Fan circuit operation – Great Plains YP4025A Operator Manual User Manual
Page 48
44
YP4025A
Great Plains Manufacturing, Inc.
401-627M
2013-04-24
Fan Circuit Operation
See also “Fan and Adjustment” on page 63.
Refer to Figure 46
Three hydraulic hoses serve the fan, and must be
properly connected for the fan to operate in the correct
direction
, at recommended speeds, and without
damage. See “Hydraulic Hose Hookup” on page 16.
1.
Always connect the case drain line
first.
This line protects the outer shaft seal of the hydraulic
motor. The case drain is a small line to the hitch,
provisioned with a specialized low-seep flat-face
case drain Quick Disconnect. Pressure spikes during
motor operation, and pressure cycles due to
temperature change are bled off by the case drain.
Motor Seal Damage Hazard:
Do not apply pressure to the case drain line. Do not change the
special QD connector. A restricted or sealed case drain line
will promptly result in motor seal damage.
2.
Connect the motor return line
second, to sump.
The planter includes an 1
1
⁄
16
in low back-pressure
QD coupler set. Install the receptacle on a tractor
sump port, and not at a normal remote return port.
The unusual size aids in ensuring correct
connection, so that the motor return line handles
high volume at low back-pressure, ensuring full
motor performance.
3.
Connect the motor inlet line
to a tractor remote
capable of the flow rates shown at “Recommended
Fan Speeds” on page 45.
4.
The fan hydraulic circuit includes a check valve
,
which provides a relief path for oil at motor shutoff.
The resulting low fan rpm provides strong indication
reversed connection.
Correct fan direction is shown at
.If reversed fan is
suspected, observe it during shutoff, as the direction
of motion is easier to see at lower rpms as it slows to
a stop (initial startup is virtually instantaneous,
making observation at start difficult).
Fan speed is controlled by the tractor circuit (and not the
seed monitor). Fan rpm is reported by the seed monitor
console.
You may stop the fan by setting the circuit to neutral or
float. The check valve slows the blades to a stop by
locally recirculating the oil.
Figure 46
Hydraulics at Fan
29800
1
2
3
4
5
1
2
3
If the fan is connected in reverse, it may not run at all
(due to no oil source at the return connection). If oil is
present, oil bypass at the check valve
prevents the
fan from reaching operating rpms. A reversed fan is
incapable of providing sufficient air flow for planting.
5
4
5
1