TM 9-2320-386-10 2-12 c. Arctic Winterization Kit (Contd). Key Item and Function 1 Power plant heater shutoff cock is opened (turned left) to let fuel enter power plant heater combustion chamber. 2 Personnel heater shutoff cock is opened (turned left) to let fuel enter person- nel heater combustion chamber. Key Item and Function 3 Hardtop closure replaces canvas cover on cab for arctic temperature operations. 4 Quilted radiator cover is attached to brush guard to maintain normal oper- ating temperatures under arctic operating conditions. 5 Aperture flap is opened or closed to control amount of air passing through radiator. 2-4. SPECIAL PURPOSE KITS CONTROLS AND INDICATORS (Contd) 2 1 2 1 3 4 5