What this article covers
Provides instructions on checking chassis cooling fan status, temperature sensor thresholds and thermal shutdown alarms to prevent hardware overheating.
ScopeAll rackmount FortiGate firewall chassis (FG-100E through FG-3700D series).
Before using the CLI
AirflowConfirm unobstructed front-to-back airflow and adequate rack spacing.
Dust and filtersInspect and clean filters using the approved maintenance process.
Ambient conditionsRecord rack inlet temperature and environmental alarms.
On-site workflow
Check fan status and RPM
Capture the reported fan state and rotational speed.
diagnose sys fan status
execute sensor listReview temperature sensors
Check CPU, system and ambient sensor values. The supplied source describes temperatures below 75°C as a typical target, while actual limits remain model-specific.
Inspect the rack environment
Check obstructed airflow, dust filters and front-to-back ventilation. Record ambient conditions at the chassis inlet.
Review thermal shutdown history
Look for thermal events, shutdowns or related crash entries.
diagnose debug crashlog readReplace or RMA a failed cooling component
Replace a field-replaceable fan tray or submit an RMA request when fan RPM remains 0 or the status reports FAIL.
Operational caution
Review before applying: Do not operate an overheating chassis longer than necessary. Avoid removing working fan modules unless the appliance and hardware procedure support hot replacement.