Juniper Networks 8 manual Fans

ERX 8.0.x Hardware Guide

Fans

Forced air-cooling keeps the temperature of the E-series modules and components within normal operating limits. In ERX-14xx models, six cooling fans are located in a tray at the top of the router (Figure 1). In ERX-7xx models, four cooling fans are located in a tray on one side of the router (Figure 3). In the ERX-310 router, two cooling fans are located in a tray on one side of the router (Figure 5).

The system monitors the temperature of each module. If the temperature of a module exceeds the maximum limit, the system immediately goes into thermal protection mode and the modules are powered off. The ERX system controller enters a low power mode, keeps the modules in a power-off condition, and does not respond to any management interface commands. For information about troubleshooting high operating temperatures, see “Troubleshooting” on page 103.

In ERX-7xx and ERX–14xx models, the fan tray has two redundant converters that power the fans (for the ERX-14xx models, a –24 V, 50 W converter; for the ERX-7xx models, a –12 V, 15 W converter). If one converter fails, the other takes over. The ERX-310 router does not have redundant converters.

For all E-series routers, the system software reports an alarm if any of the fans or converters fail.

20 Redundancy Features