TM 9-4120-402-14
Table 5-1. DIRECT SUPPORT TROUBLESHOOTING - continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
3. INSUFFICIENT COOLING ACTION. - continued
Step 5. Check sight glass after operating unit for 15 minutes with potentiometer TEMPERATURE control in
maximum COOL position. Center should be bubble free and green.
If charge is low, add refrigerant. (See paragraph 5-17.) Bubbles may also be caused by clogged
refrigerant desiccant dehydrator. (See paragraph 5-21.)
WARNING
Use great care to avoid contact with liquid refrigerant or refrigerant gas being discharged from
any container under pressure. Sudden and irreversible tissue damage can result from freezing.
Wear gloves and a face protector or safety glasses in any situation where skin or eye contact is
possible.
Prevent contact of refrigerant gas with flame or hot metal surfaces. Heat causes the refrigerant
to break down and form carbonyl chloride (phosgene), a highly toxic and corrosive gas.
Step 6. Check for refrigerant leaks. (See paragraph 5-15.)
Repair or change defective part.
WARNING
Disconnect power from the air conditioner before doing any maintenance work to the electrical
system. High voltage in air conditioner can kill.
Step 7. Check solenoid valve. (See paragraph 5-28.)
Repair or replace if defective.
Step 8. Check expansion valve for proper operation. (See paragraph 5-30.)
Replace if defective.
5-6
