Juniper SRX3400, Hardware Manual, Page: 45 / 232

hysteresis built into the correlation, so that the fans are not subject to spurious speed
changes. Also, if one of the fans in the fan tray fails, the speeds of the remaining fans are
automatically adjusted to keep the temperature within the acceptable range.
Table 15: Critical Component Temperatures and Fan Speed Transitions
Fan Speed Response Critical Component Temperature
Increase from Low to Medium Increase to 60°C
Increase from Medium to High Increase to 75°C
Decrease from High to Medium Decrease to 65°C
Decrease from Medium to Low Decrease to 55°C
If the maximum internal temperature specification is exceeded and the system cannot
be adequately cooled, the Routing Engine shuts down the system by disabling output
power from each power supply.
Related
Documentation
SRX3400 Services Gateway Chassis on page 7
•
•
Hardware Component Locations in the SRX3400 Services Gateway Chassis on page 11
•
Available Components for the SRX3400 Services Gateway on page 9
•
Replacing the Fan Tray on the SRX3400 Services Gateway on page 112
SRX3400 and SRX5600 Services Gateways Air Deflector Kits
Optional air deflector kits are available that let you install the SRX3400 and SRX5600
Services Gateways in a hot aisle/cold aisle ventilation environment. These kits convert
the services gateway from side-to-side ventilation into front-to-back ventilation. The air
deflectors contain no additional fans, so they require no additional electrical power. Air
deflector kits are not available for the SRX3600 Services Gateway.
For more information about the hot aisle/cold aisle air deflector kits, send an e-mail to
DL-Air-Deflectors@juniper.net .
The air deflector kits consist of four main components: two intake/exhaust boxes and
two side plenums. The two intake/exhaust boxes are identical to each other, as are the
side plenums.
The intake/exhaust boxes are installed above and below the services gateway to direct
intake air from the air space in front of the services gateway into the side plenum mounted
on the intake side of the device. The intake air plenum directs air into the services gateway,
and the exhaust air plenum collects the exhaust air on the opposite side of the device.
The exhaust plenum directs the exhausted air into the intake/exhaust boxes above and
below the unit, where it is expelled into the air space behind the services gateway.
The air deflector kit requires additional space around the services gateway, increasing
its overall height and width as described in
Table 16 on page 32 .
31 Copyright © 2013, Juniper Networks, Inc.
Chapter 2: SRX3400 Services Gateway Hardware Components