Rackable Systems OmniStor 4700S Series, User Manual

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Chapter 1 - Getting Started
Cooling Fan Module
9
Normally, the fan speed is controlled automatically by the SAF-TE process. It will maintain
fan RPM at the minimum required to maintain effective cooling. Should a condition occur
that requires a greater volume of air, the fan RPM will increase up to the maximum to
maintain cooling temperatures. The ability to maintain low RPMs allows the system to
operate in a noise sensitive environment.
A manual override of the fan speed is available for special circumstance environments.
Referring to the illustration on the preceding page, two jumpers are provided on the fan
module printed circuit board to override the software control of the fan speeds. This
hardware setting routes full power voltage to the fans for maximum operational speed, which
is greater than the maximum speed set by the automatic software control. This configuration
is normally used when fan speed noises are not an issue, and the ambient operating
temperature is at or above 30°C (86°F), thus ensuring that maximum available cooling is
being provided.
The jumpers JP1 and JP2 by default are offset, which enables the automatic fan speed
control. The jumper JP1 controls Fan 0 and JP2 controls Fan 1. Placing the jumper on both
pins for each jumper will override the automatic setting and configure the fans to
maximum power.