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AFO/AFI airflow change on same Switche

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  • 1.  AFO/AFI airflow change on same Switche

    Posted 07-12-2018 07:39

    Hello,

    I have a general question about ventilation.

    If I want to turn an original AFO switch (i.e. with AFO fans and power supplies) into an AFI, I simply change the power supplies and fans, but the switch chassis can remain the same? For example on a QFX5120 or EX4550-32F.

    Thanks in advance!


    #fronttoback
    #AFI
    #backtofront
    #afo
    #airflow


  • 2.  RE: AFO/AFI airflow change on same Switche
    Best Answer

     
    Posted 07-12-2018 09:06

    Yes to change airflow, just replace both the fans and the power supplies.  This applies equally to EX and QFX models.



  • 3.  RE: AFO/AFI airflow change on same Switche

    Posted 07-13-2018 01:16

    I am also desperately looking for an part number for the Expension Module and Power Supply Blanks.

    Can you or anyone else help me here?

     

    Thanks!



  • 4.  RE: AFO/AFI airflow change on same Switche

    Posted 07-23-2018 10:42

    Hi good2know.

     

    The Juniper SE or your reseller SE is your best contact for the part numbers.


    I have done some investigation and the SKUs for EX4550-32F are:

    EX4300-UM-BLNK     EX4300  blank faceplate for uplink module
    EX4200-PWR-BLNK    EX 4200 Blank Panel for Power redundant Power supply slot (Spare)

     

    The information was found in configurator tool for Juniper partners.

     

     



  • 5.  RE: AFO/AFI airflow change on same Switche

    Posted 05-13-2019 13:15

    Rather than swap out the entire PSU, is it reasonable to simply flip the fans inside the modules?   The PSUs would still identify as and AFI, but the airflow would move the other way through.

     

    I  want to go the other way from OP, make a BTF switch into a FTB.   



  • 6.  RE: AFO/AFI airflow change on same Switche

     
    Posted 05-13-2019 13:48

    I don't know about wiring of the fans in the PSU and fan modules... if you flip them, the power connector could be placed wrongly.

     

    On top - it would theoretically work but you would void all warranty related to fans and psu if you make such kind of changes to the equipment.



  • 7.  RE: AFO/AFI airflow change on same Switche

     
    Posted 05-13-2019 16:34

    @Criggie - the only approved method is to replace both the fans and power supplies.  Otherwise you would be on your own and void any warranty and/or support contract.

     

    FYI



  • 8.  RE: AFO/AFI airflow change on same Switche

    Posted 05-18-2019 19:40

    Turns out this is a bad idea, not because of warranty or support, but there are differences between AFI and AFO that go beyond how the fan is mounted.

     

    Running the fan backward physically works, but the thermister that reads the "INLET" air temp will be at the exit point of hot air, so it will not be reading the ambient air temp.  

     

    The only fix now is to make sure the switch is breathing in cool air, which may mean reverse-mounting if its an AFI, or find some way to isolate the switch's inlets from the exhaust of other things in the rack.