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Overheating
This section describes:
Ÿ Overheat Conditions
Ÿ
Overheat Management Areas
Ÿ Power-Down Strategy
Ÿ Recovery Strategy.
Overheat Conditions
An overheat condition exists when one of the 8265 temperature sensors detects an operating temperature
that exceeds a pre-defined threshold. The allowed ambient temperature operating range is 0 °C to 40 °C.
The default threshold setting is fixed at an upper limit of 60 °C (140 °F) to prevent module damage.
An overheat condition may be caused by cooling loss or excessively high ambient (room) air temperature.
The Temp LED on the active controller module blinks to warn you in the case of internal overheat
condition.
The following occurs during an overheat condition:
1. If an SNMP agent is present in the 8265, power management informs the SNMP agent of the overheat
condition.
2. A 1-minute delay is provided, during which external management entities are notified of the overheat
condition.
3. Approximately 1 minute later, the controller module applies a power down strategy to media modules
installed in the overheat management area where the overheat condition was detected.
4. The overheat indication ends when the 8265 internal operating temperature falls below the
temperature threshold and stays there for 15 minutes.
The controller module does not power down media modules occupying slots outside affected overheat
management areas. This overheat power-down strategy is based on the power class setting and slot
location of each media module.
Overheat Management Areas
The overheat power-down strategy is based on three temperature sensors in the 8265, one per installed
fan unit, that effectively divides the module payload area of the 8265 into three overlapping overheat
management areas.
Each overheat management area comprises 8 payload slots. The overlap reflects the overlapping cooling
effects of adjacent fan units (the 8265 can run with a minimum of two fan units installed, but three are
recommended).
The overheat management areas divide the payload slots as follows:
Ÿ Slots 1 through 8 (overheat management area 1)
Ÿ Slots 6 through 13 (overheat management area 2)
Ÿ Slots 10 through 17. (overheat management area 3).
Chapter 10. Managing the Intelligent Cooling Subsystem
115