Maintaining the EX9253 Cooling System
Removing a Fan Tray from an EX9253 Switch
The fan trays are hot-removable and hot-insertable field-replaceable units installed in the rear panel of the switch. You can replace them without powering off the switch or disrupting switch functions.
You must replace the fan tray within two minutes of removing the fan tray to prevent the chassis from overheating.
Before you begin to remove a fan tray:
Ensure you understand how to prevent electrostatic discharge (ESD) damage (see Prevention of Electrostatic Discharge Damage).
Ensure that you have the following parts and tools available:
An ESD wrist strap
A Phillips (+) screwdriver, number 2 (not provided)
A replacement fan tray
To remove a fan tray from an EX9253 switch chassis (see Figure 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.
- 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.
- Hold and lift the latch located on the inside of the fan tray to release it from the chassis.
- Grasp the fan tray and pull it out approximately 1 to 3 inches.
- 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 
See also
Installing a Fan Tray in an EX9253 Switch
The fan trays are hot-removable and hot-insertable field-replaceable units installed in the rear panel of the switch. You can replace them without powering off the switch or disrupting switch functions.
You must replace the fan tray within two minutes of removing the fan tray to prevent the chassis from overheating.
Before you begin to install a fan tray:
Ensure you understand how to prevent electrostatic discharge (ESD) damage (ee Prevention of Electrostatic Discharge Damage).
Ensure that you have the following parts and tools available:
An ESD wrist strap
A Phillips (+) screwdriver, number 2 (not provided)
To install a fan tray in an EX9253 switch (see Figure 2):
- 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.
- Grasp the fan tray and place one hand under the fan tray for support.
- 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.
- 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 
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 the Fan Tray in EX9253 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.
user@switch> show chassis environmentClass Item Status Measurement Temp CB 0 Exhaust Temp Sensor OK 41 degrees C / 105 degrees F CB 0 Inlet Temp Sensor OK 37 degrees C / 98 degrees F CB 0 CPU DIE Temp Sensor OK 54 degrees C / 129 degrees F FPC 0 Intake Temp Sensor OK 44 degrees C / 111 degrees F FPC 0 Exhaust-A Temp Sensor OK 51 degrees C / 123 degrees F FPC 0 Exhaust-B Temp Sensor OK 47 degrees C / 116 degrees F FPC 0 EA0 Chip OK 68 degrees C / 154 degrees F FPC 0 EA0-XR0 Chip OK 79 degrees C / 174 degrees F FPC 0 EA0-XR1 Chip OK 83 degrees C / 181 degrees F FPC 0 EA1 Chip OK 77 degrees C / 170 degrees F FPC 0 EA1-XR0 Chip OK 82 degrees C / 179 degrees F FPC 0 EA1-XR1 Chip OK 86 degrees C / 186 degrees F FPC 0 EA2 Chip OK 62 degrees C / 143 degrees F FPC 0 EA2-XR0 Chip OK 74 degrees C / 165 degrees F FPC 0 EA2-XR1 Chip OK 74 degrees C / 165 degrees F FPC 0 PF Chip OK 63 degrees C / 145 degrees F FPC 0 EA0_HMC0 Logic die OK 84 degrees C / 183 degrees F FPC 0 EA0_HMC0 DRAM botm OK 81 degrees C / 177 degrees F FPC 0 EA0_HMC1 Logic die OK 86 degrees C / 186 degrees F FPC 0 EA0_HMC1 DRAM botm OK 83 degrees C / 181 degrees F FPC 0 EA0_HMC2 Logic die OK 87 degrees C / 188 degrees F FPC 0 EA0_HMC2 DRAM botm OK 84 degrees C / 183 degrees F FPC 0 EA1_HMC0 Logic die OK 91 degrees C / 195 degrees F FPC 0 EA1_HMC0 DRAM botm OK 88 degrees C / 190 degrees F FPC 0 EA1_HMC1 Logic die OK 91 degrees C / 195 degrees F FPC 0 EA1_HMC1 DRAM botm OK 88 degrees C / 190 degrees F FPC 0 EA1_HMC2 Logic die OK 90 degrees C / 194 degrees F FPC 0 EA1_HMC2 DRAM botm OK 87 degrees C / 188 degrees F FPC 0 EA2_HMC0 Logic die OK 87 degrees C / 188 degrees F FPC 0 EA2_HMC0 DRAM botm OK 84 degrees C / 183 degrees F FPC 0 EA2_HMC1 Logic die OK 81 degrees C / 177 degrees F FPC 0 EA2_HMC1 DRAM botm OK 78 degrees C / 172 degrees F FPC 0 EA2_HMC2 Logic die OK 79 degrees C / 174 degrees F FPC 0 EA2_HMC2 DRAM botm OK 76 degrees C / 168 degrees F Power PEM 0 Absent PEM 1 Absent PEM 2 OK 49 degrees C / 120 degrees F PEM 3 OK 48 degrees C / 118 degrees F PEM 4 Absent PEM 5 Absent Fans Fan Tray 0 Fan 0 OK Spinning at normal speed Fan Tray 0 Fan 1 OK Spinning at normal speed Fan Tray 0 Fan 2 OK Spinning at normal speed Fan Tray 0 Fan 3 OK Spinning at normal speed Fan Tray 1 Fan 0 OK Spinning at normal speed Fan Tray 1 Fan 1 OK Spinning at normal speed Fan Tray 1 Fan 2 OK Spinning at normal speed Fan Tray 1 Fan 3 OK Spinning at normal speed Fan Tray 2 Fan 0 OK Spinning at normal speed Fan Tray 2 Fan 1 OK Spinning at normal speed Fan Tray 2 Fan 2 OK Spinning at normal speed Fan Tray 2 Fan 3 OK Spinning at normal speed Fan Tray 3 Fan 0 OK Spinning at normal speed Fan Tray 3 Fan 1 OK Spinning at normal speed Fan Tray 3 Fan 2 OK Spinning at normal speed Fan Tray 3 Fan 3 OK Spinning at normal speed
Removing the Air Filter Unit from an EX9253 Switch
The air filter unit consists of three parts–the outer filter cover, the air filter, and the inner cage. The air filter sits between the outer cover and the inner cage. The air filter unit is installed into the cable management brackets, and are held tightly by captive screws.
Regularly inspect the air filter. A dirty air filter restricts airflow in the unit, producing a negative effect on the ventilation of the chassis.
Do not operate the switch for more than two minutes without the air filter unit installed on it. Because the fans are very powerful, they could pull small bits of wire or other materials into the switch chassis through the unfiltered air intake. This could damage the switch and its components.
Before you begin to remove the air filter unit, ensure that you have the following parts and tools available:
A Phillips (+) screwdriver, number 2 (not provided)
A replacement air filter unit
Ensure that you understand how to prevent ESD damage (see Prevention of Electrostatic Discharge Damage).
To remove the air filter unit:
- Wrap and fasten one end of an ESD wrist strap around your bare wrist, and connect the other end of the strap to the ESD point on the switch.
- Loosen the captive screws located on either side of the
air filter unit attached to the cable management brackets on the front
of the switch.
Note It is not necessary to remove the cables from the cable management brackets to access the air filter unit or the air filter.
- Grasp the air filter unit and gently pull the air filter
unit out of the cable management brackets (see Figure 3).
Figure 3: Removing the Air Filter Unit 
Installing the Air Filter Unit in an EX9253 Switch
The air filter unit consists of three parts–the outer filter cover, the air filter, and the inner cage. The air filter sits between the outer cover and the inner cage. The air filter unit is installed into the cable management brackets, and are held tightly by captive screws.
Regularly inspect the air filter. A dirty air filter restricts airflow in the unit, producing a negative effect on the ventilation of the chassis.
Before you begin to install the air filter unit, ensure that you have a Phillips (+) screwdriver, number 2 available.
Ensure that you understand how to prevent ESD damage (see Prevention of Electrostatic Discharge Damage).
The air filter unit is installed on the cable management brackets. Before installing the air filter unit, ensure that the cable management brackets are installed on front of the switch.
To install the air filter unit:
- Wrap and fasten one end of an ESD wrist strap around your bare wrist, and connect the other end of the strap to the ESD point on the switch.
- Ensure that the air filter is right-side up.
- Grasp the air filter unit and slide into the rails on
the cable management brackets until it fits snugly on the cable management
brackets (see Figure 4).
Figure 4: Installing the Air Filter Unit 
- Tighten the captive screws to secure the air filter unit.
Removing the Air Filter from the Air Filter Unit in an EX9253 Switch
The air filter unit consists of three parts–the outer filter cover, the air filter, and the inner cage. The air filter sits between the outer cover and the inner cage. The air filter unit is installed into the cable management brackets, and are held tightly by captive screws.
Regularly inspect the air filter. A dirty air filter restricts airflow in the unit, producing a negative effect on the ventilation of the chassis.
Do not operate the switch for more than two minutes without the air filter unit installed on it. Because the fans are very powerful, they could pull small bits of wire or other materials into the switch chassis through the unfiltered air intake. This could damage the switch and its components.
Before you begin to remove the air filter, ensure that you have the following parts and tools available:
A Phillips (+) screwdriver, number 2 (not provided)
A replacement air filter
Ensure that you understand how to prevent ESD damage (see Prevention of Electrostatic Discharge Damage).
To remove the air filter:
- Wrap and fasten one end of an ESD wrist strap around your bare wrist, and connect the other end of the strap to the ESD point on the switch.
- Loosen the captive screws located on either side of the
air filter unit attached to the cable management brackets on the front
of the switch.
Note It is not necessary to remove the cables from the cable management brackets to access the air filter unit or the air filter.
- Grasp the head of the loosened screws and pull the screws
to remove the outer cover of the air filter unit.
The air filter is installed at the center of the air filter unit, behind the outer cover (see Figure 5.
Figure 5: Removing the Air Filter from the Air Filter Unit 
1—Outer cover3—Inner cage2—Air filter - Grasp the air filter and pull it straight out of the air filter unit.
Installing the Air Filter in the Air Filter Unit in an EX9253 Switch
The air filter unit consists of three parts–the outer filter cover, the air filter, and the inner cage. The air filter sits between the outer cover and the inner cage. The air filter unit is installed into the cable management brackets, and are held tightly by captive screws.
Regularly inspect the air filter. A dirty air filter restricts airflow in the unit, producing a negative effect on the ventilation of the chassis.
Before you begin to install the air filter, ensure that you have a Phillips (+) screwdriver, number 2 available.
Ensure that you understand how to prevent ESD damage (see Prevention of Electrostatic Discharge Damage).
To install the air filter:
- Wrap and fasten one end of an ESD wrist strap around your bare wrist, and connect the other end of the strap to the ESD point on the switch.
- Loosen the captive screws located on either side of the
air filter unit attached to the cable management brackets on the front
of the switch.
Note It is not necessary to remove the cables from the cable management brackets to access the air filter unit or the air filter.
- Grasp the head of the loosened screws and pull the screws
to remove the outer cover of the air filter unit.
The air filter must be installed at the center of the air filter unit, behind the outer cover (see Figure 6.
Figure 6: Installing the Air Filter in the Air Filter Unit 1—Outer cover3—Inner cage2—Air filter - Grasp the air filter, and place the air filter straight in front of the inner cage.
- Place the outer cover back in its place.
- Tighten the captive screws to secure the air filter unit.
Maintaining the Air Filter in EX9253 Switches
Purpose
For optimum cooling, verify the condition of the air filters.
Action
Regularly inspect 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. You must replace the filter every six months.
Caution Always keep the air filter in place while the switch is operating. Because the fans are very powerful, they could pull small bits of wire or other materials into the switch through the unfiltered air intake. This could damage the switch components.
EX9253 switches ship with one air filter. Spare air filters are separately orderable. The shelf life of the air filters vary from two to five years depending on the storage conditions. Store spare air filters in a dark, cool, and dry place. Wrap the air filters separately using plastic wraps and store them in an environment with RH between 40% to 80% and temperature between 40° F to 90° F. 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. If an air filter develops flakes or becomes brittle when rubbed or deformed, you must not use it.