21
NexStar Operation
HC-7X NEXSTAR
Counterbalance Override Procedures
If, in an emergency situation, it becomes necessary to lower the boom without hydraulic flow
available, the counterbalance valve located on the lift cylinder can be used to carefully perform this
action.
1. Ensure the boom will lower onto a proper support.
2. Loosen the lock nut and slowly turn adjustment screw clockwise until the boom begins to slowly
lower, counting the number of turns it takes to begin seeing movement.
3.
Remove hand/arm/fingers from cranes while boom is lowering.
4. After boom is lowered, turn adjustment screw counter-clockwise the approximate number of
turns made during lowering procedure and tighten lock nut.
Turning adjustment screw too far will cause valve to come apart on the
inside. This condition is not repairable, and the counterbalance valve must
be replaced.
Do not try to adjust any valves while boom is moving. Doing so may
result in personal injury!
Control Valve Override Procedures
1.
Push in and hold the red unloader valve (ULV) button. This will send hydraulic fluid to the valve
block.
2. Select the function valve desired and pull the knurled valve latching sleeve toward the end of
the valve stem until they are flush against each other (no gap).
3. With the latching sleeve against the end of the stem, push or pull the override stem for the
desired direction of movement (the farther the stem is depressed or pulled, the faster the
function will operate).
4. When manual operation is complete:
A. Release the unloader valve button to its original position.
B. Return the function stem(s) to its center position and center collar to avoid possible
unintended movement.
ULV
RED
BUTTON
MANUAL OVERRIDE PROCEDURES
1) PUSH IN THE UNLOADER VALVE (ULV) RED BUTTON. THIS WILL SEND HYDRAULIC FLUID
TO THE VALVE BLOCK.
2) SELECT THE FUNCTION DESIRED, THEN CLOSE THE GAP BETWEEN COLLAR AND THE END ON THE
OVERRIDE BUTTON.
3) PUSH OR PULL THE OVERRIDE BUTTON FOR THE DESIRED DIRECTION OF MOVEMENT. THE FARTHER
THE BUTTON IS DEPRESSED OR PULLED, THE FASTER THE FUNCTION WILL OPERATE.
4) WHEN MANUAL OPERATION IS COMPLETE, RELEASE THE UNLOADER VALVE BUTTON TO ITS
ORIGINAL POSITION.
NOTICE
!
WARNING