The best diagnosis is not based solely on the fault code, but on the chronological sequence before and after the alarm.
Alarm history
It shows which fault appeared first and whether secondary faults followed.
Trends
Temperatures, pressures, flow, compressor frequency, and status help to identify what has changed.
Actual measurements
Controller readings must be verified with independent instruments when a sensor error is suspected.
Goal
To find the root cause and not simply reset the last alarm.
