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OL GTAC1 at-a-glance

This online course provides new technicians and people desiring a better understanding of air conditioning systems including theory, components and troubleshooting. Topics covered include basic concepts, and descriptions, operation and basic troubleshooting of the four basic components: the evaporator, compressor, condenser and metering device. In addition other common system controls and accessories are covered. This program consists of 10 modules and is available as each module or as a complete course. To receive FAD credit you must pass the final exam.

duration cost format register*
2 hrs per module $25/module
online Complete Course

*To register for individual modules, select the module from the list below and click 'Register'.


Course Overview

Servicing heating and air conditioning systems requires a solid knowledge in the fundamental principles of air conditioning system operation. This online training series provides the background to understand both the theory and function of components used in heating and air conditioning systems. The General Training Air Conditioning series is in two sections; GTAC1 covers the theory and fundamental concepts and GTAC2 covers more advanced topics and basic troubleshooting skills. These modules are presented in simple language and concentrate on presenting the concepts in ways that can be easily understood by people new to the industry. After completing these modules, a student should possess the understanding of the concepts behind the air conditioning process, the types of systems and components, and basic troubleshooting techniques. Each module is self-paced and contains a quiz and final exam for the section, each with reference to the appropriate section of the module, allowing students to evaluate their understanding of the concepts presented. To receive FAD credit you must pass the module or final exam.

HVAC Training Objectives

Who Should Take this Training

This course is new technicians or others in the industry who wants to better understand air conditioning theory, components and troubleshooting of HVAC systems.

HVAC Training Methods Used

This course is a narrated online PowerPoint lecture with animations. Student’s achievement of the learning objectives is determined by successful completion of the module skill check and / or final online exam.

Course Details

Module 1 – Introduction to Air Conditioning

Course Overview

This module is a basic introduction to concepts behind the air conditioning process and assumes no previous knowledge of the subject matter. The module explains HVAC terminology and basic concepts of heat flow as applied in HVAC.

HVAC Training Objectives
  • Identify the items all mechanical refrigeration systems have
  • Select the definition for heat
  • Explain the difference between heat content and heat transfer
  • List the three ways heat is transferred
  • Explain the difference between sensible and latent heat
  • Identify why latent heat transfer is so important in servicing mechanical refrigeration systems
Topics Covered*
  • Introduction (24)
  • Heat – Foundation block 1 (9)
  • Heat and Temperature – Foundation block 2 (9)
  • Heat transfer – Foundation block 3 (21)
  • Kinds of heat – Foundation block 4 (11)
*All times are approximate and shown as (time in minutes).
Register for this Module

Module 2 – Temperature & Pressure

Course Overview

The second module covers heat transfer and temperature/pressure relationships. It also introduces the Ph (pressure enthalpy) chart which provides a good way to visualize the air conditioning process.

HVAC Training Objectives
  • Select a definition for Btu, Btuh and ton
  • Define “saturated” from the perspective of heat transfer
  • Describe “evaporating” and “condensing” and select where each occurs in the system
  • Express pressures above atmospheric pressure in proper terms and select where these occur in a refrigeration system
  • Use a refrigeration card to predict the saturation temperature in a coil when the pressure is known
  • Relate saturation temperature to pressure in a drum of refrigerant which contains liquid
Topics Covered*
  • Measuring heat – Foundation block 5 (16)
  • Graphing heat – Foundation block 6 (13)
  • Rate of heat transfer – Foundation block 7 (6)
  • Pressure– Foundation block 8 (29)
*All times are approximate and shown as (time in minutes).
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Module 3 – The Refrigeration Cycle

Course Overview

Module 3 introduces the function of major components and shows how these components work together to constitute the mechanical refrigeration system.

HVAC Training Objectives
  • Identify the characteristics that distinguish refrigerant from other fluids
  • Explain how latent heat transfer accomplishes most of the work done in the evaporator and condenser
  • List from memory, the four components of a mechanical refrigeration system and state the function of each
  • List typical entering and leaving conditions from the evaporator at peak operating conditions
  • Explain the difference between a superheated gas and saturated vapor
  • Determine the refrigerant conditions by using a P-H diagram
Topics Covered*
  • Basic refrigeration cycle (6)
  • Closed cycle systems (9)
  • Mechanical refrigeration components (22)
  • How to read a P-H Diagram (20)
*All times are approximate and shown as (time in minutes).
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Module 4 – Systems

Course Overview

Describes various types of systems along with the compressor/ condenser and evaporator curves.

HVAC Training Objectives
  • List from memory, the four basic types of comfort air conditioning systems
  • Define “zone” and explain how big it is
  • Identify the service problems that poor air diffuser selection and/or placement can create
  • Identify where you would expect to go in a building to do refrigerant service work on a split system
  • Define “built-up” system
Topics Covered*
  • Types of air conditioning systems (21)
  • Refrigeration systems (5)
  • Packaged products (22)
  • Split systems (7)
  • Other systems (4)
*All times are approximate and shown as (time in minutes).
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Module 5 – Compressors

HVAC Training Objectives

Basic types of compressors are introduced, stressing their construction, function, and capacity.

HVAC Training Objectives
  • Explain why liquids can cause problems in the compression area of a compressor
  • Predict what will happen to compressor and system capacity when suction pressure or discharge pressure change
  • Use the “Compressor Comparison Chart” to quickly find, compare and contrast information about the 5 types of compressors
  • List the most popular methods of capacity control for each compressor type
  • Explain how a centrifugal compressor accomplishes its job without mechanically squeezing the refrigerant vapor, as all other designs do
  • Describe what a stage of compression is in a centrifugal compressor
Topics Covered*
  • Compressor functions (20)
  • Compressor types (6)
  • Reciprocating compressors (22)
  • Rotary compressors (4)
  • Scroll compressors (9)
  • Screw compressors (5)
  • Centrifugal compressors (5)
*All times are approximate and shown as (time in minutes).
Register for this Module

Module 6 – Condensers

Course Overview

Covers operation of condensers within the refrigeration system, condenser capacity and how condenser problems relate to system troubleshooting.

HVAC Training Objectives
  • Describe the conditions of the refrigerant entering and leaving a condenser
  • List from memory, the three types of condensers most often used
  • Describe the routine maintenance you would expect to do on a water-cooled or evaporative condenser
  • Describe what symptoms show restricted flow of water or air to a condenser
  • Describe why condenser capacity control is called “head pressure control”
  • Identify some of the common condenser problems that can lead to compressor failure
Topics Covered*
  • Condenser operation (10)
  • Types of condensers (33)
  • Condenser capacity (9)
*All times are approximate and shown as (time in minutes).
Register for this Module

Module 7 – Evaporators

Course Overview

Module 7 covers basic theory and operation of common single-phase and three-phase AC induction motors, including motor starting circuits. The module also describes the various types of protective devices used with motors.

HVAC Training Objectives
  • Describe the condition of the refrigerant entering and leaving the evaporator
  • Identify what a cooler is and the two basic types
  • List from memory, three types of evaporators based on their method of construction
  • Identify and explain the main differences in safety controls between natural draft and condensing furnaces
  • Predict what happens to the condensing pressure and saturation temperature as evaporator pressure drops with cooling load
  • Explain how it is possible for a compressor to pump gas at the same rate, but to deliver less cooling capacity at low load
  • Identify some of the common evaporator problems that can lead to compressor failure
Topics Covered*
  • Evaporator function (4)
  • Evaporator types – based on flow control (13)
  • A closer look at the P_H diagram (3)
  • Evaporator types based on construction (11)
  • Chilled water systems (5)
  • Evaporator capacity (7)
*All times are approximate and shown as (time in minutes).
Register for this Module

Module 8 – Metering Devices

Course Overview

This module covers the specifics of modulating and fixed orifice refrigerant control. Shows the expansion process and superheat control within the refrigeration cycle.

HVAC Training Objectives
  • Explain how the temperature of the refrigerant can drop so dramatically through the metering system without transferring heat
  • Explain the relationship between building heating load and furnace capacity
  • Describe flash gas and why it is necessary
  • Explain how the capacity of a fixed metering device “floats with the load”
  • Explain the difference between internally and externally equalized thermostatic expansion valves
  • List the four steps required to find refrigerant superheat in a system
  • List symptoms created in a system that has an oversized nozzle or thermostatic expansion valve
Topics Covered*
  • Metering device operation (5)
  • Types of metering devices (51)
*All times are approximate and shown as (time in minutes).
Register for this Module

Module 9 – Electrical & Refrigerant Controls

Course Overview

This module introduces the operation and function of basic switches and loads in control and power circuits. Refrigerant flow controls are also covered.

HVAC Training Objectives
  • Differentiate primary from secondary controls by matching the control with the function
  • List the four most popular types of primary control devices and what each senses
  • Identify the best locations for a thermostat when used as a primary control in a residential and light commercial application
  • Explain why a humidistat would be used as a primary control
  • Differentiate between a relay, a contactor, and a starter
  • Explain the difference between operating and safety secondary controls
Topics Covered*
  • Primary controls (25)
  • Pressurestats (19)
  • Secondary operating controls (16)
  • Secondary safety controls (14)
*All times are approximate and shown as (time in minutes).
Register for this Module

Module 10 – Refrigeration Cycle Accessories

Course Overview

Refrigerant system options and accessories are explained. Benefits of these options in terms of enhanced system operation, ease of installation and servicing, and user convenience are stressed.

HVAC Training Objectives
  • Explain the differences between a basic cycle component and a cycle accessory
  • Using the diagram locate each cycle accessory at the appropriate location on the drawing
  • Explain how each of the accessories listed works and why they are necessary
Topics Covered*
  • Refrigeration cycle accessories (59)
*All times are approximate and shown as (time in minutes).
Register for this Module

Course Requirements

Completion Requirements

To receive a certificate for any module or for the complete course a student must receive a grade of 70% on the module skill check or final exam. Once you complete the exam you will be able to print a certificate.

Prerequisite requirements

Basic math skills are required to calculate electrical values in skill check problems.


This program is appropriate for anyone interested in a better understanding of the fundamentals of air conditioning systems.


This program uses a software program that uses flash animations and will run on most PC based computers. Some Apple and mobile devices may need a plugin / app to be able to run these programs.




Not applicable.


Class can be accessed 24/7 and is available for completion for 2 weeks after first login.


This program is located on the Carrier University Learning Management System. Access information and enrollment key are provided after registration.