TM 9-2320-361-10 2-27. OPERATION OF WATER TANK TRUCKS (Contd) (8) (9) (10) (11) (12) (13) (14) (15) Discharge water. Push compartment valve lever (1) or (2) forward, to closed position. Turn gravity delivery line suction valve knob (3) right, to closed position. Press nozzle (8) operating lever to release pressure. Remove nozzle (8) from hose (7) and secure. Remove hose (7) from coupling (5) and secure. Remove coupling (5) from adapter (4) and secure. Install gravity delivery line suet ion valve dust cover (6). g. Operating Water Tank Trucks During Freezing Temperatures. CAUTION Do not heat water tank with less than 10 inches of water in both front and rear tank sections. Metal expansion due to heat may cause cracks in seams and welds. (1) Remove padlock (9), lift cover clamp (11), and open filler cover (10). 2-128