Alarm history is one of the most useful diagnostic tools in modern BMS and PLC systems. To utilize it properly, the chronological sequence must be examined, not just the last message.
The first alarm is usually the most valuable
After a trip, many secondary alarms may appear. The first one chronologically often indicates the root cause.
Time and sequence
The exact time and operating stage are recorded: standby, pre-purge, ignition, low fire, high fire, or shutdown.
Correlation with trends
Gas pressure, air pressure, flame signal, and load should be compared at the exact same moment as the alarm.
Interlocks
An alarm may occur because an interlock was not confirmed. It does not necessarily mean that the component mentioned on the screen is faulty.
Recurring pattern
If the same alarm appears at a specific time or load, a common cause should be sought, such as a second consumer, pressure drop, or thermal effect.
Best practice
Saving screenshots, trends, and operating data before resetting creates a valuable history for future diagnostics.
