As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FWD AFT LAV SMOKE DETECTOR WENT OFF (REPEAT). HOT IRON TYPE ODOR EMANATING FROM THAT LAV. UPDATE-CREW TURNED OFF WATER HEATER AND RAN ALL HOT WATER OUT OF HEATER. ODOR HAS NOW DISSIPATED. NO SMOKE WAS SEEN. SMOKE DETECTOR OK. WATER HEATER OVERHEATING. ITEM DEFERED.