Power Supplies; Important Points To Remember - Dell S4820T Installation Manual

Power Supplies

The S4820T supports two hot-swappable power supplies units (PSUs) with integrated fans that provide
cooling for the system.
Power supply 0 (PSU0) is on the left side of the chassis; power supply 1 (PSU1) is on the right side of the
chassis.
Figure 9. S4820T with One AC PSU
1. PSU0
2. PSU1
The S4820T supports AC and DC power supplies with two air-flow directions (I/O to Utility and Utility to
I/O). The S4820T does not support mixing PSU types. That is, you cannot replace an AC PSU with a DC
PSU and an AC-R PSU with a DC-R PSU. The fan airflow direction for both the PSUs must be the same.
Two PSUs are required for full redundancy, but the system can operate with a single PSU.
NOTE: If you use a single PSU, install a blank plate in the other PSU slot. Dell Networking
recommends using power supply 1 (PSU1) as the blank plate slot.
When running with full redundancy (two power supplies installed and running), you can remove and
replace one PSU while the other PSU is running without disrupting traffic.
The PSUs are in a single piece with the PSU fans. You can replace the fan trays individually, but you
cannot replace the fans that are attached to the PSUs — if the fans attached to the PSU fail, you must
replace the entire PSU. For fan tray replacement procedures, refer to

Important Points to Remember

The S4820T supports two hot-swappable power supplies with integrated fans that provide cooling for
the chassis.
• The PSU slides into the slot smoothly. Do not force the PSU into a slot as this action may damage the
PSU or the S4820T chassis.
• The S4820T supports AC and DC power supplies with two air-flow directions (I/O to Utility and Utility
to I/O). The S4820T does not support mixing PSU types. That is, you cannot replace an AC PSU with a
Power Supplies
Install Fans.
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