Manitowoc National Crane NC1400H - Page 123

National Crane Published 10-30-2014 Control # 040-09 5-11
1400H OPERATOR AND SERVICE MANUAL SERVICE
TROUBLE DIAGNOSIS (continued)
CONDITION POSSIBLE CAUSE POSSIBLE SOLUTION
Hoist will not lift
or hold load
• Load too heavy.
• Hoist or boom overloaded causing RCL
shutdown.
• Relief valve setting too low.
• Motor worn.
• Sprag clutch defective.
• Load block too close to boom tip, two-block
system shut down.
• Brake worn out.
• Anti-two-block system defective.
• Check load and change to Lo-speed/Hi-pull or
applicable multipart reeving.
• Reduce load or reeve hoist properly for load lifting.
• Check and adjust if required.
• Replace motor.
• Clean or replace Sprag clutch.
• Lower load or retract boom. Check two-block
system, repair if defective.
• Repair or replace brake.
• Repair anti-two-block system.
Hoist gearbox
heats
• Gearbox grease low.
• Duty cycle too high.
• Check and fill as required.
• Reduce cycle time or speed of hoist.
Truck engine
will not start
• Emergency stop switch on crane console in
“STOP” position.
• Reset kill switch to operating position.
• Check all other normal motor vehicle systems as
outlined by normal practice.
Boom chatters
during
extension/
retraction or
doesn’t
proportion
properly
• Boom sections need lubrication.
• Wear pads not shimmed correctly.
• Boom hot from high extend duty cycle.
• Worn wear pads.
• Cylinder came out of lock.
• Extension cables out of adjustment.
• Extend or retract cables broken.
• Use dry lubricant or replace lube plugs in wear
pads.
• Reshim as described in boom assembly section.
• Slow duty cycle to cool boom and pads.
• Replace pads.
• Disassemble and reinstall keepers.
• Readjust cables and tension properly.
• Disassemble and inspect and replace cables.
Boom will not
extend
• Cables not attached correctly.
• Anti-two-block system shut down.
• Defective anti-two-block system.
• Overload causing RCL shutdown.
• Insufficient oil flow or pressure to extend
cylinder.
• Reconnect, replace and/or adjust cables.
• Lower hook, and extend load.
• Check anti-two-block system; repair if defective.
• Reduce load or radius till RCL resets and resume
operation.
• Check oil flow, repair if not to specification.
Reference Only