OPERATION
4-24 / Mid-Mount Ascendant Aerial Tower
© 2021 Pierce Manufacturing Inc. All Rights Reserved.
4-6.3
Stabilizer Interlock Override
4-6.3a
Electronic Controls Override
Your apparatus includes stabilizer interlock devices, sensors, and other electrical devices that may malfunction and
require repair. A malfunction may prevent further stabilizer operation. If this happens, you can override the interlocks
as follows:
1. Position one assistant to monitor and relay back all stabilizer movements.
2. Position a second assistant at the OVERRIDE SWITCH located above the stabilizer remote control.
3. Instruct the second assistant to pull the cover back and lift UP and HOLD switch in that position.
4. At the Manual Override Control Manifold, move the OVERRIDE SELECTION CONTROL lever to the RIGHT
and HOLD to activate the Stabilizer System hydraulic power.
5. At the Manual Override Control Manifold, operate Override Control Lever for desired function while first assistant
relays stabilizer movement.
6. Once stabilizers are in the desired position, release the OVERRIDE SELECTION CONTROL lever.
7. Instruct the second assistant to release the OVERRIDE SWITCH.
4-6.4
Hydraulic Power Supply Failure
If your apparatus engine, power take-off, or hydraulic pump fail, your apparatus includes a source of backup power.
The Emergency Power Unit (EPU) provides sufficient power to store the aerial device and stabilizers. The EPU runs
off battery power and motions will be much slower than during normal operation. Use the following procedure to
operate using the EPU.
4-6.4a
Aerial EPU Operation
NOTE:
If the electronic system has failed and the manual aerial or stabilizer controls are being used, the
EPU switch located at the manual stabilizer controls will be the only one active. For aerial EPU
operation, locate an assistant at the manual stabilizer control area who can activate the
EMERGENCY HYDRAUL POWER switch at the direction of the primary operator.
1. Remove personnel from the ladder.
2. Select the desired aerial motion by moving one of the motion control levers at the control console.
3. ENGAGE and HOLD the EMERGENCY HYDRAULIC POWER switch at the control console to begin and
sustain motion.
4. When desired motion in the selected direction is complete, RELEASE the EMERGENCY HYDRUALIC POWER
switch.
5. RELEASE the motion control lever.
6. Repeat these steps until the aerial is properly stowed.
Follow these instructions to avoid EPU system damage
•
Only use the EPU when the main hydraulic system is not operating.
•
DO NOT run the EPU for more than 30 minutes without allowing 30 minutes for cooling down.
Limiting loads and pressures will allow for more efficient use of the EPU and will also generate less
heat.
•
Only activate the EPU after the desired function is selected.