Our Attendees Demonstrate What They Learn – 2025

Hi, my name is Adel, and I would like to explain the metering device and what it does.

How the Metering Device Works

Okay, there’s a sensor bulb, and it goes over here, and the sensing bulb goes over here.

What happens is:

• When the compressor releases high-pressure liquid, it flows into the metering device.
• From there, the refrigerant slowly flows through, with 80% liquid refrigerant and 20% vapor.
• The sensor bulb detects the temperature.
• If everything is working correctly, the refrigerant turns into 100% vapor before going back to the compressor as low-pressure, low-temperature vapor.

Since the compressor doesn’t take liquid refrigerant, the metering device is essential for controlling the refrigerant flow and ensuring that only vapor reaches the compressor.

How to Test if the Metering Device is Working

If you’re not sure if the metering device is working, you can test it by following these steps:

1. Remove the sensing bulb from the system.
2. Place it in hot water.
3. Check the pressure gauge:
   • If the pressure on the gauge doesn’t move, that means the metering device is bad.
   • If the pressure changes, the metering device is still good and working properly.

Final Thoughts

That’s the reason for the metering device—it controls the refrigerant flow and ensures the compressor only gets vapor.

Hope this helps! Thank you!

Hi, guys! This is Alisia with HVAC Technical Academy, and today I’m going to be talking about a condenser fan motor.

What is a Condenser Unit?

First off, I just want to show you guys what a condenser unit is. This is the outdoor unit of an HVAC system—the outdoor condensing unit of the HVAC system.

This is what houses the condenser fan motor.

What Does the Condenser Fan Motor Do?

The condenser fan motor turns the blades just like this. But inside, it pulls air across the condenser coils, circulating air around the condenser coils.

It condenses high-pressure, high-temperature vapor into a high-pressure, high-temperature liquid.
This process transfers heat from the refrigerant system.

So, that’s pretty much what a condenser fan motor does.

How to Tell if Your System is in Cool or Heat Mode

Right now, this is a non-operating condenser unit, but if it were running and you placed your hand across the top, you would feel it blowing out hot air.

That is an indication that your system is in cool mode.
If you place your hand on top and it is blowing out cooler air, that means your system is in heat mode.
Types of Condenser Fan Motors

This right here is an Original Equipment Manufacturer (OEM) fan motor.
This one is a universal fan motor, meaning this one will cost a little more than the OEM.

What to Check When a Condenser Fan Motor Goes Bad

These fan motors do go bad. If yours stops working, the first thing I would check is the capacitor, because replacing a capacitor is much cheaper than replacing the entire condenser fan motor.

And yeah, that’s all about an outdoor condenser fan motor!

Have a good day, guys!

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Hello, this is Arthur from HVAC Technical Academy, and they’ve invited me to give you some basic knowledge about capacitors.

We see two here right now—this is a dual capacitor, and this one here is a singular capacitor. Since this one has a lower microfarad (MFD) rating, you will see that logically, as you begin to understand this, it is measuring for the fan.

This one right here is a dual capacitor because it is dealing with both the fan and the compressor.

Where Will You See It in the System?

This is a heat pump, and you’re going to see the capacitor right here, basically in the corner.

Capacitors come in different sizes, but what you want to focus on specifically is the microfarad rating (MFD).

To put it as simply as possible:

• The 70 MFD is always going to be dealing with the compressor.
• The 7.5 MFD is going to be dealing with the fan.

How to Hook It Up

When you install and hook it up, as you see here, these plugs are labeled so that you can understand where the common wire goes to the fan.

Testing a Capacitor

Now, I want to share with you a little about testing, not operation—just testing to see if it’s in operative mode.

• When you buy a capacitor from the store, you always want to test it first to make sure it’s effectively operative.
• If the measurement is not according to the 70 or 7.5 MFD, it could go over by five or under by five, and that’s acceptable.
• But if it goes below five in the measurement, using this clamp meter, then there is something wrong with the capacitor.

Signs of a Bad Capacitor

You will also see trouble with the capacitor when it is bloated out—more than likely, that means the capacitor has overheated.

• If you see a bulging or balloon-like top, you’ll know this is a bad capacitor.
• What do you do? You have to replace it with the same microfarad rating (e.g., 70 or 5 MFD).
• Some capacitors are 45+5 MFD, so you will need to match the measurement you need.

Quick Test Process

• You are going to use this device (meter) and start from Common to Fan.
• Check the measurement here for microfarads (MFD) while it is not in operation.
• When you test Common to Fan, you should see 7.5 MFD—if so, it’s up to par.
• Then, go back to C and Herm (Hermetic)—hermetic means the compressor is hermetically sealed.
• If you see 70.5 MFD, that is acceptable because it can go over or under by five.
• However, if it goes too high or too low, something is wrong with the capacitor.

Final Thoughts

So, that in a nutshell is the most basic way to test a capacitor to see if it’s in operative mode.

Again, this is not about operation—when you install and connect it, that’s a whole different ball game.

• You’re going to be using clamps to measure voltage and amps, and that’s a different lesson for another class.

Hopefully, you guys enjoyed this—it’s basic information that you need to know.

If you’re in an HVAC class, especially at HVAC Technical Academy, they’re going to test you on this, so it’s important to have some basic understanding of capacitors.

Thank you guys for listening! I’ll catch you some other time—maybe I’ll be teaching something else like a compressor or something.

Have a good day!

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Good afternoon, you guys! My name is Christopher H., and I’m at HVAC Technical Academy.

Today, I want to talk about this little device right here called the reversing valve. The reversing valve is located on the outside of the condensing unit. You can probably find it around here, but it can vary depending on different unit types.

Understanding the Reversing Valve

I would recommend learning refrigeration before getting too in-depth with the reversing valve because it’ll give you a better understanding of what it does. But to make a long story short, a reversing valve is what reverses the flow of refrigerant.

• If you’re in cooling mode and switch to heat, it’ll basically switch the cycle around.
• This means it’ll put your cool side where your heat side is.
• If you can see this—and if you’re not color-blind, you feel me—just follow the arrows and see how everything flows.

What it does is reverse the refrigerant flow back and forth through these tubes.

How the Reversing Valve Works

To go more in-depth:

• Refrigerant goes in through the top and comes out through the bottom, distributing it through the other parts of the refrigeration cycle.
• Inside, there’s a shifter that you can’t see, but that shifter moves the refrigerant left and right.
• What makes the shifter move? Pressure.

The Role of the Solenoid

That pressure comes from this smaller device right here called the solenoid.

• Basically, what you see here is what’s inside the reversing valve, just in a much smaller form.
• When the solenoid is energized, it sends a pressure signal back to the reversing valve, making it shift left or right.
• And like I said, all it’s doing is reversing the flow of refrigerant to match the setting you have it on.

So, that’s basically what a reversing valve does in short.

My name is Christopher, I go to HVAC Technical Academy, and I gotta thank Danny, gotta thank everybody, and of course, thank you guys!

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Hello, my name is Desmond, and we’re at HVAC Technical Academy. I’m going to tell you about your compressor.

An air compressor is a pneumatic device that converts mechanical power into compressed air, which can be used to power your outdoor condenser unit.

Where is it located?

It is usually found in the outdoor unit of your air conditioning system, either on the side or at the rear of the house.

How does it work?

The compressor squeezes refrigerant gas molecules together, which increases the refrigerant’s temperature and pressure.

Also, this is the heart of your unit. If you need to get it replaced, in most cases, it would be better cost-wise to replace the whole unit rather than just the compressor.

Thank you for watching! Anything else you need to know? Ask Google!

That was quick—okay, let me make sure.

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Hello, guys! My name is Jorge, and I’m here at HVAC Academy. I’m going to break down what nomenclature is.

So, here we have a Carrier unit condenser, and the main things about your nomenclature are your model number and your serial number.

Understanding Model and Serial Numbers

First off, the model number is going to give you the type and size of your unit. The serial number is going to give you the year and week the unit was manufactured.

For example, let’s look at the serial number on this unit. It reads 0218, followed by other letters and numbers. What does 0218 tell me? It tells me that this unit was manufactured in the second week of 2018.

Now, moving to the model number, I try to look for the big numbers. This one reads 25HCC5 4883. I stop at 48—what does that mean? The 48 tells me the unit has 48,000 BTUs.

To calculate the tonnage, you divide 48,000 BTUs by 12,000 BTUs:
48,000 ÷ 12,000 = 4
This tells me that this is a 4-ton unit.

Another Example: A Lennox Unit

I want to show you another unit over here—this is a Lennox.

Looking at the model number, I find 60—this tells me that it has 60,000 BTUs. To determine the tonnage:
60,000 ÷ 12,000 = 5
This means this is a 5-ton unit.

Now, looking at the serial number, I see it says 11919. What does that tell me? It tells me that this unit was manufactured in the 19th week of 2019.

One More Example: Another Carrier Unit

I want to show you one more unit—follow me!

Looking at this Carrier condensing unit, I check the serial number. It starts with 1N15. Again, what does this tell me? This tells me that this unit was manufactured in the 19th week of 2015.

Next, I go down to the model number and find 30. I assume that means this is a 30,000 BTU unit. To calculate the tonnage:
30,000 ÷ 12,000 = 2.5
So, this is a 2.5-ton unit.

Final Thoughts

If you’re not familiar with nomenclature, take a picture of the label, Google it, and it will tell you exactly what the unit is.

Thank you! I’m Jorge from HVAC Technical Academy.

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Hi, my name is Monique, and I’m at HVAC Technical Academy. Today, we’re going to be talking about the thermostat—what the letters stand for, what it does, and how it operates.

I’m going to take off the covering of the thermostat right here. It has the letters that indicate how it functions and what each one does.

• R – 24 volts, which is the power
• G – The blower motor
• Y – The contactor that calls for the condenser motor fan
• C – The common, which is the ground
• O – Reverse valve
• If it’s a heating system, it will have:
  • B – A heat pump that energizes in heat mode
  • W – Heat strip
  • W/E – Emergency heat
  • W2 – Stage two

Testing the Thermostat for Power

To test if your thermostat has power, you’re going to check R to Y, which calls for the condenser motor fan on the outside. If it’s not working properly or if there’s no low voltage on the contactor, that could indicate a problem.

That’s all I know for now about thermostats. I hope I gave you enough information.

Thank you!

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All righty, hello there! My name is Pedro, here at HVAC Technical Academy, and I will be showing you guys how to test a transformer and how one works.

So, this right here is a transformer. As you can see, we have two—one right here and one right here. The reason we have two in this system is because, let’s say, it’s for a two-story house. This transformer right here will be controlling this zone board.

How a Transformer Works

A transformer has two legs of power—120V, which bumps up to 240V on the transformer. Then, it bumps it down to 24V for things like your thermostat relays, boards, and other low-voltage components.

How to Test a Transformer

To test it, we grab our multimeter and set it to VAC. I’ll set it here so you can see.

• Then, we’ll grab our two leads (two prongs) and place one on Common and one on 240V.
• As you can see, we’re getting 242V—it’s okay to get a little over or a little below, but not too much.

Now, we’re going to test our low-voltage side, which would be the other side for things like our thermostat.

• You would go to the back side, put a probe here, and another probe right here.
• As you can see, we’re getting 27V—that is good!

And that, ladies and gentlemen, is how a transformer works and how to test it.

Thank you!

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Hello, my name is Stephanie, and today I’m going to tell you how a contactor works and how to test one.

As you can see, in this case, we’re looking at the condenser, and the contactor is located here, which is usually found in the casing that covers the capacitor and the U contactor, where the high voltages come in and everything.

Okay, so before you test anything, you definitely want the power off—you want to be safe, okay? Sometimes that can mean power on or power off, but in this case, since this system isn’t connected, we’re going to learn how to check it with the power off.

What Does a Contactor Do?

First of all, the contactor allows the electricity to pass through and power whatever device or wire the thermostat calls for.

For instance, if we need to turn on the fan blower motor, this bad boy here will click in, allowing the energy to pass through, hit the capacitor, and the capacitor will start and run whichever device the thermostat called for that has to do with the condenser, in this case.

How to Test a Contactor

Usually, when you test a contactor, you want to test it in Ohms, all right?

If you don’t know what Ohms are, you can take a quick look at this thing right here—our metering device. I always say look for the one that looks like the horseshoe. You see it there? Zoom in—little horseshoe—all right?

To test it, set your sticks on your machinery condenser, and you pretty much want to place your point on the little screws here—on the bottom and the top.

Do it this way—you’re not going to get anything, okay? So, you want to do it here and here. This is basically checking for continuity.

And when you press this in—uh-oh, what happened? There you go! Switch over! Sorry about that.

When you press this bad boy in—there you go—I gotta stick it on there, you guys!

As you can see, this contactor works. CU, you’re hearing that hum noise because the energy is now flowing through. It’s not—It is now—It is not.

This side is the side that has the part that basically does not transfer the electricity all the time.

But as you can see here, this side does not have the push-in device, which means this side always has continuity, all right? Because it’s always going to be providing power.

Final Thoughts

Want to know more information about a contactor? Google it!

But overall, those are your basics.

Thank you!

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Hey everyone, Breezy here from HVAC Technical Academy! Just a quick reminder—learning to use tools properly in the lab is just as important as practicing safety while doing it. New attendees are getting hands-on experience with essential HVAC tools, all while following the safety guidelines that will keep them and their team protected on the job.

Remember, safety isn’t just a rule—it’s a habit that sets you up for success in the field. Keep practicing, stay sharp, and always put safety first! See you in the lab! 🔧⚡ #HVACTechnician #HVACTraining #SafetyFirst