FUNCTIONS AND CONTROLS
GTZZ14EJ&16EJ Maintenance Manual
101
© May 2023
The maximum working envelope limit function is essen-
tial for the safe operation of the machine, which, if failed,
may affect the stability of the machine. It is recom-
mended to check the maximum working envelope limit
function every 3 months or after 250 hours of operation.
NOTICE
If the machine operation cannot be accurately
restricted during the test, please immediately lower
the platform to the stowed position, turn off and mark
the machine, and contact a qualified service
technician for inspection and repair.
A travel switch is used to detect the boom position and
limit the boom from further extending when the boom
length exceeds the maximum horizontal reach.
1. Start the machine from the turntable control box.
2. Move the articulated boom luffing switch to fully re-
tract the articulated boom.
3. Move the main boom luffing switch and the jib boom
luffing switch (if any) to adjust the main boom and
jib arm (if any) horizontal.
4. Move the main boom telescoping switch to extend
the main boom.
5. GTZZ14EJ: When the main boom extends to the
farthest position, the main boom cannot continue to
extend, nor can it be lifted or lowered, but can be re-
tracted, and the turntable can slowly rotate. Then
measure the horizontal reach, which should be
7.6m (24ft 11in) (distance from the center of the
slewing bearing to the outermost side of the
platform).
6. GTZZ16EJ: When the main boom extends to the
farthest position, the main boom cannot continue to
extend, nor can it be lifted or lowered, but can be re-
tracted, and the turntable can slowly rotate. Then
measure the horizontal reach, which should be
9.3m (30ft 6in) (distance from the center of the slew-
ing bearing to the outermost side of the platform).
7. Move the main boom telescoping switch to fully re-
tract the main boom.
9.5 OVERLOAD LIMIT FUNCTION
The rated load capacity of the platform is clearly speci-
fied in the Machine Specifications section of this man-
ual, and if the platform is overloaded, the machine
operation should be limited.
The proper functioning of the overload limit system is
essential for the safe operation of the machine, which
may affect the stability of the machine. It is recom-
mended to check the overload limit function every 3
months or after 250 hours of operation.
Select flat, level, unobstructed and solid ground to per-
form the following tests with the platform unloaded:
1. Start the machine.
2. Fully raise and lower the boom and retract and ex-
tend the boom twice separately to ensure that the
machine has no obvious shaking and abnormalities,
and is properly lubricated.
3. After lowering the platform to the stowed position,
gradually apply load to the platform according to the
rated load capacity of the platform.
NOTICE
If the machine operation cannot be accurately
restricted during the test, please immediately lower
the platform to the stowed position, turn off and mark
the machine, and contact a qualified service
technician for inspection and repair.
The test results should be as follows if the overload limit
system works normally:
Table 9-2
Mode Test results
KG mode
When the load on the platform exceeds 230kg (507lb), the buzzer will sound, the overload
indicator light will flash, the display will indicate overload, and all functions will be disabled.
After the excess load is removed, all functions will be resumed.
Non-KG mode
When the load on the platform exceeds 230kg (507lb), the buzzer will sound, the overload
indicator light will flash, the display will indicate overload, and certain functions will be disabled.
But the main boom can be retracted, the articulated boom can be lowered, the turntable can
rotate slowly, and the main boom can be lowered after fully retracted. After the excess load is
removed, all functions will be resumed.
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