Ls closed/pfc down pressure calibration – Great Plains 3PYPA Operator Manual User Manual
Page 170
166
3PYPA
Great Plains Manufacturing, Inc.
401-647M
03/20/2012
LS Closed/PFC Down Pressure Calibration
Tractors with Load Sensing Closed Center Hydraulics
(LS Closed) or Pressure Flow Compensating (PFC) Sys-
tems
Release locking disk
.
2.
Close bypass valve
for no oil flow by turning
knob
on valve clockwise completely.
3.
Tighten locking disk
.
4.
With tractor at half throttle, adjust flow-control valve
on tractor so openers raise and lower at a reason-
able speed. Keep tractor at one-half throttle for
remaining steps.
Note: Faster opener raise/lower increases potential for oil
over-heating, wear and tractor damage.
5.
Engage tractor hydraulics and lower openers. Lock
hydraulic lever on tractor for continuous operation.
6.
Release locking disks
and
. Adjust pressure-
control valve
knob
for opener down pressure so
gauge
is at 600 psi.
7.
While watching gauge
, slowly turn knob
on
bypass valve
counterclockwise. Adjust bypass
valve
just until needle on gauge
begins to move
down from 600 psi. Use locking disk
to lock
bypass valve at this setting.
Note: The higher the bypass pressure, the greater the po-
tential for oil over-heating and tractor damage.
However, for proper opener operation the bypass
valve must be set at least 300 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 300
psi above the opener down pressure setting.
8.
Adjust pressure-control valve
to desired opener
down pressure per “Hydraulic Down Pressure” on
page 60. Tighten locking disks
and
.
9.
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 oper-
ate the planter with very high opener down pressure,
you may need a bypass-valve setting above 600 psi.
Null4:
Equipment Damage Risk:
Use bypass valve on load-sensing tractors. Failure to use the
bypass valve on load-sensing tractors may cause major tractor
damage.
Figure 167
Hydraulic Down Pressure Valves
29803
5
7
6
1
2
3
4
3
1
4
3
3
5
2
6
7
7
4
1
1
7
3
2
3
5