Operator`s manual

the oil to return to the reservoir (1) via the filter (4). To prevent a build-up of excess pressure in the
hydraulic lines, the check valve, which is part of the filter (4), allows oil to return to the Reservoir (1) if the
filter is clogged.
When the accelerator button on the Outrigger Control Panel is pressed, or the green Throttle Control
Button on the Ladder Control Console is pulled up, the hydraulic oil follows the same path as described
above and the Relief/Unloader Valve (14) opens a little more. When oil is directed to the ladder hydraulic
circuit, the Hydraulic Pressure Gauge (15) on the Ladder Control Console indicates that there is hydraulic
pressure to the ladder hydraulic circuit. When the green Throttle Control Button is pulled up and the
ladder is stationary, pilot pressure is 450 psi.
5.3 AUXILIARY POWER
If truck engine power is not available, pressure still can be raised by either the electric pump or the hand
pump. The hydraulic flow follows the same path as that used when the main pump (7) is available.
However, the rate of oil flow when using either auxiliary system is less than that provided by the main
pump.
5.4 OUTRIGGER HYDRAULICS
Selector valve (12) directs the flow of oil to the outrigger circuit (see Figure 5-2-1) when the
"OUTRIGGER" position is selected. The outrigger cylinders (52 and 54) are activated in one direction or
the other by the Outrigger Control Valves (50 and 53). When the Outrigger Control Valve is in the
"EXTEND" position, the flow of oil is directed to the upper side of the outrigger cylinders. In the
"RETRACT" position, the flow of oil is directed to the lower end of the cylinders.
A twin pilot check valve (51) is located at each cylinder to lock the cylinder in place in the event of a line
pressure drop.
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