Table 4-2 Unit Troubleshooting - Continued
TEST OR INSPECTION
HYDRAULIC SYSTEM - Continued
LADDER DOES NOT OPERATE
Step 1. Check position of manual override.
Ensure manual override handle is in neutral position and moves fr ely.
Step 2. Check that aerial system has engaged.
Ensure DIVERTER VALVE AERIAL/OUTRIGGER switch is in AERIAL position.
Step 3. Check for possible aerial interlock malfunction.
Refer to electrical troubleshooting procedures to test aerial interlock system
Step 4. Check that diverter valve has not shifted to aerial position.
Refer to electricai troubleshooting procedures and test diverter valve solenoid, if solenoid
tests good refer to Direct Support maintenance to replace diverter valve.
Step 5. Check for malfunctioning ladder control valve.
Refer to Direct Support maintenance level to repair or replace control valve.
Step 6. Check for low hydraulic oil level.
Refill to proper level.
Step 7. Check for leaks in hydraulic swivel.
Refer to Direct Support maintenance level to replace hydraulic swivel.
Step 8. Check for defective swing motor thermal relief valve in port N of swing cross-over manifold
Replace swing motor thermal relief valve if SYSTEM PRESSURE is not within 2400-2450
PSI when DIVERTER VALVE AERIAL/OUTRIGGER switch is in AERIAL position (see