How to diagnose an AC that isn’t cooling
A systematic approach finds the cause faster and avoids unnecessary parts. Follow electrical safety and EPA rules.
7 steps →How-to guides
HVAC Technician How-To Guides
Step-by-step guides to common HVAC technician tasks: the practical side of the job.
Common HVAC technician tasks
Step-by-step overviews of tasks HVAC technicians perform regularly. Use them to understand the job, prepare for training or refresh your memory.
How to check refrigerant charge using subcooling
On systems with a TXV, subcooling is the standard way to verify charge. Use the manufacturer’s target.
7 steps →How to perform seasonal AC maintenance
Regular maintenance prevents breakdowns and keeps efficiency high.
7 steps →Before you practice
Learn every core task
Our HVAC Technician training walks through these procedures and more, alongside vocabulary, safety and career-launch lessons.