There is a new version of check_equallogic (20121228) available. Andreas Jud informed me, that in his Equallogic the fan in the power supply died but the power supply itself was still working.
To catch this (hopefully) rare case, the "ps" check type was modified to also monitor the power supply fans.
Note that the fans of the enclosure are still monitored through the "fan" check.
Download as always in Nagios Plugins -> check_equallogic.
Oh and by the way: May you all have a great start into the new year!