IBM DS3950, Installation, User'S, And Maintenance Manual, Page: 142 / 252

Recovering from an overheated power supply and fan unit
Each storage subsystem contains two power supply and fan units. Each power
supply and fan unit contains a built-in temperature sensor designed to prevent it
from overheating. Under normal operating conditions, with an ambient air
temperature range of 5° C to 40° C (41° F to 104° F), the fans in the power supply
and fan units maintain a proper operating temperature inside the module.
If the internal temperature reaches 65° C (149° F), the power supply shuts down
automatically. If both power supplies shut down because of overheating, the
module has no power, and all indicator lights are off.
The following factors can cause the power supplies to overheat:
v
An unusually high room temperature
v
Fan failures in the power supply and fan units
v
Defective circuitry in the power supply
v
Blocked air vents
v
Failures in other devices in the configuration or cabinet
If a fan failure causes overheating or the operating environment becomes too hot
(greater than 55° C), the Global Fault LED on the storage expansion enclosure
turns on. The power supply and fan unit Fault and Service Action Allowed (SAA)
LEDs on the back of the storage subsystem also turn on. “Controller LEDs” on
page 105 shows the location of these LEDs.
Attention: Because the power supply and fan unit CRU Fault and SAA LEDs are
lit when the operating environment temperature is too hot (greater than 55° C), do
not assume the power supply and fan unit CRU is bad. Take action to cool down
the environment first. When the operating environment temperature is within the
specified operating environment range, the power supply and fan unit Fault and
SAA LEDs will be unlit if there are no problems with the power supply and fan
unit CRU.
If the module temperature exceeds 45° C (113° F), the storage management
software displays a Needs Attention icon in the Subsystem Management window.
If event monitoring is enabled, and event notification is configured, the software
issues the following two critical problem notifications:
v
If one power supply shuts down, the storage management software displays a
Needs Attention status in the Subsystem Management window.
v
If both power supplies shut down, the module shuts down, and the storage
management software displays a Not Responding status in the Array
Management window.
Use the following procedure to resume normal operation after a power supply
shutdown.
Attention: Risk of damage from overheating - The power supplies
automatically shut down when the air temperature inside the cabinet reaches 68°
C (154° F). If the power supplies shut down, immediately remove all cabinet
panels to help cool the cabinet air temperature and to prevent damage to the
DS3950 storage subsystem configuration components.
1.
Remove the front cover.
2. If applicable, mute the alarm.
3. Did you use the procedure “Troubleshooting the storage subsystem ” on page
101 to identify an overheating problem?
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IBM System Storage DS3950 Storage Subsystem: Installation, User’s, and Maintenance Guide