LaCie 12big Rack Fibre 8 Troubleshooting & Problem SolvingUser Manual page 644.4.4. Thermal Monitoring and ControlThe 12big Rack Fibre 8 and 12big Rack Fibre Expansion storagesystem uses extensive thermal monitoring and takes a number ofactions to ensure component temperatures are kept low and alsoto minimize acoustic noise. Air flow is from front to rear of the en-closure.Table 19Symptom Cause ActionIf the ambient air is below 25° C (77° F)and the fans are observed to increase inspeed then some restriction on airflow maybe causing additional internal temperaturerise.Note: Fan’s increasing speed is not a faultcondition.The first stage in the thermal control processis for the fans to automatically increase inspeed when a thermal threshold is reached.This may be caused by higher ambient tem-peratures in the local environment and maybe perfectly normal.1. Check the installation for any air-flow restrictions at either the front orrear of the enclosure. A minimumgap of 25 mm at the front and 50mm at the rear is recommended.2. Check for restrictions due to dust build-up; clean as needed.3. Check for excessive re-circulation ofheated air from rear to the front. Ensurerack fan system is operating properly.4. Check that all blank modules are inplace.5. Reduce the ambient temperature.Sensors detect a hot “critical” threshold hasbeen exceeded in the enclosure or a mod-ule.A sensor is indicating a critical hot condi-tion.Refer to Table 08.1. Identify the module that is indicat-ing a temperature threshold hasbeen exceeded.2. Replace the defective module. If it wasa defective enclosure proceed with re-placing the enclosure.
