As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) PRESSURIZATION PROBLEMS OCCURRED SHORTLY AFTER TAKEOFF BACK TO OTTAWA (CONTROL). ON DESCENT THROUGH 23,000 FEET. CREW EXPERIENCED RAPID DEPRESSURIZATION. MASKS WERE DONNED AND DESCENT ACCELERATED TO BELOW 10,000 FT. MAINTENANCE DETERMINED THE CAUSE TO BE THE PRESSURIZATION CONTROLLER, CONTROLLER REPLACED. NO FURTHER ACTION REQUIRED.