HVAC Fundamentals

Heat Transfer

Conduction, convection and radiation, and why every HVAC system is really a heat moving machine.

Concepts

The Refrigeration Cycle

How a vapor compression system moves heat from where it is not wanted to where it can be rejected.

Concepts

Superheat and Subcooling

The two measurements that tell you how a refrigerant circuit is really being fed and drained.

Concepts

Temperature and Heat

Temperature measures intensity, heat measures quantity. Confusing the two is the root of many bad diagnoses.

Concepts

Gas Furnace Sequence of Operation

Step by step through a call for heat on a modern induced draft furnace, and what each step proves.

Concepts

Pressure and Temperature Relationship

Why a pressure reading tells you a saturation temperature, and how technicians use that link every day.

Concepts

Ignition Systems

Standing pilot, intermittent pilot, hot surface and direct spark ignition, and how each proves flame.

Concepts

States of Matter and Phase Change

Why refrigeration uses boiling and condensing rather than simply moving warm and cold fluid around.

Concepts

Flame Sensing and Rectification

How a furnace proves flame with a single rod, and how to measure and interpret the microamp signal.

Concepts

Sensible and Latent Heat

The difference between heat you can measure with a thermometer and heat that removes moisture from the air.

Concepts

Airflow Fundamentals

CFM, static pressure and why airflow problems are behind a large share of service calls.

Concepts

Heat Pump Defrost Cycle

Why an outdoor coil frosts in heating, how the control decides to defrost, and what normal defrost looks like.

Concepts

Electricity Fundamentals

Voltage, current, resistance and power, and how they show up in HVAC line and control circuits.

Concepts

Ohm's Law and the Power Formula

The arithmetic behind every electrical reading you take, and how to use it to predict what a meter should show.

Concepts

Series and Parallel Circuits

How HVAC wiring is arranged, and why safety devices are in series while loads are in parallel.

Concepts

Psychrometrics Basics

Dry bulb, wet bulb, dew point and relative humidity, and what the psychrometric chart tells you about a coil.

Concepts

Heating and Cooling Load Basics

What a load calculation accounts for, and why sizing from square footage or the old unit causes problems.

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Comfort and Indoor Air Quality

Comfort is more than temperature. Humidity, air movement, filtration and ventilation all shape how a space feels.

Concepts

Single Stage, Two Stage and Variable Capacity

How staged and modulating equipment differs from single stage, and what that means for comfort and setup.

Concepts

Refrigerant Types and Handling

Blends, glide, safety classifications and why you never mix refrigerants or charge a blend as vapor.

Concepts

Combustion Basics

What clean combustion requires, what the products of combustion tell you, and why analysis beats guessing.

Concepts