TM-9-2320-361-24-2 Field Maintenance Manual Volume 2 for M44A2 Series Trucks
Page 858 of 1144
TM 9-2320-361-24-2 0426 00 0426 00-6 ENGINE COOLANT HEATER TESTING (Contd) FLAME DETECTOR SWITCH TEST 1. Place switch (3) in START position. 2. When indicator lamp (4) illuminates, place switch (3) in RUN position. 3. If indicator lamp (4) does not light adjustor, replace flame detector switch (6) (WP 0417 00). 4. Place switch (3) in OFF position. FUEL CONTROL VALVE TEST 1. Place switch (3) in START position. 2. When indicator lamp (4) illuminates, place switch (3) in RUN position. 3. Check fuel consumption at flowmeter (1). Fuel consumption should be 8-11 cc/min at low heat, and 14-19 cc/min at high heat. Replace fuel control valve (7) if fuel consumption rate is not within limits (WP 0421 00). 4. Check operating amperage on ammeter (2). If operating amperage exceeds 4 amperes, check heater wiring. Replace damaged parts (WP 0417 00–WP 0425 00) as necessary. 5. Move switch (5) from LO to HI position. Burning in heater (8) should intensify or decrease. Replace fuel control valve (7) if burning in heater (8) does not intensify or decrease (WP 0421 00). 6. Place switch (5) in LO position. 7. Place switch (3) in OFF position. BLOWER MOTOR TEST 1. Place switch (3) in START position. 2. When indicator lamp (4) illuminates, place switch (3) in RUN position. Allow heater to run for a few minutes. NOTE Purge time is the interval from turning control box to OFF position until the indicator lamp goes out. 3. Place switch (3) in OFF position and record purge time. Burning should stop within thirty seconds; blower motor should continue to run up to three minutes. Replace or adjust flame detector switch (6) (WP 0417 00) if purge time exceeds three minutes.