Checklist D Procedures; Calibrate The Platform Overload System (If Equipped) - Genie GR-12 Service Manual

Section 3 • Scheduled Maintenance Procedures

Checklist D Procedures

D-1
Calibrate the Platform Overload
System (if equipped)
Yearly calibration of the platform overload system
is essential to safe machine operation. Continued
use of an improperly calibrated platform overload
system could result in the system failing to sense
an overloaded platform. The stability of the
machine is compromised and it could tip over.
Perform this procedure with the
machine on a firm, level surface.
1 Raise the platform approximately 2 feet / 70 cm.
2 Tag and disconnect the wire harness from the
load sense limit switch.
The load sense limit switch is
located near the platform support.
3 Set a multi-meter to measure continuity.
Connect the leads from the multi-meter to the
black and red wires disconnected from the limit
switch in step 2.
4 Determine the maximum platform capacity.
Refer to the machine serial plate.
5 Using a suitable lifting device, place a test
weight equal to that of the maximum platform
capacity at the center of the platform floor.
Secure the weight to the platform. Refer to the
chart below.
Standard Platform
(GR-12 and GR-15 models)
(GR-20 models)
AWP and Fiberglass Platform
(all models)
Stockpicker Platform
(GR-12 and GR-15 models)
(GR-20 models)
3 - 26
Determine the limit switch trigger point:
6 Gently move the platform up and down by hand,
so it bounces 1 to 2 inches / 2.5 to 5 cm.
7 Check the continuity between the black and red
wires originating from the limit switch of the
platform overload assembly.
Result: There is no continuity. Slowly tighten
the load spring adjustment nut by turning it
clockwise just until the limit switch closes and
shows continuity.
Result: There is continuity. Slowly loosen the
load spring adjustment nut by turning it
counterclockwise just until the limit switch
opens and shows no continuity.
Fine adjustment of the switch trigger point:
8 Continue moving the platform up and down and
adjust the load spring adjustment nut clockwise
or counterclockwise just until the limit switch is
alternately opening and closing.
9 Remove the continuity tester from the limit
switch wires. Securely install the wires onto the
limit switch.
229 kg
159 kg
159 kg
229 kg
159 kg
GR-12 • GR-15 • GR-20
November 2005
The platform will need to be
continuously moved up and down
while making adjustments.
When the limit switch is adjusted
correctly, there will be continuity
slightly longer than no continuity.
Part No. 84700
REV B