A B737-200 ON INITIAL CLB AT 3000 FT TO 11000 FT EXPERIENCED DIFFICULTY COOLING THE PAX AND CTL CABIN. RETURN TO THE FIELD CAUSED BY FAILED L AIR CYCLE MACHINE AND R PACK DEICING VALVE.

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DURING TAXI OUT; INFORMED BY FLT ATTENDANT THAT CABIN WAS GETTING WARM. I SELECTED FULL COLD IN AUTO MODE ON BOTH PACKS. BOTH AIR MIX VALVES SHOWED FULL COLD AND DUCT TEMP APPROX 80 DEGS F. OUTSIDE AIR TEMP WAS 88 DEGS F AND FULL (119) PAX. WE STARTED L ENG TO HELP COOL DOWN THE CABIN. DURING CLBOUT (APPROX 3000 FT MSL) FLT ATTENDANT INFORMED US THE CABIN WAS GETTING EXTREMELY HOT. I SELECTED FULL MANUAL COLD ON BOTH TEMP SELECTORS. PASSING 6000 FT NOTICED WARM AIR EXITING GASPER FAN; AND DUCT TEMP SHOWED 120 DEGS F WITH BOTH AIR MIX VALVES SHOWING FULL COLD. WE CHKED CIRCUIT BREAKERS AND THE FLT OPS MANUAL. BREAKERS CHKED GOOD AND FLT OPS MANUAL HAD NO GUIDANCE FOR THIS SIT. APPROX 20 MI N OF MCO INFORMED ZJX OF OUR RETURN TO MCO. ACARS MESSAGE SENT TO FLT CTL; MCO MAINT NOTIFIED; FLT ATTENDANTS NOTIFIED AND A PA WAS MADE TO THE PAX. DURING DSCNT WITH PWR IN IDLE; DUCT TEMP SHOWED 75 DEGS F AND CABIN TEMP SHOWED 90 DEGS F. BOTH AIR MIX VALVES STILL SHOWED FULL COLD. MAINT FOUND THE 35 DEG CTLR AND SENSOR HAD FAILED ON THE R PACK AND THE L PACK AIR CYCLE MACHINE WAS SEIZED. THIS WAS THE REASON WE COULD NOT CTL THE CABIN TEMP. THE CAPT DISCUSSED THE SIT WITH MAINT; THE DISPATCHER AND THE DUTY PLT. THE L PACK WAS PLACARDED INOP AND THE R AIR CONDITIONING SYS WAS REPAIRED AND THOROUGHLY OPS CHKED. THE ACFT WAS REDISPATCHED TO RDU WITH THE L AIR CONDITIONING SYS INOP. GASPER FAN WAS LEFT ON DURING ENTIRE FLT TO HELP COOL THE CABIN. CRUISING AT FL250 THE DUCT TEMP SHOWED 50 DEGS F AND THE CABIN TEMP INDICATED 75 DEGS F. PAX AND FLT ATTENDANTS RPTED THE CABIN WAS STILL WARM AND STUFFY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT ON THE RETURN MAINT FOUND THE L PACK AIR CYCLE MACHINE SEIZED AND WAS DEFERRED PER THE MEL AS THE PACK INOP. THE RPTR SAID THE FINDING ON THE R PACK WAS A 35 DEG DEICING VALVE THAT FAILED ALLOWING THE R WATER SEPARATOR TO ICE UP; BLOCKING COOL AIR FLOW.