Nortel Passport 15000, Установка и обслуживание оборудования, Страница: 104 / 874

104 Chapter 7 Cooling units
241-1501-240 5.2S2
Fan replacement
Replace a fan promptly, if it fails, to maintain the required temperature in the
Passport switch.
• “Prerequisites to fan replacement” (page 104)
• “Fan replacement task flow” (page 105)
Prerequisites to fan replacement
• You need the appropriate version of a fan:
— A0758423 for any fan in an NTHR51AA lower (rear) cooling unit
or an NTHR52AA upper (front) cooling unit
— A0522179 for the middle fan of an NTHR51AB lower (rear) cooling
unit or an NTHR52AB upper (front) cooling unit
— A0522182 for either side fan of an NTHR51AB lower (rear) cooling
unit or an NTHR52AB upper (front) cooling unit
• The PEC of the cooling units NTHR51AB and NTHR52AB is visible on
its mounting ear. The mounting ears are blank for the NTHR51AA and
NTHR52AA versions. To distinguish a lower cooling unit NTHR51AA
from an upper unit NTHR52AA, observe the cable connectors that are
only on the mounting ear of a lower cooling unit.
• The NTHR51AA and NTHR51AB versions of the cooling units are
interchangeable, but their parts are not.
• The NTHR52AA and NTHR52AB versions of the cooling units are
interchangeable, but their parts are not.
• Single-fan failures are indicated by both a minor and a major alarm. You
should attend to single-fan failures as soon as possible and within 48
hours. You must attend to multiple fan failures immediately before the
fabrics’ shut-down threshold is reached.
• Minimize the impact or risk of having a fan out of service by always
replacing only one fan at a time.
• When a fan still does not operate after replacing the fan and its controller,
replace the cooling unit as indicated in “Cooling unit replacement”
(page 100).