IBM SAN512B-6, Installation, Service And User Manual

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Note: If airflow direction for a power supply assembly does not match the chassis
airflow direction as stored on WWN cards, the power supply will have a "fault"
status. However, LED operation for the power supply will not indicate a fault. If
airflow direction for a fan assembly does not match the chassis airflow direction,
the fan LED will indicate a fault condition.
You can use external labels as a guide. The power supply and fan assemblies are
labeled with a green "E" or orange "I" airflow symbol on the faceplate. The symbol
also appears on the top of the FRU. All fans and power supplies in a chassis must
have the same label affixed to guarantee airflow direction is consistent.
The orange I symbol indicates an intake FRU. This unit pulls air in from the
nonport side of the device and exhausts it out the port side. This is called
back-to-front airflow or intake airflow. This symbol should appear on FRUs with
part numbers that contain an NPI.
The green E symbol indicates an exhaust FRU. This unit pulls air in from the port
side of the device and exhausts it out the nonport side. This is called front-to-back
airflow or exhaust airflow. This symbol should appear on FRUs with part numbers
that contain an NPE.
Ensure airflow direction of power supply and fan assemblies match airflow
direction of the chassis configured on installed WWN cards. If power supply or fan
air flow direction does not match, the FRU will fault. Faulty fans can cause
increase in temperature.
Airflow direction can be verified by entering the chassisShow command. Following
is an example from command output indicating mis-matching airflow. WWN units
should indicate "Non-portside Intake".
POWER SUPPLY Unit: 1
Power Source: AC
Fan Direction: Non-portside Intake
...
FAN
Unit: 2
Fan Direction: Non-portside Intake
...
WWN
Unit: 1
System AirFlow: Non-portside Exhaust
...
WWN
Unit: 2
System AirFlow: Non-portside Exhaust
Figure 51. Airflow labels
Chapter 12. Fan Assemblies
175