Toro Greensmaster 3250-D 04383 Service Manual page 61

Mow and Backlap (Serial Number Above 270000000)
The gear pump (P1) is directly coupled to the hydrostat
which is driven directly by the engine. Taking its suction
directly from the hydraulic reservoir, the gear pump (P1)
supplies oil flow to the hydraulic manifold block and to
the cutting reel motors. Maximum circuit pressure is lim-
ited by solenoid relief valve (S1R1) which is located in
the hydraulic manifold.
With the engine running and the Functional Control and
Raise/Lower/Mow levers positioned so the reels will
not turn (see Operator's Manual), solenoid relief valve
(S1R1) in the hydraulic manifold is de--energized. The
de--energized (S1R1) by--passes flow from the gear
pump (P1) to the oil filter and hydraulic reservoir. Addi-
tionally, manifold pressure reducing valve (PRV) will re-
main seated to prevent the reel motors (and reels) from
rotating.
Mow
With the engine running and the Functional Control and
Raise/Lower/Mow levers positioned so the reels will
turn (see Operator's Manual), solenoid relief valve
(S1R1) is energized. In the energized position, this
valve directs oil flow to the reel motors and also func-
tions as the mow circuit relief valve.
Greensmaster 3250--D
Oil flow from manifold port (P1) flows through the reel
speed control valve (FC1). Flow across the speed con-
trol valve is pressure compensated by the logic cartridge
valve (EP). The logic cartridge valve maintains a pres-
sure differential of 75 PSI (5.2 bar) across the speed
control valve. Any excess flow above the speed control
valve setting is by--passed to the reservoir through the
logic cartridge valve. With the backlap valve (MR) in the
mow position, oil flows through the backlap valve, out
manifold port (MA), and to the reel motors that are con-
nected in series. Oil flows through the left (M2), right
(M3), and then rear reel motor (M1) as it turns the motors
in the mow direction.
When in the mow position, manifold pressure reducing
valve (PRV) will shift allowing oil to return to the reservoir
through the manifold block and oil filter.
Backlap
Backlapping operation is the same as mowing opera-
tion, except for the position of the backlap valve (MR).
When the backlap valve (MR) is in the backlap position,
oil flows through the rear (M1), right (M3), and then left
(M2) reel motor as it turns the motors in the backlap
direction.
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Hydraulic System (Rev. I)