Grove Published 3-22-2021, Control # 702-02 5-57
GRT8120 OPERATOR MANUAL SET-UP AND INSTALLATION
Setting the Offset Angle without an Auxiliary Crane
If an auxiliary crane is not available, the extension head must
rest on the ground before the angle is changed.
1. Extend and set the outriggers.
2. Program the Rated Capacity Limiter (RCL) with the
correct rigging code for the chosen boom extension
offset angle (refer to Entering the RCL Code, page
5-57).
3. Swing boom over rear of crane.
4. Lower and extend the boom until boom extension nose
touches the ground and pressure is relieved from the
adjusting pin (1, Figure 5-79).
If unable to touch the ground due to the limitations of the
rigging code, incline the crane (refer to Inclining the
Crane, page 5-57).
5. Remove the adjusting pin.
6. Raise or lower the boom until the adjusting pin can be
installed into the hole for the required angle (refer to
Figure 5-79).
7. Install the pin into the 0° or 20° offset hole, and then
secure with the retaining clip. If offset is to be 45°,
remove pin and store in the operator cab.
Entering the RCL Code
Enter the RCL rigging code for the boom extension offset
angle in accordance with the current rigging mode of the
crane, refer to the Load Chart, Chapter Remarks.
When adjusting the angle without an auxiliary crane, you
must enter an RCL rigging code. The RCL rigging code
depends on:
• the rigged outrigger span
• the rigged counterweight
• the working position.
The superstructure must be in a working position permitted
by the Load Chart for the RCL rigging code that was entered.
Inclining the Crane
In order to set the offset angle of the adjustable extension,
you must set it down on the ground by extending and
lowering the main boom over the rear.
Depending on the space available, the condition of the
terrain or a limitation on the telescoping due to the current
rigging mode, it may be that the nose of the boom extension
cannot be set on the ground by telescoping and lowering the
main boom.
In this case, you can use the outriggers to incline the crane.
1. Fully extend the front outriggers and jack cylinders.
2. Fully extend the rear outriggers.
3. Extend the rear jack cylinders until the rear wheels are
just off the ground.
Offsetting the (Optional) Hydraulic Boom
Extension
Use the following procedure to set the offset for the hydraulic
boom extension. The hydraulic boom extension offset range
is 0° to 45°.
1. In the operator cab, enable the Luffing Jib Enable/
Disable Switch. For more information about the Luffing
Jib Enable/Disable Switch, see Operator Seat and
Armrest Controls (Dual Axis), page 3-20.
2. Using the right joystick, raise or lower the hydraulic
(luffing) boom extension. For more information about the
Boom Lift – Main Hoist – Telescope – Luffing Jib
Controller (Dual Axis), see Operator Seat and Armrest
Controls (Dual Axis), page 3-20.
CAUTION
Rope Damage!
The hoist cable can be damaged if it is reeved while the
extension nose is on the ground. Unreeve the hoist cable
from the extension nose before adjusting the offset angle.
WARNING
Tipping Hazard!
Make sure that the wheels do not touch the ground when
the crane has been inclined. This prevents a reduction in
the stability of the crane, which could lead to it tipping over
when setting the angle of the lattice extension or
overloading the axles, causing serious injury or death.
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