National Crane Published 10-30-2014 Control # 040-09 5-9
1400H OPERATOR AND SERVICE MANUAL SERVICE
TROUBLE DIAGNOSIS
The following chart lists malfunctions which may occur during equipment operation, followed immediately by possible
cause and possible solution. These are not all inclusive but are designed to help isolate the problem and should be checked
before calling the factory Service Department.
CONDITION POSSIBLE CAUSE POSSIBLE SOLUTION
No response to
control
• RCL power switch in truck cab off.
• Load too heavy.
• RCL inoperative.
• PTO not engaged.
• Low hydraulic fluid supply.
• Suction line blocked.
• Broken hydraulic pressure line.
• Defective hydraulic pump.
• Incorrect relief valve setting.
• Relief valve sticking.
• Turn RCL power switch on.
• Check Capacity Chart.
• Insure RCL is programmed properly and Anti Two
Block/Overload solenoids are powered.
• Engage PTO.
• Check and fill as required.
• Drain tank and hose and remove blockage.
• Replace as required.
• See Pump Service Manual.
• Adjust relief.
• Clean relief or replace.
Poor hydraulic
system
performance
• Pump not operating at proper speed or
proper displacement.
• Low hydraulic fluid supply.
• Relief valve sticking.
• Relief setting too low.
• Worn pump, motor or cylinder.
• Plugged filter.
• Valve spools not fully open.
• Plugged diffuser.
• Boom holding valves out of adjustment or
dirty.
• Hydraulic oil too cold.
• Line restricted.
• Plugged suction strainers.
• Internal valve crack.
• Load too heavy.
• Oil temperature too high.
• Check PTO ratio, pump size and engine speed for
proper oil flow (see pump manual).
• Check and fill as required.
• Remove and clean.
• Readjust to proper setting.
• Replace bad part.
• Change filter.
• Adjust linkage so valve has full throw.
• Remove from tank and clean.
• Adjust or clean as required.
• Warm oil or use less viscous oil.
• Check lines; clean and repair as necessary.
• Remove strainers from tank and clean.
• Replace valve.
• Check Capacity Chart and reduce load.
• Reduce engine RPM or slow cycle time to cool oil.
Add oil cooler option if not equipped.
To Next Page
Loading...
