HVAC/R Troubleshooting & Field Diagnostics

Stop guessing. Diagnose with evidence.


HVAC/R systems do not fail in neat textbook categories. A weak-cooling complaint may begin with airflow, a low-voltage control problem can imitate a component failure, and abnormal refrigerant readings can be consequences rather than causes. HVAC/R Troubleshooting & Field Diagnostics teaches you how to move from symptom to verified root cause with a disciplined, measurement-driven process.


Built for HVAC/R students, apprentices, service technicians, maintenance professionals, and instructors, this practical visual guide connects electrical, refrigeration, airflow, heating, heat-pump, and control-system evidence into one diagnostic method.


Inside, you will learn how to:

• Trace wiring diagrams and sequence of operation before replacing components.


• Interpret voltage, current, resistance, capacitance, sensors, control boards, and compressor electrical behavior.


• Use pressure, temperature, superheat, and subcooling as coordinated evidence instead of single-reading shortcuts.


• Diagnose static-pressure, duct, filter, coil, blower, humidity, and comfort problems.


• Troubleshoot gas furnaces, heat pumps, reversing valves, defrost, auxiliary heat, ECM blowers, inverter compressors, communicating systems, and electronic expansion valves.


• Work intelligently with modern A2L systems including R-32 and R-454B while keeping manufacturer instructions and applicable requirements in control.


• Apply the PROVE method: Pinpoint the complaint, Read the system state, Obtain measurements, Verify the suspected cause, and Evaluate operation after correction.