Dell PowerVault 221S (SCSI) - Manual (Page 8)

Introduction: Dell PowerVault 220S and 221S Systems Installation and Troubleshooting Guide
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NOTE: For the full name of an abbreviation or acronym used in this table, see " Abbreviations and Acronyms ."
Temperature Probes
Your storage system contains four temperature probes that monitor system temperature and shut down the system in the
event of overheating. Each EMM and both the primary and secondary backplanes contain temperature probes. Table 1-6
identifies the location of each probe.
Table 1-6. Temperature Probe Locations
Probe Location
Probe 0 Primary EMM
Probe 1 Secondary EMM
Probe 2 Drive backplane behind drive ID #3
Probe 3 Drive backplane behind drive ID #12
Power Supply/Cooling Modules
Your storage system supports two combined power supply and cooling modules. While the system is designed to operate
normally with only one functional power supply, both cooling modules (each with two blowers) must be present for proper
cooling. If only one power supply is needed, a blank must be inserted into the other slot to mount the second cooling module.
In this nonredundant power-supply configuration, the power-supply blank has the capacity to transfer power and control
signals to and from the cooling module.
If one blower within a cooling module fails, your storage system reverts to a nonredundant fan configuration. The remaining
three blowers in both cooling modules operate at higher speeds to maintain proper system cooling and produce higher
acoustical noise than in the redundant fan configuration (with four blowers in two cooling modules).
CAUTION: A power supply and cooling module can be removed from a powered-on system for a maximum
period of five minutes. Beyond that time, the system begins to overheat, and at a critical temperature,
shuts down to prevent damage.
The cooling module is securely mounted to the power supply using a hook-and-latch fastener. This simplifies the removal and
installation of cooling modules and power supplies.
Figure 1-7 illustrates the power supply and cooling module features and LED indicators. Table 1-7 lists the function of each
power supply and cooling module indicator.
Figure 1-7. Power Supply and Cooling Module LED Features and Indicators
Table 1-7. Power Supply/Cooling Module LED Indicators