Great Plains 3S-4000F Operator Manual - Manual (Page 33)

Great Plains Manufacturing, Inc. Table of Contents Index Operating Instructions 29
2014-06-10 Table of Contents Index 195-394M
Refer to Figure 21
4.
Adjust pressure-control valves on drill for opener
down pressure so gauges are at 1800 psi.
5. While watching gauges on drill, slowly turn knob on
bypass valve counterclockwise. Adjust bypass valve
just until needles on gauges begin to move down
from 1800 psi. Lock bypass valve at this setting.
(See also note below.)
6. Adjust pressure-control valves on drill to desired
opener down pressure as explained under
“Hydraulic Down Pressure All Openers” on
page 54.
Note: The higher the bypass pressure, the greater the
potential for oil heating and premature 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 1800 psi is a good starting point for setting the
bypass valve, if you consistently operate the drill with low
opener down pressure you can set the bypass valve
below 1800 psi. If you consistently operate the drill with
very high opener down pressure, you may need a
bypass-valve setting above 1800 psi.
Figure 21
Opener Down Pressure Control
Valves
15557