LaCie 12big Rack Network
Troubleshooting & Problem Solving
User Manual
page 33
4.5.4. Thermal Monitoring and Control
The LaCie 12big Rack Network enclosure uses extensive thermal
monitoring and takes a number of actions to ensure component
temperatures are kept low and also to minimize acoustic noise. Air
flow is from front to rear of the enclosure.
Table 16 - Thermal Monitoring and Control
Symptom
Cause
Action
If the ambient air is cool
(below 25 °C) and the fans
are observed to increase in
speed then some restriction
on airflow may be causing
additional internal tempera-
ture rise.
Note: This is not a fault
condition.
The first stage in the thermal control process
is for the fans to automatically increase in
speed when a thermal threshold is reached.
This may be caused by higher ambient
temperatures in the local environment and
may be perfectly normal.
Note: This threshold changes according to
the number of drives and power supplies
fitted.
1. Check the installation for any airflow restrictions at ei-
ther the front or rear of the enclosure. A minimum gap
of 25mm at the front and 50mm at the rear is recom-
mended.
2. Check for restrictions due to dust build-up; clean as
appropriate.
3. Check for excessive re-circulation of heated air from
rear to the front, use in a fully enclosed rack installation
is not recommended.
4. Check that all Blank modules are in place.
5. Reduce the ambient temperature.
4.5.5. Thermal Alarm
Table 17 - Thermal Alarm
Symptom
Cause
Action
1. Ops Panel UNIT FAULT
LED amber.
2. An amber LED on one or
more Power Supply Units.
If the internal temperature measured in
the airflow through the enclosure exceeds
a pre-set threshold a thermal alarm will
sound.
1. Check local ambient environment temperature is below
the upper 35°C specification.
2. Check the installation for any airflow restrictions at ei-
ther the front or rear of the enclosure. A minimum gap
of 25mm at the front and 50mm at the rear is recom-
mended.
3. Check for restrictions due to dust build-up, clean as
appropriate.
4. Check for excessive re-circulation of heated air from
rear to the front, use in a fully enclosed rack installation
is not recommended.
5. If possible shutdown the enclosure and investigate the
problem before continuing.
