As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING THE CLIMB PHASE OF FLIGHT CABIN ALTITUDE CLIMBED AT 1500’/MIN AFTER CLIMBING THROUGH 20000 FEET CABIN PRESSURIZATION COULD NOT BE CONTROLLED, DECENT BELOW 10000 REQUIRED AND RETURNED TO KYIP. CORRECTIVE ACTION: UPON INVESTIGATION FOUND RT MOISTURE SEPARATOR CLAMP LOOSE, R&R O-RINGS AND RE SECURED CLAMPS IAW AMM 21-55-41, OPS CHECK GOOD IAW AMM 21-31-00, LEAK CHECK GOOD IAW AMM 21-55-41.