Manitowoc NATIONAL CRANE 900A - Jib HCA Adjustment

2-19
Jib HCA Adjustment
1. Set HCA Selector Switch to JIB position.
2. Remove the console cover depending on the crane
model.
3. Start the truck and set the crane up for operation,
including erecting the jib, as prescribed in the Safety and
Operation section.
4. Set up a test weight that is equal to the jib load
rated capacity.
5. With the jib erect and the boom fully extended.
Elevate the boom to 80°.
a. Raise the test weight with the winch.
6. Set the Jib Compensating Pressure Switch:
a. Boom down to rated radius.
b. Remove the acorn nut from the jib
compensating pressure switch and loosen
the locking nut.
i. Slowly turn the set screw
counter clockwise until the
pressure switch trips. HCA
system trip will be indicated
when the HCA Indicator Light
becomes lit.
7. Boom up to reduce the radius of the test weight.
a. Lower the test weight to the ground,
using the winch if necessary, to reset the
jib compensating pressure switch.
8. Check Rated Radius:
a. Raise the test weight with the winch
b. Boom down very slowly until the jib
compensating pressure switch trips.
c. Measure the radius of the test weight and
verify that it does not exceed the rated
radius as specified on the capacity chart.
9. If the radius is not correct, adjust the Jib Pressure
Compensating Switch.
a. To increase the allowable radius of the
test weight:
i. Turn the set screw Clockwise to
increase the radius.
b. To decrease the allowable radius of the
test weight:
i. Turn the set screw Counter-
Clockwise to decrease the radius
10. Repeat Steps 7,8, and 9 until the jib compensating
pressure switch is properly set.
11. After proper adjustment is verified, tighten the
locking nut on the jib Compensating Pressure
Switch and install the acorn nut.
12. Return the boom to a firmly supported position.
13. Stop the Truck Engine .
14. Replace the console cover.
'4$&$
1. Boom 2. Jib
'4$&%('$6$
1. Jam Nut 2. Acorn Nut
Reference Only