As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA FLIGHT NR 2257: AFTER PUSH BACK AND ENGINE START, DEICE CONT CIRCUIT BREAKER TRIPPED. AIRCRAFT RETURNED TO BLOCK. MAINTENANCE REMOVED AND REPLACED TMCU AND NR 2 HIGH PRESSURE SOV (P/N 820971-2). PERFORMED FUNCTIONAL CHECK OF THE AIRFRAME PNEUMATIC DEICING SYSTEM IAW Q400 AMM 30-11-00-720-801. FUNCTIONAL TEST GOOD. ALL OTHER INDICATIONS NORMAL. AIRCRAFT RETURNED TO SERVICE.