What was found
AFT LT LAV SMOKE DET BEEPING IN FLT. WATER HEATER WAS VERY HOT INITIALLY OPENED DETECTOR AND DISCONNECTED BATTERY NO ODOR DETECTED. PULLED CB'S FOR AFT LT LAV MIRROR, FLUSH MOTOR AND WATER HEATER. RAN HOT WATER UNTIL COOL. AFT F/A INTERPHONE PANEL WAS WARM BUT BECAME COOL. RE-ATTACHED SMOKE DET BATTERY RED LIGHT OUT, NO BEEPING. RESET ALL CB'S, INSPECTED AFT LT LAV FOUND WATER HEATER OVERHEATING. PULLED AND COLLARED C/B FOR WATER HEATER. FWD TO MCO AND PLAC PER MEL 25-00-12D. ALSO FOUND WATER IN SMOKE DETECTOR. REPLACED SMOKE DETECTOR, NO WATER LEAKS FOUND.