TM 9-2320-386-10 2-112 2-48. OPERATION OF SWINGFIRE HEATER a. General. The swingfire heater is a portable heater that can be used to heat the cargo body enclosure, engine and battery compartment of M35A3 cargo trucks equipped with swingfire heater arctic winterization kit. It may also be used to thaw frozen equipment. CAUTION Use only gasoline to operate swingfire heater. Using any other fuel may result in damage to swingfire heater. NOTE Each swingfire heater has its own fuel tank. b. Operation of Swingfire Heater. (1) Remove fuel tank cap (5) from swingfire heater (7) and fill fuel tank (4) with gasoline. Install fuel tank cap (5) on swingfire heater (7). (2) Depress pressure pin (3) to check operation of air shutoff valve. If pressure pin (3) does not return to out position, notify your supervisor. (3) Loosen wingnut (6) by turning counterclockwise and open cover (1). (4) Turn diaphragm valve (8) all the way clockwise. (5) Close cover (1) and tighten wingnut (6) by turning clockwise. (6) Make sure fuel regulator knob (2) is closed by turning clockwise. 3 2 1 7 6 5 4 8 7