TM 9-4120-388-14
Table 4-2. Unit Troubleshooting (Cont.)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
step 4. Be sure that excessive cold, outside air is not being introduced through the fresh air damper.
Fully dose damper; then, if condition improves adjust properly.
Step 5. Check air flow out of conditioned air (evaporator) discharge grille. If airflow volume is low:
a. Adjust conditioned air (evaporator) intake grille louvers.
b. Clean and service or replace conditioned air filter element. (See para 4-33.)
c. Clean and service or replace mist eliminator. (See para 4-35.)
d. Clean evaporator coil and entire evaporator section. (See para 4-64.)
Step 6. Check for loose or damaged wires and terminals.
Disconnect Input power before performing internal electrical troubleshooting.
Voltages used can be deadly.
Tighten loose or damaged terminals. Repair or replace damaged wires. (See para 4-36.)
step 7. Check operation of heater thermostat (S4).
Test thermostat. (See para 4-60.)
Replace thermostat if defective. (See para 4-60.)
Step 8. Check individual heaters (HR1 through HR6).
Test heaters. (See para 4-61.)
Replace defective heaters. (See para 4-61.)
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