Skip to main content

OL GTAC2 at-a-glance

This online course provides new technicians and people desiring a better understanding of air conditioning systems including theory, components and troubleshooting. This series builds on the concepts covered in General Training Air Conditioning I. Topics covered include refrigerant characteristics, system dehydration and charging, refrigerant piping and system installation. In addition part load operation and troubleshooting methods are covered. This program consists of 9 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 – Refrigerant Characteristics

Course Overview

This module discusses refrigerant types, characteristics, and oil compatibility of pure azeotropes, and zeotrope blends. It focuses on proper application and safe handling for new, replacement refrigerants used in air conditioning and refrigeration systems.

HVAC Training Objectives
  • Define what a refrigerant is
  • Explain how ODP and GWP are changing the refrigerants we use
  • Explain the difference between an azeotropic and a zeotropic and the meaning of the terms glide and fractionation
  • List three methods for detecting leaks in systems charged with fluorocarbon refrigerants
  • From memory, list at least four damaging effects of moisture in the refrigeration cycle
  • Use a P/T chart for a pure refrigerant or azeotropic blend to find saturation temperature when pressure is given
  • Use a P/T chart for a zeotropic blend refrigerant to find its bubble point and dewpoint temperature when pressure is given
Topics Covered*
  • Introduction (14)
  • Industry in transition (9)
  • Classifying refrigerants (6)
  • Application tips (7)
  • Refrigerant properties (22)
*All times are approximate and shown as (time in minutes).
Register for this Module

Module 2 – Refrigerant Oils

Course Overview

The second module covers oils used in air conditioning systems and how they are properly applied. Topics include compatibility with new, replacement refrigerants and change-out procedures.

HVAC Training Objectives
  • List four purposes served by oil in the mechanical refrigeration system
  • State the difference between fluid film lubrication and boundary lubrication
  • List four types of oil, according to their source, and state which ones are used as refrigerant oils
  • Describe the differences between synthetic oil and mineral oil
  • Describe the safest way for a service technician to select the proper oil for any application
  • List at least four ways a service technician can prevent contamination of the oil-refrigerant solution
Topics Covered*
  • Introduction (14)
  • Kinds of oil (9)
  • Performance quality of oil (10)
  • Oil-refrigerant solutions (7)
  • Oil problems (17)
*All times are approximate and shown as (time in minutes).

Register for this Module

Module 3 – Refrigerant Piping

Course Overview

Module 3 familiarizes you with enough detail to spot and modify obvious field piping errors. Topics covered are piping requirements, sizing, insulation, and support and piping loops.

HVAC Training Objectives
  • List at least six things to look for in a well-designed, field-piping system
  • Name at least five dangers of oversizing suction or hot gas lines
  • Identify the places in a mechanical refrigeration system where oil return presents the biggest problem
  • Explain how oil return is handled in systems that use a miscible or partially-miscible refrigerant
  • Check the size of all three of the major refrigerant lines using the Ballpark Line Sizing Charts
  • Check the suction and hot gas riser size using the Ballpark Sizing Charts
  • When given a suction line size, find the riser sizes for riser A and riser B of a double suction riser
  • List from memory, at least four possible fixes for flash gas at the metering device
  • Explain which refrigerant lines are insulated and with what material. Also explain how often and under what circumstances each line may be insulated
Topics Covered*
  • Pipe requirements (8)
  • Pipe sizing (13)
  • Risers (12)
  • Flash gas – causes and solutions (6)
  • Supports and piping loops (7)
*All times are approximate and shown as (time in minutes).
Register for this Module

Module 4 – System Dehydration

Course Overview

This module discusses moisture problems and their effect on air conditioning systems, and the importance of moisture elimination during evacuation.

HVAC Training Objectives
  • Predict what will happen to a system that is improperly dehydrated
  • List four examples of the damage water does in a system
  • State the maximum PPM of water for “dry” refrigerant and oil
  • Define “deep vacuum”
  • State the steps in deep vacuum method of dehydration
  • Explain how to check a system for tightness and dryness following deep vacuum evacuation/dehydration
  • Describe the steps for the triple evacuation process
  • Explain how a filter-drier dehydrates a system even though the moisture stays in the system
Topics Covered*
  • The need for dehydration (23)
  • Dehydration methods (41)
*All times are approximate and shown as (time in minutes).
Register for this Module

Module 5 – Charging, Recovery, Recycling & Reclamation

Course Overview

This module explains how to charge, recover and recycle traditional and replacement halocarbon refrigerants. It also focuses on tools and equipment used.

HVAC Training Objectives
  • State the differences between refrigerant recovery, recycling and reclamation
  • Identify the refrigerant type when given the color of the refrigerant cylinder
  • Label the five ports on a standard gauge manifold
  • Identify the procedures that can be done when an in-line service valve position is given
  • Identify two areas in a system where refrigerant can be stored during servicing operations
  • Explain the differences between a recovery unit and a recovery/recycle unit
  • List at least two special precautions required for charging zeotropic blends which are not required when charging pure refrigerants or azeotropic refrigerant blends
  • Determine system superheat or subcooling using a temperature sensor gauge manifold and the pressure-temperature chart for the refrigerant involved
  • State how to adjust system charge when superheat is too high and when subcooling is too high
Topics Covered*
  • Introduction (13)
  • Tools and equipment (11)
  • Refrigerant recovery (8)
  • Refrigerant charging (33)
*All times are approximate and shown as (time in minutes).
Register for this Module

Module 6 – Installation Procedures

Course Overview

All facets of refrigeration system installation are covered including planning, piping, brazing, wiring, pump down, prestart checks, and start-up and safety essentials.

HVAC Training Objectives
  • Prepare a planning check list for an installation
  • List from memory, the four areas of safety that are a consideration for any installation
  • Describe three ways to control equipment vibration and noise at its source
  • Specify, from memory, sizing and pitch guidelines for condensate lines
  • State two or more precautions required in handling and storing “ACR” copper piping
  • Explain the similarities and differences between brazing and soldering methods
  • Explain how nitrogen used while soldering or brazing helps insure maximum system life
Topics Covered*
  • Introduction (13)
  • Equipment placement (6)
  • Vibration isolation and noise control (17)
  • Piping systems (28)
*All times are approximate and shown as (time in minutes).
Register for this Module

Module 7 – Heat Pumps

Course Overview

Module 7 covers the overall concept of the heat pump, its operation, benefits and disadvantages, operating economics, servicing concerns and how water-source heat pumps are used for heat reclaim in commercial buildings.

HVAC Training Objectives
  • List six basic components you would expect to find on any heat pump system
  • Predict frequency of compressor operation above the balance point, at the balance point and below it
  • Explain the ways heat pump operation changes when defrost is activated
  • List three possible causes for restricted airflow
  • Predict the outdoor temperature where the heat pump will perform at its highest COP
  • State what the balance point of a heat pump system is
  • List three methods for lowering the balance point of a heat pump system
  • Explain how heat is reclaimed, rather than wasted, by a water source heat pump system
Topics Covered*
  • Introduction (15)
  • How a heat pump works (12)
  • Kinds of heat pumps (20)
  • Installation and servicing considerations (12)
  • Heat pump applications (6)
  • Supplementary heat (10)
*All times are approximate and shown as (time in minutes).
Register for this Module

Module 8 – Part Load

Course Overview

Operating problems often show up at part load rather than at full capacity. These are the problems on which this module focuses, concentrating on the refrigeration cycle.

HVAC Training Objectives
  • Describe when part load occurs and how often
  • Describe the differences in systems with and without capacity-controlled components
  • Indicate what happens to evaporator capacity as suction pressure and temperature change
  • Predict what will happen to highside and lowside pressures, compressor power draw and length of “on” cycle as condensing unit capacity increases for a system without capacity controlled components
  • Explain what will happen to lowside and highside conditions, as well as compressor power draw and length of the “on” cycle, when a condensing unit switches to a lower capacity step
  • Describe how hot gas bypass stabilizes system operation below a preset suction pressure
  • Describe the effects of oversizing a comfort system
Topics Covered*
  • Introduction (14)
  • System equilibrium (18)
  • Capacity control methods (34)
  • What to expect on various systems (4)
  • Equipment oversizing (5)
*All times are approximate and shown as (time in minutes).
Register for this Module

Module 9 – Troubleshooting

Course Overview

This module introduces basic refrigeration system troubleshooting. Study diagnostic tools along with troubleshooting, logic, information, and charts.

HVAC Training Objectives
  • List from memory, the five key ingredients required for successful troubleshooting
  • List from memory, at least four safety precautions a technician should take when servicing a system
  • Select from a list the four most common electrical meters used in air conditioning service and match them to their function
  • Explain the difference between a symptom and the root cause of a problem
  • Select from a list the five important instruments used in troubleshooting refrigeration problems and match them to their use
  • List the system vital signs that must be measured in order to troubleshoot the mechanical refrigeration system
  • Use the Component Symptom Analysis and System Symptom Analysis chart to identify the possible causes for a given system problem
Topics Covered*
  • Electrical troubleshooting (24)
  • Troubleshooting the mechanical refrigeration system (36)
  • Troubleshooting exercises (16)
*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.