As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CABIN PRESSURIZATION DUMPED WHEN CLIMBING THROUGH FL200. SYSTEM WOULD NOT RESPOND TO ANY INPUTS TO THE CONTROLLER. IS AIRCRAFT HAS BEEN RETURNED TO REVENUE SERVICE, REF # MEC-012747. REPLACED PINCHED O-RING ON INLET TUBE TO COLD AIR UNIT, TEST FLIGHT WAS GOOD.