What was found
ELP - FLT 13608 - CABIN WOULD NOT PRESSURIZE PAST 2.5 PSI DURING CLIMB OUT. THE CABIN CONTINUED TO CLIMB DURING ASCENT PHASE OF FLIGHT AND CREW ELECTED TO RETURN TO POINT OF DEPARTURE AT EL PASO, TEXAS. NO EMERGENCY PROCEDURES WERE REQUIRED AND AIRCRAFT LANDED WITHOUT EVENT. DURING TROUBLESHOOTING AND INSPECTION OF THE SYSTEM, DISCOVERED THE OUTFLOW VALVE CONTAINED SOME DEBRIS PREVENTING IT FROM CLOSING. THE DEBRIS WAS REMOVED AND FROM THE OUTFLOW VALVE, THE AIRCRAFT WAS GROUND RUN AND THE PRESSURIZATION SYSTEM CHECKED NORMAL PER MM, CHAPTER 21-30-5. (X)