TM 9-2320-209-20-3-4 c. Replacement. FRAME 1 Soldier A 1. Put air inlet adapter (1) in place on firewall (2) as shown. Aline two screw holes and put in two screws (3). Using screwdriver, hold two screws and tell soldier B when ready. Soldier B 2. Using 11/32-inch wrench, screw on and tighten two nuts and washers (4). 3. Put heater duct (5) on air inlet adapter (1). Using screwdriver, tighten duct clamp (6). GO TO FRAME 2 23-11