Fan circuit operation (s/n-) – Great Plains YP825A3P Operator Manual User Manual
Great Plains Manufacturing, Inc.
Fan Circuit Operation (S/N-)
Applies to planters with serial numbers:
(YP3P425A s/n B1004M-)
(YP3P625A s/n B1006P-) (YP3P825A s/n B1007R-)
Refer to Figure 22
Three hydraulic hoses serve the fan, and must be
properly connected for the fan to operate in the correct
, at recommended speeds, and without
Always connect the case drain line
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.
Connect the motor return line
second, to sump.
The planter includes a 1
inch 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
Connect the motor inlet line
to a tractor remote
capable of 4.5 gallons/minute. If a priority remote is
available, use it for the fan.
The fan hydraulic circuit includes a check valve
which provides a relief path for oil at motor shutoff.
If the fan is connected in reverse, flow through this
valve results in low fan rpm, providing 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 butterfly
valve (and not the seed monitor).
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.
Hydraulics at Fan
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
fan from reaching high rpm. A reversed fan may send
some air to the meters, but is incapable of providing
reliable air flow for planting.
Fan speed can change as oil heats to operating
temperature. Re-check meter pressurization more often
during early operations.