TM 9-2320-361-34 17-19. ENGINE COOLANT HEATER TESTING THIS TASK COVERS: a. Preparation e. Blower Motor Test b. Igniter Test f. Restriction Thermostat Test c. Flame Detector Switch Test g. Overheat Switch Test d. Fuel Control Valve Test h. Test Equipment Removal INITIAL SETUP APPLICABLE MODELS All TEST EQUIPMENT 24-volt DC power source Fuel container Coolant container (5gal.) Test stand Thermometer Flowmeter Multimeter (Appendix B, Item 3) MATERIALS/PARTS Antifreeze (Appendix C, Item 3) REFERENCES TM 9-2320-361-20 TM 9-2320-361-34P EQUIPMENT CONDITION Engine coolant heater removed (TM 9-2320-361-20). GENERAL SAFETY INSTRUCTIONS ● Keep fire extinguisher nearby when working with open fuel lines. ● Do not perform procedure near open flame, smoking, or sparking object. . Do not perform procedure in enclosed areas. ● Allow time for heater to cool before removing from test equipment. a. Preparation WARNING ● Do not perform this procedure while smoking or within 50 feet of sparks or open flame. Fuel is flammable and can explode easily, causing injury or death to personnel and damage to equipment. ● Exhaust gases can kill. Do not operate personnel heater in enclosed areas. Ensure work area is well-ventilated and exhaust fumes are directed away from test area. NOTE ● Perform “preparation” subtask before performing any test and perform “test equipment removal” after each test is complete. ● Heater must be tested in same position as mounted on vehicle. . Use proper coolant required for engines which are being heated. Water cannot be used because the overheat switch and restriction thermostat are set for temperatures above the boiling point of water. 1. Connect coolant heater (13) to test equipment using schematic on next page. NOTE . Coolant container must be vented and raised above the test apparatus in order for thermosyphon circulation to occur. ● Fuel pump, fuel filter, heater, wiring harness, fuel tubing, control box, and coolant must be the same type used on vehicle. 17-48