What was found
FLT 491, BOS-DEN, AIR RETURN TO BOS, CABIN TEMP ZONE 1 RAN AWAY, STAYING AT 156 DEGREES, CYCLED HOT AIR VALVE, NO HELP. REMOVED AND REPLACED RAM AIR INLET ACTUATOR PER 21-61-00 AND REMOVED AND REPLACED NR 2 PACK CONTROLLER, ALL OPS CHECK GOOD PER AMM 21-61-00.