What was found
STANDBY PITOT HEAT PRESS CAME ON DURING INITIAL CLIMB FOLLOWED BY A PROX SYSTEM FAULT ABOUT FIVE MINUTES LATER AND CHIMES SOUNDING (CABIN/COCKPIT) AT RANDOM. RETURNED TO SLC, HAD TO DO A MANUAL GEAR EXTENSION BECAUSE OF THREE RED INDICATIONS ON GEAR AND NORMAL EXTENSION WOULD NOT WORK. THREE GREEN AFTER MANUAL EMERGENCY EXTENSION PLUS ANTI-SKID MESSAGE AND STEERING INOPERATIVE. FLY-BY, TOWER TO VERIFY THREE DOWN AND LOCKED. LANDED WITHOUT INCIDENT. REMOVED AND REPLACED PSEU IAW CRJ M/M 52-61-00. PERFORMED GEAR SWING AND CHECKS OF OTHER EFFECTED SYSTEMS. ALL CHECKED GOOD.