TM 9-2320-209-34-2-3 21-5. POWERPLANT HEATER TEST. TOOLS: No special tools required SUPPLIES: None PERSONNEL: One EQUIPMENT CONDITION: Truck parked, engine off, handbrake set. a. Preliminary Procedure. Remove power plant heater. Refer to para 21-6. b. Testing. WARNING Smoking, sparks or open flames are not allowed within 50 feet of work area during this task. Fuel can explode, causing injury to personnel and damage to equipment. Exhaust gases of any fuel are very poisonous. Be sure exhaust is directed out of work area. Be sure work area is well ventilated. Failure to do so could result in injury or death to personnel. CAUTION Be sure test stand is equipped with proper con- trol box. Proper control box is pn G-701633. Damage to equipment will result if improper con- trol box is used. Test stand must also be equipped with a coolant container of about five-gallon capac- ity. Container should be higher than heater. Con- tainer must be vented. Coolant used must be of same type as used in engine. Pure water cannot be used. Failure to use proper coolant could cause overheating and improper operation of thermostats, damaging heater. NOTE A fuel burning coolant heater test stand and stop watch is needed to perform these tests. Such a test stand can be fabricated. Refer to ST 9-194. (1) Fuel control valve. CAUTION Fuel flow and leak tests must be done with fuel control valve in the position it normally operates. Fuel used must be of the type Failure to do this could result ment, causing serious damage normally used. in a wrong measure- to equipment. 21-2