MX240 Ethernet Services Router Hardware Guide
few minutes without the air filter in place. For maintenance instructions, see “Maintaining the Air Filter” on page 68.
Maintaining Cooling System Components
This section discusses the following topics:
■Maintaining the Air Filter on page 68
■Maintaining the Fan Tray on page 68
Maintaining the Air Filter
A dirty air filter restricts airflow in the unit, producing a negative effect on the ventilation of the chassis. The filter degrades over time. Periodically replace the filter in use, as well as spares. We recommend that you replace the filter every 6 months. For procedures to replace the air filter, see “Replacing the Air Filter” on page 94.
CAUTION: Always keep the air filter in place while the router is operating. Because the fans are very powerful, they could pull small bits of wire or other materials into the router through the unfiltered air intake. This could damage the router components.
Use spare filters within one year of manufacture. Check the date of manufacture printed on the filter. Store spare air filters in a dark, cool, and dry place. Storing air filters at higher temperatures, or where they can be exposed to ultraviolet (UV) radiation, hydrocarbon emissions, or vapors from solvents, can significantly reduce their life.
Maintaining the Fan Tray
The fan tray contains multiple fans that work in unison to cool the router components. If one fan fails, the host subsystem adjusts the speed of the remaining fans to maintain proper cooling. A red alarm is triggered when a fan fails, and a yellow alarm and red alarm is triggered when a fan tray is removed.
To display the status of the cooling system, issue the show chassis environment command. The output is similar to the following:
user@host> show chassis environment
Class | Item | Status | Measurement |
| |||
Temp | PEM 0 | OK | 45 | degrees | C / 113 | degrees F | |
| PEM 1 | OK | 45 | degrees | C / 113 | degrees F | |
| PEM | 2 | Absent |
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| PEM | 3 | Absent |
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68■ Maintaining Cooling System Components
