Great Plains 3S-4000HDF Operator Manual - Manual (Page 26)

22 3S-4000HD/HDF Table of Contents Index Great Plains Manufacturing, Inc.
195-067M Table of Contents Index 2013-06-13
Setting the Bypass Valve
Refer to Figure 12
A bypass valve is plumbed into the opener down
pressure circuit. Tractors with load-sensing,
closed-center hydraulics require this bypass valve to
protect the tractor hydraulic system.
If you are unsure what type of hydraulic system is on
your tractor, contact your tractor manufacturer.
Turn the locking disc counter-clockwise to enable
adjustment.
Turn the adjustment knob counter-clockwise to
increase flow.
Turn the adjustment knob clockwise to decrease flow.
Turning it fully clockwise stops all bypass flow.
Tractors with Open Center Hydraulics
Release locking disc. Close bypass valve for no oil flow
by turning knob on valve clockwise completely. Tighten
locking disc. Always operate the drill with the bypass
valve locked closed.
Tractors with Pressure Compensating
Closed Center Hydraulics (PC Closed)
Release locking disc. Close bypass valve for no oil flow
by turning knob clockwise completely. Tighten locking
disc. Always operate the drill with the bypass valve
locked closed.
Tractors with Load Sensing Closed Center
Hydraulics (LS Closed) or Pressure Flow
Compensating (PFC) Systems
Equipment Damage Risk:
Failure to use the bypass valve on load-sensing tractors may
cause major tractor damage.
1. Release locking disc. Initially close bypass valve for
no oil flow by turning knob on valve clockwise
completely.
2. With tractor at half throttle, adjust flow-control valve
on tractor so openers raise and lower at a
reasonable speed. Keep tractor at one-half throttle
for remaining steps.
Note: The faster openers raise and lower, the greater
potential for oil heating, premature wear or tractor
damage.
3. Engage tractor hydraulics and lower openers. Lock
hydraulic lever on tractor for continuous operation.
See “Raising and Lowering Openers” on page 26.
Figure 12
Bypass Valve
19045
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