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Maintaining the EX9251 Cooling System

Removing a Fan Tray from an EX9251 Switch

Before you remove a fan tray:

Ensure that you have the following parts and tools available:

  • An ESD wrist strap

  • Phillips (+) screwdriver, number 2

  • A replacement fan tray

The fan tray in an EX9251 switch is a hot-insertable and hot-removable field-replaceable unit (FRU). You can remove and replace it while the switch is running without turning off power to the switch or disrupting switching functions.

CAUTION:

Do not remove the fan tray unless you have a replacement fan tray available.

To remove a fan tray from an EX9251 switch chassis (see Figure 1):

  1. Wrap and fasten one end of the ESD wrist strap around your bare wrist, and connect the other end of the strap to the ESD point on the switch.
  2. Loosen the screw on the fan tray faceplate using the Phillips (+) screwdriver, number 2.
    Warning:

    To avoid injury, keep tools and your fingers away from the fans as you slide the fan tray out of the chassis. The fans might still be spinning.

  3. Hold and press the latch located on the inside of the fan tray to release it from the chassis.
  4. Grasp the fan tray handle, and pull it out approximately 1 to 3 inches.
  5. Place one hand under the fan tray to support it, and pull the fan tray completely out of the chassis.
Figure 1: Removing a Fan Tray from an EX9251 SwitchRemoving a Fan Tray from an EX9251 Switch

Installing a Fan Tray in an EX9251 Switch

Before you begin to install a fan tray:

Ensure that you have the following parts and tools available:

  • An ESD wrist strap

  • Phillips (+) screwdriver, number 2

CAUTION:

You can remove and replace the fan tray while the switch is operating. However, you must replace the fan tray within two minutes of removing the fan tray to prevent the chassis from overheating.

The fan tray in an EX9251 switch is a hot-insertable and hot-removable field-replaceable unit (FRU). You can remove and replace it while the switch is running without turning off power to the switch or disrupting switching functions.

To install a fan tray in an EX9251 switch (see Figure 2):

  1. Wrap and fasten one end of the ESD wrist strap around your bare wrist, and connect the other end of the strap to the ESD point on the switch.
  2. Grasp the fan tray handle, and place one hand under the fan tray for support.
  3. Place the fan tray on the respective slot, and carefully push the fan tray into the chassis until the socket lock snaps into place and holds it.
  4. Tighten the screw on the fan tray faceplate using the Phillips (+) screwdriver, number 2 to secure the fan tray in the chassis.
Figure 2: Installing a Fan Tray in an EX9251 SwitchInstalling a Fan Tray in an EX9251 Switch
Note:

If you have a Juniper J-Care service contract, register any addition, change, or upgrade of hardware components at https://www.juniper.net/customers/support/tools/updateinstallbase/ . Failure to do so can result in significant delays if you need replacement parts. This note does not apply if you replace existing components with the same type of component.

Maintaining Fan Trays in EX9251 Switches

Purpose

For optimum cooling, verify the condition of the fans.

Action

  • Monitor the status of the fans. A fan tray contains multiple fans that work in unison to cool the switch components. If one fan fails, the speed of the remaining fans is adjusted to maintain proper cooling. A major alarm is triggered when a fan fails and a minor alarm and a major alarm are triggered when a fan tray is removed.

  • To display the status of the cooling system, issue the show chassis environment command. The output for EX9251 switches is similar to the following: