HP D5970A - NetServer - LCII Installation Manual page 20

Chapter 2
NOTE
Once lit, the PRFL (Predictive Fail) LED will continue to
blink yellow even if the fan speed problem is intermittent and
fan speed has again reached acceptable levels. To determine
whether fan speed is currently a problem, you must cycle
power to the power supply. The easiest way to do this is to pull
out the power supply, wait at least 15 seconds, and then
reinsert it. (You can do this during system operation, but only
if the other two power supplies are present and operating
normally.) If the power supply's fan speed is still a problem,
the PRFL LED continues to blink. If the fan speed is now
acceptable, the PRFL LED does not light.
CAUTION If you remove a power supply, it is imperative that you wait at
least 15 seconds before reinserting it. The delay gives the
power supply's inrush protection circuit time to reset itself. If
the circuit does not have time to reset, the supply draws a
larger than normal inrush current and may trip main circuit
breakers or UPS breakers.
12
Controls, Indicators, and Ports