HVAC Training Videos: Ultimate Tech Guide for 2026

Welcome to the world of HVAC. It’s a field filled with complex systems, specialized parts, and the satisfying challenge of making things work. To succeed, a technician needs to understand not just what each component does, but how they all work together. This guide breaks down the essential topics you need to master. Whether you are a new tech or a seasoned pro, think of this as a roadmap, and remember that quality hvac training videos can be your best tool for visualizing these concepts in action. For deeper dives into fundamentals, explore our HVAC category.

The Heart of Cooling: Refrigeration and DX Systems

Every cooling system, from a window AC to a commercial freezer, operates on the same core principles. Understanding this cycle is the foundation of all HVAC work.

Refrigeration Components and Theory

At its core, refrigeration is the process of moving heat from where it’s not wanted to where it’s less of a problem. This is achieved through the vapor compression cycle, which relies on four main components: the compressor, condenser, expansion device, and evaporator.

1. Evaporator: Low pressure liquid refrigerant boils into a gas, absorbing heat from the indoor air.

2. Compressor: This is the heart of the system. It takes the low pressure gas and compresses it into a high pressure, high temperature gas.

3. Condenser: The hot gas releases its heat to the outside air and condenses back into a high pressure liquid.

4. Expansion Device: This component creates a sudden pressure drop, causing the high pressure liquid to become a very cold, low pressure mix of liquid and vapor, ready to enter the evaporator again.

Understanding how pressure and temperature are related for different refrigerants is key. For example, a system with air trapped inside will show abnormally high head pressure, hurting performance. Grasping this theory is the first step toward effective troubleshooting.

DX System Troubleshooting and Repair

DX, or Direct Expansion, is the most common type of system you will encounter. Troubleshooting it means methodically checking each part of the cycle. You start by verifying airflow (clean filters, running fans) and then move to the refrigerant side. Key indicators like superheat (heat added to the vapor after boiling) and subcooling (heat removed from the liquid after condensing) tell you the system’s story.

Undercharged AC Diagnosis

One of the most common issues in a DX system is an undercharge, which means there is a refrigerant leak. The symptoms are classic:

• High superheat: There isn’t enough refrigerant to boil off properly in the evaporator.

• Low suction pressure: Less refrigerant means lower pressure on the low side of the system.

• Low subcooling: The condenser has less refrigerant to work with, so it can’t cool the liquid down as much after it condenses.

Finding and fixing the leak, then properly evacuating and recharging the system by weight, is the only correct repair. If you’re preparing for Section 608, review our EPA certification resources alongside detailed hvac training videos on leak detection.

Controlling Refrigerant: Metering Devices

The expansion device is the gatekeeper that controls how much refrigerant enters the evaporator. Problems here can mimic other system faults, making them tricky to diagnose.

Capillary Tube Repair and Brazing

A capillary tube is a simple, fixed metering device, essentially a very long, thin copper tube. Its tiny inner diameter means even a small piece of debris can cause a major restriction. When a cap tube is partially clogged, you will often see frost form right at the blockage.

Repairing one requires precision. The new tube must have the exact same length and diameter. Brazing it into the system is delicate work, as too much heat can easily plug the tiny opening. Technicians always purge nitrogen gas through the lines during brazing to prevent internal oxidation, which could create scale and cause another clog.

Electronic Expansion Valve (EEV) Testing

An EEV is a modern, smart metering device that uses a small motor to precisely control refrigerant flow. To test an EEV, you check both its electrical and mechanical function.

• Electrical Check: Use a multimeter to measure the resistance of the motor’s windings. An open or shorted winding means the EEV motor is bad.

• Functional Check: See if the valve is actually controlling superheat. If the EEV is stuck closed, you will see high superheat and low suction pressure. If it’s stuck open, the evaporator will flood with refrigerant, causing superheat to drop to zero, which is very dangerous for the compressor.

All About Heat: Furnaces and Defrost Controls

When the weather turns cold, your focus shifts to heating systems. Gas furnaces and heat pumps have their own unique components and common problems. This is another area where hvac training videos can be invaluable for learning the sequence of operations and brushing up on safety best practices.

Gas Furnace Overview

A gas furnace uses burners to heat a metal chamber called a heat exchanger. A blower fan pushes air across the hot exterior of the heat exchanger, warming the air before sending it through the ducts. The combustion gases, including carbon monoxide, are safely kept inside the heat exchanger and vented outside. Modern high efficiency furnaces have a secondary heat exchanger to pull even more heat from the exhaust gas, achieving over 90% efficiency.

Flame Sensor Troubleshooting

A flame sensor is a critical safety device. It’s a small metal rod that confirms the burners have lit. If the control board doesn’t get a signal from this sensor, it shuts off the gas to prevent a dangerous situation. The most common furnace problem, by far, is a dirty flame sensor. In fact, some reports show nearly 75% of winter furnace issues stem from dirty or faulty flame sensors.

Troubleshooting is usually simple:

1. Turn off the power.

2. Remove the sensor.

3. Clean the metal rod gently with light steel wool or an abrasive pad.

4. Reinstall it.

If cleaning doesn’t work, you can test the sensor with a multimeter that reads microamps. A healthy flame signal is typically between 1 and 5 microamps.

Defrost Control Board Diagnosis

In winter, the outdoor coil of a heat pump can frost over. The defrost control board is the brain that tells the system when to melt this ice. If a board fails, the unit might become a solid block of ice, or it might get stuck in defrost mode, blowing cold air inside. Diagnosis involves testing the board’s sensors and forcing a test cycle to see if the board properly energizes the reversing valve and shuts off the outdoor fan.

Power and Air: Motors and Electrical Testing

No HVAC system runs without electricity and airflow. Understanding motors and knowing how to use a multimeter are non-negotiable skills for every technician. See our electrical category for step-by-step multimeter tips.

Indoor Fan Motor Open Winding Diagnosis

An open winding means a wire inside the motor has broken. The symptom is straightforward: the fan won’t run at all. To diagnose it, you turn off the power and use a multimeter to check the resistance between the motor’s common wire and its speed wires. A good winding will show a few ohms of resistance. If your meter reads infinite resistance (often displayed as OL), that winding is open, and the motor needs to be replaced. A blower motor that stops running without tripping the breaker is a classic sign of an open winding.

Motor Overload and Safety

Motor overload is when a motor draws too much current because it’s working too hard, causing it to overheat. This can be caused by a dirty filter restricting airflow, a seized bearing, or low voltage. To prevent damage, motors have built in overload protectors that act like a circuit breaker. If a motor is constantly tripping its internal overload, you will notice it shutting down and restarting after it cools. The key is to find and fix the root cause, not just reset the power.

Multimeter Testing (Continuity, Resistance, Diode)

Your multimeter is your best friend for electrical diagnosis.

• Continuity: This test tells you if a circuit is complete. It beeps if there’s a path for electricity to flow. It’s perfect for checking fuses, wires, and switches.

• Resistance (Ohms): This measures how much a component resists electrical flow. You use it to check motor windings, heating elements, and sensors like thermistors.

• Diode Test: This checks components that should only allow electricity to flow in one direction. It’s useful for diagnosing issues on electronic control boards.

Thermistor Testing and Splicing

A thermistor is a type of resistor whose resistance changes significantly with temperature. They are used as sensors all over HVAC systems. To test one, you check its resistance with a multimeter and compare the reading to a temperature and resistance chart from the manufacturer. If the reading is way off or shows an open circuit, the thermistor is bad. When replacing and splicing a thermistor, it’s crucial to use weatherproof connectors to protect the connection from moisture, which can alter the resistance reading and confuse the control board.

Maintenance and Procedures: The Pro’s Approach

Great technicians are not just good at fixing things, they are systematic and thorough in their approach to every job. Following proper procedures ensures safety, efficiency, and customer satisfaction. The best hvac training videos often focus on these crucial procedures.

Maintenance Service Checklist

A maintenance checklist is a technician’s guide to a thorough tune up. It ensures nothing gets missed. Key tasks include:

• Replacing air filters

• Cleaning condenser and evaporator coils

• Checking refrigerant charge

• Measuring motor amperages

• Cleaning the condensate drain line

• Testing safety controls

• Tightening electrical connections

Following a checklist not only improves system reliability but also helps identify small problems before they become major breakdowns. For example, simply replacing a clogged filter can lower an AC’s energy consumption by 5% to 15%.

Commercial HVAC/R Tune Up and Troubleshooting

Commercial systems are bigger and more complex, but the principles are the same. A tune up is critical because these systems are often mission critical for a business. For checklists and procedures, visit our commercial HVAC maintenance hub. Commercial troubleshooting is highly systematic. Technicians use checklists and follow a logical path, starting with the simple things (power, settings) before moving to complex diagnostics. An iced over coil in a walk in freezer, for example, would lead a tech to diagnose the entire defrost system, from the timer to the heaters and sensors.

Drain Line Installation and Troubleshooting

Every air conditioner produces water (condensate). The drain line’s job is to get that water outside or to a drain. Proper installation requires a continuous downward slope and a P trap to prevent air from being pulled back into the unit; for drainage basics, see plumbing fundamentals. The most common problem is a clog from algae and slime buildup, which causes water to back up and overflow. This is one of the leading causes of water damage from indoor AC units.

Common Drain Cleaning

Cleaning a condensate drain is a simple but vital maintenance task. You can use a wet dry vacuum to suck the clog out from the drain’s termination point outside. You can also use pressurized nitrogen or CO2 to blow the clog out. Pouring a cup of distilled white vinegar down the line once or twice a year can help prevent algae from growing in the first place.

Low Pressure Cutout Troubleshooting

A low pressure cutout is a safety switch that shuts off the compressor if the suction pressure drops too low. This protects the compressor from damage due to a refrigerant leak or a frozen evaporator coil. When this switch trips, a technician connects gauges to see what the actual pressure is. If the pressure is truly low, they investigate the cause, like a leak or a restriction. If the pressure is normal but the switch is open, the switch itself may be faulty.

Service Call Standard Operating Procedure

A standard operating procedure, or SOP, for a service call ensures a professional and effective visit every time. It includes greeting the customer, listening carefully to their description of the problem, performing a thorough diagnosis, clearly explaining the issue and the solution, performing the repair safely, and testing the system completely before leaving. Sharpen your customer communication with our soft skills guides.

Thermal Imaging Camera Training

A thermal imaging camera is a powerful diagnostic tool that allows you to see heat. In HVAC, it can instantly show you air leaks in ductwork, hot spots on an electrical panel, or uneven temperatures on a condenser coil that indicate a blockage. Proper training is needed to understand how to interpret the images and adjust for factors like surface emissivity to get accurate readings. You can also explore our advanced training for techs for IR camera best practices. Many modern hvac training videos now include modules on using this technology.

The HVAC field is constantly evolving, but the fundamentals of thermodynamics, electricity, and airflow remain the same. Continuous learning is the key to staying sharp and effective. If you’re looking to turn this knowledge into hands on skill, consider exploring an online learning platform. For instance, you can find many hvac training videos and interactive simulations in SkillCat’s online HVAC training programs that cover these topics in depth.

Frequently Asked Questions

1. What are the best HVAC training videos for beginners? For beginners, the best hvac training videos focus on the fundamentals. Look for content that clearly explains the refrigeration cycle, basic electrical theory, and tool safety. Topics like “How a Thermostat Works” or “The Four Main Components of an AC” are great starting points.

2. Can I learn HVAC troubleshooting from videos alone? Videos are an excellent resource for understanding concepts and seeing procedures demonstrated. However, true mastery of troubleshooting comes from combining that knowledge with hands on practice. Use videos to learn the theory, then apply it in a safe, controlled environment or a lab setting.

3. Do HVAC training videos cover commercial systems? Yes, many resources offer specialized hvac training videos for commercial refrigeration and large scale HVAC systems. These videos cover topics like three phase power, rooftop units, chillers, and building automation systems, which are more complex than residential equipment.

4. How can I verify the information in an HVAC training video is accurate? Look for videos from reputable sources, such as established training schools, equipment manufacturers (like Carrier or Trane), or well known industry experts. Cross referencing information with service manuals and industry textbooks is also a good practice to ensure accuracy.