As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMBOUT, CABIN CONTINUED TO CLIMB PAST ALTITUDE CALLED FOR (5500 FEET) AT 2400 FEET, CLOSED CARGO HEAT VALVE WENT TO MANUAL CONTROLLER FULL CABIN CONTINUED TO CLIMB AND RETURN TO NEWARK. *S/D* REMOVED AND REPLACED EQUIPMENT COOLING VALVE AS PER MM 21-58-21.