TM 9-4120-404-14
Table 3-3. Unit Troubleshooting.
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
5. REDUCED HEATING CAPACITY.
Step 1. Check air flow out of conditioned air outlet louver. If air flow volume is low:
Adjust intake air louvers.
Clean and service or replace conditioned air filter element.
Clean evaporator coil.
Step 2. Check operation of temperature control potentiometer.
Set control to fully WARM then, if condition improves, adjust properly.
If condition does not improve, test temperature control potentiometer per
Step 3. Check operation of heater cutout switch (S3).
Test and replace defective heater cutout switch per para. 3-30.
Step 4. Check individual heating elements (HR1 through HR6).
Replace defective heating element per para. 3-29.
WARNING
Disconnect input power before performing internal electrical troubleshooting.
Voltages used can be deadly.
Step 5. Check for loose or damaged wires and terminals.
Tighten loose or damaged terminals. Repair or replace damaged wires.
3-35
