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    QFX5200 Cooling System Description

    The cooling system in an QFX5200-32C consists of five fan modules and a single fan in each power supply; QFX5200-48Y cooling system consists of six fan modules and a single fan in each power supply. The switch can be set up to work in one of two airflow directions:

    • Airflow In–Air comes into the switch through the vents in the field-replaceable units (FRUs)
    • Airflow Out–Air comes into the switch through the vents in the port panel.

    Caution: Airflow In and Airflow Out fans and power supplies cannot be mixed in the same chassis.

    This topic describes:

    Fan Modules

    The fan modules in QFX5200 devices are hot-insertable and hot-removable field-replaceable units (FRUs). These fan modules are designed for one of the two available airflow directions (Airflow In or Airflow Out). The fan modules are also color-coded for the airflow direction as well. The fan modules are installed in the fan module slots on the FRU panel.

    The QFX5200-32C fan modules have five fan modules numbered 0 through 4 when counting from left to right.

    The QFX5200-48Y fan modules have six fan modules numbered 0 through 5 when counting from left to right.

    Figure 1 and Figure 2 shows the fan modules.

    Figure 1: QFX5200-32C Fan Module

    QFX5200-32C Fan Module

    Figure 2: QFX5200-48Y Fan Module

    QFX5200-48Y Fan Module

    You remove and replace a fan module from the FRU end of the chassis. The switch continues to operate for a limited period of time (30 seconds) during the replacement of the fan module without thermal shutdown.

    Note: All fan modules must be installed for optimal operation of the switch.

    The fan modules are available in four product SKUs that have different airflow directions—FRU-to-port airflow and port-to-FRU airflow On legacy switches or switches with LCDs, this airflow is also called front-to-back and back-to-front. Table 1 lists the available fan module product SKUs and the direction of airflow in them:

    Table 1: Fan Modules in QFX5200 Switches

    Fan Module

    Airflow Diagram

    Label on the Fan Module

    Color of Fan Module

    Direction of Airflow in the Fan Module

    Power Supplies

    QFX5200-32C-FANAFI

    Figure 3

    AIR IN

    Juniper Azure Blue

    FRU-to-port, that is, air comes in from the end of the switch with the fans; air exhausts from the switch end with ports (also known as back-to-front airflow).

    You must install only power supplies that have AIR IN labels in switches in which the fan modules have AIR IN labels.

    QFX5200-32C-FANAFO

    Figure 4

    AIR OUT

    Juniper Gold

    Port-to-FRU, that is, air comes in through vents on the end with ports; air exhausts out the end with the fans (also known as front-to-back airflow).

    You must install only power supplies that have AIR OUT labels in switches in which the fan modules have AIR OUT labels.

    QFX5200-48Y-FAN-AFI

    Figure 5

    AIR IN

    Blue

    FRU-to-port, that is, air comes in from the end of the switch with the fans; air exhausts from the switch end with ports (also known as back-to-front airflow).

    You must install only power supplies that have AIR IN labels in switches in which the fan modules have AIR IN labels.

    QFX5200-48Y-FAN-AFO

    Figure 6

    AIR OUT

    Red

    Port-to-FRU, that is, air comes in through vents on the end with ports; air exhausts out the end with the fans (also known as front-to-back airflow).

    You must install only power supplies that have AIR OUT labels in switches in which the fan modules have AIR OUT labels.

    In data center deployments, position the switch in such a manner that the AIR IN labels on switch components are next to the cold aisle, and AIR OUT labels on switch components are next to the hot aisle.

    Figure 3: Air In Airflow Through QFX5200-32C

    Air In Airflow Through QFX5200-32C

    Figure 4: Air Out Airflow Through QFX5200-32C

    Air Out Airflow Through QFX5200-32C

    Figure 5: Air In Airflow Through QFX5200-48Y

    Air In Airflow Through QFX5200-48Y

    Figure 6: Air Out Airflow Through QFX5200-48Y

    Air Out Airflow Through QFX5200-48Y

    Do Not Install Components with Different Airflow or Wattage in the Switch

    Do not mix power supplies with different airflow. If the power supplies are color-coded, ensure they are either all match. Likewise, ensure that all fan modules have the same airflow and match the airflow of the power supplies. Fan modules are also color-coded that match the power supplies.

    Mixing components with different airflows in the same chassis hampers the performance of the cooling system of the switch and leads to overheating of the chassis.

    Caution: The system raises an alarm if a fan module fails or if the ambient temperature inside the chassis rises above the acceptable range. If the temperature inside the chassis rises above the threshold temperature, the system shuts down automatically.

    Do not mix fan modules with different wattage. Only use the replacement fan modules that are designed for use with your product number. See Table 1 for the correct part number for your QFX5200 device.

    Caution: Do not mix AC and DC power supplies in the same QFX5200-32C chassis. You may mix AC and DC power supplies in the same QFX5200-48Y chassis, but the fans and power supplies must have the same airflow direction. Also note that load sharing is not the same for AC and DC power supplies.

    However if you need to convert a QFX5200 device to have a different airflow, you can change the airflow pattern. To convert an AIR IN product SKU to an AIR OUT product SKU or an AIR OUT product SKU to a AIR IN product SKU, you must replace all of the fans and power supplies at one time to use the new direction. The system raises an alarm when the system is converted, which is normal.

    Modified: 2018-03-26