Airflow; Figure 7: Horizontal Fan Tray - Juniper PTX Series Hardware Manual

Copyright © 2012, Juniper Networks, Inc.
Cooling zone 1—The upper
of which contain six fans, cool the components installed in the front card cage (FPCs
and PICs), and the CCGs. Both horizontal fan trays are interchangeable with each other.
Cooling zone 1 has two sections:
Cooling zone 1 section 1 cools FPCs 0 through 4.
Cooling zone 1 section 2 cools FPCs 3 through 7.
NOTE: FPCs 3 and 4 can be cooled by either cooling zone 1 section.
When FPCs are installed in a section, the software sets the fan speeds according to
the temperature. When no FPCs are installed in cooling zone 1 section 1, the left fans
in the horizontal fan trays in cooling zone 1 are set to 30% of maximum speed. When
no FPCs are installed in cooling zone 1 section 2, the right fans in the horizontal fan
trays in cooling zone 1 are set to 30% of maximum speed.

Figure 7: Horizontal Fan Tray

Airflow

Figure 8 on page 20 shows the airflow through the packet transport switch.
Chapter 3: PTX5000 Hardware Components Overview
and lower
Fan Tray 1 Fan Tray 2
horizontal fan trays, each
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