Great Plains PFH-20 Operator Manual - Manual (Page 16)

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Section 2 Operating Instructions
PH-15, PH-20, PFH-15 and PFH-20 Coulter Command System 148-384M 6/21/2004
Great Plains Mfg., Inc.
The Coulter Command couples a microprocessor with
electro-hydraulics to provide a state-of-the-art system for
maintaining coulter depth regardless of the terrain or soil
type. It also provides coulter depth adjustment from the
tractor cab. A manual feature allows manual control of the
front hydraulic tongue cylinder for hitching, unhitching, or
making adjustments. To understand the Coulter Com-
mand system, one must be familiar with the functions of
the Hydraulics and the Electronic controls.
Load Sensing Hydraulics
To operate Coulter Command, some tractors with load-
sensing or constant-flow hydraulics require a bypass
valve, Great Plains part number 810-400C. Contact your
Great Plains dealer to order the bypass valve.
After installing the bypass valve, set valve as follows:
1. Close bypass valve for no oil flow by turning knob (1)
on valve clockwise. See Figure 2-1.
Figure 2-1
Bypass Valve
2. Adjust flow-control valve for tractor to a maximum of
10 gpm. If you do not have a flowmeter, hook a stan-
dard 8-inch stroke, 4-inch bore cylinder to the circuit.
At 10 gpm, the cylinder will take about 2.6 seconds to
extend.
3. Engage tractor hydraulics for Coulter Command.
4. Using a pressure gauge, turn knob on bypass valve
counterclockwise until pressure gauges reads 1800
psi. Lock bypass valve at this setting.
NOTE: Failure to install a bypass valve on load-sens-
ing tractors may cause major tractor damage. Consult
your tractor dealer to verify if the bypass valve is need-
ed.
17987
Hydraulic Hook-Up & Function
Tractors with closed-center hydraulic systems and
variable displacement hydraulic pumps.
(If you are not familiar with your tractor's hydraulics, con-
sult your tractor dealer.)
For tractors with closed-center hydraulics or pressure/flow
compensated hydraulics which are powered by a variable
displacement hydraulic pump, turn the knurled control
knob on the left side of the hydraulic valve completely
clockwise and lock it in place with the circular lock disk. Do
not apply any torque to the control knob after it bottoms out
or valve damage may occur. Be sure the lock disk is
snugged to prevent the control knob from vibrating loose in
field operation.
The tongue cylinder hydraulic circuit consists of the hoses
from ports "P" and "T". Once the hydraulic valve is set for
CLOSED CENTER operation, the Coulter Command
tongue cylinder circuit requires live hydraulic power sup-
plied to the port labeled "P". This is accomplished by
pushing FORWARD on the tractor remote hydraulic lever
and LOCKING IT OPEN in this position.
•
On John Deere tractors equipped with SOUND-GUARD
R Body you must use the LEVER LOCK CLIP John
Deere Part No. R52667 to lock the lever in the forward
position. See your tractor dealer for purchase and instal-
lation of this clip.
•
On John Deere 7000 Series tractors, rotate valve detent
selector to MOTOR POSITION to lock the lever in the
forward position.
•
On Case-IH Magnum tractors use the circuit designed
for HYDRAULIC MOTOR CONTROL and lock the lever
forward in the detent position. The detent pressure will
probably have to be turned up to its maximum setting.
DO NOT tie the hydraulic lever on past the detent posi-
tion with a strap. This could shift the spool beyond its de-
signed operating position and cause system damage.
See your tractor dealer for hydraulic system details.
•
On other model tractors use the circuit designed for HY-
DRAULIC MOTOR CONTROL and lock the lever for-
ward in the detent position. The detent pressure will
probably have to be turned up to its maximum setting or
some other mechanical detent holder will have to be
used to hold the lever forward. See your tractor dealer
for the proper means of providing constant pressure/
flow to the tongue cylinder circuit.
The Coulter Command hydraulic circuit requires a flow
rate of 8 to 12 gallons per minute for efficient operation. On
high flow rate tractors, the flow control on the tractor re-
mote may have to be turned down so as not to exceed 12
gallons per minute. Flow rates higher than 12 gallons per
minute will not damage the valve, but may cause poor
Coulter Command performance.
The remote tractor hydraulic lever will have to be locked in
Section 2
Operating Instructions