Ls closed/pfc down pressure (s/n a1025s+) – Great Plains 3PYP Operator Manual User Manual
Page 166
162
3PYP
Great Plains Manufacturing, Inc.
401-312M
2014-09-09
LS Close
d/PFC Down Pressure
(S/N A1025S+)
For (S/N A1007S to A1024S) and (S/N A1006S-) see
previous page
Tractors with Load Sensing Closed Center Hydraulics
(LS Closed) or Pressure Flow Compensating (PFC)
Systems
Refer to Figure 159
Failure to use the bypass valve on load-sensing tractors may
cause major tractor damage.
1.
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
reasonable 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
pressure-control valve
for opener down
pressure so gauge
is at 600 psi.
7.
While watching gauge
, slowly turn knob
bypass valve
counterclockwise. Adjust bypass
knob
just until needle on gauge
begins to move
down from 600 psi. Use locking disk
bypass valve at this setting. (See also note below.)
8.
Adjust pressure-control valve knob
opener down pressure per “Hydraulic Down
Pressure” on page 52. Tighten locking disks
and
.
Note: The higher the bypass pressure, the greater the
potential for oil over-heating and tractor damage. At
the same time, 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.
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 159: s/n A1025S+
Hydraulic Down Pressure Valves
29803
1
2
3
4
5
6
7
5
6
7
7
4
3
6
3