Initial down-pressure setup, Initial down-pressure setup, pc closed, Initial/seasonal setup, ls and pfc closed – Great Plains 3P4025AH Operator Manual User Manual
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48
3P4025AH
Great Plains Manufacturing, Inc.
411-099M
2014-07-29
Initial Down-Pressure Setup
Initial Down-Pressure Setup, PC Closed
These instructions are for Pressure Compensating
Closed Center systems. For a Load Sensing or Pressure
Flow Compensating system, continue lower on this page
at “Initial/Seasonal Setup, LS and PFC Closed”.
PC Closed systems provide over-pressure protection,
and do not require the use of the bypass valve.
If not already done, perform step 1 through step 3 on
page 47.
Continue at “Down-Pressure Adjustment” on page 49.
Initial/Seasonal Setup, LS and PFC Closed
For a Pressure Compensating Closed Center system,
“Initial Down-Pressure Setup, PC Closed” above.
Complete “Initial Needle Valve Setup” on page 47.
This setup requires moving the planter to field conditions,
hitched to the tractor to be used.
Refer to Figure 36
1.
If not already done, perform step 1 through step 3 on
page 47.
2.
With tractor at half throttle, adjust the flow-control
valve on the tractor so that partial fold/unfold (and
lift-assist raise/lower) occur at a reasonable speed.
Keep tractor at one-half throttle for remaining steps.
Note: Faster cylinder movement increases potential for
oil over-heating, wear and tractor damage.
3.
Engage tractor hydraulics and lower openers. Lock
hydraulic lever for the down-pressure remote for
continuous operation.
4.
Release locking disks
and
. Adjust
Pressure-Reducing Valve
knob until gauge reads
600 psi.
5.
While watching the gauge, slowly turn the Bypass
Valve Knob
counterclockwise. Adjust bypass
valve just until the gauge needle begins to move
down from 600 psi. Use locking disk
to secure the
bypass valve at this setting. (See also advisories at
right.)
Continue at “Down-Pressure Adjustment” on page 49.
Machine Damage Risks:
Failure to use the bypass valve on load-sensing tractors may
cause major tractor damage.
The higher the bypass pressure, the greater the potential for oil
over-heating and tractor damage. However, for proper opener
operation the bypass valve must be set at least 200 psi above
the opener down-pressure setting when the tractor is at
one-half throttle. Therefore, you should set the bypass valve as
low as possible while staying at least 200 psi above the opener
down pressure setting.
Note: While 600 psi is a good starting point for setting
the bypass valve, if you consistently operate the
planter with low opener down pressure you can
set the bypass valve below 600 psi. If you
consistently operate the planter with very high
opener down pressure, you may need a
bypass-valve setting above 600 psi.
Figure 36
Down Pressure Bypass Setup
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