What was found
(CAN) LOUD NOISE WITH HEAT REPORTED BEHIND SEAT 36A. FLOOR BECAME TOO HOT TO TOUCH. NR 2 PNEUMATIC SYSTEM SELECTED OFF, NOISE STOPPED, BUT AREA BETWEEN 36A AND LAVATORY BECAME HOTTER. PNEUMATIC ISOLATION VALVE 1-2 IN THE NORMAL POSITION (CLOSED). OVER A PERIOD OF 30 MINUTES, AREA BEGAN TO COOL. AIRCRAFT DIVERTED. FOUND AFT LAV/GALLEY VENT REGULATING LINE DAMAGED. LINE AND BULK CARGO HEAT VALVE REPLACED AND LEAK CHECK CARRIED OUT OK.