TM 9-4120-371-14
Table 4-2. TROUBLESHOOTING (Cont.)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 5. Check to be sure that excessive cold, outside air is not being introduced through the fresh air
damper.
Fully close damper; then, if condition improves, adjust properly.
Step 6. Check air flow out of conditioned air (evaporator) discharge grille. If air flow volume is low:
a. Adjust conditioned air (evaporator) intake grille louvers.
b. Clean and service or replace conditioned air filter element. (See para 4-34.)
c. Clean and service or replace mist eliminator. (See para 4-36.)
d. Clean evaporator coil and entire evaporator section. (See para 4-65.)
Step 7. 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 4-37.)
Step 8. Check operation of heater thermostat (S4).
Test thermostat. (See para 461.) Replace thermostat if defective.
Step 9. Check individual heaters (HR1 through HR6).
Test heaters. (See para 462.) Replace defective heaters.
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