HVAC/R
Training, technical articles, field observations and practical experience in heating, ventilation, air conditioning and refrigeration.
HVAC/R has been part of both my professional work and teaching background. This section brings together the training material, technical resources and field-related articles I have written over the years.
Structured HVAC/R Training
The site now includes structured material covering electrical systems, mechanical refrigeration, heating and cooling equipment, and air distribution. Choose the area you want to study below.
HVAC/R & Electrical
The main training hub for HVAC/R electrical material, including circuits, meters, relays, transformers, thermostats, schematics and troubleshooting.
Air Conditioning / Refrigeration
A structured course covering the refrigeration cycle, refrigeration theory, compressors, condensers, evaporators, metering devices and refrigerant line sets.
Basic Electrical Training
A complete electrical training manual written for HVAC technicians, beginning with electrical fundamentals and progressing through practical control circuits and troubleshooting.
Refrigeration Theory
Study heat, temperature, pressure, saturation, pressure-temperature relationships, temperature glide, superheat, subcooling, refrigeration capacity and the pressure-enthalpy diagram.
How to Use a Meter
Learn how to measure voltage, current and resistance, understand what those measurements mean, and use the Hop-scotch method to trace circuits systematically.
Electrical Troubleshooting
A standalone practical guide to diagnosing HVAC electrical problems using sequence of operation, schematics, meter readings and a logical process.
Mechanical Systems and Air Distribution Training
The Air Conditioning / Refrigeration material is organized into sections so students can begin with the refrigeration cycle, develop the theory behind refrigerant behavior, study the major system components and piping, and then understand how the air-distribution system affects heating, cooling, comfort and equipment performance.
The Basic Refrigeration Cycle
Begin with mechanical refrigeration and follow the refrigerant through the compressor, condenser, metering device and evaporator.
Refrigeration Theory
Build the physical foundation for refrigeration by studying heat, pressure, phase change, saturation, P-T relationships, superheat, subcooling and capacity.
Compressors
Study compressor operation, compressor types, lubrication, electrical components, protection and common failure conditions.
Condensers
Learn how high-pressure refrigerant rejects heat, condenses into liquid and becomes subcooled before leaving the condenser.
Evaporators
Study the heat-absorbing portion of the refrigeration system, including refrigerant boiling, airflow, latent cooling and superheat.
Metering Devices
Learn how fixed orifices, thermostatic expansion valves and electronic expansion valves control refrigerant flow into the evaporator.
Refrigerant Line Sets
Study ACR tubing, line sizing, oil return, vertical risers, insulation, filter-driers, brazing, nitrogen purging, leak testing and evacuation.
Refrigerants & EPA Section 608
Structured training covering refrigerant fundamentals, individual refrigerants, environmental effects, cylinders, service tools, charging, leak detection, contamination control, evacuation, safety, recovery and EPA Section 608 certification.
Air-Conditioning and Heating Duct Systems
Study residential and light-commercial duct systems, heating and cooling airflow, static pressure, pressure measurements, filtration, Manual D fundamentals, air balancing, duct leakage and systematic troubleshooting.
Restoring and Organizing Older Training Material
Over the years I wrote a substantial amount of HVAC/R training material for technicians and students.
Some of that work was written specifically for schools or organizations and cannot simply be republished here. Other material was developed independently, published under my own copyright, or created for training outside those organizations.
I have been restoring that material to this site because it does no good sitting in a box or on an old hard drive. If it can help another technician, student or instructor, it is worth making available again.
How I Approach HVAC/R Training
The emphasis is on understanding what the system is doing, not simply memorizing a list of parts or procedures.
Understand the System
Before troubleshooting equipment, you need to know what it is supposed to do and in what order it is supposed to do it.
Understand the Circuit
Even complicated electrical systems can be broken down into a source, path, switches and loads.
Measure Before Replacing
Use the meter to prove what the circuit is doing before deciding that a component is bad.
Ask Why It Failed
Finding the failed part is only part of the job. A good technician also tries to determine why that part failed.
HVAC/R Articles & Field Notes
HVAC/R training posts, technical observations, field examples and other material from the site. New HVAC/R posts will appear here automatically.
More HVAC/R Posts
The posts above show the most recent HVAC/R material. The complete category archive contains the older HVAC/R articles and training posts as well.
Using This Material
For Students
Work through the structured material in order when possible. Understanding system operation, refrigeration theory, circuits, controls, airflow and measurements makes troubleshooting much easier.
For Instructors
The material may be used as a resource by directing students to the appropriate pages on this site. Please respect the copyright and usage terms associated with the material.
More Technical and Educational Material
Continue into the structured HVAC/R training material or explore other technical and educational areas of the site.