Great Plains PFH-20 Operator Manual - Manual (Page 22)

20
Section 3 Troubleshooting
PH-15, PH-20, PFH-15 and PFH-20 Coulter Command System 148-384M 6/21/2004
Great Plains Mfg., Inc.
Depth sensing gauge wheel
not lowering to the ground
when Precision Hitch is low-
ered, or depth sensing gauge
wheel cylinder not fully
extending when the machine
is lowered. The lift switch cam on the rockshaft is not
properly adjusted. Adjust the lift switch cam. See "Lift Switch"
under Section 2 "Operating Instructions"
on Page 16.
Relief valve "M3" is set too low. Turn valve adjustment screw on top of valve
"M3" one eighth turn clockwise. Valve "M3"
is preset to relieve at 600 psi. Turning the
adjustment screw one eighth turn clockwise
increases the relief setting by approxi-
mately 75 psi.
!
CAUTION
Any attempt to set valve "M3" above 1200
psi could result in system malfunction. Set-
ting the valve "M3" above 750 psi will slow
down the lift cycle time.
Transport lift cylinders will not
retract completely. (Transport
tires will not lift off the
ground.) Relief valve "M4" is set too low. Turn valve adjustment screw on top of valve
"M4" one eighth turn clockwise. Valve "M4"
is preset to relieve at 900 psi. Turning the
adjustment screw one eighth turn clockwise
increases the relief setting by approxi-
mately 75 psi.
!
CAUTION
Any attempt to set valve "M4" above 1200
psi could result in transport frame or trans-
port rockshaft damage.
Problem Possible Cause Solution
Hydraulic Schematic
System Schematics
If problems occur in the hydraulic or electric systems,
refer to the schematics below and on page 21 to help
locate the problem.
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