TM9-4120-400-14
Table 4-2.
TROUBLESHOOTING - continued
MALFUNCTION
TEST OR INSPECTION
C O R R E C T I V E ACTION
4. INSUFFICIENT COOLING. - continued
Step 7. Check if supply air outlet louver is blocked or set in closed position. (See para 4-14.)
Remove blockage or open louver.
Step 8. Observe evaporator fan motor for worn or defective condition. (See para 4-41.)
Replace motor.
Step 9. Check if evaporator and condenser fans are loose or defective. (See para 4-41 and 4-44.)
Tighten setscrew or replace fan.
Step 10. Check area near condenser guard and fresh air inlet for heat source over 12F (40C).
Remove heat source.
5. COMPRESSOR WILL NOT START.
Step 1. Check that compressor or control circuit breakers or selector switch is properly set.
Reset controls properly.
Step 2. Check if contacts of HIGH-or-LOW PRESSURE cut-out switch are open.
Reset pressure switches. Notify supervisor if condition continues.
Tighten loose connections. Fix wiring if necessary.
Step 4. Make continuity check of control circuit to determine whether open circuit exists.
Fix open circuit or replace wire.
Step 5. (Three phase units only.) Check phase sequence relay.
Step 7. Check forward and reverse resistance of rectifier assembly diodes. (See para 4-39.)
Replace bad rectifier.
4-33