As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT PERFORMED AN AIR TURNBACK. BOTH NR 1 AND 2 ENGINES DEICE FAULTED IN FLIGHT. FAULTED AGAIN AFTER RESETS. WITH ICE ACCUMULATING AND FURTHER ICE EXPECTED ENROUTE AND APPROACH, THE CREW MADE THE DECISION TO RETURN TO DEPARTURE. NO EMERGENCY WAS DECLARED. MAINTENANCE REPLACED THE NR 1 ENGINE DEICE REGULATOR SHUTOFF VALVE. OPS CHECKED GOOD. AIRCRAFT RETURNED TO SERVICE.