TM 9-4120-388-14
Table 5-1. Troubleshooting for Direct Support Maintenance - Continued.
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
2. COMPRESSOR SHORT CYCLES.
Step 1. Check for obstructions in front of condenser guard.
Remove obstructions and/or roll up and secure canvas cover.
Step 2. Check if HIGH PRESSURE cutoff switch RESET is out.
Push HIGH PRESSURE switch to RESET.
3. lNSUFFICIENT COOLING ACTION.
Step 1. Check control settings.
a. Move mode selector switch to COOL.
b. Move temperature selector switch to INCREASE.
If normal cooling does not resume in 15 minutes, go to Step 2.
NOTE
Frost on the evaporator coil is usually caused by an obstruction to airflow or dirty evapo-
rator coil, filter, or mist eliminator.
Step 2. Make sure grilles are open.
Replace if defective. (See para 4-23 and 4-24.)
Step 3. Be sure evaporator and condenser fans are tight on motor shaft. (See para 4-62.)
Tighten if loose. (See para 4-62.)
Step 4. Check area near condenser guard and fresh air inlet for heat source over 120F (40C).
Remove heat source.
Step 5. Check sight glass after operating unit for 15 minutes with temperature switch in maximum COOLER position.
Center should be bubble free and green.
Add refrigerant. (See para 5-12.)
Use great care to avoid contact with Iiquid refrigerant or refrigerant gas being dis-
charged from any container under pressure. Sudden and irreversible tissue dam-
age can result from freezing.
Wear thermal protective gloves and a face protector or safety glasses in any situa-
tion where skin or eye contact is possible.
Prevent contact of refrigerant gas with flame or hot metal surfaces.
Heat causes the refrigerant to breakdown and form carbonyl chloride (phosgene),
a highly toxic and corrosive gas.
5-3
