Note- Read an d understand the instructions in this chapter before starting the maintenance
work.Also see the contents of "Chapter 1 BeforeStarting MaintenanceW ork."
Table29-1 Typesof PDU m aintenance
Configuration Active/hot Active/cold Inactive/hot Inactive/cold Systemstopped
Building block configuration
Unsupported Supported Unsupported Unsupported Supported
Table29-2 Maintenanceflow
Task Replacement
1 Preparation 29.3
2 Removingthe PDU 29.4
3 Installingthe PDU 29.5
4 Restoringthe system 29.6
29.2 Before Maintaining the DedicatedPower Distribution Unit
Thissectio n describes the types and flow of maintenance of the PDU, as well as some
precautions.

29.2.1 T ypes of maintenance

Table29-1 lists the types of maintenance for the PDU. For the definition of
maintenance,see "4.3 Understanding Types of Maintenance."

29.2.2 Maintenance flow

Table29-2 lists the sequence of the mai ntenance procedure for the PDU.

29.2.3 P recautions for replacement

Notethe following points when you replace a PDU.
■TheSP ARC M10-4S and the crossbar box are connected to the two PDUs with
power cords. Thus the system can continue to operate even if one of the PDUs
fails.Do not, however, operate the system for an extended period when one unit
Chapter29 Maintainingthe Dedicated Power Distribution Unit Mounted on the Rack for Expanded Connection 455