As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CLT 2234 - UNABLE TO PRESSURIZE AIRCRAFT AFTER TAKEOFF. FLIGHT RETURNED TO CLT WHERE AN OVERWEIGHT LANDING WAS MADE WITHOUT FURTHER INCIDENT. MAINTENANCE REMOVED INSULATION FROM OUTFLOW VALVE AND REPLACED OUTFLOW VALVE AND PRESSURE CONTROLLER. REFERENCE USAA950381.