely better than confidently making something up.
We have manuals for a reason.
We have technical support for a reason.
We have other technicians for a reason.
Nobody knows everything.
Give a crap.
This might be the biggest one.
Care about your workmanship.
Care about the customer’s house.
Care whether you actually fixed the problem.
Care about the technician who has to work on it next.
Care enough to learn when you don’t know something.
You can teach somebody how to change a capacitor pretty quickly.
Teaching someone to care whether they did it correctly is the bigger lesson.
What Should a Student Know After Week 20?
We’re not expecting mastery after one Saturday.
We’re building skills.
By the end of Week 20, our students should be more comfortable with:
- Identifying and reading an analog manifold gauge
- Understanding basic pressure and saturation-temperature relationships
- Understanding the purpose of low-loss fittings
- Measuring return and supply temperatures
- Calculating temperature split
- Brazing copper
- Replacing basic condenser electrical components
- Making and inspecting electrical connections
But we’re also trying to build something that isn’t as easy to put on a checklist.
Confidence.
Not fake confidence.
Not pretending you know everything.
The confidence that comes from actually putting your hands on equipment, making mistakes, asking questions and doing it again.
We’re Not Just Teaching Air Conditioning
The goal of this program isn’t to produce somebody who knows how to change a capacitor.
We’re trying to develop HVAC technicians.
People who can troubleshoot.
People who understand why they’re taking a measurement.
People who know how to use their tools.
People who can admit when they don’t know something.
People who keep learning.
People who communicate with customers.
People who respect someone’s home.
People who take pride in their work.
And people who understand that sometimes the difference between a good technician and a bad customer experience has absolutely nothing to do with the air conditioner.
Sometimes it’s explaining what you’re doing.
Sometimes it’s cleaning up after yourself.
Sometimes it’s putting down a drop cloth.
And sometimes…
it’s wiping your dirty fingerprints off the friggin’ wall.
Welcome to HVAC.
See You in Week 19
We’re documenting the Klein Cooling HVAC Trade Program week by week here inside A/C University.
Over time, the topics you see in these weekly classes — electrical, refrigeration, airflow, brazing, troubleshooting, tools and everything else — will become their own deeper A/C University lessons.
Students will be able to use them for review.
Future students will be able to see exactly what they’re signing up for.
And our customers will get to see how we’re training the next generation of technicians who may someday work in their homes.
If you’re already in the trade and something we put here helps you?
Use it.
Good information should be shared.
And if you’re thinking about joining a future class?
Start with Week 1.
We’ll show you exactly what we do here.