Diagnose
21 symptoms → causes → fixes
Guided Flow
Step-by-step: symptom → cause → test
Refrigerant P/T
96 refrigerants, dew/bubble, glide
Calculators
Superheat, subcool, Manual J, delta-T
Service Guides
6 PM & repair procedures
Equipment Reference
8 system types compared
Glossary
39 HVAC terms
HVAC Quiz
10 field questions
Parts Reference
8 common part crossrefs
Company Directory
33 makers, contractors, supply
Refrigerant work requires EPA Section 608 certification. Lockout/tagout and discharge capacitors before touching any HVAC circuit.