What was found
SEA FLIGHT NR 2263: WHEN AIRFRAME ICE PROTECTION WAS SELECTED, THE NR 2 BOOT PAIR ON THE FO'S SIDE DID NOT INFLATE RESULTING IN A DEICE PRESSURE CAUTION LIGHT. RAN THE CHECKLIST. ALL PRESSURES WERE NORMAL. WHEN DESCENDING INTO WARMER TEMPERATURES, THE SYSTEM STARTED WORKING NORMALLY. MAINTENANCE REMOVED AND INSTALLED SERVICEABLE RT OUTBD DDV IAW Q400 AMM 30-11-16-000-801 AND 30-11-16-400-801. OPS TEST PASSED IAW Q400 AMM 30-11-16-710-801. WITH VALVE REMOVED, PURGED DEICE LINES TO REMOVE MOISTURE. NO MOISTURE WAS NOTED. AIRCRAFT WAS RETURNED TO SERVICE.