Ten real diagnostic scenarios — insufficient cooling, high humidity, frozen evaporator coils, short cycling, low airflow, high static pressure, compressor and pump failures, control issues, and poor indoor air quality — each worked from symptoms through measurement, diagnosis, and corrective action.
Replacing a compressor and hoping the cooling complaint doesn't come back is a technician's move, not an engineer's. This module is built around the opposite discipline: measure first, form a hypothesis consistent with the measurement, then test that hypothesis with a targeted change. It draws directly on this program's load-calculation, refrigeration, controls, and installation modules — troubleshooting is that same knowledge applied under pressure, against a real fault an occupant is waiting on.
Every scenario below was chosen because it has at least two plausible causes that present nearly identically — a frozen coil that could be restricted airflow or low charge, a pump noise that could be cavitation or trapped air — and each requires a specific measurement, not an assumption, to tell apart.