National Crane
Published 5-27-2018 Control # 039-06
5-31
800D
SERVICE
Anti-two Block Trouble Diagnosis — Hydraulic
Note: None of the internal parts of the unloader valves are serviceable.
Anti-Two Blocking System fails to
shut down hoist up, boom down
and boom extend
Do all three functions fail to
shut down
Remove unloader and flush
to dislodge contamination
that is blocking orifice
Check to ensure ATB
electrical system is working
properly. Refer to ATB
electrical diagnosis
Work with individual section
which fails to shut down
Examine solenoid valve for
sticking spool due to corrosion,
burrs, contamination, etc.
HYDRAULIC
ELECTRICAL
NO
YES
Disconnect drain line from
outlet end of unloader valve
Operate function at low
engine RPM
Oil flow from open port in
unloader valve
YES
NO
Poppet is not shifting.
Remove unloader and flush
to dislodge contamination.
Inspect to see that poppet is
free to shift in housing
Reinstall, retest and replace
unloader if problem persists
Reconnect drain line to outlet
end of uploader valve
9388
Fo
r
Reference
Only
Содержание National Crane 800D
Страница 1: ...Operator and Service Manual National Crane 800D F o r R e f e r e n c e O n l y ...
Страница 4: ...F o r R e f e r e n c e O n l y ...
Страница 98: ...MAINTENANCE 800D 3 10 Published 5 27 2018 Control 039 06 THIS PAGE BLANK F o r R e f e r e n c e O n l y ...
Страница 194: ...SPECIFICATIONS 800D 8 4 Published 5 27 2018 Control 039 06 THIS PAGE BLANK F o r R e f e r e n c e O n l y ...
Страница 216: ...INSTALLATION 800D 9 22 Published 5 27 2018 Control 039 06 THIS PAGE BLANK F o r R e f e r e n c e O n l y ...
Страница 232: ...CRANE INSTALLATION 800D 10 16 Published 5 27 2018 Control 039 06 THIS PAGE BLANK F o r R e f e r e n c e O n l y ...
Страница 252: ...SCHEMATICS 800D 2 Published 5 27 2018 Control 039 06 F o r R e f e r e n c e O n l y ...
Страница 255: ...F o r R e f e r e n c e O n l y ...
Страница 256: ...F o r R e f e r e n c e O n l y ...