TM 9-4120-403-14
TABLE 4-2. UNIT TROUBLESHOOTING (cont)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 2. Check operation of time delay relay (K9)
Test relay. (See para 4-39.) Replace if defective.
Step 3. With unit operating in COOL mode, check condition of refrigerant in sight glass.
If color is in yellow zone, or if numerous bubbles appear in the window, turn selector
switch to OFF, and notify your supervisor.
Step 4. Check operation of temperature control thermostat (S 1)
Test thermostat. (See para 4-28.) Inspect sensing bulb and capillary for damage or
leakage. Replace if defective. If malfunction still exists, notify your supervisor.
6. REDUCED HEATING CAPACITY
Step 1. Check operation of heater thermostat (S3).
Test thermostat. (See para 4-54.) Replace thermostat if defective.
Step 2. Check individual heaters (HR1 thru HR6).
Test heaters. (See para 4-58.) Replace defective heaters.
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