Replacing Fan Trays

A tray of cooling fans provides forced air cooling for components in the ERX routers. The fan trays are hot-swappable; you can replace them without powering down the system. However, if you do not replace the fan tray within approximately 2 minutes, the system enters thermal protection mode in JunosE Release 14.2.x and earlier. In JunosE Release 14.3.x and later, the failure or removal of fans generates only log messages and does not initiate thermal protection mode. For information about thermal protection mode, see Monitoring Temperatures of Modules.

You can monitor fan status by observing the LEDs on the SRP module or on the fan tray behind the faceplate. For complete LED information, see Understanding Status LEDs to Troubleshoot.

Note: On the SRP module, when the LED alternates between OK and FAIL in 10–second intervals, a non-critical fan failure exists. Noncritical warnings are not indicated on the fan tray LEDs; if the red FAN FAIL LED is illuminated, either a critical or non-critical failure exists.

Caution: If the red FAN FAIL LED on the SRP module is illuminated and none of the fans are spinning when you remove the fan tray, power down the system until a new fan tray is available. Operating an ERX router with inadequate air circulation can damage the modules.

Caution: Do not use the fan tray handle to carry the fan tray assembly. Use the handle only to pull the tray out of the chassis.

Figure 43: Fan Tray in ERX14xx Models

Fan Tray in ERX14xx Models

Figure 44: Fan Tray in ERX7xx Models

Fan Tray in ERX7xx Models

Figure 45: Fan Tray in ERX310 Router

Fan Tray in ERX310 Router

Removing the Fan Tray

To remove the fan tray:

  1. (ERX14xx models only) Place a flathead screwdriver in the groove where the top bezel meets the chassis on the top of the system, and lever the top bezel off the front of the system.
  2. With an appropriate screwdriver (using a No. 2 Phillips screwdriver, if necessary), loosen the captive screws located at the corners of the fan tray.

    Warning: Do not place your fingers near the fans when removing the fan tray. The blades might still be moving.

  3. Pull the fan tray halfway out of the shelf.

    Warning: Slowly slide the fan tray out of the chassis. The tray does not have stops to prevent it from sliding all the way out.

  4. Pull the tray out of the chassis.

Installing the Fan Tray

To install the fan tray:

Caution: Do not use the fan tray handle to carry the fan tray assembly. Use the handle only to push the tray into the chassis.

  1. Hold the tray horizontally (ERX14xx models) or vertically (ERX7xx models and ERX310 router) or so that the captive screws point toward you and you can read text on the labels.
  2. Place the bottom corners of the tray housing in the plastic shelf guides of the fan tray compartment; push toward the back of the chassis halfway, and stop.
  3. Push the fan tray toward the back of the shelf until it stops.

    An electrical connector on the back of the fan tray pairs with an electrical connector at the back of the shelf.

  4. With an appropriate screwdriver (using a No. 2 Phillips screwdriver, if necessary), tighten the captive screws.

    Alternate between screws when tightening them to ensure that the electrical connectors at the back of the tray fit tightly.

    Caution: Do not overtighten the screws.

  5. (ERX14xx model only) Push the top bezel back on the front of the system.