National Crane
Published 5-27-2018 Control # 039-06
7-13
800D
SIDE SHIMMING OF BOOM SECTIONS
CONTROL VALVE RELIEF ADJUSTMENT
The control valves supplied on this crane are equipped with
adjustable relief valves. After some time of use, it may be
necessary to make some adjustment in pressure because of
spring weakening, etc. The relief valves are adjustable only
through a specific pressure range.
Both the inlet of the main control valve and inlet of the hoist
valve have screw adjustable main relief valves. Turning the
relief in increases pressure relief setting; turning the relief out
decreases pressure relief setting.
The turn circuit pressure can be checked by plugging a port
on the turn motor with a pressure gauge. The pressure on
the main control valve stack should be checked by booming
the lift cylinder down against the end of the cylinder stroke.
The hoist circuit pressure can be checked by plugging a port
on the hoist motor with a pressure gauge.
The mid-inlet relief in the main control valve is a dual-
pressure relief. Adjustment is detailed below.
Mid-inlet Relief Adjustment
Relief Cartridge Adjustment:
Refer to the “Specifications”
section for correct standard pressure setting.
Adjusting the relief valve for the standard pressure
setting.
1. Remove the fitting from the relief valve at C.
2. Loosen jam nut A1 and with a wrench on the body at A2
either screw the body in or out. Screwing the body in
increases the pressure setting. Screwing the body out
reduces the pressure setting. The pressure can be read
on the gauge on the console during adjustment.
3. Once the correct pressure is attained, tighten jam nut A1
while holding the body with the wrench at A2.
4. Recheck the pressure on the console gauge to ensure
that tightening the jam nut has not changed the pressure
setting.
Never set pressure above recommendations
.
5. Reinstall the fitting at C.
Adjusting the relief valve for the secondary pressure setting.
Disconnect Drain Line from
Outlet End of Unloader Valve
Install Cap Fitting to Plug
Outlet End of Unloader Valve
Operate Function
Function Operates Correctly
No
Yes
Oil is Passing Through the
Check Valve in Another
Unloader
The Poppet in the Unloader is Not
Seated Correctly. Remove Unloader
and Flush to Dislodge Contamination
Cap Each of the Other Unloaders
in Turn to Identify the Unloader
with the Faulty Check Valve
Flush to Remove
Contamination Otherwise
Replace Unloader Valve
Reinstall, Retest and Replace
Unloader if Problem Persists
9421
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 ...