What was found
ON FLIGHT 4060 THE CREW REPORTED THAT THE PACK 2 VALVE CLOSED ON EICAS. THE CREW RESET PER AOM, PACK 2 VALVE RESET THEN CLOSED AGAIN (PACK 2 VALVE CLOSED). THIS WAS FOLLOWED BY A BURNING ODOR IN THE COCKPIT, WHICH CLEARED AFTER 3 MINUTES. THE AIRCRAFT WAS REMOVED FROM SERVICE. FOUND COUPLING AT DUAL TEMPERATURE CONTROL VALVE BLOWN OUT THAT GOES TO THE HEAT EXCHANGER. REMOVED AND REPLACED THE COUPLING IAW AMM 21-60-01. THE OPERATIONAL CHECK WAS GOOD. NO ODOR NOTED. THE AIRCRAFT WAS RETURNED TO SERVICE.